Bovine Reproduction Flashcards
1
Q
What is the bovine reproductive year?
A
Gestation period = 280 days
Need to get back in calf by 80 days
Lactation for 305 days
Dry period is 60 days
Oestrous every 21 days
2
Q
How is ovine and equine oestrous distinguished?
A
Sheep show oestrous when days shorten, horses show oestrous when days lengthen,
3
Q
Define fertility.
A
The ability of a cow to give birth to a live calf at approximately 12 month intervals.
4
Q
Define sterility.
A
The total inability of a cow to become pregnant and to give birth to a liver calf.
5
Q
Define infertility/subfertility.
A
A reduced fertility, so the cow is ultimately capable of becoming pregnant and giving birth to a live calf but the interval may be much longer than 12 months.
6
Q
What are possible reproductive difficulties in cattle?
A
- Failure to cycle
- Failure to be mated
- Failure to conceive - fertilisation failure, early embryonic death
- Late embryonic death (happen before day 16, cow does not recognise it is pregnant, corpus luteum died and comes back intro oestrous) and abortions
- Dystocia
- Stillbirths
- Neonatal mortality
7
Q
What is caused by PGF2a? How does this affect different stages of bovine gestation?
A
PGF2alpha produced by endometrium through counter current blood supply delivery to ovary, which destroys CL.
- If given to a cow that has been pregnant for 2 weeks, cow will abort.
- If given to a cow in the muddle of oestrous but have not seen signs, will bring forth CL and show signs of oestrous 3 days after.
8
Q
What diseases affect hormone levels?
A
Lameness
Infectious diseases
Mastitis
Parasitism
Fatty liver
Ketosis
9
Q
What nutritional factors affect hormone levels?
A
- Energy or protein deficiency/imbalance
- Malnutrition
- Mineral or trace element deficiencies - P, Cu, Mn, Se, I, Co
- Excess Mb
10
Q
What stresses can affect hormone levels?
A
Social
Weather
High milk yield
11
Q
What are the effects of affected hormone levels on bovine reproduction?
A
Hypothalamus > GnRH > anterior pituitary > lack of LH and FSH causing:
- Delayed ovulation
- Lack of follicular development
- Ovulation failure > anovulation > regression atresia or cystic ovaries
12
Q
Describe the cyclicity pattern of first ovulation.
A
First ovulation do not show oestrous, short CL.
13
Q
Describe a normal bovine cyclicity pattern.
A
Normal has little peak and then 3 regular oestrous cycles, often does not get this far as cow usually pregnant by day 85. Act of suckling inhibits reproduction cycle.
14
Q
Describe an interrupted bovine cyclicity pattern.
A
Can get interrupted cyclicity with very high yield milk cows, 60L milk per day will have effect of nutrition and stop cycling persistent luteal phase means progesterone does not destroy CL.
15
Q
How long does involution of the uterus take after calving?
A
42-50 days
16
Q
Define puberty in heifers.
A
7-18 months of age when heifers have reached 35-40% of mature body weight. Want to be in calf 14-15 months to have a calf for 24 months.
17
Q
What is puberty onset by in cows?
A
Genotype
Season of year
Growth
Nutrition
Social cues
Climate
Disease
18
Q
What is the duration of oestrous?
A
6 hours
19
Q
What signs to high yielding cows exhibit?
A
Less mounts per heat period
Less intense expression of heat
20
Q
When does ovulation occur in cows?
A
Ovulation occurs spontaneously 9-15 hours after the end of standing oestrus. Occurs 24 hours after the LH surge.
21
Q
What are the chances of successful insemination at different stages of oestrous?
A
At the onset of standing oestrus CR = 40%
At mid-oestrus = 80%
6hrs after the end of oestrus = 60%
24hrs after end of oestrus = 10%
22
Q
What is the effect of old age on fertility?
A
- Decreased in older cow
- Maiden heifers usually very fertile
- 1st calvers have highest dystocia rate which lowers fertility and makes it more difficult or prolonged to get them in calf again
23
Q
What are the only reliable signs of oetsrous in cattle?
