Cattle Flashcards
What are the benefits of a compact calving pattern?
Even batches of calves to rear > easy management of calves, efficient feeding of calves
Cows at same stage of pregnancy and lactation - efficient feeding of cows and efficient supervision at calving > easy calvings, fewer deaths, fertile cows for rebreeding. Good milk supply, calves of optimum birthweight, fewer difficult calvings, healthy calves with a high potential for growth, cows in correct body condition, fertile cows for re breeding.
What is the aim of an efficient beef suckler herd?
To calve the herd over a short season 9-12 weeks at the same tim each year and wean one calf per cow.
How can you achieve a compact calving period?
Have fertile cows, cycling at the start of breeding period, have fertile bulls run with cows for a restricted breeding period (9-10 weeks), have a good replacement heifer breeding policy, avoid introducing infectious infertility diseases.
How can cow fertility be maximised?
Key to beef cow fertility is in nutritional management. when calculating winter rations for beef cows one must make allowance for maintenance, pregnancy and lactation requirements. cows in good body condition can be allowed to mobilise body fat to contribute to daily ME requirement and save on feed costs. Body condition score BCS at calving directly related to post calving anoestrus period/fertility. Cows BCS 2 or less at calving les likely to conceive during a restricted mating period as may be anoestrus during much of breeding period. aim for target condition scores at key times of the year. Seperate off thin cows and feed extra or wean early, ensure adequate trace element vitamin mineral supplementation. copper and selenium may often require supplemenation. avoid sudden changes in level of feeding untill 6 weeks post mating period. minimise periparturient problems eg dystocia. have control measures to avoid introduction of infectious diseases that may affect fertility e.g venereal campylobacter, leptospirosis, BVD, IBR. Pd cows 6-8 weeks after end of breeding period and plan culling poly.
How should bulls be selected?
Ideal bull produces calves that are born easily, grow rapidly and produce carcases of good conformation. estimated breeding values available for common breeds to aid bull selected as they assess the genetic potential of an animal. BLUP (best linear unbiased prediction) system utilises data from performance records of the animal itself, its relatives and progeny and removes environmental effects where possible. Newly purchased young bulls should be screened for BVD status and if >2 yo for johnes and or where possible sourced from disease free herd. other disease screening eg, IBR, lepto depends on herd status and may simply choose to vaccinate. Hire bulls and non virgin mature bulls are a major disease risk especially campylobacter fetus venerealis.
Describe a breeding soundness evaluation for bulls
Ideally all bulls should have annual breeding soundness assessment to help avoid economic losses due to use of infertile bulls.
1 - physical examination, general health, musculoskeletal system.
2 - reproductive system examination - visual appraisal of scrotum shape. measure scrotal circumference (in general over 15 months >31cm, over 2yo > 34 cm, separate breed standards available), Palpate testicles and epididymides carefully (orchitis, epididymitis, edegeneration), palpate accessory sex glands (vesiculitis), palpate sheath and inspect tip of penis (haematoma, trauma, phymosis, persistent frenulum, fibropapilloma).
3. Semen evaluation - collect semen by electro ejaculation, artificial vagina or rectal massage and assess volume/density, motility, gross and progressive, minimum 60% progressive motiity) and % normal sperm morphology (minimum 70% normal), handling of semen sample is critical (temperature.
4. Serving capacity assessment - need to observe bull mating females to ensure good libido and normal intromission.
A full breeding soundness evaluation should include all 4 components but even doing parts 1 and 2 will help to ensure unsound bulls are not used.
What bull to cow ratio should be used?
young bull - 20/30 cows max
Mature bull - 40/50 cows max
What general management should be used for bulls?
Nutrition - young bulls <2 1/2 years old require fed for maintenance and growht. bulls should be fit not fat.
Housing - when not working keep in well fenced, outdoor paddock or bull pen with exercise area. foot care - regular foot trimming essential. lameness is most common problem of bulls. don forget to include bulls in herd vaccination and worming programmes.
Describe replacement heifer breeding management
Best source of replacements is to buy yearling bulling heifers from known source. aim is to have heifers calving down at 2-21/2 year old to easy calving bull in good body condition, 2-3 weeks ahead of main herd calving period. isolate from main herd for 2-3 weeks and screen purchased replacements for BVD status, vaccinate for leptospirosis, BVD, IBR depending on herd health status, check for freemartins/non breders and misalliance pregnancies. Ensure adequate nutrition prior to and during mating period. feed for maintenance and growth. aim for critical minimum mating weight at first service of around 65% of mature cow weight. ensure no trace element deficiencies or parasite problems prior to mating. mate with easy calving bull for 6-7 weeks only. PD and remove non pregnant heifers for sale. Feed during pregnancy for CS3 at calving, too fat - dystocia, too thin - extended post partum anoestrus. if possible run first calvers as a separate group untill pregnant again.
What are the advantages and disadvantages of AI?
Advantages - allows use of best bulls with known EBVs for various traits. reduces costs of keeping stock bulls, removes risk of venereally transmitted diseases. may tighten calving period as all cows receive first service on day 1 of breeding period. Disadvantages - heat detection may be a problem if not using fixed time AI, handling for AI, cost.
Describe the double prostaglandin injection for oestrus synchronisation?
Double prostaglandin injection - cows/heifers injected twice with PG, 11 days apart and fixed time AI 72 and 96 hours following second iinjection. best restricted to maiden heifers as results may be poor in cows due to anoestrus at the time of synchrony.
Describe progesterone releasing intravaginal devices for oestrus synchronisation?
Device inserted for 8-10 days with prostaglandin luteolytic injection given 1-2 days before device removed. AI at 48 and 72 hours after device removed or once at 56 hours. Progesterone based synchrony is superior in beef cows as it will induce oestrus and ovulation in cows that may be anoestrus. the degree of synchrony is superior to double PG programmes especially if GnRH injection is given at the time of CIR insertion to cause emergence of a new follicular wave.
How do you maximise pregnancy rate with fixed time AI?
Ensure cows/heifers on a good steady plane of nutrition and cyclical before synchrony and for six weeks following AI. ensure no trace element deficiencies parasite problems and that infectious diseases controlled, have good handling system for AI etc, minimise stress, will get higher pregnancy rates if use double AI. realistic pregnancy rates achieved to synchronised AI, cows 55-65% and heifers 65-75%.
What are the key targets indicating high fertility performance in a beef herd?
Barren cow rate 65%, calf crop > 94%.
What is the average milk price in the EU?
31ppl
What are the aims and objectives of preventative medicine?
Optimising health status, by prevention of disease and losses due to subclinical disease. Increased efficiency and productivity, increased longevity by reducing forced culling death rates, ensuring good animal welfare and husbandry, production of good quality produce and ensuring food safety, maximising profitability.
Describe the objectives set in health plans?
Must be SMART Specific Measurable Achievable Relevant Time based - met within a reasonable period if not the reasons for failure should be examined. Targets can be set using data from standard texts. They must be up to date and specific for each individual farm. The costs for some of the most important disease conditions have been worked out and thus the value of these targets can be demonstrated to the farmer.
Describe the overview components of a preventative medicine programme
Objectives - defining objectives is a basic component of any preventative medicine programme and the key point is that these vary from farm to farm. Each farm must be treated as an individual. The targets must be agreed between the farmer and the vet. Implementation of a programme - data evaluation - method of recording farm health data to assess current performance. Clinical examination of the animals. Farm inspection - will concentrate on management of the farm and includes ration evaluation, feeding and pasture management, milking routine. Decision making - based on monitoring, evaluation and interpretation of all the factors discussed in implementation of your advice. Follow up.
What are the different sections of a preventative medicine or health plan?
- DEtails of farm. 2 current production data. 3. production targets - monitoring and recording of past and current performance. Setting of targets in context of farm and husbandry erformance. 4. reproductive performance. 5. nutritional management. although detailed nutritional management and ration formulation is usually left to Nutritional advisers. Health plans should incorporate regular body scoring, use of metabolic profiles, advice on changes in ration etc. 6. replacement policy -will vary depending on whether or not the farm is closed or not. 7. Disease contorl. 8. Control of infectious disease. 9.Parasite control - may be necessary for endo parasites such as gastrointestinal, lungworm, fasciolosis, ectoparasites such as lice, sheep scab, mange mites, blowfly and tick borne diseases. 10. neonatal care. 11. Biosecurity. 12. Medicines usage. 13. Stockmanship and management. 14. Calendar of health plan.
Describe the Biosecurity measures which help in the control and even eradication of diseases resulting in reduced drug usage and increased profitability?
Maintain a closed herd/flock. Most common source of new diseases. Operate an isolation policy for purchased stock - ideally animals should be bought from a herd/flock of known health status that matches that of the receipient herd. Purchased stock should be isolated away from all other stock for a minimum period of 4 weeks and regularly inspected for signs of disease. 3. Provide clean feed and water -food and water eg streams, rivers and flooded pastures may all represent a risk and the introduction of disease e.g salmonella, liver fluke. 4. Control visitors and vehicles - high risk visitors including lambing help, contractors, veterinary surgeons, feed companies, knacker services. 5. control rodents and birds, 6. Define and monitor health status in addition to the prevention of new infections the herd/flock needs to be monitored regularly to assess the health status. Operate a disease control programme which involves vaccination, strategic medication, culling, husbandry and nutritional advice.
What is the average lifespan of a dairy cow?
Only 3.04 lactations. The overall culling rate remains constant at about 20-24%.
What are the main reasons for culling?
Forced or involuntary culls - These are animals that must be culled due to death disease or poor reproductive performance and represent over half of all cows culled. the three most common reasons are infertility, mastitis and lameness. Selected or voluntary culls - these are animals that the farmer chooses to cull for reasons such as poor milk yield, old age, poor conformation, temperament etc. the ideal situation is for the dairy farmer to minimise culling through forced reasons and thus have control over which cows are culled. Infetility 4.9%, mastitis 3.5%, lameness 2.2%, age 3.6%, yield 0.9% other including death 6.3%.
What are the major disease problems in UK dairy herdS?
Infertility, mastitis and lameness. for every 100 cows per year -
Fertility 26.1, mastitis 37.5, lameness 22.3. They are all associated with peri parturient cow and in particular the metabolic sterss of early lactation. They all have a multifactorial aetiology. they may not be seen as spectacular individual cases but the farmer may be unaware of the extent of the problem. Observed clinical cases are usually only the tip of the iceberg with far greater number of subclinical cases that will be inhibiting milk production. they are inter related and can increase susceptibility to each other e.g a cow with milk fever will be more susceptible to mastitis. They all cost money. Other production diseases include assisted calving, digestive disease including LDAs, hypomagnesaemia, hypocalcaemia, ketosis, lameness, injury.
Describe the two main types of costs associated with disease:
Direct costs - treatment cost, veterinary costs, labour costs (herdsmans time), discarded milk (antibiotic withdrawal), reduction in milk yield, mortality.
Indirect costs - increased culling rate, possible risk of fatality, susceptibility to other disease, extended calving interval, extra services per conception.
What is the cost of culling a dairy cow?
a farmer will receive approx £600 from the sale of a cull cow. However the cost of replacement heifer is £2000 on average in the UK. other costs that must be taken into account include the lower milk yield from a heifer (14000 litres for the subsequent lactation equating to £322) and the smaller calf from a heifer (£8). Figure in 2012 for the cost of a cull cow range from £1328 for a live cull at the end of lactation to £3307 for a fatality in early lactation. The cost of a fatality is even greater as farmer will not receive any income from dead cow and will pay to get her removed.
What is the cost of infertility to the farmer?
Failure to get the cow back in calf when the farmer wants. a 365 day calving interval is still accepted as being the target for the average dairy herd in the UK. The cost of an extra day on the calving interval is often quoted to be £3 per day. This is made up of reduced milk per cow per year as well as reduced calf sales and extra AI costs.
What is the cost of mastitis to the farmer?
Although mastitis rates have fallen in the last 40 years, rates have steadied at around 40 cases/100 cows/ year. the major costs are due to treatment costs - relatively minor by herdsman. cost of discarded milk, lower milk yields - reduces lactation by approximately 5% - 15% in severe cases. higher culling rate. 90% of mastitis will be mild, and 0.2% fatal, average cost of mastitis is £201. can be up to £1709 for a fatal case.
What are the costs of lameness to a UK dairy farmer?
Main economic losses due to poorer fertility - delayed return to oestrus and poor demonstration of oestrus signs, reduced intakes of food, prolonged NEB in early lactation - increased calving interval, increased number of services per conception. Higher culling rate, lower milk yields 21/2-5%, severe up to 15%. Predisposition to other diseases. An average case of lameness based on 41% digital lameness, 38 interdigital and 21% solar ulcers will cost 178£ ranging from 81- £324 for a solar ulcer.
What is the average cost of a case of milk fever?
Costs involved in the majority of cases that respond to farmers treatment alone are relatively low (£40) but can escalate markedly if the case becomes complicated. An average case has been calculated to cost £209.62.
What is the aim of an efficient beef suckler herd?
To calve the herd over a short season (9-12 weeks) at the same time each year and wean one calf/cow. The benefits of a compact calving period include - even batches of calves to rear so easy management of calves and efficient feeding of calves. Cows at same stage of pregnancy and lactation so efficient supervision at calving, efficient feeding of cows.
How can a compact calving period be achieved?
Have fertile cows, cycling at the start of the breeding period. Have fertile bulls run with cows for a restricted breeding period (9-10 weeks). Have good replacement heifer breeding policy. Avoid introducing infectious infertility diseases.
How can cow fertility be maximised?
Key to beef cow fertility is in nutritional management. When calculating winter rations for beef cows one must make allowance for maintenance, pregnancy and lactation requirements. Cows in good body condition can be allowed to mobilise body fat to contribute to daily ME requirement and save on feed costs. One Kg of LWL provides approx 35 MJ/ME to the cow. Body condition score BCS at calving is directly related to post calving Anoestrus period/fertility. Cows BCS 2 or less at calving are less likely to conceive during a restricted mating period as may be anoestrus during much of breeding period. Aim for target condition scores at key times of year. separate off thin cows and feed extra or wean early. Ensure adequate trace element/vitamin/mineral supplementation. copper and selenium may often require supplementation. Avoid sudden changes in level of feeding until 6 weeks post mating period. Minimise peri parturient problems eg dystocia. Have control measures to avoid introduction of infectious diseases that may affect fertility e.g venereal campylobacter, leptospirosis, BVD, IBR. PD cows 6-8 weeks after end of b reeding period and plan culling policy.
How should bulls be selected for optimum fertility?
Ideal bull produces calves that are born easilsy, grow rapidly and produce carcases of good conformation. Estimated breeding values available for common breeds to aid in bull selection as they assess the genetic potential of an animal. BLUP system utilises data from performance records of the animal itself, its relatives and progeny and removes environmental effects where possible. Newly purchased young bulls should always be screened for BVD status and if > 2 yo for johnes where possible sourced from disease free herd. Other disease screening e.g IBR, lepto, depends on herd status and may simply choose to vaccinate. Hire bulls and non virgin mature bulls are a major disease risk especially campylobacter fetus venerealis.
