Farm animals 2 Flashcards
1
Q
Describe the sitting examination of the genitalia for the breeding soundness examination of a ram
A
- Must sit squarely to fully extreude penis
- Examine inner thighs for flush
- Check for vasectomy scars
- Examine prepuce for injuries, ulcers, deformities
- Examine glands and vermiform appendage for injuries, ulcers etc. and to prove penis can be fully extended
2
Q
Explain the role of chorioptic mange in infertility of rams
A
- May cause inflammation of the scrotum
- Increases local temperature, causes damage to sperm
3
Q
What is required for an infertility investigation of a ram?
A
- Full breeding soundness examination
- Semen evaluation
- Ultrasound examination
4
Q
What certification would be appropriate for the following findings in an infertility examination of a ram?
- General physical exam: normal
- External genitalia normal and scrotal circumference acceptable
- Good semen sample produced
A
Ram can be used with confidence
5
Q
What certification would be appropriate for the following findings in an infertility examination of a ram?
- General physical exam: abnormal but minor/curable
- External genitalia abnormal but minor/curable
- No/poor semen sample produced
A
Not able to decide at this examination
6
Q
What certification would be appropriate for the following findings in an infertility examination of a ram?
- General physical exam: abnormal and not suitable for breeding
- External genitalia abnormal
- Poor semen sample produced
A
Ram is not suitable for breeding
7
Q
Discuss the value of a semen sample for infertility investigation of a ram
A
- Single sample not always representative of the state of the ram
- Do not condemn ram based on semen sampling alone, some do not want to give sample
8
Q
What is the potential outcome for a ram that is deemed not perfect but still fertile?
A
- Can’t afford to cull all of these, but not suited o high pressure situations
- May be ok with low ewe numbers, or in mating groups
9
Q
What scenarios are appropriate for a ram deemed perfect at fertility examination?
A
Good for high pressure situations so can be used for single sire mating, or with large numbers/synchronised ewes
10
Q
Which rams are predisposed to urolithiasis?
A
Mainly fattening wethers or young rams
11
Q
Describe the development of urolithiasis in rams
A
- Precipitation of insoluble salts of Mg, NH4 and phosphates
- Form sludge with protein in urinary tract
12
Q
Outline the clinical signs of urolithiasis in rams
A
- Abdominal pain and anorexia
- teeth grinding, bleating
- Stranguria/anuria
- Crystals around preputial orifice
- Swollen prepuce
- Wide based stance, HL back, frequent stretching
13
Q
Where does urolithiasis most commonly occur in rams?
A
Either at ischial arch or vermiform appendage
14
Q
What is a potential consequence of urolithiasis in rams?
A
- Bladder rarely ruptures, but urine leaks out into peritoneum
- Hydronephrosis of right kidney
15
Q
Outline the risk factors for urolithiasis in rams
A
- High concentrate feeding (high P availability e.g. feeding on ewe cake)
- Low forage intake
- High P or Mg in diet
- ow ratio of Ca:P (increases P absorption)
- Low water intake
- Texels predisposed
16
Q
Outline the treatment options for urolithiasis in rams
A
- Encourage lots of drinking
- Muscle relaxants
- Retrograde catheterisation
- Excision of vermiform appendage
- Surgery rarely useful as salvage
- Consider NH4Cl/NaCl in feed (encourage drinking)
17
Q
Discuss the preventionof urolithiasis in rams
A
- Feed less concentrate, more forage
- Ensure adequate water intake
- Feed low P, low Mg
- Ensure ratio of Ca:P at least 2:1, preferably 3:1
- Include 1.5% salt in diet to increase water intake (total Na content 6g/kg DM)
- Include 1.5% NH4Cl in diet to acidify urine
18
Q
What is balanoposthitis in the ram also known as?
A
Pizzle rot, sheath rot, ulcerative balanitis, ulcerative posthitis
19
Q
Describe the cause balanoposthitis in rams
A
- Corynebacterium renale, and high dietary protein
- C renale produces urease which hydrolyses urea to ammonia
20
Q
Which group of rams are predisposed to balanoposthitis and why?