A
Standing to be mounted and head mounting. Standing to be mounted by another cow and does not try to avoid or escape.
24
Q
What is expression of oestrous influenced by?
A
Time post-partum
Time of day and year
Loafing areas (enough space to interact)
Lameness
Footing surfaces – will not mount if slippery
Nutrition
Body condition
Weather
Other cows in or around oestrus
Social
Pain or fear
Genetic factors
Presence of calf and suckling
25
List some possible heat detection aids.
- Heat mount detectors, paints, sprays, KaMar, Bovine Beacon, Estrus detect etc.
- Clear identification: freeze brands, large ear tags and neck bands
- Staff training and financial bonuses
- Good records and a 21 days calendar
- Pedometers, Heatime, Cogent Pinpoint - many other new technological products now available
- Vasectomised bull and a chin ball marker
- Retaining a-cow with cystic ovarian disease
- Close circuit television and time lapse video
26
What are some alternative methods of heat detection?
- Prediction of oestrus by milk progesterone analysis
- Oestrus synchronisation
- Ovulation synchronisation
- Natural service
- Measurement of vaginal electrical resistance using a probe
- Measurement of changes in milk temperature in the milking cluster
27
What do suckler beef cows commonly exhibit?
Anoestrus post-partum
28
What problems could occur at parturition or post-calving that could delay the onset of first oestrous?
Retained placenta
Metritis
Milk fever
Mastitis
Ketosis
Lameness
Poor nutrition
29
What does post-partum fertility depend on?
On condition:
- Too fat or too thin conditions reduce fertility
- A BCS of about 3 at calving should ensure that the cow does not drop below 2.5 at the time of service
30
What are the consequences of long or short gestation periods?
Birth weight – for each additional day in utero the rise can be between 186-540g/day Depending on sex and breed, with disproportionate growth of hips and shoulders
Dystocia – particularly common in heifers carrying male calves
Abortion affects milk yield
30
What does gestation length depend on?
Breed of dam
Genotype of foetus (breed of sire)
Sex of foetus
Number of foetuses
Parity of dam
Season
Nutrition
31
What are the veterinary herd fertility services?
- Motivation of client to achieve targets
- Regular visits (fortnightly routine call, larger herds will need more visits)
- Ultrasound scanning for early pregnancy and ovarian structures
- Oestrous synchronisation programmes
- Post natal checks
- Collect fertility data
32
When on a herd fertility visit, what is done with the AI cows on the list?
- Record ID
- Get a history
- Record BCS
- Record health status (include lameness, rumen fill) and medicines given
- Communicate to the farmer your findings and instructions
- Record these findings and actions
- Optional: teat scores, cleanliness scores, faecal score
33
How is a vaginal exam conducted?
1. Look and smell, including under the tail
2. Tear off enough tissue to clean area
3. Lift tail with dirty hand and place on elbow of clean hand
4. Wipe vulva towards anus with tissue until clean with dirty hand
5. Lift tail with dirty hand
6. Inserted lubed clean hand into vagina
34
What should you take note of during a vaginal exam?
Note vaginal wall for tears
Gently the cervix for size and if opened/closed
Urethral fossa and false UF (diverticulum)
Any discharge
35
What should you take note of during rectal examination?
- Temperature
- Faeces – good for consistency and nutrition information
- Peristalsis – gives indication of health
- Rectal Wall
- Internal structures
36
Name the internal structures you should/may feel on rectal examination?
Left kidney
Rumen
Small intestine/caecum
Aorta dorsal to hand
Pelvic brim
Cervix
Uterus
Bladder
37
Describe palpation of the uterus on rectal examination.
- Tube-like, soft tissue structure with a cranial bifurcation and a dorsal ridge depicting two horns.
- In older, multiparous cows, may extend over the pelvic brim.