Describe a bull breeding soundness evaluation?
Should consist of 1. physical examination - general health, musculoskeletal system. 2 Reproductive system examination - visual appraisal of scrotum shape, measure scrotal circumference ( in general over 15 months > 31cm, over 2yo > 34 cm, separate breed standards available.) palpate testicles and epididymides carefully (orchitis, epididymitis, degeneration), palpate accessory sex glands (vesiculitis), palpate sheath and inspect tip of penis (haematoma, trauma, paraphymosis, persistent frenulum, fibropapilloma). 3. semen evaluation - collect semen by electro ejaculation, artificial vagina or rectal massage, and assess volume/density, motility and % sperm morphology. 4. Serving capacity assessment - need to observe bull mating females to ensure good libido and normal intromission. A full breeding soundness evaluation should include all 4 components but even doing parts 1 and 2 will help to ensure unsound bulls are not used.
What should minimum sperm motility and morphology be?
60% progressive motility minimum and 70% normal sperm morphology.
What is the appropriate bull to cow ratio?
Young bull - 20-30 cows maximum. Mature bull - 40/50 cows maximum.
Describe general management of bulls
Nutrition - remember young bulls t forget to include bulls in herd vaccination and worming programmes.
Describe replacement heifer breeding management?
Best source of replacements is to buy yearling/bulling heifers from known source. Aim is to have heifers calving down at 2-21/2 years old to easy calving bull in good condition (CS2-3 weeks) ahead of main herd calving period. Isolate from main herd for 3-4 weeks and screen purchased replacements for BVD status, vaccinate for leptospirosis, BVD and IBR, depending on herd health status. Check for freemartins/non breeders and misalliance pregnancies. Ensure adequate nutrition prior to and during mating period. Feed for maintenance and growth (0.7kg/day). Aim for critical minimum mating weight at first service o around 65% of mature cow weight. Ensure no trace element deficiencies or parasite problems prior to mating. Mate with easy calving bull for 6-7 weeks only. PD and remove non pregnant heifers for sale. Feed during pregnancy for CS3 at calving, too fat - dystocia too thin - extended post partum anoestrus. If possible run first calvers as a separate group until pregnant again.
What are the advantages and disadvantages of aI in beef herds?
Advantages of AI - allows use of best bulls with known EBVs for various traits. Reduces costs of keeping stock bulls. Removes risk of venereally transmitted diseases. May tighten calving period as all cows receive first service on day 1 of breeding period. disadvantages - heat detection may be a problem if not using fixed time AI, handling for AI etc, cost.
What are the two different oestrus synchronization methods available for fixed time AI?
Double prostaglandin injection - cows/heifers injected twice with PG, 11 ays apart and fixed time AI 72 and 96 hours following second injection. Best restricted to maiden heifers as results may be poor in cows due to anoestrus at the time of synchrony.
Progesterone releasing intravaginal devices - Device inserted for 8-10 days with prostaglandin (luteolytic) injection given 1-2 days before device removed. AI at 48 hours and 72 hours after device removed or once at 56 hours. Progesterone based synchrony is superior in beef cows as it will induce oestrus and ovulation in cows that may be anoestrus. The degree of synchrony is superior to double PG programmes especially if GnRH injection is given at the time of CIDR insertion to cause emergence of a new follicular wave.
How can you maximise pregnancy rate with fixed time AI?
Ensure cows/heifers on a good steady plane of nutrition and cyclical before synchrony and for six weeks following AI. Ensure no trace element deficiencies/parasite problems and that infectious diseases are controlled. Have good handling system for AI etc, minimise stress. will get higher pregnancy rates if using double AI. Realistic pregnancy rates achieved to synchronise AI - cos 55-65% and heifers 65-75%.
Describe a typical synchronisation programme for fixed time AI in beef cows
Day 0 - insert CIDR Day 7 - Inject PG day 9 - Remove CIDR Day 11 - 1st AI Day 12 - 2nd AI Day 13 - introduce sweeper bulls
What are the key targets indicating high fertility performance in a beef herd?
Barren cow rate - 65%
Calf crop >94%
Describe the cascade for food producing species
In all species - if there is a product that is licensed for the particular condition being treated and the particular species then this product should be used. If no such product exists then a product licensed for use in that species for a different condition may b e used OR a product licensed for that condition in another food producing species may be used. If no such product exists in 1 then a product available in another member state (EU) may be imported but only provided that the product is licensed for use in a food producing species in that state. In addition the prescribing veterinary surgeon must ensure that the treatment is only used for animals on a single holding. Ensure that the drug is listed in the EU table of permitted substances. The vet must also specify a withdrawal period - if the medicine prescribed does not state a withdrawal period for that species then the VS must stipulate a withdrawal period which should not be less than 7 days for milk and eggs and 28 days for meat and 500 degree days for meat from fish. Keep appropriate records for a period of 5 years which include name and address of owner, identification of animals treated, date, diagnosis, details of drug and dose used including batch numbers, duration of treatment, withdrawal period applied.
What are MRLs and ADIs?
ADI - when an individual eats meat, milk eggs honey etc there is an assurance that levels of drugs in these products are within safe limits. Maximum residue limits MRLs are set for certain drugs based on the calculated ADI (acceptable daily intake) for that particular drug. Withdrawal periods are then established which take into account the MRL for the drug and its pharmacokinetics in the animal; allowing a determination of the amount of time it takes for levels of the drug to fall below the MRL and hence identifying a suitable withdrawal period for that product.
How are withdrawal periods set?
Withdrawal periods are then established which take into account the MRL for the drug and its pharmacokinetics in the animal allowing a determination of the amount of time it takes for levels of the drug to fall below the MRL and hence identifying a suitable withdrawal period for that product.
What are the ADIs for milk, meat eggs and honey?
The calculation of the ADI includes an extremely large safety factor. The MRL calculation assumes an average daily intake per person of 500g of meat, 1.5 litres of milk, 2 eggs and 20g of honey.
What records should be kept for food producing animals receiving drugs?
At the time of purchase - proof of purchase, name and address of supplier, name and batch number of drug, date of purchase, quantity, withdrawal period. At the time of administration - name of product, amount of product, date of administration, withdrawal period, identification of animals treated. if product administered by the veterinary surgeon then the vet can enter the information directly into your records or give you the information which should also include the name and address of the administering veterinary surgeon. At the time of disposal - name of product, amount disposed of, how disposed of. All records must be kept for five years.
What records should the veterinary surgeon keep when prescribing to food producing animals?
Date and nature of transaction, identification of the product, quantity, name and address of either the supplier or the recipient, a copy of any prescriptions and the name and address of the person who wrote the prescription, batch number and date once product is in use. Remember the legal categories of veterinary medicines. Think of the list and see which ones are relevant to drugs used in farm
What records should be kept for drugs prescribed under the cascade:
Date of examination of animal, name and address of owner, identification of animals treated, diagnosis, trade name of the product if there is one, batch number, name and quantity of active ingredient, dose administered duration of treatment, withdrawal period.
Describe in feed medication
Medicines that are incorporated into feed are now either classified as POM -v or POM VPS under the new legislation. Since they are POM drugs then a prescription is required. in the case of written prescriptions these require a specific MFSp medicated feed stuff prescription which will contain additional details to a standard prescription.
What information must be present on a MFSp?
The name and address of the person prescribing product, qualifications of person, name and address of owner, species of animal, identification and number of animals, premises at which the animals are kept if this is different, date of prescription, signature or other authentication of the person prescribing the product, name and amount of product prescribed, dosage and administration instructions, necessary warnings, withdrawal period if relevant, manufacturer or distributor of feed stuffs, inclusion rate of veterinary product and inclusion rate of active substance, any special instructions, percentage of the prescribed feedingstuffs to be added to the daily ration.
Describe how the absorption of drugs is different in ruminants?
The ruminal microflora is capable of catalysing hydrolytic and reductive reactions and so may readily inactivate orally administered drugs before they ever reach the systemic circulation. Orally administered drugs may adversely affect gastrointestinal microflora and interfere with normal digestive processes. This may occur particularly with orally administered drugs but may also be associated with systemic administration. Oral modified drug release delivery systems (boluses) take advantage of the unique anatomy. Bolus retained in the rumen which allows time for the sustained or pulsatile release of drugs to occur.
Describe how the metabolism of drugs differs in ruminant species?
In ruminant species highly significant changes are observed in metabolic capability in preruminant versus the ruminant. This is associated with changes in the diet resulting in a change in the nature and complexity of nutrients to which the liver is exposed. Differences in hepatic metabolism of certain anthelmintic drugs such as benzimidazoles, clorsulon, probably explains the higher dose requirement seen in cattle and goats verrsus sheep for these anthelmintics. For drugs that undergo hepatic metabolism, half lives seem to be shorter in cattle and horses compared to dogs and cats. Exceptions include theophylline in the horse and phenylbutazone in cattle.
Describe the differences in excretion of drugs in ruminant animals?
Urinary pH - the urinary pH in herbivorous animals such as sheep cattle and horses is generally alkaline ph 7-9. in contrast to carnivorous animals where urinary ph is acidic 5–5.7. This may affect elimination of certain drugs through the urinary tract. in general acidic drugs will be predominantly ionised in an alkaline pH and elimination should be enhanced since the drug will remain in the urine. by contrast alkaline drugs will be primarily unionised and therefore are more readily reabsorbed from the urine reducing the rate of their elimination. note that milk fed animals generally excrete an acidic urine.
How do the pharmacodynamics differ in ruminant animals?
Differences may occur at the receptor level. eg for example a2 adrenoceptor agonist xylazine. the dose required on a mg/kg basis in cattle is very significantly less than in some other species - thought to be an increaed sensitivity of the receptor site in this species.
Describe the practical aspects of farm and production therapeutics in terms of bulk administration, rumen boluses, long acting injections etc.
Bulk administration in feed or water - dose needs to be based on the expected feed or water consumption and obviously there will be an individual animal variation. Rumen boluses primarily employed for the delivery of anthelmintics to cattle. the use of multi dose injectors are used to deliver IM or SC injections.. It is very important to change the needle at regular intervals. pour ons primarily used for certain anthelmintics. Long acting injections especially relevant in relation to antimicrobials. certain drugs by nature of the drug itself or the formulation have long half lives reducing the need for repeated treatments.
what can be done to prevent injection site lesiosn occuring? What are the consequences?
Lesions caused in young calves often will not resolve and may often enlarge as the animal matures. in an ideal world injections should be given s/c but need too have a carcass friendly injection site and still adhere to the label requirements for the drug. Ideally i/m injections should be given in the neck away from the more expensive cuts of meat. Maximum volume for injection should be 10mls. Needle selection can be important. 16 or guage needle depending on size of the animal. 5/8 or 1/2 inch ideal for s/c an 1 or 1 1/2 inch ideal for IM. keep injection sites 4 inches apart if possible.
What are the targets for heifer rearing?
calve at 22-26 months old, conception at 15 months, 85% adult body weight at calving, 60% adult body weight by service. For a calf born at 40Kg growing to be 700kg adult weight this means an average daily weight gain of 0.9Kg.
Describe the best start for calves in terms of husbandry
Manage dry cow nutrition and consider whether pre calving vaccination is necessary. Provide clean dry well lit calving pens. ensure navels are dipped as soon as possible after birth e.g iodine. Ensure adequate colostrum intake. 10% body weight by 6 hours old and a further 2.5% by 12 hours old. Ensure adequate colostrum quality (encourage monitoring by farmer or you). Use colostrometer or specific gravity refractometer. Monitor levels of passive transfer - serum total protein >5.2g/L is the target, <4.8g/dL is inadequate. 5.5g/dL has been correlated with low levels of disease. Zinc sulphate turbidity test or gamma globulins.
Describe the onward management for optimum growth of calves
It is not recommended to feed calves waste milk (significant contamination with bacteria and possible antibiotic residue). Calves should be offered milk at least twice a day from clean buckets or bottles. Some producers use large drums with teat feeders or robotic milk feeders which allow more frequent feeding. Important that milk replacer is made up correctly. Calves should be offered creep concentrate feed from two weeks of age and should have access to good quality forage. Calves should have access to fresh clean water from birth onwards. Calves require four to six litres of water for every 1Kg of concentrate consumed. encourage measurement and recording of calf weights (calf weigh bridge or measurement of heart girth using a weigh tape.) this measurement should continue once youngstock are no longer in small groups (measure height to withers if heart girth not possible) weigh opportunistically when heifers being handled for other reasons.
What procedures should be taken by the vet/farmer when things go wrong with calves?
Encourage farmers to keep records of mortality and causes when possible. Mortality should be >3% but may be 10%. Encourage farmers to record treatments. Calves must be checked twice daily. Consider calf scoring to help record ill health and guide farmer decision making. Encourage the farmer to call the vet early for advice. Congenital problems are not uncommon. Carefully auscultate the heart when opportunities arise. Calves suffer from digestive problems sometimes (failure of oesophageal groove closure, failure of milk clot formation, liquid milk overflow to duodenum, Abomasal bloat, rumenal impaction). These problems are often associated with poor husbandry around feeding. Calves can get post weaning scour. Calves can also suffer from trace element deficiencies (hypomagnesaemia, vitamin E, selenium). Naval ill and its consequences can be prevented but will need prompt treatment with broad spectrum antibiotics to prevent sequelae such as joint ill, septicaemia, meningitis.
What do the welfare of farmed animals regulations state for calves?
Must have bovine colostrum within 6 hours of birth, sufficient iron to maintain good health and a mean haemoglobin conc of 4.5mmol/l. when they reach >2 weeks old, 100g/d fibrous food must be fed increasing to 250g/day at 20 weeks old. Must be fed at least twice a day. Must be fed a sufficient quantity of fresh drinking water per day. If hot weather or calf is ill, must be fed fresh drinking water at all times. Sick or injured calves must be isolated as necessary with dry bedding, no individual stalls after 8 weeks unless veterinary instruction, access to dry bedded lying area. Inspection - housed calves 2 x day, outside calves 1 x day. No transport until navel healed. No markets until 7 days old, no more than 1 market in 28 days.
What happens with male calves?
To reduce the number of unwated male dairy calves some farms use sexed semen. Male and excess female dairy breed calves may not have the conformation required for the traditional beef market however if carefully reared and butchered it can enter the bull beef market. Rearing of dairy calves for veal is controversial. 100% milk diets have been banned there has been a growing interest in rose veal (6-12 month old dairy produced calves). Dairy farmers may choose to breed some of their cows or heifers to a beef breed bull to produce calves that have better confirmation for the beef trade. These are reared as for the dairy heifers and sometimes will be sold on to calf rearing, store or finishing units. the lifetime feed costs of such animals are likely to be higher than for more traditional beef breeds, not least because they are usually reared on artificial milk replacer for at least the first few weeks and are weaned much earlier than beef calves.