A
Wethers - penis less developed, more likely to urinate into prepuce, fed on high protein
21
Q
Describe the clinical signs of balanoposthitis
A
- Small necrotic ulcers at sheath margin initially
- Painful, swollen sheath
- Strong smell of ammonia
- Sheep recumebnt and inappetant
- Increased risk of fly strike
22
Q
Outline the treatment and control of balanoposthitis in rams
A
- Reduce protein in diet
- reduce feed intake, increase water intake
- Acidify urine using NH4Cl per os
- Give topical antiseptc and systemic antibiotics
23
Q
Describe the relationship between balanoposthitis and vulvovaginitis in sheep
A
- Reports of vulvovaginitis in ewes associated with Myoplasma
- Balanitis of unknown aetiology (deep ulcer on glans penis) associated with vulvitis (ulcers and oedema) in ewes after mating
- Little effect on fertility
24
Q
What non-hormonal method may be used to synchronise and advance breeding season of ewes?
A
The ram effect - introduce rams just before natural breeding season
25
How can the synchonicity resulting from the ram effect be improved?
Treat with progesterone before, or at time of introduction of rams
26
What commercially available pharmaceutical options are available for advancing the breeding season of ewes?
- Progestagen based methods alone e.g. sponges
- Progestagen based methods with follicle stimulating treatment e.g. PMSG/eCG
- Melatonin implants
27
Discuss the advantages of melatonin implants for the induction and synchronisation of oestrus in ewes
- Low labour pressure
- Reduces spread of oestrus
- Low pressure on rams
- Triggers natural hormonal events giving multiple fertile cycles
28
Discuss the disadvantages of melatonin implants for the induction and synchronisation of oestrus in ewes
- No ovulation synchronisation or induction
- No effect on prolificacy
- Cannot be used for fixed time AI
- Cost
- Need to plan well in advance
29
Discuss the advantages of progesterone sponges alone for the induction and synchronisation of oestrus and ovulation in ewes
- Only moderate increase in labour pressure
- Oestrus and ovulation synchronised
- Will advance breeding season
- Potential to improve porlificacy
30
Discuss the disadvantages of progesterone sponges alone for the induction and synchronisation of oestrus and ovulation in ewes
- High pressure on rams
- If used off season, may have lower prolificacy
- Cannot be used for fixed time insemination
- Cost
31
Discuss the advantages of progesterone sponges + PMSG injection for the induction and synchronisation of oestrus and ovulation in ewes
- Synchronise and induce ovulation
- Basal or enhanced prolificacy
- Can be used for fixed time insemination
32
Discuss the disadvantages of progesterone sponges + PMSG injection for the induction and synchronisation of oestrus and ovulation in ewes
- High labour intensiveness
- High pressure on rams
- Potential for too many multiples if over estimate PMSG dose
33
Discuss the use of Ovsynch in sheep
- Off license in UK
- Usually disappointing results
- No efficacy out of seasons, poor oestrus expression in sheep, labour intensive
34
What are the challenges faced when aiming to breed sheep early before/in the season?
- No previous luteal phase so no P priming
- Possible lower ovulation rate
- Ram's fertility not yet at its peak
35
Briefly outline the method of using melatonin implants in sheep
- Rams in flock injected with 3 melatonin implants at base of ear
- Separate rams from ewes
- 7 days later, ewes in flock treated with single implant at base of ear
- Rams introduced to ewe 40 days after melatonin implantation in females
36
How long are progestagen sponges generally inserted in ewes for?
12-14 days, 14 days if used during breeding season
37
What should the ram:ewe ratio be following induction of oestruc and ovulation with progestagen sponges and eCG?
- In season 1:10
| - Out of season 1:5
38
Following abortion in sheep, what material should be sent for analysis?
- Ideally foetus + placenta
Otherwise:
- Section of placenta incl. more than 1 cotyledon, with large margins of intercotyledonary membranes
- Foetal fluid from thorax or abdomen
- Foetal stomach contents collected aseptically
- Fresh spleen
39
What flock information is required as part of the history when investigating abortions in a sheep flock
- No. of ewes, type of flock
- Expected lambing dates
- Ewes housed for lambing? If so, when
- Diet and how much
- Closed or open flock? Where if buy in
- Previous abortions
- Vaccinations
- Ultrasound scanning data if available
- Recent handling or transportation of ewes
40
What abortion specific information is required as part of the history when investigating abortions in a sheep flock?