- In some cows it may all be within the pelvis
- In cows on heat, it may be small, bunched and harder than normal
38
How are corpus lutea, follicles and cysts be detected on rectal examination?
- Hard, circular structure (like knuckle) is most likely a CL
- Softer, circular structure (like bubble wrap) is most likely a follicle
- If larger than 2.5 cm (or thumb tip to first joint) then may be a cyst
39
What are the uses of ultrasound scanning for pregnancy diagnosis?
- Extremely useful tool to assist in examination of reproductive tract
- Can determine pregnancy to less than 30 days post service
- Can distinguish structures on ovary
- Can detect fluid in uterus
- Can see foetal heart beat
- Can size and age foetus
- Can also be a good diagnostic tool for other conditions in caudal abdomen
40
What is the effect of increasing or decreasing frequency of ultrasound upon pregnancy diagnoses?
- Increasing frequency (MHz) increases resolution
- Decreasing frequency increases depth such as when viewing PDs > 55 days
41
How can you identify a follicle on an ultrasound scan?
They are fluid filled
42
Why does cystic ovarian disease occur?
- Occurs due to either failure of LH surge at ovulation OR failure of follicle to respond to LH surge
- So, follicle fails to ovulate and grows to form a cyst
- Follicle initially produces oestradiol and prevents further follicles forming, then becomes inactive and can persist for weeks, or may produce progesterone
43
What should you beware of with cystic ovarian disease cows?
Don’t use PGF2α if there is any possibility of pregnancy
44
What can you feel on rectal examination at 6 weeks of gestation?
Swelling in pregnant horn at cranial end and underneath bifurcation only. Very difficult to feel. Cup hand around bifurcation and compare the 2 horns for firmness/fluidity. Foetus too small to feel.
45
What can you feel on rectal examination at 7 weeks of gestation?
Distinct and fluid feel to cranial pregnant horn and significantly different to firm non-pregnant horn. Foetus too small to feel.
46
What can be felt on rectal examination at 8 weeks of gestation?
Pregnant horn now size of half-filled water balloon. No placentomes. Can still feel difference to other horn. Foetus size of mouse but do not feel.
47
What can be felt on rectal examination at 10 weeks of gestation?
Fluid feel now usually in both horns. Bifurcation around level of pelvic brim. No placentomes. Uterus size of water filled balloon. Gentle patting of bifurcation end may feel golf-ball size foetus.
48
What can be felt on rectal examination at 12 weeks of gestation?
Uterus usually over pelvic brim. Ovaries may be out of reach. Placentomes starting to become palpable (like peas when gently sweep hand over uterus). Foetus size of rat.
49
What can be felt on rectal examination at 4 months of gestation?
Arm in fully and sweep downwards. Uterus is immediately palpable. Very fluidy. Placentomes size of rocks. Gently pat uterus at bifurcation end and can feel foetus but no features. No fremitus. Foetus size of small cat.
50
What can be felt on rectal examination at 5 months of gestation?
Arm in fully and sweep downwards. Uterus goes beyond reach and large placentomes present. Uterine artery is thickness of stethoscope but no fremitus. Very difficult as cow feels like she is not pregnant as you cannot reach the calf.
51
What can be felt on rectal examination at 6 months of gestation?
Arm in fully and sweep downwards. Uterus goes beyond reach and large placentomes present. Patting now reveals foetus with discernible features (head). Fremitus present approximately hand’s breadth in from tuber coxae and vertical. Uterine artery is thickness of stethoscope and pulses with “whoosh”. Foetus size of Jack Russell dog.
52
What can be felt on rectal examination at 7 months of gestation?
Insert arm and feel head beyond pelvic brim with front feet. Feet feel small. Foetus size of border collie.
53
What can be felt on rectal examination at 8 months of gestation?
Very difficult to tell when due to calve from 7 months onwards but head will feel like small calf with larger front feet. Foetus size of labrador
54
Why do false negatives occur in PD?