Describe the stack effect
On still days in a livestock building the heat produced by the stock as a by product of their metabolism of energy, is available to warm the air. this warm air rises and leavs via the ridge. if it is wide enough to allow this. This stale air is replaced by colder fresher air entering at eaves level. If this moist air is not allowed out at the ridge, it condenses on the underside of the cold roof and falls as condensation droplets.
What are the factors involved in generating a stack effect?
The factors involved are the height difference between the inlet and outlet, the temperature difference, inside temperature and out, the inlet area, the outlet area and the velocity of arflow to the outside gnerated by the housed livestock. The difference in density of warm air and cold air generates a hydrostatic pressure head, which causes airflow in at lower level and out at a higher level. Steeper pitched roofs vent better than shallow roofs because of a greater height difference between inlet and outlet. Flat roofs are to be avoided for livestock housing because of the problems in creating natural airflow. The most influential factor in creating good stack efect is a decent opening at the ridge.
What is the minimum sq m outlet area per calf?
0.04sq m outlet area per calf (4sq m outlet per 100 calves) to balance this outlet the inlet area should be four times the outlet area. for large dairy cows, allow about 0.1sq m outlet per cow (10 sq m per 100 cows), again with about four times the minimum inlet area.
Describe a healthy environment for calves?
Ensure good siting of the bilding on an open sunny location away from other stock. do not have too many calves in a single airspace, split the facilities so reducing the risk of airborne infection. provide adequate ventilation, preferably natural but with fans if necessary. ensure protection from draughts. keep dust and pathogen levels low. Never restrict ventilation in an attempt to raise air temperature. provide good natural light levels. keep out birds and vermin.
What is a stress free environment for calves?
Newly arrived calves must be allowed time to rest and acclimatise. newly arrived calves should be kept apart from other calves for long enough to avoid cross infection. Allow good visual contact between individually penned calves with perforated walls which allow the calves to have visual and tactile contact. all calves above 8 weeks old must be group penned. keep groups small and well matched for size without overcrowding. provide spacious follow on penning in airy buildings as calves grow and progress through the sysetm, keeping groups intact to avoid stress. Be organised, keep calm and quiet avoiding unnecessary noise.
How can you provide a dry lying area for calves?
Provide a generous amont of good dry bedding, maintain a dry bed, design pens to drain directly to an external channel never through adjacent pens which can encourage the spread of disease, prevent water spillage or leaks into pens, especially within lying areas, avoid condensation drips caused by poor ventilation, prevent roof leakage due to poor maintenance..
How much space is adequate for calves?
Each calf must be able to adopt a comfortable lying poositioon whatever teh housing system but especially when individually penned. individual pens should be at least 1m wide and preferably 1.8m long. calves in groups should be able to choose locations within the pen for lying down to avoid draughts and away from feeding and drinking points. Provide good pen space to encourage healthy exercise.
What problems can be seen with too much moisture in a livestock building?
supports microbial activity, promotes bacterial growth, absorbs energy, acts as a transport medium, increases slippery floors - stress. Seen as dirty water lying, dirty cattle, damp floors in areas that could be dry, water ingress, leaking drinkers, condensation, staining of underside of roof
What problems can be seen with too little fresh air in a livestock building?
Lack of fresh air increases survival time of airborne pathogens, lack of fresh air increases concentration of gaseous emissions, lack of fresh air can reduce oxygen concentrations. Smells of ammonia/dampness, elevated air temperatures, no ventilation in corners
What can be the problems associated with too much or too little air speed in a livestock building?
Too much - associated with excessive energy losses - animals avoiding certain areas, huddling, hairy coat, high intake/low production rates.
too little - associated with lack of fresh air, animals avoiding certain areas, smell.
What are potential solutions to too much moisture in a building?
Drainage 1 in 60 or 1 in 20 below straw. Drainage within pen between bens within building and outside. manure management and straw management, air inlets and outlets, decent gutters and downpipes, consider concrete
What solutions are there to problems with too much air speed?
Air inlets and outlets - protection from wind to above animal height, greater use of perforated wall caldding, elimination of draughts at animal height.
How do you assess the air inlets and outlets of a building?
Assess roof - No outlets - guarunteed contribution to problems. Area of opening in roof - depends primarily on slope of roof and energy density within building. Flat roof bad > 17 degree slope good. Area of opening in roof 2- only two ball park figures - 0.04m2 per calf, 200mm wide open ridge for adult and growing cattle. Area of inlet at least twice the area of outlet. Always look to eliminate draughts at animal height. Large openings do not control air speed they increase them. Large openings that may create stress should have galebreaker type, space boarding, or yorkshire boarding. inlet and outlet areas are best as a series of diffuse openings along the ridge and walls. Less risk of stagnant areas within the building.
Describe the aetiology of rotavirus infection in calves
Most common cause of diarrhoea in neonatal calves. Rotavirus can be isolate from up to 40 percent of normal calves. Infection results from the ingestion of faecal contaminated material. The virus attacks epithelial cells of the upper mid then lower small intestine causing desquamation. Loss of these cells results in reduction of absorptive capacity and secretory defence mechanisms. Loss of mature differentiated cells with absorptive capacity at the tips of the illi and survival of cells in the crypts secreting fluidds, exacerbates the problem. Loss of cells secreting disaccharidases so sugars are fermented in large colon producing organic acids with the hydrogen ions contributing to the metabolic acidosis. Diarrhoea results in loss of water, sodium, chloride and bicarbonate ions. Loss of intracellular potassium ions occurs because hydrogen ion replacement occurs (buffering in an attempt to reduce metabolic acidosis).
What are the clinical signs of rotavirus?
Range from no observed abnormality through to severe diarrhoea and dehydration with high mortality. the incubation period is 1-3 ays depending upon the level of viral challenge. Calves most commonly affected at 8-14 days old. Acute onset of diarrhoea with passage of watery yellow/green faeces. Typical early signs include a reluctance to stand and suck, mild depression and salivation. Without fluid therapy the calf rapidly becomes dehydrated hypothermic and recumbent. The abomasum and intestines are often distended with fluid and gas and sloth when balloted. The eyes are sunken and the ski becomes tight and inelastic. Calves treated with oral rehydration have normal hydration status but have become severely acidotic causing depression/stupor, weakness and recumbency.
How is diagnosis of rotavirus made?
In a typical beef herd outbreak, the high morbidity of scour affecting calves age 8-14 days with losses occurring despite oral fluid therapy should suggest rotavirus as the primary causal agent. Same day confirmation by PAGE test on fresh faeces can be obtained from a veterinary laboratories. Four or more calves should be sampled (30g faeces not swabs) to allow a meaningful interpretation of the herd problem. Rotavirus frequently isolated from normal calves without diarrhoea.
What is the treatment of rotavirus?
The calf should be isolated in a warm dry and well bedded pen. Intravenous fluids are essential because severely affected calves are acidotic with variable degrees of dehydration. A 16 Gauge catheter should be stitched in a jugular vein as this makes fluid administration much easier because the calf can be left unattended. A typical treatment regime would be: 1 litre of isotonic saline plus 50 percent of estimated bicarbonate deficit during first 20 min then 3 more litres of isotonic saline plus remainder of estimated bicarbonate deficit over next 2-4 hours. 1 litre of oral electrolyte 4 to 8 times daily. Oral antibiotics coontraindicated. Parenteral antibiotics should be used to control concurrent focal infections eg navel ill. milk should not be diluted with electrolyte solution. alternate milk and electrolyte solution every two hours. offer fluid by teat not oesophageal feeder.
What factors are likely to increase the level of rotavirus challenge in a dairy herd?
The persistence of infection in dirty calving boxes/yards
the failure to feed sufficient good quality colostrum at the correct time. not feeding calves stored colostrum during the first two weeks of calfs life.
What factors are likely to increase the level of virus challenge in beef herds?
- A protracted calving period in the same field or building especially if the cows calve in that field every year.
- Failure to remove newly calved cows and calves from the group still to calve.
- The purchase of calves from markets to set on to cows which have lost a calf is an excellent source of enteropathogens.
- concurrent cryptosporidial infections . these are most severe when the same field is used for lambing in the spring and for calving cows in the autumn.
- Factors which lead to the lack of production or ingestion of suitable quantities of good quality colostrum.
Should cows be vaccinated for rotavirus?
Once a herd has experienced losses due to rotavirus infection, annual/alternate years vaccination is ssneitla. in the face of an outbreak it takes 14 days for adequate antibody to accumulate in the colostrum. In subsequent years cows must be vaccinated 1-3 months before the calving date. vaccination against rotavirus infection every second year appears to be an effective programme on many farms. Vaccination reduces the mortality to almost zero if used in conjunction with sound husbandry practices but bouts of diarrhoea can still occur when the calf is 10-14 days old. these outbreaks are usually mild and controlled using oral electrolytes as supportive therapy.
Describe a typical outbreak of coronavirus infection in calfs
Coronavirus diarrhoea are similar to or more severe than those observed for rotavirus infection. coronavirus infection is much less common than rotavirus. Typical clinical signs include depression, reluctance to suck and passage of faeces containing mucus and milk curds. The disease can progress rapidly to weakness, recumbency, severe dehydration and death. Coronavirus infections cause diarrhoea in calves up to 20 days old.
Describe the aetiology of coronavirus
Coronavirus infections differ from rotavirus infections in that the coronavirus replicates in the epithelial cells causing severe damage in the small intestine and progresses caudally into the colon. Infection of epithelial cells with virus results in the loss of cell function causing abnormal absorption and secretion before desquamation occurs 48-96 hours later. The loss of epithelial cells results in shortened villi and occasionally adjacent villi fuse. Cuboidal epithelium replaces the previous columnar cells. The regenerating epithelium consists of functionally immature cells which like in rotavirus cases are unable to carry out normal absorptive and secretory functions.
What is the treatment and control for Coronavirus?
Treatment for coronavirus infection is as for rotavirus. Annual/alternate year vaccination with a combined rotavirus, coronavirus and K99 combined vaccine is an invaluable insurance policy in all beef herds but is perceived as costly by farmers.
What is Enterotoxigenic E. coli? How does it cause disease?
Refers to strains of E. coli possessing the K99 antigen. Recent surveys have shown the incidence of K99 E. coli is low but when it does occur in a herd losses can be high. The ability to adhere to the gut mucosa and the production of a heat stable toxin results in the hypersecretion of fluids into the gut with rapid dehydration collapse and death. ETEC are non invasive and the villi remain intact. K99 E. coli rarely produces systemic colibacillosis.
What are the clinical signs of Enterotoxigenic E. coli?
The disease characteristically affects calves aged 1-3 days old. There is sudden onset of profuse yellow white diarrhoea without mucus or blood. There is rapid and severe dehydration. The calf quickly becomes recumbent. Sequestration of fluid in the abomasum and intestines give the abdomen a bloated appearance which sloshes on succussion. The rectal temperature may be elevated in the early stages but rapidly falls to subnormal. Affected calves are rarely acidotic. Diagnosis based on severe diarrhoea with high mortality affecting calves 1-3 days old. Confirmation following isolation of K99 + E. coli from 30gfaecal samples.
What is the DDx for Enterotoxigenic E. coli?
Recumbency in 1-3 day old calves could include congenital heart defects, Neosporosis and atresia coli/ani, events at parturition such as femoral nerve paralysis and neonatal infections - septicaemia/bacterial meningoencephalitis.
What is the treatment of Enterotoxigenic E. coli?
fluid therapy (these calves are rarely acidotic) antibiotic resistance is not a problem with most K99+ isolates. Always check for the presence of navel ill/septicaemia as such cases require parenteral antibiotics. Control by the movement of all pregnant cows to clean pastures and isolation of newly calved cows should markedly reduce the incidence of ETEC disease.
How does specific K99 antibody work?
It acts locally in the small intestine by interfering with the attachment of ETEC to the intestinal mucosa. Locatim (vetoquinol) is a concentrated bovine lacto serum containing specific immunoglobulins G against E. coli F5. Vaccinate all pregnant animals immediately with Rotavec corona K99 but it will take 10-14 days for sufficient protective antibody to accumulate in the colostrum. Oral antibiotics may be administered at birth as temporary prophylactic measure. Ensure all calves receive equivalent to 10% body weight of colostrum within the first six hours of life.
What is septicaemic colibacillosis?
It occurs in calves less than 2 weeks old on farms with poor husbandry standards. Scour is only seen in the agonal stages. Two factors are critical in the development of septicaemic colibacillosis; 1 inadequate passive immunity from colostral immunoglobulins.
2) exposure and invasion via the nasal, oropharyngeal and mucous membranes, tonsil, upper resp, or intestine of E. coli serotype able to produce an overwhelming bacteraemia , endo toxaemia and death. the umbilicus is not a major portal of entry for bacteria. Calves with sufficient circulating immunoglobulins are resistant to septicaemic colibacillosis. it has been suggested that nil to minimal immunoglobulin concentrations allow a septicaemia whereas more marginal concentrations allow a bacteraemia with bacteria localising in joints, endocardium or meninges.
What are the clinical signs of septicaemic colibacillosis?
Calves less than 2 weeks old. Incubation period of 24 hours between challenge and clinical signs with a course as short as 6-8 hours in septicaemic cases Diarrhoea is a terminal clinical sign. Septicaemia - lethargy, depression, failure to suck, recumbency. Bacteraemia - localisation in the eye, joints, endocardium etc. Episcleral injection. Salivation and yellow mucoid diarrhoea occur terminally, seizure activity, periods of opisthotonus, nystagmus and death.
What is the treatment for septicaemic colibacilosis?
Septicaemic case - florfenicol as most commonly caused by E. coli. Hopeless prognosis if calf showing seizure activity. Meningitis - florfenicol. supportive therapy including NSAIDS. High dose of soluble corticosteroid to reduce cerebral oedema remains controversial in the treatment of bacterial meningoencephalitis. poor prognosis unless treated very early. Polyarthritis - parenteral antibiotics and more importantly thorough joint lavage with lactated ringers solution. Do not flush joints with diluted antiseptic solutions. poor prognosis if carpal/hock joints involved. Prevention - with colostrum and hygienic calving accomodation.
Describe when cryptosporidiosis infection is most likely to occur?
C parvum is not a host specific and severe outbreaks occur when there is a build up of infection towards the end of calving period especially if the same fields or buildings are used for autumn/winter calving then spring lambing as the protozoan parasite can remain dormant on pasture for months. Cryptosporidiosis is more frequently recorded in beef calves than dairy calves. Cryptosporidiosis is a zoonotic disease and has been frequently reported in school children visiting open farms.
What are the clinical signs of Cryptosporidiosis?
Diarrhoea is caused by the physical loss of villous absorptive area and exacerbates viral infections. In some instances no clinical disease results from cryptosporidium spp infection. Beef calves aged 10-21 days old are most commonly affected. There is profuse yellow green diarrhoea with much mucus present. There is only mild dehydration but the calf rapidly looses condition over 2-5 days and has a dull tucked up apperaance. there is a reluctance to suck and examination of the dam often reveals a full udder. Whilst morbidity is high the mortality rate in uncomplicated cases is usually low.