- Number of abortions
- Dates of abortions so far
- Clinical status of aborted ewes
- Age of ewes aborting
- Ewes homebred or bought in
- Appearance of aborted lambs
- Isolation of aborted ewes from ewes yet to lamb?
41
Outline the steps that should be taken following abortion in sheep
- Isolate aborted ewe, dispose of abortion products and bedding, disinfect pen/area
- Initiate antibiotic therapy if ill ewe, or RFM
- Do not foster lambs onto aborted ewe
- Mark ewes for maangemetn purposes
- Submit material for investigation
- Emphasise to farmer need for hygiene and zoonotic risk
42
What are the 3 most significant causes of abortion in sheep in the UK?
- Enzootic abortion of ewes (Chalmydophila)
- Toxoplasmosis
- Campylobacteriosis
43
How is Chlamydophila infection spread in sheep?
Oral transmission
44
Explain the pathophysiology of EAE
- Organism invades placenta at 90days gestation → suppurative necrotising placentitis
45
When do abortions with EAE typically occur?
Last 3 weeks of pregnancy
46
Describe the clinical status of the ewe following abortion as a result of EAE
Vague malaise for 24 hours but not identifiably sick
47
Describe the typical appearance of the placenta in an abortion resulting from EAE
- Thickened areas between cotyledons
| - Typical brownish exudate over surface
48
How is EAE diagnosed?
- Examination of fresh placenta
- Ziehl-Neelsen staining showing red elementary bodies
- Vaginal swabs/swabs from coat if obvious necrotic debris present
- Histopath: inflammatory infiltrate, intracytoplasmic inclusions in chorionic epithelial cells-
49
What test forms the basis of health accreditation schemes for EAE?
Serological testing
50
Outline the control of EAE
- 3 vaccines possible
- 2 live: use in non-pregnant
- 1 inactivated: use in face out outbreak, can be given to pregnent to reduce chance of abortion
- Whole flock treatment of long acting oxytet 20mg/kg 3-6 weeks before lambing increase no. of viable lambs born to ewes with known infection
- Mark, isolate affected, dispose of bedding
51
What is the source of infection for toxoplasmosis in sheep?
Cats - shed oocysts then ingested on feed/in water by sheep
52
Explain the pathogenesis of toxoplasmosis in sheep as a cause of abortion
Tachyzoites invade placenta → placentitis, pyrexia
53
What are the potential consequences of infectionwith Toxoplasma gondii in sheep during pregnancy? What is the outcome dependent on?
- Resorption
- Barrenness
- Mummification
- Stillbirth
- Abortion
- Live lamb
- Depends stage of gestation and infective dose
54
Describe the typical appearance of the placenta in an abortion resulting from toxoplasmosis in sheep
- Dark cotyledons, white speckles of necrosis
- Sectioning cotyledons reveals gritty texture if necrotic foci have mineralised
- Intercotyledonary areas grossly normal
55
What foetal appearance is suggestive of abortion as a result of toxoplasmosis in sheep?
8-10cm mummified foetus, dark brown leathery appearance
56
Describe the diagnosis of toxoplasmosis abortion in sheep
- IFAT on fluid from foetal thorax/abdomen
- Histopath of placenta: coagulative necrosis of cotyledons, mineralisation fo haematoxylin, eosin secretions
- Neuropathology: non-suppurative meningoencephalitis
- IHC possible on formalin fixed paraffin embedded tissue to demonstrate antigen even if autolysis
57
Discuss the control of toxoplasmosis abortion in sheep
- Prevent access to feed by cats
- Vaccine (toxovax), lasts 18mo but natural infection boost immunity, give to non-pregnant ewes at least 3 weeks before tupping
- In feed decoquinate 2mg/kg possible, but generally only fed in last 4-6 weeks so may not prevent infection
58
How is campylobacteriosis spread in sheep?
- Carrier sheep
| - Contaminated feed and water
59
When does abortion as a result of campylobacteriosis occur in sheep?
Last 6 weeks of gestation
60
Describe the typical presentation for campylobacter abortion in sheep
- Abortion storms up to 20%, last 6 weeks of gestatoin
- Birth of live weak lambs possible
- Occasionally mild diarrhoea in ewes before abortion
- Usually occurs in waves every 4-5 years
61
When does abortion typically occur in relation to infection with campylobacter species?