- Unable to palpate uterus correctly
- Recorded service date was incorrect
- Cow may have been served again since recorded date
55
Why do false positives occur in PD?
- Unable to palpate uterus correctly
- Uterus not completely involuted – history
- Pyometra/mucometra
- Subsequent prenatal death
56
Describe the bovine placenta.
Multiple placentomes within the placenta. The placentome is made up of the cotyledon foetal side and the caruncle on the uterine side
57
What is aging pregnancies by palpation based on?
- Amniotic vesicle size
- Foetus size
- Placentome size – variable in size and number
- Uterine horn size
- Middle uterine artery size and fremitus
58
What is the risk of palpation?
- Bursting amniotic vesicle
- Damaging foetus or foetal membranes
- Membrane slip plus palpation of amniotic vesicle increase risk of abortion especially in early stages of pregnancy
59
What are the less common lab based pregnancy diagnoses?
- Milk Progesterone
- Oestrone Sulphate
- Bovine pregnancy-associated glycoprotein
- Bovine pregnancy specific protein-B
60
What is the milk progesterone test?
Test for non-pregnancy. It relies on testing progesterone levels 18-24 days after AI when they should be decreased if not pregnant
61
Why do false positives occur in milk progesterone tests?
- Cow inseminated at wrong time (dioestrus)
- Persistent CL (due to chronic infection)
- Luteal cyst
- Shorter than average interval between oestruses
- Prenatal death after sampling
62
Why do false negatives occur in milk progesterone tests?
- Inadequate mixing of milk sample
- Exposure of sample to heat or UV light
- Incorrect ID of sample
63
What are the properties of all year-round calving systems?
- Cows calving at any time of the year
- No seasonal emphasis
- No period when the whole herd is dry
- Can be extensive grazing systems or fully housed herds
64
What are the properties of seasonal block calving systems?
- Calve as a single group in a 12 week window
- Aim for 365 day target calving interval
65
What are the signs of low fertility on a farm?
- Low profit
- Vet found empty cows
- Cows returning to service
- Cows take longer to cycle
- Cows in seasonal calving herds are late calving
66
What are the management factors of fertility?
Heat detection
Insemination skill
Environmental stresses
Vaccinations
Transition cow nutrition
67
What are the cow factors of fertility?
Dystocia
Retained foetal membranes
Uterine infections
Twins
68
What are the herd factors of fertility?
Bull fertility
Breed
Age
Production
Infectious disease
Nutrition
69
What are the important things to record for herd fertility?
- Cow ID, age, and lactation number
- Voluntary wait period (VWP)
- Calving date
- Heat dates (incl. pre-mating if possible)
- AI service dates and sire used
- Pregnancy testing dates and results
- Abortion dates
- Calving problems – twins, RFM
- Other health problems – ketosis, LDA, uterine diseases
- Body condition scores
- Mobility scores
70
What is a voluntary wait period?
Management imposed period of rest after calving where farmer chooses not to breed. Commonly 42-50 days
71
What are the benefits of a voluntary wait period?
- Allows the cow to recover from the stressors of calving
- Allow uterine involution to occur
72
What are the key performance indicators of normal herd fertility?
- Submission rate – 1st service submission rate, all service submission rate
- Heat detection efficiency
- Calving to conception interval – calving to 1st service, 1st service to conception
- Conception rate – 1st service conception rate, 100d in calf rate
- Pregnancy rate/fertility efficiency
- Calving index/interval
73
What 2 things is successful herd fertility a function of?
Serving the cows – heat detection
Achieving pregnancy – conception rate
74
Define submission rate.
Proportion of cows that are submitted for AI/service of the whole group that are ready for service, over a defined period, such as 21 or 24 days.
75
Define the 1st service 24 day submission rate percentage.
Proportion mated that are eligible during 1st 24 days of a mating period.
76
Define returns submission rate percentage.
Cows that should have been submitted for re-service due to not being pregnant.
77
What are 4 post-partum anoestrous risk factors?