Describe cryptosporidiosis in lambs
Most cases occur during the second half of the lambing period in housed flocks. lambs aged 3-7 days are most commonly affected. There is profuse yellow green diarrhoea with only some mucus. Affected lambs quickly become dull, tucked up and reluctant to move often standing hunched behind shelters. There is rapid dehydration in severe cases with recumbency and eventual death. Unlike calves a severe challenge of C parvum can cause lamb losses during adverse weather conditions if supportive therapy is not administered. Convalescence of surviving lambs is protracted.
How is diagnosis of cryptosporidiosis made?
Calves - change the calving accomodation and move cows and their newborn calves as soon as they are born from the remainder of the herd. in lambs - diagnosis is difficult because the clinical signs and epidemiological findings also fit E. coli infections in lambs aged 3-5 days. Demonstration of cryptosporidia spp oocysts on faecal smear after giemsa stain. Other enteropathogens may also be involved. Identification of organisms on stained gut sections of post mortem material is the preffered laboratory method.
What is the treatment of cryptosporidiosis?
In uncomplicated cases ensure that the calf is properly hydrated and use oral electrolyte solutions as necessary. Halofuginone lactate is licensed for the prevention and treatment of diarrhoea caused by C parvum. For prevention of diarrhoea, calves should be dosed for seven consecutive days starting within one to two days of birth. For treatment, calves should be dosed for seven consecutive days starting within one day of the onset of diarrhoea. Halofuginone lactate has a low toxicity index and the data sheet instructions must be carefully followed. Lambs - oral flui therapy is essential and 150-200 mls of oral rehydration solution 4-6 times daily is recommended.
How can cryptosporidiosis be controlled?
Do not use same fields for calving/lambing. Change field every year or when clinical cases occur int hat season. Move newborn animals immediately onto clean pasture.
What is coccidiosis?
A problem of housed, intensively reared lambs. Disease can occur in calves during dry summer months associated with contaminated water courses and feed areas (E alabamensis). There is speculation that periweaning scour syndrome of dairy calves is caused by coccidiosis.
What is the aetiology of coccidiosis?
Caused by infection by the protozoan eimeria spp which parasitizes the epithelium lining the alimentary tract E zuernii, E bovis and E alabamensis.
What are the clinical signs of coccidiosis?
It was a problem in weaned dairy calves confined outdoors during the summer months in small dirty paddocks where faecal contamination of grazing and feed troughs rapidly builds up. Now coccidiosis is more common in spring born beef calves at pasture during summer months with infection acquired from contaminated surface water. In severe clinical coccidiosis there is a sudden onset of profuse foetid diarrhoea containing mucus and flecks of fresh blood. There is considerable staining of the perineum and tail. Straining with partial eversion of the rectum which may result in prolapse. Clinical signs are more usually less marked with chronic wasting and poor appetite the presenting signs. Small clots of fresh blood and mucus are passed but the diarrhoea is not so marked. Anaemia is uncommon. Rectal temp often normal. Morbidity is high but mortality even in severe cases is low.
What is the DDx for crypto?
Calves - parasitic gastroenteritis, salmonellosis, lead poisoning. If only one calf - intussusception, BVD, necrotic enteritis, ragwort. Lambs outdoors - PGE especially nematodiriasis.
Indoors - Poor nutrition of both lamb and dam, strongyloids westeri infestation, liver abscessation/pyaemia, chronic pneumonia.
What is the treatment for crypto?
Move from infected pastures. sulphamezathine given orally for 3 days was the standard treatment. Fluid therapy may be indicated in certain cases. Decoquinate and diclazuril can be used for the treatent and prophylaxis of coccidiosis in lambs. toltrazuril and diclazuril can be used for both treatment and prophylaxis in calves. decoquinate can be used in feed for prevention of coccidiosis in dairy calves.
What are wheezes?
Continuous single pitch sound which usually occurs during inspiration and occasionally during both inspiration and expiration. result from vibration of airway walls caused by air turbulence in narrowed airways.
What are crackles?
Sudden sound towards the end of inspiration or less frequently during both inspiration and expiration. Caused by sudden opening of small airways plugged by mucus, pus and other debris.
What is pasteurellosis? (transit fever)
An acute infection resulting in broncho pneumonia affecting cattle aged between 3 months and 2 years old.
Describe the aetiology of pasteurellosis? (transit fever)
Genetic selection has resulted in domesticated cattle with small lungs relative to metabolic demands and such reduced respiratory capacity can contribute to decreased resistance to Aerogenous exposure to infectious agents particularly during periods of exertion. Reductions in body weight which occur over transportation of long distances, poor appetite after arrival and changes in ration may compromise immune system function and predispose calves to respiratory disease. The importance of the respiratory tract innate defences - intact epithelium including ciliated cells, mucus, interferon, and phagocytes.
PAsteurellae are part of the normal flora of the nasopharynx. A number of factors including Pi3, BRSV or IBR infection, stress, overcrowding poorly ventilated buildings, transportation, starvation, allow increases in numbers or virulence of pasteurellae in the nasopharynx. Mannheimia haemolytica is believed to be responsible for up to 90% of cases. others attributed to P multocida.
What are the clinical signs of pasteurellosis?
The farmer notices that the animal does not come forward for concentrate feeding. The affected animal is often dull and may stand by itself in a corner of the pen. the rectal temperature is elevated but the animal does not appear ill, there is a mild serous ocular and nasal discharge. there is an increased respiratory rate and effort. the animal may appear gaunt if it has been inappetent for more than one day. Coughing is not a feature of pneumonic pasteurellosis. there are few abnormal sounds to be heard on auscultation of the chest.
How is diagnosis of pasteurellosis made and what are the DDx?
IBR - check other cattle in the group for clinical signs of IBR. nasal swabs are of little use to diagnose pasteurellosis as these bacteria are commensals of the upper respiratory tract. DDX - IBR hepatocaval thrombosis in individual animal.
What is the treatment of pasteurellosis?
Up to 50% of affected animals may recover in 3-7 days without antibiotic treatment. 75-80% of lung isolates of pasteurellae are sensitive to oxytetracycline but this drug is now rarely used by vets. recommended dose 10mg kg/iv. Continue treatment with single long acting injection or for 3-5 consecutive days. Rectal temperature should fall to near normal by the third day of treatment. tilmicosin has advantage of a single long acting injection. Has been ovetaken by tulathromycin (draxxin), gamithromycin (zactran) and tildipirosin. Florfenicol can be administered on day 1 and day 3 or as a single long acting injection. Enrofloxacin and other fluoroquinolones are highly effective against pasteurellae spp should be held in reserve. Marbofloxacin would be choice.
How can response to antibiotic treatment be monitored?
Antibiotic re treatments should be based upon recurrence of significant pyrexia during the monitoring of recovering cattle which takes place at regular two to four days intervals after completion of the initial treatment course. Field studies have demonstrated a marked reduction in calf rectal temperature 24 hours after the start of antibiotic treatments indicating efficacy of that antibiotic in the treatment of bacterial respiratory disease.
When should antibiotic re treatment be undertaken?
Antibiotic re treatment becomes necessary when bacterial infection recurs during the period of viral induced compromise of host defence mechanisms in the upper respiratory tract. Recurrence of pyrexia 5-14 days after first antibiotic treatment can occur in 20% -50% of treated calves. Use the same antibiotic because re infection of compromised lung has occurred. Antibiotic re treatment rates are considerably higher in calves 2-5 months old than weaned cattle.
When is the antibiotic treatment defined as a failure?
When there has been a failure of the rectal temperature to fall after 48 hours or recurrence of pyrexia 2-4 days after first antibiotic treatment. With the exception of peracute BRSV cases where the animal is severely dyspnoeic, corticosteroids should be avoided untill the rectal temperature begins to fall.
How is pasteurellosis controlled?
No obvious measures for pasteurellosis have been shown to work consistently well. improved ventilation of buildings and delaying stressful procedures may help to reduce the disease prevalence. Pasteurella vaccines not found to be very successful in the UK. Metaphylactic antibiotic injection- No evidence to support - expensive and not consistent with good practice especially if using a fluoroquinolone. There are obvious animal welfare benefits from the early detection and effective treatment of respiratory disease by the vet.
What is haemophilus somni? What is the treatment?
Aetiology and clinical signs similar to those described for pasteurellosis and specific diagnosis can only reliably be made at necropsy findings with marked fibrinous pleuritis and pleuopneumonia. Florfenicol and fluoroquinolone drugs effective. Occasionally thromboembolic meningo encephalitis reported in cattle following episodes of H soni respiratory disease. syndrome presently very uncommon in the UK. Animals become obtunded, ataxic and sternally recumbent.
What is chronic suppurative pulmonary disease?
Bacterial in origin developing as a result of unsuccessful treatment or incomplete recovery from earlier pneumonia episodes. Recrudescence of infection is often associated with a stressor such as transport, sale or calving. CSPD often associated with persistent BVD in growing cattle. affected growing cattle are dull, in poor condition, pot bellied, with a dry rough and starig coat, and are intermittently febrile. Affected animals cough frequently and have an occasional muco purulent nasal discharge. the respiratory rate is increased with an obvious abdominall component to respiration. the appetite is poor. Obvious crackles are heard. Clinical signs in adult cattle are poorly defined and often present with a normal rectal temperatuer, poor milk yield, reduce appetite and weight loss.
What is the treatment of Chronic suppurative pulmonary disease?
Growing cattle are unlikely to grow well and should be culled. treatment with procaine penicillin for secondary infection of lung pathology with T pyogenes injected daily for 6 weeks. success rate much higher for recently calved heifers and adult cattle.
What is infectious bovine rhinotracheitis?
IBR is a highly contagious infectious disease affecting cattle of all ages. the disease is characterised by sever inflammation of the upper respiratory tract. Bovine herpes virus 1, also causes infectious pustular vulvo vaginitis in the female and infectious balanoposthitis in the male.
What are the clinical signs of Infectious bovine rhinotracheitis?
Clinical signs generally first appear either 2-3 weeks following housing or other stressful events such as calving. The morbidity rate may be 100% but the mortality rate is less than 2%. Sudden onset illness, febrile 41-42, purulent ocular and nasal discharges, affected animals are inappetant, very depressed, slow to rise and stand with the head held lowered. Conjunctivae are oedematous and there is partial prolapse of the third eyelid. Tear staining of the face is pronounced. there is halitosis due to pus in larynx and trachea and varying degrees of dyspnoea. Affected animals cough frequently and palpation of the larynx is resented. Milder clinical signs with occasional coughing and poor production can occur. IBR virus has been found to enhance the pathogenicity of moraxella bovis. This is important in herds with endemic IBR infection where severe IKC lesions can develop in calves.
How is diagnosis of IBR made?
Careful inspection of all animals in the group. fluorescent antibody test FAT requires cells so rub corneal sac vigorously. If veterinary laboratory not local, make smears on glass slides and dry in air before posting. Never believe a negative FAT test.
What is the treatment and control options for IBR?
Vaccinate all animals in the group immediately if IBR is suspected on clinical findings. Marker gE vacines are available for more sophisticated control programmes. sick animals should be treated daily for three to seven days with a parenteral procaine penicillin. Never use corticosteroids. IBR vaccination is relatively inexpensive at £3 per dose either by single intranasal or intramuscular injection and should be boosted annually.
What is bovine respiratory syncytial virus?
BRSV is considered to be the most important respiratory virus predisposing to pneumonia in young cattle and in severe infections can precipitate disease and sudden death without bacterial infection.
What are the clinical signs of bovine respiratory syncytial virus?
In some outbreaks one or two animals may be found in severe respiratory distress with mouth breathing, rapid abdominal movements and death within 12 hours. In other studies involving housed calves seroconversion to BRSV has occurred without any clinical signs of respiratory disease. In most respiratory disease outbreaks involving BRSV there is an increased respiratory rate and frequent coughing. A serous nasal discharge is usually observed. There is no occular involvement. Secondary bacterial invasion frequently occurs which makes the prognosis even more guarded. the rectal temperature ranges from 39.5 to 42.
How is a diagnosis of BRSV made?
Lavage to obtain virus identified by FAT is the most useful test in acute respiratory disease. FAT on frozen lung sections requires a dead anima in the acute phase of the disease process. paired serology from 4-6 calves, 2-3 weeks apart, is costly and of little use in tackling the problem at the start of an outbreak. A four fold increase in titre 25% of sample population is considered indicative of BRSV involvement.
What is the treatment of BRSV?
In severly dyspnoeic calves a single injection of corticosteroids such as dexmathasone may be life saving. the rationale for such treatment is that inhalation of virus into the caudo dorsal lung field sets up an allergic reaction with the development of extensive emphysema, NSAIDs are not nearly so effective. Bronchial smooth muscle relaxants are of little benefit in the acute phase of the disease. Recurrence of fever and respiratory disease signs are common 5-14 days after the first episode. the same antibiotic should be used to treat these reinfections as that used successfully in the first outbreak.
How is control of BRSV implemented?
Vaccination is widely used to control BRSV induced respiratory disease. Rispoval 4 is a live attenuated bovine respiratory syncytial virus, Containing IBR, Pi3, BDV antigens which is administered intramuscularly on two occasions, four weeks apart, two weeks prior to the anticipated challenge eg housing. Single intranasal vaccination with rispoval RS (also contains Pi3 antigen) is as effective as two intramuscular injections and is claimed to be effective in the face of a BRSV induced respiratory disease outbreak. Reducing stocking density and improving ventilation/reducing humidity wherever possible would improve the disease situation on most units.
Describe Pi3 infection
the clinical signs attributable to Pi3 infection as defined by seroconversion during the respiratory disease outbreak, are generally mild. most outbreaks occur during october/november and are common following housing. it is not uncommon for Pi3 and BRSV infections to occur simultaneously.
What is mycoplasma (enzootic or cuffing pneumonia)
Poorly defined clinical disease where mycoplasma dispar may act in conjunction with Pi3 infection. Insidious onset disease more commonly encountered in young weaned dairy replacement heifers where young susceptible calves are mixed with or placed in pens adjacent to older cattle. there may be a considerable range in calves rectal temperatures 39.2-40.5. Appear dull, unthrifty, with a dry staring coat. there are usually no ocular or nasal discharges. frequent bouts of coughing are noticeable when the animals are handled.
What is the treatment of M bovis?
Few reports of outbreaks i the uK. may also cause severe intractable mastitis and polyarthritis. treatment is with florfenicol or fluoroquinolone but not tilmicosin or tulathromycin.