7-25 days after infection
62
Which campylobacter species are implicated as causing abortion in sheep?
C foetus and C jejuni
63
Outline the diagnosis of campylobacter as a cause of abortion in sheep?
- Gram smears of placenta and foetal stomach to demonstrate Campylobacter species
- IHC if smears not diagnostic (useful where autolysis, or scavenged tissues_
64
Outline the prevention and control of campylobacteriosis abortion in sheep
- Vaccines not available in UK
- Isolate aborted ewes in outbreak, careful disposal of material and contaminated bedding vital
- Remove susceptible animals from suspected areas, reduce stocking density
65
Explain how abortion storms occur with Campylobacter
- One sheep aborts due to Campy, highly infections 2-3 weeks later
- Pregnant ewe picks this up, aborts in next 1-3 weeks
- More and more sheep infected each time
66
Give examples of Salmonella species that are important in abortion in sheep
S enterica subspp. Montevideo, Dublin, Derby, Diarisonae, Abortusovis, Typhimurium
67
What is the source/route of infection for salmonellosis leading to abortion in sheep
- Mechanical spread by wild birds possible
- Abortion material heavily contaminated, bacteria excreted in faeces contaminated feed/water/pastures
- If host specific serotype then carrier sheep
68
Describe the clinical signs of salmonellosis abortion in sheep
- Abortion storms
- Aborted foetuses and placenta usually fresh with no lesions
- Ewes that die of salmonellosis have acute metritis with RFM
- Stillborn or dead within first week lambs have acute abomasitis and enteritis
69
Compare the clinical appearance of different serotypes of salmonella causing abortion in sheep
- Montevideo: little ill health
- Typhimurium and dublin: enteric and systemic signs (anorexia, diarrhoea, sudden death due to septicaemia, illness in farm workers, farm dogs and other livestock)
- Abortusovis rare in UK, occasional deaths in ewes and lambs up to 3 weeks old, at first infection up to 60% of flock abort
70
Outline the diagnosis of salmonellosis abortion in sheep
- Culture (MacConkey agar) in lab and smears
- Can use enrichment agar
- Serotyping to specify
71
Outline the prevention and control of salmonellosis abortion in sheep
- Cattle Dublin and Typhimurium vacc used off license in outbreak esp. if prolonged lambing period (2-3 injection 10 days apart)
- Isolate affected animals
- Antibiotics for septicaemic animals
- anecdotal evidence that long acting oxytet 7 days apart may reduce incidence of disease in Montevideo outbreak
72
What is the source of infection for Border disease in sheep?
Purchase of persistently infected replacements
73
Describe the clinical signs seen with border disease abortion in sheep
- Barren ewes
- Still births
- Abortions
- PI lambs
- PI lambs ill at 6-12 months
- Outcome dependent on stage of gestation at infection
- If non-pregnant usually inapparent infection
74
Outline the consequences of pestivirus infection in early pregnancy in sheep (<60 days)
- Foetal death → resorption, mummification, abortion or still birth
- Some survive → hairy shaker (wool changes, tremors, domed skull, abnormal appendicular skeleton)
- NB will not always show typical signs, may just have poor growth
75
Outline the consequences of pestivirus infection in late pregnancy in sheep (>85 days)
- Foetus immunocompetent
- Some die → abortion/stillbirth
- Most survive and have antibodies
76
Outline the consequences of pestivirus infection in middle of pregnancy in sheep (60-85 days)
- Outcome difficult to predict
- Immune system developing
- Can lead to immune mediated damage esp. in CNS
- Usually strongly antibody positive
77
Outline the diagnosis of border disease in sheep
- PCR or virus isolation from foetal tissue e.g. spleen
- Histopath esp. of brain
- Procolostral heparin blood samples for antibodies and antigens (ELISA)
- Serological testing of proportion of ewes (e.g. 10%) to assess presence of disease
78
What is a typical antigen and antibody profile of dams of hairy shaker lambs?
- Antibody negative
| - Antigen positive - persistently infected
79
Outline the prevention and control of border disease in sheep
- Closed flock or test all replacements
- Test rams for AI routinely
- Do not co-graze or mix pregnant ewes with cattle
- Cull all newborn PIs
- If buy in PI, maintain in close contact (indoors) for 2 months before tupping to expose all naiive animals when not pregnant, and allow seroconversion
80
Which Listeria species are associated with abortion in sheep?