- Low body condition score at calving
- Poor dry period nutrition and negative energy balance post calving
- Lameness problems in herd
- Post parturient disease
78
What are 2 risk factors of oestrous occurring but not being detected?
- Poor heat detection technique
- High yielding cows reduced oestrus signs
79
Define conception rate.
Percentage of cows pregnant of those served. Take care, it is actually a measure of pregnancy not conception. Many more cows will conceive than are actually pregnant.
80
What may affect return to oestrous?
Fail to fertilise or embryo fails to signal = return to oestrous 18-24 days later
Late embryonic death = will return to cycle but delayed
81
Why may failure of fertilisation occur?
- Bull fertility is low – check bull semen
- Poor AI technique or bad semen handling
- Wrong timing service – due to heat detection errors, genetics
82
Why may there be early embryonic losses?
- Ineffective nutrition management
- Infectious diseases – campylobacter, BVD, leptospirosis, IBR
- Stress
- Lameness, SCC, mastitis
83
What are the risk factors of long calving to conception?
- Poor conception rates
- Early/late embryonic loss
- Cows not being detected when they return to oestrus – heat detection efficiency and accuracy
- Abnormal cycles
84
Define calving interval.
The interval in days for an individual cow between one calving and another. Calving index – is the average of the calving intervals of all cows in the herd.
85
When is the most profitable lifetime yield for heifers?
Heifer calves at 2 years
86
How is beef herd fertility measured?
Calving spread is a good measure of cows fertility performance. Better to have less spread – vaccinate, feed at same time
87
Describe beef herd cyclicity.
- To maintain a compact calving period the calving interval must be 365 days
- Beef cows generally don’t show first oestrus until 40-50 days post-partum
- So bull needs to go back in by 80 days after the planned start of calving date
- Late calving cows will not have sufficient time to resume cyclicity and become pregnant again
88
What are the management strategies to maximise beef fertility?
- Manage cow body condition/nutrition
- Avoid difficult calving's
- Control infectious disease
- Replacement heifer management
- Monitor bull fertility
89
When are breeding soundness examinations in bulls done?
Infertility investigation
Pre-purchase
Pre-breeding season
90
Why may a bull lack libido?
- Breed variation – dairy bulls more hyped than beef bulls
- Variation within breeds
- Age
- Bullying by females or other males
- Noise and distractions
- Unusual environments
- Boredom
- Lack of exercise
- Overweight
- Overuse
- Severe debility
- Intercurrent disease
- Pain – can rupture latissimus dorsi in the back and be subtly lame and not mount
- Rupture of corpus cavernosum penis
- Uncertainty about foothold
91
Why may a bull be hesitant to mount but have good libido?
- Painful musculoskeletal lesion
- Penile fibropapillomata
92
Why may a bull fail to exteriorise the penis?
- Adhesions
- Phimosis
- Stenosis of preputial orifice
- Impotence
- Spiral deviation within prepuce
- Congenitally short penis
93
Why may a bull have no intromission?
- Deviation – spiral, ventral. Penis forms a spiral before ejaculation, but cannot get into vagina is this forms before entering the vagina
- Persistent penile frenulum
94
Why may a bull not thrust?
Damaged dorsal nerve of penis
95
How is the penis examined?
- Before and after mating
- Xylazine
- Pudendal nerve block
96
What is a penile haematoma?
- Broken/ruptured penis/CCP
- Due to sudden angulation of penis
- Causes tunica albuginea of corpus cavenosum tears at weak point, which is at the dorsal aspect of the distal bend of the sigmoid flexure
97
What are the clinical signs of penile haematoma?
- Swelling cranial to the scrotum
- Stiff, short stride
- Temporary oedematous eversion of prepuce
- 50% cases have abscessation
- Initial reluctance to serve, then inability to extrude penis due to formation of adhesions
98
What is the prognosis of penile haemtoma?
- Infection, abscessation, adhesions
- Damage to dorsal nerve of penis
- Vascular shunts from corpus cavernosum to dorsal veins
99
How does a bull get a spiral deviation of the penis?