What is pulmonary thromboembolism from the caudal vena cava (hepatocaval thrombosis)
An uncommon condition which develops following the haematogneous spread of a large number of septic emboli from a thrombus in the caudal vena cava. Pulmonary arterial thrombo embolism occurs with eventual fatal rupture of pulmonary arterial aneurysms. Animal may be found dead having bled to death through respiratory tract. in the majority of cases there is a history of respiratory disease. clinical signs develop rapidly initially resembling pasteurellosis. Febrile 41 degrees C, apparent response to antibiotic therapy although short term as signs re appear 3-10 days later. Respiratory rate is increased with shallow painful respirations, coughing. at this stage frank blood at nostrils or coughed up - death follows in 1-14 days from massive intrabronchial haemorrhage with the animal found in a pool of bloos.
Describe chronic suppurative pulmonary disease?
Bacterial in origin developing as a result of unsuccessful treatment or incomplete recovery from earlier pneumonia episodes. it is a flare up of infection from a chronic septic focus which is responsible for the occasional adult animal presenting with signs of an apparently sudden onset disease. Recrudescence of infection is often associated with a stressor such as transport or calving.
What are the clinical signs of chronic suppurative pulmonary disease?
Typical cases are dull with chronic weight loss, intermittently febrile 39-39.5, production rate is reduced to 50-75% of predicted milk yield. there is increased respiratory rate around 40 breaths per minute with an abdominal respiratory component and a moist productive cough. there may be evidence of a purulent nasal discharge most obvious when the animal lowers its head to eat. there may be evidence of thoracic pain, crackles may occasionally be heard in the antero ventral chest but such sounds may not be obvious.
Describe diagnosis in adult cattle of chronic suppurative pulmonary disese?
Difficult in adult cattle as clinical signs are vague. serum protein profile indicating chronic bacterial infection is helpful but not specific to lung disease. fibrinogen assay does not warrant extra cost. ultrasonographic examination of both lungs/pleurae is quick. can use linear 5Mhz scanner. DDx - endocarditis, liver abscesses, Tuberculosis
What is the treatment of chronic suppurative pulmonary disease?
Main bacterial isolate is A pyogenes. attempt treatment of adult cattle with procaine penicillin injected daily for 6 weeks. Cost is 40-50 for treatment course. Success rate is approximately 50%. poorer prognosis when sonographic changes extend 5-10cm dorsally above the point of the cows elbow. Check BVDv status even in calved heifers. Correct treatment of respiratory disease as calves.
What is fog fever?
An atypical interstitial pneumonia of cattle/acute bovine pulmonary emphysema. Fog fever has a sudden onset causing severe respiratory distress in adult beef suckler cows 1-2 weeks after moving on to a lush silage hay aftermath in july august. Circumstential evidence links the disease with the ingestion of large amounts of the amino acid L tryptophan and its conversion in the rumen to 3-methyl indole and indole acetic acid.
What are the clinical signs of fog fever?
There is a sudden onset of severe respiratory disease. an expiratory grunt can often be heard from 30 yards away. the animal stands with its neck extended, head lowered, and moves very reluctantly. the nostrils are flared and the animal mouth braethes. the mucous membranes are cyanotic. there is frothy saliva around the protruding tongue. the rectal temperature is normal. rapid pulse 80-120 beats per minute. mortality rate in severely affected cases is 95%. Less severely affected cattle improve over a 10-14 day period. subcutaneous emphysema often develops over the thorax and along the back. Auscultation reveals widespread harsh crackles. usually no more than 2-5 percent of cattle at risk are Severely affected. mild fog fever - sleepy looking, tachypnoeic, and hyperneoic.
What is farmers lung?
An extrinsic allergic bronchiolo-alveolitis which develops in housed adult cattle following repeated exposure to mouldy hay containing spores derived from micropolyspora faeni and thermoactinomyces vulgaris. farmers lung is now rare due to improvements in beef cow nutrition and housng. individual animals show a sudden onset of severe dyspnoea, occasionally with mouth braething. there is frequent coughing with the production of thick mucus. the animal is alert, the reduced milk yield and anorexia which may be present are secondary to the respiratory diistress. mild to moderate attacks may go unnoticed, or dyspnoea may appear after exercise. The respiratory rate is increased with loud crackles audible antero ventrally due to the presence of tenacious mucus in the airways. Treatment - corticoseroids not in the last 5 months of pregnancy. Control - avoid mouldy hay. feed silage/barley straw.
What is vegetative endocarditis?
the provisional diagnosis of vegetative endocarditis is based upon clinical findings of chronic weight loss, pyrexia and often multiple joint effusions. typically encountered two to four months after parturition where the uterus is a potential source of infection, other septic foci act as the source of the bacteraemia in younger animals. Animals typically present with poor milk yied of several days to weeks and weight loss manifest as poorer body condition compared to other animals in the group. rectal temp marginally elevated. typically obvious effusion of hock carpal and fetlock joints. stifle and elbow less commonly. Heartrate may be elevated but may be no murmur. Lesions involving the tricuspid valve may result in ascites and peripheral oedema.
What is the DDx for vegetative endocarditis? How is it treated?
Bacterial polyarthritis - uncommon in adult sheep. Pleurisy and traumatic reticulitis (pain). Treatment with procaine penicillin for 10 days or more - usually unsucessful. Prevention based on timely and effective treatment of focal bacterial infections eg metritis, mastitis foot abscess.
What is dilated cariomyopathy?
Occasionally reported in 2-3 year old hostein cattle - genetic component. Bright and alert with normal appetite until agonal stages. clinical signs include marked peripheral oedema, jugular distension, ascites and pleural effusion which develop over several mnths. The heart rate is increased but sounds often muffled due to pleural effusions. DDx - right sided heart failure due to lung pathology or mediastinal mass. No treatment for DCM and affected cattle should be eutanased. necropsy reveals enlargement of the heart with a rounded globose shape.
Which congenital abnormalities may occur in the bovine gastro intestinal tract?
Cleft palate/harelip, pro/brachygnathia, atresia ilei (gut distension so may cause dystocia), coli: not uncommon, progressive abdominal distension by 2-3 days of age( surgical repair rarely possible. Ani: die within 1 week if untreated - surgical repair possible in some cases.
What is stomatitis/pharyngitis? What is the cause?
Inflammation of the mouth/pharynx. Physical injury - dosing guns, stomach tubes scrapie i/d boluses, foreign bodies, tooth maloclusion. Clinical signs: salivation, halitosis, quidding, submandibular and pharyngeal swelling. treatment: symptomatic relief with anti inflammatories/antibiotics. poor prognosis with iatrogenic pharyngeal rupture.
What is bovine papular stomatitis?
Parapoxvirus same as pseudocowpox virus. Zoonosis. Clinical signs: calves 1-12 months commonly affected. Expanding papular rings on muzzle. Nostrils and buccal mucosa. May be transient anorexia, salivation, mild pyrexia. spread by contact. Treatment: none required, recovery in 4-7 days though lesions slower to heal improve.
What is the presentation of actinobacillosis infection?
Can present in various forms:
wooden tongue - most common
Intestinal form - rare, lesions in oesophagus, oesophageal groove, cardia, rumen reticulum.
Cutaneous form - rare. caused by actinobacillus lignieresii a commensal gram -ve bacteria.
What are the clinical signs of actinobacillosis?
wooden tongue - salivation, dysphagia/anorexia, tongue protruding, enlarged submandibular Lns, selling under jaw. oral examination reveals painful swollen tongue, yellow lesions visible below mucosa.
Intestinal - insidious onset, chronic progression. Ruminal bloat most marked following eating. Non painful. Afebrile. rumination abnormal - prolonged gurgling pus retching. wt loss with normal appetite.
Cutaneous - often several animals, large granulomas and ulcers mouth head and chest.
What is the treatment of wooden tongue?
5 day course of streptomycin (penstrep combo) or potentiated sulphonamides. Or devomycin.
Iodides (not in pregnant animals. (older treatment, can break down granulomatous lesions).
What is seen in infection with actinomycoses? (lumpy jaw)
Actinomyces bovis gram + bacteria causing pyogranulomatous ostitis/osteomyelitis in bones of the head especially mandible. rarely soft tissue - alimentary tract. Clinical signs are firm bony swelling on jaw usually at level of central cheek teeth. surrounding painful soft tissue swelling usually present. dysphagia with gradual emaciation. animal bright. discharging sinuses internal or external. possible tooth displacement and pathological fractures. Treatment as for wooden tongue but prognosis very poor. can try high dose penicillin/streptomycin for 14 days in early caises. aim for remission then slaughter.
Describe infection with oral and laryngeal necrobacillosis? (calf diptheria)
Fusobacterium necrophorum bacteria plus trauma. concurrent disease or nutritional deficiency may predispose. Clinical signs - usually affects calves 1-3 months of age but laryngeal form may affect older calves. oral form - swelling of cheeks, necrotic halitosis, anorexia, salivation & pyrexia. Examination of oral cavity reveals lesions on cheeks, tongue etc. Occasionally overwhelming spread of infection. Laryngeal form - anorexia, pyrexia, cough, inspiratory stridor and dyspnoea, salivation, halitosis. swollen and painful laryngeal region.
What is the treatment of oral and laryngeal necrobacillosis?
Systemic antibiotics (potentiated sulphonamides, oxytetracycline, penicillin). Laryngeal: long term high dose antibiotics (lincomycin injection reported to be successful but not licensed in cattle). corticosteroids in acute stages to reduce laryngeal oedema. Tracheostomy if necessary. Poor prognosis in advanced cases due to suppurative chondritis.
What is choke?
Obstruction at the larynx, thoracic inlet, or thoracic oesophagus. Potatoes fed whole and not chewed. chopped swede or turnip unchewed. Salivation and repeated attempts to swallow. Progressive bloat according to nature of obstruction. Diagnosis: history of feeding, visual and palpatioon. Treatment - assess severity of rumenal tympany. emergency trocharize if necessary. Relax oesophagus eg buscopan injection. Allow 5 minute, gag then attempt to massage obstruction up to pharynx. If thoracic obstruction - use orogastric tube or probang to gently push in on the rumen. Last resort - create temporary rumenostomy and allow obstruction to degenerate over 3-4days, risk of oesophageal necrosis/rupture. Always give antibiosis and anti inflammatory treatment.
What is upper alimentary squamous neoplasia?
Bracken toxin inducing bovine papilloma virus. Signs - oropharyngeal - wasting, coughing, salivation. 2 - oesophageal - wasting, signs of choke, bloat. 3. rumenal tumours in association with 1 or 2. exacerbate wasting with diarrhoea. No treatment.
What is megaoesophagus?
Rare. Can be congenital. or acquired due to neurological damge. Signs are recurrent bloat, regurgitation and discomfort on eating. Diagnosis with contrast radiography. Treatment - supportive (+ temporary rumenotomy) treat any infection
Describe simple indigestion
Sudden diet change - upset in rumen microflora. Moderate CHO excess, excess oral antibiotic, sour/fermenting food etc. Signs are rumenal atony, inappetance, milk drop, dullness + colic. Reduced faecal quantity becoming diarrhoeic. Non pyrexic. Diagnosis - signs, history, full clinical examination - rule out other causes of rumen stasis. Treatment - rumen stimulants and palatable forage. Rumen inoculum; probioitcs, multi B vitamin injections. Calcium borogluconate in early lactation cows. Control - good nutritional management.
Why does carbohydrate overload cause disease? (Ruminal lactic acidosis, barley poisoning)
Imbalanced concentrate to roughage ratio. CHO engorgement following access to feed store usually, feed change or using finely ground cereal. As easily fermentable CHO is digested VFA production increases & rumen pH falls water absorbed from systemic circulation causing dehydration. Low rumen pH reduces motility - stasis and mild bloat. G-ve bacteria killed > release of endotoxin. Chemical damage to rumen wall > rumenitis.
What are the clinical signs of carbohydrate overload (barley poisoning)
Mild - discomfort, anorexia, reduced ruminal activity, ruminal distension, diarrhoea. Severe - anorexia, depression, dehydration, tachycardia, rumen stasis, abdominal pain, laminitis. Toxaemia > pyrexia then hypothermia, hyperaemic of mm’s, scleral congestion etc. acidosis > tachypnoea, weakness, ataxia, reduced vision, recumbency, opisthotonus, coma, death. Sequelae - progressive systemic acidosis, circulatory shock and death in severe cases. Recovered cases may get fungal rumenitis and chronic bloat. secondary liver abscessation. F necrophorum and actinomyces pyogenes, laminitis, cerebro cortical necrosis all possible
What is the treatment of carbohydrate overload?
if pulse >100bpm and rumen ph 10% roughage in any diet. prevent escapes and have locked food bins. crack or roll grains - do not grind.
What is rumen parakeratosis?
seen in animals fed 100% concentrate diet, or secondary to CHO overload. There is rumenitis > escape of rumen flora, liver abscesses, laminitis. Signs: vague illness, pain, indigestion. treatment - balanced diet, antibiosis. .
What is juvenile ruminal tympany?
Juvenile - failure in oesophageal closure so milk enters rumen, subsequent fermentation acidosis and rumenal atony. rapid onset L flank distension following milk feed, discomfoort and chronic pasty scour. treatment - decompression - stomach tube/needle/trochar, oral antibiosis, feeding management.
Describe frothy bloat in adult cattle?
Usually high protein levels in lush leguminous pasture - clover rich swards. V common on N zealand. bloat causing legumes are susceptible to rapid digestion by rumen microflora. occasionally seen in feedlot cattle fed finely ground grain. Rumen fluid viscosity raised therefore small bubbles form from rumen fermentation products. froth forms which cannot be eructated normally. Signs: acute rumen tympany, distress, recumbency, death in extreme cases. Diagnosis - usually a group problem, with a history of lush grazing, failure to relieve bloat with stomach tube, froth blocks tube. Treatment- move affected animals off pasture. drench/stomach tube with anti foaming agent eg vegetable oil or silicone drench. trocarisation of rumen can be done to relieve tympany. gradual introduction to risk pasture will prevent it. daily drenching with anti foaming agent. monensin in supplementary feed or bolus.
What causes free gas bloat?
Any condition causing oesophageal obstuction or interference with normal eructation may cause free gas bloat eg lesions of oesophageal groove, actinobacillosis or papillomatosis, physical obstruction/choke, physical pressure on oesphagus/vagal nerve by enlarged mediastinal bronchial LNs, common in 3-6 month old stirks following chronic pneumonia. thoracic mass eg thymic lymphosarcoma, neurogenic causes, tetanus, vagal indigestion, lateral recumbency, milk fever.
What are the signs of free gas bloat? how is it treated?
Distended left sublumbar fossa, progressive distress, usually a single animal, passage of stomach tube confirms free gas. Treeatment: pass tube to relieve bloat, insert trocar/canula or create surgical fistula if recurrent problem. Establihs primary cause if possible and treat accordingly eg antibiotics for actino.
What is vagal indigestion?