Monocytogenes and ivanovii
81
What is the source of infection for listeriosis abortion in sheep?
Soil, decaying vegetation, latent carrier
82
Describe the typical presentation of listeriosis abortion in sheep
- Several disease manifestations: septicaemia, encephalitis, abomasitis, typhlocolitis, abortion
- Abortion at any stage of pregnancy, 7 days after infection
- Aborting ewes rarely unwell
83
Describe the typical appearance of aborted material as a result of listeriosis
- Autolysed
- Few lesions
- Occasionally: tiny miliary yellow white foci seen in liver of aborted foetus, circular erosions in abomasum, enlargement of mesenteric LNs
84
Outline the diagnosis of listeriosis abortion in sheep
- Smears of foetal stomach contents
| - Culture from placenta and foetal stomach contents
85
Outline the prevention and control of listeriosis abortion in sheep
- Treatment of in contact ewes in face out an outbreak to reduce losses
- Identify likely source of infection, feed good silage, remove uneaten silage daily
86
What is the causative pathogen of Q fever?
Coxiella burnetti
87
What is the source of infection with Q fever?
- Infected via oropharynx
| - C burnetii forms spores that persist in environment, and can persist in ticks
88
Describe the typical presentation for abortions resulting from C burnetii in sheep
- Last week of pregnancy
- Possible stillborn or live weak lambs
- Causes infertility in cattle (unknown in sheep)
89
Describe the typical appearance of the aborted material resulting from C burnetii in sheep
- Indistinguishable from EAE
- Thickened intercotyledonary areas
- Exudate over surface
90
Outline the diagnosis of C burnetii as a cause of abortion in sheep
- Ziehl-Neelsen stained smears (red coccobacilli - intra and extracellular, similar to C abortus)
- Serology or histopath to confirm
- Complement fixation test possible
- IHC on formalin fixed sections
- PCR of milk, faeces, or vaginal swabs to detect antigen in some countries
91
Outline the prevention and control of C burnetii as a cause of abortion in sheep
- Susceptible to tetracyclines (treatment in outbreak may reduce abortions, but does not prevent shedding or reduce zoonotic risk)
- Vaccine in France but no market for this in UK
92
Define the maximum residue limit
The maximum concentration of a residue that is legally permitted or acceptable in or on a food, given as ug/kg of that food
93
Define the Acceptable Daily intake
An estimate of the amount of substance, expressed on a bodyweight basis, that can be ingested daily over a lifetime without appreciable risk to the consumer
94
List some important zoonotic pathogens that may be found in milk
- Bovine TB
- Campylobacter, Salmonella
- Rat bite fever (streptobacillus moniliformis)
- Zoonotic diptheria
- Streptococcus pyogenes
- E coli
- Y enterocolitica
- Staph aures
- Brucellosis (not UK)
- Pseudomonoas aeruoginosa
95
Which species must not be housed with milking cows?
Pigs and poultry, breeding rams and Billies
96
Briefly outline the steps in the circulation cleaning approach for a milking plant
Warm rinse → hot wash cycle → alkaline detergent → cold rinse
- Drain pipes of residual milk
- Rinse with 40˚C water
- Wash using chlorinated alkaline detergent (break down fat + protein)
- Hot water cycled through at 70˚C until exits system at same temp
- Then circulate detergent solution at 60-70˚C for 5-8 mins
- Occasionally replace with acid-based milkstone remover
- Cold rinse +/- disinfectant e.g. sodium hypochlorite, enough to ensure hot wash solution out of plant
97
Briefly outline the acid boiling wash cleaning protocol for milking plants
Water >96˚C, run to waste with dilute nitric or sulphanilic acid to prevent deposit build up
98
Compare the 2 main methods of milking plant cleaning in the UK
- Acid boiling wash (ABW) quicker, uses fewer chemicals vs circulation cleaning
- ABW unpopular in UK due to cost of heating large amounts of water
99
How much water is needed approximately per milking unit for an effective wash cycle?
15-20 litres
100
Discuss milking routine hygiene with regards to mastitic cows
- Ensure buckets, lines, separate clusters used for mastitic cows are clean as well as main cleaning
- If mastitic cows are to be milked by same clusters as normal, place these at the end of the milking group