Deviation/spiralling prior to intromission
100
What are the clinical signs of spiral deviations of the penis?
- Failure to extrude penis – spiralling within prepuce/spiralling once cows hindquarters touched
- Sudden/gradual onset
101
What is phimosis?
Stricture of preputial orifice
Leads to strangulation
102
How is phimosis treated?
Remove wedge from orifice surgically but careful if genetic and not traumatic, will only treat and perpetuate genetic problem
103
What is balanoposthitis?
- Inflammation of penis and prepuce
- Non-specific infections and trauma
104
What does impotence lead to in the bull?
An escape route for blood, such as shunts, or blockage in proximal penis prevents blood reaching distal part
105
What are the causes of impotence in the bull?
- Congenitally abnormal large distal veins draining corpus cavernosum within body of penis
- Corpus cavernosum drained by distal network of small veins
- Corpus cavernosum drained by veins which develop at site of traumatic injury to tunica
- Dorsal canals of corpus cavernosum blocked by fibrous tissue, haematoma or thrombus
106
How does testicular hypoplasia in the bull present?
Small firm testes
Small epididymis
Small scrotum
Normal libido
107
What are the signs of testicular degeneration?
- Failure of spermatogenesis
- Increased flaccidity
- Increased immature
- Malformed spermatozoa fibrosis of seminiferous tubules
108
What are the causes of testicular degeneration?
- Systemic infection
- Trauma ischaemia
- Extreme heat/cold
- Congenital occlusion of efferent ductules causing back pressure and so oedema and then degeneration
- Autoimmunity
- Toxins
109
Why may a bull's testicle be enlarged?
Orchitis
Abscess
Haematoma
Rarely neoplasia
110
What is orchitis?
Unilateral – inflamed and hot causing the other to degenerate. Often with periorchitis and epididymitis
111
How is orchitis treated?
Antibiotics
NSAIDs
Unilateral castration
112
What are the problems that can affect the epididymis of bulls?
Trauma
Infection
Segmental aplasia
Congenital occlusion
113
What can congenital occlusion cause in the bull?
- Spermatocele (cystic dilation of the epididymis)
- Inspissated sperm accumulate behind lesions
- Epididymal wall usually ruptures and build up back pressure in the testicle leading to sperm granuloma
- Eventual testicular degeneration
114
What are the acute clinical signs of seminal vesiculitis in bulls?
- Severe pain (on examination and defaecation)
- Purulent discharge after service
- Pus in semen
- Enlarged and firm
115
What are the chronic clinical signs of seminal vesiculitis in bulls?
- Pus in semen
- Fibrosis (firm)
- Loss of lobulations
- No pain
- Usually older bulls
116
What are the infectious sexually transmitted causes of bovine abortion?
Campylobacter fetus
BHV-1
BVD
Mycoplasma
Ureaplasma
Leptospires
Tritrichomonas fetus
Histophilus somni
C. renale
117
What are the infectious non-sexually transmitted causes of bovine abortion?
Salmonella Dublin
Bacillus licheniformis
Schmallenberg virus
118
How can abortion causing infectious agents be classified?
Primary – those agents acting directly upon the uterus, placenta, foetus
Secondary – those agents causing systemic diseases which as a secondary effect adversely influence conception/pregnancy
119
Define abortion in bovine.
Production of 1 or more calves less than 271 days after service or AI. They are either dead or live for less than 24 hours.
120
When is investigation necessary for abortions on farm?
When frequency exceeds 3-5%
121
What action should be taken following abortion under the Brucellosis Orders?
- Reported to DEFRA
- Aborting or aborted cow must be isolated together with the foetus or calf and placenta
- The placenta and foetus should be disposed of by incineration or deep burial
- All abortions should be treated as infectious and potentially zoonotic until proven otherwise
122
Following an abortion, which samples are collected for the lab?