A fairly rare sporadic disease of adult cattle. damage/irritation to vagal nerve which may occur at different sites? most commonly associated with anterior peritonitis (traumatic reticulitis), liver abscess, mediastinal abscess and lymphosarcoma. Mechanical impairment of reticular motility leads to failure of normal ingesta passage through reticulo-omasal orifice and pylorus. this outflow abnormality of the reticulo rumen and abomasum leads to the signs seen - enlargeed impacted rumen with initial hypermotility, chronic enlargement of dorsal and ventral rumen sacs leads to Ll shaped distension of abdomen, progressive inanition/weight loss/dehydration, scant faeces, occasional bradycardia.
What causes traumatic reticulitis?
Occurs sporadically in adult airy cattle following ingestion of sharp metal objects and their localisation in the reticular wall. Outbreaks of disease have been reported caused by disintegration of tyres used on silage clamps and their incorporation into the mixed wagon, and following farm building work, bonfires etc.
What are the clinical signs of traumatic reticulitis?
Classical clinical signs are only observed when the foreign body is in contact with the peritoneal lining of the abdominal cavity and may last only 2-3 days then adhesions restrict movement. the rectal temperature is within the range 39-39.5. Sudden on set anorexia, dramatic fall in milk production e.g 30 litres/day to 2-3 litres/day. animal stands with an arched back and moves reluctantly last to enter the milking parlour. described by the farmer as stiff. complete ruminal atony, initial abdominal distension then becomes tucked up and gaunt resulting from poor appetite and shrunken rumen. Animal shows evidence of anteior abdominal pain, taut abdomen, refusal to turn sharp corners, ears back, fixed glazed stare. animal is constipated. defecation and urination frequently accompanied by grunt. pain response elicited, grunt or kick when back dipped behind withers or pressure applied slowly behind the xiphisternum with a pole then suddenly released (hyperalgesia). In cases where the foreign body has penetrated the reticular wall and is in contact with the diaphragm or omasum the clinical signs are less well defined and no grunt can be elicited.
How is diagnosis of traumatic reticulitis made?
Made on clinical findings and confirmed during surgery. ultrasonography will identify excess peritoneal fluid/exudate/fibrinous reaction surrounding the penetrating foreign body. reticular abscesses are identified after about 10 days by which time this reaction will seriously affect the outcome. linear array 5Mhz canners, used for bovine fertility work will provide diagnostic quality images. Metal detectors are a waste of time due to other metallic material collecting in the reticulum. routine haemoatology is non specific. peritoneal sampling - high protein and cell count comprised of mainly neutrophils and presence of bacteria, indicates septic peritonitis.
Describe surgery for Treatment of traumatic reticulitis
High left flank laparotomy under distal paravertebral analgesia. two 5mm nylon tape loops placed 15cm apart in muscular layer of rumen wall following its exteriorisation. incise into rumen between tape loops using scissors. place rumen on to right arm while an assistant holds tape loops. pass arm through 20cm raft of dry fibrous rumen content before entering fluid. angle hand toward xiphisternum taking rumen back in through wound if necessary providing that the rumen incision is small enough to fit tightly around your arm and there has been no leakage of rumen contents. the wall between the rumen and reticulum is 15cm high off the abdominal floor. pass hand along rumen floor then upward and forward into the reticulum. Carefully search the honeycomb lining for the wire. Check for adhesions. Remove foreign body. Rumen closed with an inversion suture of 3 metris chronic catgut. abdominal wound closed routinely. recovery even after successful removal of a foreign body is slow and it may take the cow four weeks to regain previous milk yield due to localised peritonitis interfering with reticular contractility and propulsion of digesta.
What is an LDA? When does it occur?
Left sided abomasal displacement. Occurs during the winter housing period in dairy cows most commonly but not exclusively in the month following calving. some association with hypocalcaemia, twinning, endometritis and high concentrate, low fibre rations. increasingly, LDA is seen in recently calved heifers and during the summer months. never seen in suckler cows or intensively fattened cattle.
What are the clinical signs of an LDA?
Variable, may be complicated by presence of other disease conditions namely metritis and secondary acetonaemia. Most severe when LDA occurs in conjunction with acute metritis in the 5-7 days after calving. the cow is often febrile, depressed, toxaemic, anorexic with a reduced milk yield. There is profuse often foetid diarrhoea, the animal is drawn up and flanks sunken, there may be moderate dehydration. The distended abomasum occupies the craniodorsal area of the left side of the abdominal cavity and auscultation and succussion reveals high pitched tinkling sounds. Rumen movements can be heard caudally in the sublumbar fossa. Rectal examination fails to reveal any abnormality. in cases occuring more than 10 days after calving there are typically clinical signs of chronic endometritis and secondary ketosis. a typical case is presented 15-30 days post calving ,history of poor milk yield, reduced appetite with chronic weight loss up to 50kg since calving, one unit of condition score, the cow is slow to move and dull. the coat is dry and staring. rectal temperature is often normal.
How is diagnosis of an LDA madE?
Diagnosis is based on thorough clinical examination remembering that more than one condition may exist at the same time i.e metritis and LDA, and secondary ketosis and LDA. diagnosis is confirmed on surgery. Parecentesis of the displaced abomasum contents (aided by ultrasonography) would reveal the presence of fluid containing no protozoa and a pH of 2 but such testing is rarely undertaken/necessary.
is roling the cow the correct treatment for an LDA?
Treatment - rolling the cow takes time, requires three people and may only be 40% effective at best. there is the risk of inhalation of rumen contents when the cow is in dorsal recumbency especially if she has been heavily sedated. surgical correction of LDA is the preferred option. There are many surgical techniques but right flank omentopexy is the preferred method. In some practices, toggling is performed because of perceived cost saviour to the farmer but this method is not without its problems (85% sucess rate).
Describe the right flank approach to LDA surgery.
Intravenous NSAID such as ketoprofen or flunixin administered preoperatively to effect analgesia. Surgery is performed in the standing cow under distal paravertebral analgesia. The abomasum is football sized and lies high up on the left side under the costal arch boyed by its gas content. A right laparotomy incision is made and the abomasum deflated using a 14 guage needle connected to a flutter valve or suction pump. upon release of the gas the abomasum sinks towards the midline pulled down by its liquid contents. The greater omentum is grasped with your left hand as near to the ventral midline as possible and gently pulled up to the ventral margin of the incision. the sows ear and pylorus can readily be identified and an omentopexy or pylorpexy performed whereby a continuous suture taking 4cm bites of omentum or pylorus is made and this suture continued to close the peritoneum and internal oblique muscle layer. the laparotomy wound is then closed routinely. Oral fluids 50-60 litres to distend shrunken rumen.
What supportive therapy should be given for LDA surgery?
for acute endometritis with LDA: treat for 3 consecutive days with oxytetracycline, administered intravenously on day 1. NSAID such as ketoprofen or flunixin to treat toxaemia - preoperatively to effect analgesia. 3 litres of 7.2% hypertonic saline intravenously on day 1 to treat endotoxaemia. Secondary acetonaemia: corticosteroid such as dexamethasone and 400mls 50% dextrose i/v, propylene glycol orally b.i.d.
How can LDA be controlled?
As the aetiology is incompletely understood control measures are vague btu the following are suggested: prompt treatment of retained placenta and early cases of metritis, provision of long fibre i.e h ay in early post partum period. avoid high concentrate levels immediately following calving. control measures for hypocalcaemia including use of acidifying diets during the dry period. Prevent over fatness of dry cows/heifers.
Toggling of the aboasum through the ventral abdominal wall overlying the tympanitic abomasum has been described as a more cost effective procedure. Describe how this procedure is done?
The cow is cast i nto orsal recumbency and the abomasum located in the midline by percussion. two toggles with nylon sutures are introduced into the abomasum through wide bore trochars approximately 5-10 cms apart, the trochars are removed and the nylon sutures tied together. Failure to accurately locate the abomasum may result in toggling other viscera although this method is reported to be about 85% effective.
Describe dilation and right sided displacement of the abomasum?
This occurs occasionally in dairy cows 3-6 weeks following calving. Less common than LDA. Probable cause is primary distension of the abomasum due to atony caused by high concentrate intake and secondary fermentation. Accumulation of fluid and gas leads to distension and dorsal displacement on the right hand side of the abdomen. Clinical signs include history of poor milk yield, inappetance and weight loss. auscultation reveals high pitched tympanic sounds just cranial to the right sublumbar fossa. torsion of the abomasum may occasionally result. Treatment - reported treatments for abomasal dilation include 400mls 40% calcium borogluconate i/v and substitute concentrates with hay for 2-5 days, plus oral and iv fluids as necessary. Hyoscine has been reported to be useful but there is little supporting evidence. Right omentopexy may relieve the problem but why such surgery should be successful is uncertain.
What is an abomasal volvulus?
Following dilatation a 180-270 torsion may occur resulting in an abdominal catastrophe. once torsion occurs the cows condition deteriorates rapidly within 12 hours. The cow may be recumbent and there is obvious right sided abdominal swelling. rapid dehydration, toxic injected mucus membranes. rapid heart rate >100/minute. cold sweat with subnormal rectal temperature. Obvious tympanic viscus occupying most of the right side abdomen extending as far forward as the seventh intercostal space. the liver becomes displaced from the abdominal wall - no longer identifiable during ultrasound examination.
What is the treatment for abomasal volvulus?
Surgical correction of the torsion is difficult but can be attempted in the standing patient using a right flank approach. improve cardiovascular function prior to surgery by administering hypertonic saline followed by rapid intravenous infusion of large volumes of isotonic saline. Prognosis is poor in cows with heart rate >100/minute and serum chloride <80mmolL due to sequestration of chloride ions in abomasum.
Describe abomasal ulcers in calves
In young calves (2-3 week old) this condition is likely to be complicated by secondary fungal infection of the ulcer as such cases have often received prolonged oral antibiotic treatment by the farmer. Oral electrolytes made up to 2 litres given 4 times daily will maintain the calf but the prognosis is poor for those cases which will not suck or eat within 3-4 days.
Describe abomasal ulcers in adult dairy cows?
Clinical signs include poor milk production in the early post partum period, weight loss and melena. Few cows bleed to death despite very low PCV values as low as 10%. In severely affected cows, emergency slaughter may be the best option. In less Severely affected cases supportive therapy including i/v fluids, kaolin and pectin, magnesium oxide have all been recommended but are ineffective. most cows recover over a period of several weeks.
What is abomasal impaction?
It is sometimes recognised during the winter months in beef cattle fed poor quality diets of wheat straw and liquid urea supplements only. pregnant suckler cows may suffer from this condition when on similar diets but the development of starvation ketosis and other metabolic disturbances assume greater importance. The animal is often in poor condition, slow, dull with a long dry winter coat and abdomen is often pear shaped. very scant hard balls of faeces with copious mucus in rectum. Very sluggish rumen. The rumen can easily be pitted. Ddx - inadequate diet/starvation, vagus indigestion, peritonitis. Treat with 250g sodium chloride in 25-50 L water by stomach tube. Multivitamins given IV. !6-24 L saline iv. Repeat treatment day 2 if necessary. 5-10 litres mineral oil or liqud paraffin.
Describe when hair balls occur in cattle?
May occur in association with heavy louse infestation. hair balls are a common coincidental finding at post mortem of young calves. Where blockage of the pylorus occurs there is an acute onset of abdominal pian, kicking at its belly, frequently getting up and down. auscultation reveals a fluid and gas filled viscus under considerable pressure in the lower right hand side of the abdomen. The role of hair balls in cases of ill thrift is uncertain - they may simply be result rather than a cause.
Describe caecal dilation and torsion?
Occurs in dairy cows fed restricted roughage and high levels of concentrates. also may occur following change of pasture. Incompletely fermented carbohydrate reaching the caecum is fermented and the resultant volatile fatty acids produced cause caecal atony. Decreased motility leads to dilation impaction and possible torsion. there is a drop in milk yield over several days and poor appetite. the animal shows tenesmus but there are scant faeces in the rectum. rumen activity is normal but the cow is drawn in. On rectal examination a 15-25 cm diameter cylindrical blind ended viscus is easily palpable extending into the pelvis. The caecum may kink on itself (retroflex) and therefore not be palpable on rectal exam.
What is the treatment of caecal torsion and dilation?
Rectal palpation of the blind end of the caecum extending into the pelvis is pathognomonic. Remission of the caecal dilation has been recorded following transportation to surgery facility. Access is achieved through a right flank laparotomy under distal paravertebral anaesthesia. exteriorisation and drainage through an incision made in the blind end of the caecum is a simple procedure. recovery of previous milk yield may take several weeks.
Describe umbilical hernias in cattle. When might they need treated?
Umbilical hernias less than 5cm diameter are of no consequences. Larger hernias frequently contain omentum and small intestine and are most commonly presented for cosmetic reasons in breeding heifers, strangulation of hernia sac contents is very uncommon in cattle. hernia rings greater than 10cms may require a mesh during closure. umbilical hernias can be readily distinguished from umbilical abscesses during clinical examination but occasionally both conditions can occur together when the extent of the infection can be determined ultrasonographically.
What is a patent urachus?
A tubular connection between the bladder and umbilicus which persists after birth with small quantitis of urine dribbled from the umbilicus. can be difficult to detect when there is concurrent omphalophlebitis/umbilical abscess and purulent discharge. clinical signs usually not detected until the urachus/bladder becomes infected or a urachal abscess and adhesions develop. More common in male calves. The condition may be overlooked and resolve with time.
Describe a calf with an infected patent urachus
Affected calves are poorly grown, intermittently febrile and may show pain on urination, they often have cystitis. urinalysis is helpful in the diagnosis - ascending infections of the urinary tract via the urethra are very uncommon in young ruminants. a corded structure up to 2cm in diameter may be felt on deep palpation extending from the umbilicus to the apex of the bladder but this is not always easy especially if there is considerable painful umbilical reaction. ultrasonographic findings may prove difficult to interpret. Do not mistake digesta in small intestine for infected urachus.
Which bacteria are most commonly isolated from urachal abscesses?
Trueperella pyogenes, streptococci, and staphylococci most commonly isolated therefore treatment with penicillin - excreted in urine for up to 4-6 weeks is indicated but the prognosis is poor. surgical resection is difficult because of adhesions to small intestine and possibly the bladder. Such surgery is often further complicated by umbilical infection. wound breakdown of resected umbilical lesions is not uncommon.
Describe the legislation in place for castration?
Calves, lambs and goat kids can be castrated by rubber ring 2 months of age by any method requires local anaesthetic and in lambs > 3 months of age requires anaesthetic. Pigs castrated > 7 days of age require an anaesthetic.
How can calves be castrated?
Calves can be castrated by rubber ring if applied <7 days of age. this is an efficient and safe technique if carried out at the correct age and requires no local anaestheetic. complications are limited to failure to apply ring properly leaving a rig calf. Illegal application of rings to older calves can lead to gangrenous ischaemia of scrotum and possibly tetanus.
Describe the open surgical castration of calves.
This is an act of veterinary surgery in calves > 2 months of age and requires an anaesthetic. Ideally carried out at 1-3 months of age but farmers often present beef calves for castration at 6+ months. Local anaesthesia is carried out by injection 3-5ml of procaine under the scrotal skin into the testicle. Lignocaine no longer licensed for food animal use. GA only considered for mature bulls or complicated cases. Combination of xylazine and ketamine suitable for field anaesthesia or deep sedation. Make large J shaped incision on lateral wall of scrotum over tensed testicle extending through vaginal tunic. Ensure incision extends into base of scrotum to llow adequate post op drainage. grasp testicle and separate vascular part of spermatic cord from non vascular epididymal ligament complex. Make several rotational turns of testicle to twist proximal cord and then wrap around forefinger before applying steady traction to cord to rupture vessels within abdomen. The ruptured vessels will recoil within the abdomen and cause haemostasis. If remnant of ductus deferens is hanging from base of scrotum it should be pulled distally and trimmed. spray scrotal wound with topical oxytetracycline. Some give post op penicillin. Unlike horses, tetanus anti toxin not routinely given.
What are the potential complications with open surgical castration?
Haemorrhage may be seen where the vascular portion of the cord is snapped off close to the testes. Avoid this by ensuring the cord is grasped as high up as possible before applying traction. The vascular cord can be grasped with a pair of clean artery forceps and pulled out of the scrotal neck before applying traction. In most cases a clot will form and the haemorrhage will be controlled. if b lood continues to run out in a steady stream then packing of the scrotum can be attempted. often develop a large scrotal haematoma/abscess which needs drained. gut tie is a rare complication of surgical castration of older calves - the remnant of the spermatic cord recoils into the abdomen and can become adherent to the abdominal wall or viscera causing slow onset mechanical obstruction of the bowel.
What are rig calves/ incomplete testicular descent?
Cryptorchid calves are occasionally presented for castration. If only one testicle is descended the calf should not be unilaterally castrated as the remaining testicle may descend at a later date and the bull calf become fertile leading to unexpected misalliance pregnancies. Cryptorchid calves should be left entire and reared as bulls. in some cases a partially descended testicle will be palpable in the inguinal area and can be removed with care. sedation/anaesthesia may be required to facilitate this surgery.
Describe bloodless castration with burdizzo.
Burdizzo castration is often carried out by stockmen and should be carried out before 2 months of age otherwise local anaesthetic is required. The technique involves pulling down on the testicles to get access to the neck of the scrotum. The burdizzo clamp is applied twice across each side of the spermatic cord taking care to stagger the position of crushing. the clamps cause crushing of the spermatic vessels which leads to ischemic necrosis of the testicles over the following weeks. Calves should be checked after 1-2 months to ensure the technique has been effective. Poor technique or using burdizzos that are not matched to size of calf can lead to partial castration leaving calves that may be sterile due to blockage of epididymis but continue to develop as bulls due to testosterone production from viable testicle. Subsequent surgical castration of these calves is difficult due to adhesions within the vaginal tunic and cord.
How should lambs and goat kits be castrated?
They should be castrated by rubber ring <7 days of age. Otherwise, the simplest method is to grasp the base of the scrotum with forceps and remove with a single cut. the testicle can then be grasped within their tunics and are removed with simple traction. in older lambs or adult sheep local or preferably GA (xylazine and ketamine) is required. closed or open castration with emasculation of the cord is preferred to reduce risk of haemorrhage. Ligatures can be applied before emasculation of the cord however this requires good surgical cleanliness. protection against tetanus s required and most sheep/goats are vaccinated with multivalent clostridial vaccines. post operative antibiotic and analgesia should be given following surgical castration of older lambs/goats. Drugs such as flunixin, ketoprofen and meloxicam are licensed for cattle and can be used under the cascade legislation for sheep/goats.
What is vasectomy? how is the surgery done?
Vasectomy is used as a technique to produce teaser rams and occasionally bulls and boars. The ram is positioned on its hind quarters or in dorsal recumbency following sedation (xylazine) and local anaesthesia or epidural. Local must be carefully injected subcutaneously in the site of incision over the spermatic cord without puncturing the cord as this will cause peri operative swelling/haematoma. General anaesthesia with pentobarbitone or xylazine/ketamine is preferred by some practitioners. An incision is made in the skin over the spermatic cord at the level of the Accessory teats. The spermatic cord is exteriorised following blunt dissection and the vas deferens localised medially within the spermatic cord between the thumb and index finger. the tunic is nicked with the scalpel blade and vas deferens freed from connective tissue, it is then ligated twice and the section between sutures is removed. The ligated ends of the vas deferens are incorporated into different fascial planes during closure to reduce possibility of re canalisation. The skin incision is closed with interrupted mattress suture. Sperm granulomas may develop but do not affect behaviour.
Describe the legislation in place for dehorning/disbuding?
Chemical cautery eg hornex paste can be applied <7days of age without need for anaesthetic however all methods of disbudding and dehorning in cattle of any age require an anaesthetic. disbudding/dehorning calves is not an act of veterinary surgery and can be carried out by trained stockpersons.
How can cattle be disbudded/dehorned?
ideally at 2-6 weeks when easily handled and horn bud still small. following a cornual nerve block using 2-4 ml procaine per side the bud is removed by red hot gas/electric disbuding iron. the bud should be totally removed by burning the surrounding tissue right down to the surface of the skull. the skull of the calf is thick in this area. topical antibiotic spray should be applied to the wound but is noot essential. haemorrhage is normally completely controlled by the cauterising effect of the disbudding iron though occasionally calves will rub the skull wounds. calves 1-3 months will develop horn buds that may be too large for removal with hot iron and these will require cutting with hoof shears or dehorning scoops prior to thermal cautery. At around 6 months dehorning shears or embryotomy wire will be required for horn removal. With both these techniques the horn must be cut level with the base of the skull, normally exposing the frontal sinus and ring of horn vessels. The cut ends of the cornual artery should be identified, clamped and pulled with artery forceps to assist haemostasis. When dehorning large beef calves add 3-4ml of 2% xylazine injection to a bottle of 100ml local anaesthetic. Giving this gives local analgesia plus mild sedation.
What complications may follow dehorning?
Haemorrhage from the nose is often seen immediately after dehorning older cattle and is simply due to blood running through the sinuses and draining into the nasal cavity. it is not a cause for concern. Rarely, fatal haemorrhage from cornual artery bleeding can occur following dehorning of large calves so calves should always be checked for spurters after dehorning and haemostasis. sinusitis is occasionally seen in older cattle after dehorning. cattle may appear dull and reluctant to feed at barriers and may have obvious purulent discharge from dehorning wound. treatment by reuglar flushing with dilute povidone iodine along with systemic antibiotics is normally effective and sinus trephination rarely needed.
Describe the disbudding of goat kids
Goat kids have a much larger area of horn bud relative to calves and the horn grows rapidly necessitating early disbudding <7 days old. ideally a short acting general is give (eg saffan or propofol) which can be supplemented by local anaesthetic. local anaesthesia of the horn bud requires blocking of the cornual branches of the lacrimal and infratrochlear nerves using a maximum of 1ml 2% lignocaine per kid to prevent toxicity. A red hot iron is applied briefly to the skull ensuring a large enough area of skin surrounding the bud is destroyed before gently scooping off the bud. NB the skull is much thinner than calves and overheating can cause brain damage so the iron must only be applied with gentle pressure for short periods only.
Describe umbilical hernias in calves
Umbilical hernia is a relatively common hereditary defect in holstein dairy calves. uncomplicated cases present as variable sized, soft, reducible swellings at the umbilicus. Most hernial rings are <5cm will normally cause no clinical problems and become insignificant as calves grow. Larger hernias may lea to problems as abomasum enters the hernial sac and forms local adhesions leading to motility problems. surgery indicated in larger hernias and when clinical problems develop. Surgery is carried out with the calf in dorsa recumbency following xylazine sedation and local. The sac is dissected free and returned into the abdominal cavity. Large umbilical hernias may require closure with polypropylene mesh implants though this may nto be economically viable in most cases.
Describe what can happen with complicated umbilical hernias in calves?
Umbilical hernias may be complicated by the presence of subcutaneous abscessation or infection of the umbilical vessel/urachal remnants. this will lead to painful, inflamed umbilical swelling that may be hard to reduce. there is often an intermittent purulent discharge from the umbilicus at the most ventral point of the hernia. ultrasound is useful for investigating the extent and type of infection present. simple subcutaneous abscesses will require lancing and drainage. Infection of the umbilical vein or urachus may require radical surgical excision via laparotomy before any hernial defect is repaired. Conservative treatment of calves with chronic purulent omphalophlebitis/urachitis with or without associated hernia, using systemic antibiotics is rarely successful and these calves often fail to thrive.
How should bull nose ringing be done?
All mature stock bulls should have nose rings inserted to aid handling and restraint. to insert a copper nose ring the bull must be restrained in a crush and a halter applied. light sedation with xylazine may be required in fractious bulls. local anaesthetic is injected with a fine needle into the nasal septum. the septum is punctured just cranial to the cartilaginous septum using a leather lunch or trocar before pushing the sharp end of the open ring through the defect. the ring is closed and the retaining screw is carefully tightened and snapped off flush. Rings smaller than 3 inches are rarely inserted as young bulls will quickly outgrow smaller rings.
How does infection with leptospira hardjo occur?
Infection follows bacterial penetration of mucous membranes/skin. In non immune lactating or pregnant animal rapid multiplication in uterus or udder followed by bacteraemia. BActeraemia persists for 6-9 days until humoral antibodies appear. leptospira can persist after initial bacteraemia in CNS, repro tract and kidneys. following acute infection renal shedding of leptospires in urine occurs after about 114 days and may persist for months or intermittent shedding may occurs for years. Pasteurisation will destroy any lepto excreted in milk. Following infection antibody titre may disappear but carrier state still exists.
What are the different routes of transmission of leptospira hardjo?
Infection arises frmo contact with infected urine or from water/pasture contaminated with urine. products of abortion also source of infection. most spread probably occurs in spring/summer at pasture. venereal transmission possible from bulls carrying lepto in accessory sex glands. Leptospira hardjo not carried by vermin/wildlife. sheep can carry and excrete leptospira hardjo. LEptospires do not tolerate drying, exposure to sunlight, ph <5.8 or extremes of temperature. pasture unlikely to remain infected for more than two months after animals are taken off it. Risk factors for lepto infection: open herd, shared bulls, mixed grazing with sheep, shared grazing/water courses.
What are the clinical syndromes of infection with leptospira hardjo?
- Milk drop - occurs 2-7 days after initial infection of non immune cow. sudden reduction or cessation of yield. may get thick colostrum like blood tinged milk in all quarters. udder goes soft and flabby. may be slightly lethargic/stiffness and anorexia with pyrexia.
- Abortion - abortion may occur 3-12 weeks following infection, most abortions occur in last trimester. may also get weak/premature calves born.
- Inferility - May cause embryonic death. venereal transmission possible. May not effect pregnancy as lepto killed by uterine defenses around oestrus. semen from AI stud bulls has streptomycin added. split herd vaccination trials show some evidence of overall improved fertility parameters.
How is diagnosis of leptospira hardjo made?
Microscopic agglutination test (MAT) used to detect antibodies to lepto hardjo in serum and more recently this is being replaced by an ELISA. problems in interpretation of serology with lepto infection in cattle. Carrier animals may have negative MAT test. False positives also occur. In acute infection paired serum samples taken 3-4 weeks apart will Normally demonstrate seroconversion. Maternal serology may be of limited use as serotitre may be high low or negative by time abortion occurs. in abortion outbreak, some aborted cows have MAT titres of > 1/400 then this is likely to be significant. ELISA titre likely to remain positive for much longer following infection. Antibodies in foetal fluids - may indicate exposure to lepto in utero after period of immunocompetence >4 months. foetus may die before mounting an immune response. fluorescent antibody test to detect lepto antigen in foetal tissues eg kidney, liver. Best test to confirm diagnosis of lept abortion but in practice labs seldom get positive results as delay in submitting samples.
What is the treatment of leptospira hardjo?
Streptomycin/dihydrotreptomycin single i/m dose of 25mg/kg will probably eliminate infection in most cases. This dose is higher than data sheet recommendations. oxytetracycline or amoxycillin also likely to be effective. antibiotic treatment may still leave carrier state in some cattle. Antibiotic treatment of clinical milk drop case indicated to reduce excretion and zoonotic risk.
Describe the control/preevention of lepto hardjo?
Combination of management decisions to reuce risk of infection, antibiotic treatment and vaccination. two killed, adjuvanted vaccines available in the UK. primary course of immunisation consists of two injections 4 weeks apart followed by annual boosting. vaccinal MAT titres may fall to low levels within 3-4 months but are not correlated to protective immunity. ELISA test detects vaccinal antibodies for up to a year or more. vaccination should prevent urine shedding following exposure and will protect against milk drop and abortion. In some herds which have been fully vaccinated for several years there may still be renal carriers of infection so cessation of vaccination may lead to reappearance of clinical disease.
Describe different control strategies for control of leptospira Hardjo.
- Closed herd - no evidence of previous infection - avoid mixed grazing with sheep and fields with shared water courses. any additions to breeding herd including bulls should be isolated for 3 weeks and treated with streptomycin 25/mg/kg twice 10-14 days apart. 2. herd experiencing acute infection for first time - milk drop, abortions etc - consider whole herd antibiotic treatment to reduce risk of spread of infection and zoonotic risk. start vaccination programme for whole herd. bought in replacements should be vaccinated before entry. 3. Herd with evidence of endemic infection from herd screening or abortion serology etc - decision must be made on economic/ COSHH grounds whether vaccination worthwhile. if herd vaccination started should continue annual booster for whole herd. heifers should complete vaccination course before first mating.
Describe the key points regarding leptospira hardjo blood tests, source of infection and vaccinations.
Blood tests cannot be used to classify individuals as infected or non infected. seronegative animals may be infected and seropositive animals may have overcome their infection. Serology if of value in assessing the status of a herd or in the diagnosis of acute infection. The commonest source of infection is the purcahse or hire of an infected animal or contact with infected animals on common grazing. Vermin or other wildlife species play no part in spreading L hardjo infection. Clinical disease may only be apparent when infected first enters a herd. herds may be chronically infected without apparent diseaese. Vaccination can prevent clinical disease (abortions and milk drop) but may not eradicate infection. The COSHH regulations cover exposure to infected urine or uterine discharges. the regulations require a herd owner to ensure that his employees are informed of the potential risks from L hardjo and offer protection from infection risk. for this reason many dairy herds are vaccinated.
Describe the epidemiology of Malignant catarrhal fever?
A herpeves virus (ovine herpes virus 2) which has not been fully characterised but is sheep associated. Sheep appear to be most likely reservoir of infection. MCF is a relatively sporadic disease affecting cattle and deer. it is unusual to see more than one case on a single farm over a long time period. Contact with sheep or goats around lambing seems to be necessary for transmission to cattle. method of transmission unknown. May occur months after contact with sheep suggesting prolonged incubation or latent infection. virus is very fragile and will not survive more than a day outside the carrier host. Cattle are dead end hosts and don’t transmit MCF.