Blood, milk, placenta, foetal stomach contents, foetal blood, brain, other internal organs
123
What are 3 protozoal causes of bovine abortion?
Neospora caninum
Tritrichomonas fetus (not UK)
Babesia – causes redwater
124
Why may the cause of abortion be failed to be idnetified?
- Cause occurred much earlier
- Foetus retained after death for some time causing autolysis
- Foetal membranes not available
- Toxic and genetic factors not identified in specimens
- Many causes unknown or physiological
- Interpretation of tests can be difficult
125
What are the 6 main ways that bovine herpes virus 1 may present?
Respiratory (IBR)
Conjunctival (IBR)
Abortion
IPVV/IBP
Encephalomyelitis
Enteritis
126
What is the effect of bovine herpes virus 1 on pregnancy?
- May cause embryonic death and repeat breeding
- Abortions usually from 5 months onwards
- Infection late in pregnancy may cause stillbirths or non-viable calves
127
How can bovine herpes virus 1 be controlled?
- Eliminate carriers if they can be identified
- Killed vaccine available for pregnant stock, but won’t prevent abortion if female is already infected
- Marker vaccines
128
What does infectious pustular vulvo-vaginitis cause?
Does not prevent conception per se, but can cause embryonic death (not abortion)
129
What are the clinical signs of pustular vulvo-vaginitis?
Vulval hyperaemia
Vesicles
Ulcers
Pain
Straining
Frequent urination
Tail swishing
Pyrexia
Milk yield decreased
Vaginal discharge
130
What are the clinical signs of infectious balanoposthitis in bulls?
Preputial discharge
Similar lesions on penis and prepuce
Libido decrease but fertility normally unaffected
131
What is the effect of blue tongue virus on fertility?
- Temporary infertility in bulls and rams
- Reduced conception rates in Cows (infertility)
- The virus can cross the placenta and infect the foetus
132
What are the clinical signs of leptospirosis in cattle and sheep?
Bovine: abortion, milk drop, infertility. Subclinical has reduced milk yield and weak calves
Sheep: usually no signs evident, minor cause of abortion, importance source of infection for cattle
133
What are the risk factors of leptospirosis in cattle?
- Bought in cattle
- Use of a bull
- Grazing with sheep
- Abscess to water courses
134
How should bought in stock be treated to prevent leptospirosis infection?
- Isolate, possibly treat with antibiotics and vaccinate
- Keep in isolation until about 1 week after second vaccination
135
What are the management factors to reduce risk of leptospirosis infection in cattle?
- Prevent access to watercourses
- Minimum 2 month gap between sheep grazing and cattle grazing pasture.
- Minimum 2 month gap between slurry spreading and cattle grazing
- Use AI rather than hired or shared bull
- Operate a closed herd
- Biosecurity
136
How does leptospirosis vaccination affect abortion?
If placenta already damaged, will not prevent abortion
137
How does salmonella cause abortion in cattle?
Secondary to systemic disease. Most occur in late pregnancy in the absence of systemic illness
138
How is salmonella controlled to prevent bovine abortion?
- Isolate aborters for 5 weeks
- Dispose of products of abortion very carefully
- Decontaminate environment
- Consider vaccination where S. Dublin is a persistent problem
139
What are the sources on farm of bacillus licheniformis?
Thrive in mouldy hay, feed, straw
Silage
Ingestion – haematogenous spread
140
What are the clinical signs of bacillus lichniformis?
- Usually abort in late pregnancy
- Usually sporadic but occasional small outbreaks
141
How is bacillus licheniformis diagnosed?
- Gross appearance of placenta (similar to mycotic abortion)
- Isolation of bacillus from placenta, foetal stomach and vaginal discharge
142
How is bacillus licheniformis controlled?
- Difficult as the organism is ubiquitous
- Improve ventilation
- Avoid contaminated and poor quality feed and bedding
143
What are the clinical signs of campylobacter foetus var venearlialis in males?
None, asymptomatic carriers
144
What are the clinical signs of campylobacter foetus var venearlialis in females?