What are the clinical signs of MCF?
Acute onset illness with depression, anorexia and pyrexia. other characteristic signs include intense scleral congestion, erosive stomatitis of the buccal mucosa and muzzle, profuse muco purulent occulo nasal discharge, leads to stertor, generalised superficial lymph node enlargement, muscle tremors, hyperaesthesia, incoordination, head pressing, generalised exudative dermatitis, diarrhoea.
How is diagnosis of MCF made?
History of sheep contact and characteristic clinical signs (CNS signs rare with any other mucosal disease). Widespread vasculitis on PM. Diff diagnosis are IBR, BVD, BTS, VSV, FMD. Serological test available for MCF antibodies but this test may not be positive at the time of initial clinical signs. demonstration of viral genome in blood.
What is the treatment of MCF?
No treatment indicated in MCF as mortality is close to 100%. high doses of corticosteroids given systemically may give temporary improvement of clinical signs. death normally occurs 5-10 days after onset of clinical signs. Euthanasia on humane grounds should be recommended. occasionally an MCF case survives the acute disease to either recover or become chronic. Chronic MCF cases may show apparent temporary recovery but often relapse and rarely survive. control relies on avoiding contact with sheep.
Describe the aetiology of sporadic bovine leukosis (lymphosarcoma)
The cause of sporadic lymphosarcoma is unknown and affected cattle are seronegative for EBLvirus (enzootic bovine leukosis) caused by a retrovirus is a notifiable disease and currently not present in the UK. The disease is rare and sporadic in cattle and appearsin 3 main forms - juvenile, thymic and skin forms although a more generalised multicentric form can be seen.
Describe the juvenile form of sporadic bovine leukosis
occurs in calves aged 2weeks to 6 months. this form is characterised by generalised enlargement of all lymph nodes. superficial LNs are visible from a distance in some cases. gradual weight loss, depression and other signs related to tumour masses in thorax and abdomen. death inevitable after a variable length of illness.
Describe the thymic form of sporadic bovine leukosis
Occurs in older cattle typically 1-2 years of age. characterised by massive enlargement of thymus and local LNs. Thymic mass causes jugular engorgement, oedema of brisket extending to submandibular region and chronic bloat due to oesophageal compression. gradual weight loss and death.
Describe the skin form of sporadic bovine leukosis.
Normally in cattle <3 yo. cutaneous plaques of varying size appear over the neck, back, flank and thighs. lesions can develop rapidly, become covered in a necrotic pale scab and then may regress. peripheral LNs are also enlarged. recurrence of lesions is likely and often will be associated with tumours developing elsewhere eg meninges, heart, abomasum, spleen. weight loss and death related to pathology in internal organs.
How is diagnosis of sporadic bovine leukosis made?
Diagnosis of sporadic lymphosarcoma is normally made on clinical signs and post mortem. cattle showing signs of generalised lymphosarcoma should be reported to loal animal health office who may request serology for EBL. There is no serological test for sporadic leukosis as the aetiology is unknown. Biopsy of peripheral LNs or skin lesions is useful. post mortem findings depend on the form of disease but in addition to LNs, tumour masses can be found in a wide variety of organs including heart, abomasum, liver, spleen and CNS.
Describe bovine viral diarrhoea virus? What are the two distinct bioptypes?
It is a pestivirus closely related to viruses causing border disease BD in sheep and classical swine fever in pigs. Two distinct forms distinguished by effects on cell culture: cytopathic and non cytopathic (ncp). >9% of uk dairy herds have exposure to BVD and 40% of scottish beef herds show evidence of active infection. Viraemic animals shed virus in nasopharyngeal secretions, urine, aerosol droplets. faeces not a major source of virus excretion. Main transmission is by contact with viraemic animal. Sheep and deer can also act as vectors. Can also be transmitted in fresh or frozen semen of infected bulls.
What are the clinical signs of acute BVD infection?
it is seen when previous unexposed antibody negative animal becomes exposed to non cytoopathic BVD virus. Following transient viraemia the animal seroconverts within 3-4 weeks and may remain antibody posivie for years. Many acute infections are subclinical. signs: pyrexia, leucopaenia, dullness, oral/nasal erosions which quickly heal, transient scour, milk drop. Most affected animals recover uneventfully. May temporarily lower immunity to other infectious diseases eg salmonella, IBR, RSV, coccidia.
Describe the different sequelae to acute BDVD infection?
In a non pregnant animal - clinical recovery followed by seroconversion and long standing immunity.
Pregnant animal - acute BVD infection during pregnancy in naive cow/heifer can cause various problems associated with transplacental infection of the foetus in utero. Depending on the stage of pregnancy can get: embryonic death, foetal death/abortion, mummmification, congenital defects of CNS and eyes, weak /premature calves, live persistently viraemic calves or live normal seropositive calves.
Describe BVD infection in a pregnant animal <120 days of gestation
May lead to birth of live persistently infected PI calf. this is caused by failure of the foetus to recognise virus as foreign due to immune system not being fully functional. <120 days immunotolerant. PI calves are born viraemic and remain so, acting as potent transmitters of BVDV infection.
Describe what occurs when a pregnant animal 90-150 days of gestation is infected with BVD?
May lead to congenital abnormalities forming catarats, retinal dysplasia, cerebellar hypoplasia, CNS dysmelination, cerebral cavitation etc. These calves may be born showing ataxia, blindness and are normally antibody positive if sampled before sucking colostrum.
What happens if a pregnant animal is infected >150 days of gestation with BVD
Infection >150 days gestation often gives live seropositive calves born at full term. Abortion can occur following infection at any stage of pregnancy but is not common. Colostrally derived antibodies normally disappear in calves by 6 months but can persist for as long as one year.
What is mucosal disease?
Can only occur in animas which have been born persistently viraemic following in utero exposure to Ncp BVD in early pregnancy. Mucosal disease occurs when PI animal becomes superinfected with CpBVD virus. The CpBVD virus can arise from genetic assortment of the NcpBVD virus within the PI anima, from transfer of genetic material from a heterologous strain to the NcpBVD strain or can arise as an entirely new strain. most cases occur in 6 month to 2 year age group which may coincide with the waning of passive immunity. Most PI animals die within the first two years of life but a few can survive until much older. PIs are a main source of virus for transmission of disease.
What are the clinical signs of mucosal disease?
Acute onset depresison, pyrexia, anorexia. Salivation around muzzle, widespread oral /nasal erosions/ulcers especially on hard palate, gums, dental pad. often mucopurulent nasal discharge. profuse diarrhoea/dysentry with shreds of gut mucosa/blood present in terminal stages. May be interdigital skin erosions/ulcers present and occasionally dermatitis. Rapid weight loss and death within 5-10 days.
How is diagnosis of BVD/ mucosal disease madE?
Acute BVD infection - paired acute/convalescent sera 3-4 weeks apart to demonstrate rising titre (ELISA test), hard to interpret in calves< 6mo as maternally derived antibodies still present.
Mucosal disease - Characteristic pm findings - virus isolation from p.m tissues. Take blood sample and test for antibody/antigen. Normally antibody negative, antigen positive on ELISA test. may be low antibody titre along with virus positive due to persistent maternally derived antibodies.
3. Persistent infection - PI calves can often be clinically normal before developing mucosal disease but may commonly be presented as chronic ill thriven or stunted calves. can confirm PI status testing tissue or blood for persistent viraemia. Ear notch testing can be done at any age. IDEXX BVDV serum antigen test used by some labs accurately detects PI calves from 1 month of age in the presence of maternal antibodies. Take two samples 3-4 weeks apart to confirm persistent virus positive status. Newborn calves can also be tested for virus status if sampled before suckling coostrum. Herd screening - to establish BVD status of herd - monitor BVD free herds. Bulk milk and or first lactation screens (dairy only).
What is the treatment of BVD?
Acute BDV - symptomatic supportive treatment for enteritis.
Mucosal disease - no effective treatment, will invariably die.
Persistent infection - PI animals should be disposed of as they act as a source of infection. if old enough can attempt salvage slaughter if symptomless.
Is BVD a cause of infertility in bulls?
BVD virus can be spread in semen of PI bulls or in bulls experiencing acute BVD with transient viraemia. will lead to low pregnancy rate due to embryonic death or later foetal death/abortion. occasionally infected semen can cause conception and birth of Live PI calf. bulls are tested for BVD before entering AI studs.
What are the different control options for BVD?
Do nothing - many herds are endemically infected with BVD and disease is partly controlled by PI calves acting as vaccinators of herd. when most adult animals in herd seropositive then disease losses not so obvious to farmer. Not ideal as ongoing losses likely especially if naive breeding females introduced. Vaccination - 2 inactivated BVD vaccines now available in the UK. initial vaccination 2 doses 3-4 weeks apart before first service followed by boosters at 6 or 12 month intervals, depending on the vaccine used. if all breeding females are vaccinated then this should control disease by preventing acute BVD and production of PI calves. Eradication - BVD eradication is possible following whole herd blood testing and elimination of PI carrier animals. if farmers go for eradication then strict herd biosecurity measures must be maintained to prevent re introduction of disease as herd will soon become naive. scotland is in process of eradicating BVD.
What is bovine neonatal pancytopaenia?
It affects calves, causes bleeding from intact skin, injection sites, tagging sites, nose and rectum. Destruction of bone marrow causes pancyotpaenia. Can be associated with use of pregsure BVD vaccine. Rare.
What is necrotic enteritis in beef suckler calves?
This disease is seen almost exclusively in spring born suckled calves and normally affects calves in 2-4 month old age goup. Most cases are seen at pasture in june/july. The morbidity is usually low but mortality rates in affected calves are high. disease often recurs in same herd in successive years. common clinical signs are depression and pyrexia in acute stages, diarrhoea often profuse and haemorrhagic then progressing to more scant muco haemorrhagic faeces, tenesmus and abdominal pain, respiratory signs, pale mucous membranes due to anaemia, occasional oral and nasal ulcers.
What are the typical clinical chemistry and gross pathology signs in necrotic enteritis?
Anaemia and leucopaenia caused by a severe non regenerative neutropenia. cases exhibiting profound neutropenia carry a poor prognosis. many affected calves have high blood urea levels associated with kidney pathology. The gross pathology - crusting of the nasal mucosa with oral ulceration, oral ulcers often restricted to hard palate, ulcers often overlaid by necrotic debris and secondary fungal infection can be seen in the larynx rumen abomasum and small intestines. the ileum caecum and colon are the areas of the intestinal tract most commonly affected with lesions sometimes extending as far as the rectum. the ulcerative lesions vary frmo small discrete punctate lesions to large linear diptheritic placques overlying peyers patches. The ulcers are often full thickness. Kidneys appear swollen and pale with infarcts present. Lung lesions typical of inhalation pneumonia often seen in association with severe pharyngeal and laryngeal ulcerative lesions. Aetiology remains unclear. Treatment symptomatic and give sulphonamides and fluid therapy.
What is salmonellosis? Which animals does it mainly affect?
Salmonellosis is mainly a problem of young calves but any age group can be affected. outbreaks in adult dairy beef and cows are not infrequent. S. typhimurium and S dublin are the most common serotypes causing disease in UK cattle. S dublin most common.
Describe infection of salmonellosis?
Faecal oral infection is the most common route of infection. S. Dublin Infection normally arises from exposure to infected purchased animal or from carrier animals in herd. In infected herds cows can become symptomless carriers and excrete at times of stress. Liver fluke damage can predispose cows to excrete, as S dublin will persist in gall bladder/bile ducts. S typhimurium infection normally arises due to contact with infected purchased animal particularly if passed through markets or via contaminated feed stuffs, pasture or water courses. Most outbreaks of salmonellosis occur in winter months.
What are the clinical signs of salmonellosis in calves?
Very variable in severity depending on age and immunity, virulence and infecting dose, concurrent disease. often 2-6 week old calves affected. Can be acute septicaemia and death with either serotype. S. dublin may cause pneumonia. Commonly dull, anorexic, pyrexic and have pasty faeces with blood present. Develop more watery foul smelling diarrhoea with shreds of gut lining passed (s. typhimurium). progressive dehydration with tucked up abdomen. High morbidity and mortality can be >60%. Calves that survive can go on to develop chronic ill thrift due to polyarthritis/physitis due to initial septicaemic episode. Extremities may slough following septicaemia.
What are the clinical signs of salmonella infection in adult cattle?
Salmonella infection causes enteritis and septicaemia often with abortion if infection occurs in late pregnancy or shedding of the causative organism into milk. S dublin can cause abortion with no signs of enteritis/septicaemia. Severity of clinical signs in outbreak varies considerably in adults. most severe in stressed groups of animals eg newly calved dairy cows, cows in poor body condition, cows in late pregnancy etc. concurrent disease eg BVDV will increase severity. main signs: acute enteritis/dysentery often blood and shreds of mucosa, pyrexia, acute milk drop it lactating, depression/anorexia, septicaemia/dehydration, abortion followed by septic metritis in some cases. Morbidity variable 10-70% depending on virulence of serotype, dose of inoculum, degree of immunity, concurrent stress etc. mortality variable as above. some strains more pathogenic than others.
What is the treatment of salmonellosis?
Isolate affected animals if possible to limit spread. Systemic antibiotics - controversial. Efficacy dubious in adult cattle and may prolong excretion if used at insufficient doses. Also potential for emergence of resistant strains. prompt treatment of calves during outbreak may prevent septicaemia and sequelae and clinical impressions suggest a shorter course of disease with higher recovery rate. must check strain sensitivity in vitro as multiple resistance to commonly used antibiotics is widespread. Enrofloxacin, apramycin, florfenicol and clavulanate potentiated amoxycillin are normally effective in vitro. Supportive treatment - NSAIDs, oral or iv fluids, nursing. control of herd outbreak by personal hygiene, raw milk not consumed, isolation pens, do not share feed buckets, foot dips etc.
How can salmonella be prevented on farm?
Avoid introducing infected animals: maintain a closed herd quarantine introduced stock for 4 weeks, source new stock from other farms not dealers, avoid shared bulls and communal grazing. Isolate sick animals with dedicatioon isolation boxes. Practice disease security - clean and disinfect buildings between occupancies, provide good drainage and waste removal, maintain good fences to prevent access of neighbouring stock, protect feed stores from vermin including birds, avoid contamination of water sources, only spread slurry on arable land, leave grazing land at least 3 weeks after spreading slurry, insist visitors have clean boots, consider vaccination.
What is winter dysentery?
An acute highly contagious diarrhoea that occurs in epizootic fashion in a herd in winter housing period. disease spreads by the faecal oral route. Importance because of production losses. Bovine coronavirus has been demonstrated in the faeces and colonic epithelium of affected cattle and the disease has been reproduced experimentally in susceptible adult cows by exposure to coronavirus isolated from calves.