- Mucopurulent vaginal discharge
- Repeat breeder due to early embryonic death (EED)
- Abortion at 4-7 months of gestation
145
What is the first sign of disease in campylobacter foetus var veneearlis?
A large number of returns to oestrus following service with this bull. Only later may abortions be seen.
146
How is campylobacter foetus var venearlis diagnosed in females?
- Isolate organism from vaginal discharge or products of abortion
- Vaginal microscopic agglutination (MAT)
- Collect mucus in luteal phase of cycle and examine for antibodies
- PCR is commercially available
- Serology is useless
147
How is campylobacter foetus var venearlis diagnosed in males?
- Bacteriological examination of semen
- Florescent antibody test (FAT) on preputial washings/scrapings.
- Virgin heifer test – not ethical
- PCR
148
What are the 3 epidemiological factors of campylobacter foetus var venerealis?
- Transmission is venereal
- Untreated bulls remain permanently infected
- Cows overcome the infection and develop immunity over 3-6 months
149
How is Campylobacter foetus var venerealis controlled?
- Use A.I
- To avoid infected females infecting or reinfecting a male, allow two normal pregnancies by AI before resuming natural breeding
150
How is campylobacter foetus var venearlialis treated?
- Antibiotic therapy systemically for several days and by penile and preputial irrigation.
- 4 consecutive FAT should be negative before bull is re-used on clean stock
151
What are the disease entities associated with mycoplasmosis?
Granular vulvovaginits
Abortion and premature birth
Venereal transmission
152
How is Q fever transmitted?
Airborne infection
Ticks
Contaminated needles
153
How is Q fever diagnosed?
Demonstration of organism in stained smears of cotyledons and foetal stomach contents
Serology
154
What are the clinical signs of chlamydophilia psittaci?
- Early embryonic deaths
- Abortion in late pregnancy with/without systemic disease
155
How is chlamydophila psittaci diagnosed?
Isolation of organism from ocular discharge in affected animals and cotyledonary smears. Serology of dam and foetal pleural fluids.
156
What does brucella abortus cause?
Can cause abortion storms
157
How is brucella abortus diagnosed?
- All abortion/premature calvings must be reported
- Blood, milk and vaginal swabs taken if requested by DEFRA
158
How is brucella abortus controlled?
Checked routinely via the monthly bulk milk test
159
What is mycotic abortion?
Many fungal agents involved. Abortions usually sporadic, but up to 10% of herd may abort
160
What are the UK's most common mycotic abortive agents?
Aspergillus, absidia and mucor
161
How do fungi cause bovine abortions?
Ingestion/inhalation > blood stream > uterus > placentitis and endometritis> foetal infection
162
How can neospora caninum abortions be diagnosed in cattle?
- Abortion usually mid-term
- Mummification may occur
- Histopathology of foetal tissues
- Parasites in CNS or heart confirmed by immunoperoxidase
163
How are calves diagnosed for neospora caninum?
New-born congenitally infected calves typically have a very high antibody response. Calves should be tested either before colostrum intake, or after having colostrum from their dam
164
What are the clinical signs of noespora caninum in cattle?
- Infertility – abortion, early foetal death, mummified foetuses, stillbirths
- Neuromuscular disease in neonatal calves
- Reduced milk production
165
How can neospora caninum ne controlled?
- Cull infected cattle or do not breed for replacements
- Select seronegative heifer replacements
- Restrict access of dogs (and other animals) to feed and water sources
- Improve hygiene at calving and abortion including the careful disposal of all placentae, even those from ‘normal’ calvings
166
What is trichomonas?
Flagellate protozoan parasite of the bovine prepuce, vagina and uterus. Venereal transmission
167
What are the clinical signs of trichomoniasis in males?
Balanoposthitis with slight catarrhal discharge
168
What are the clinical signs of trichomoniasis in females?
Repeat breeders with vaginal discharge, pyometra with acyclicity, abortion usually 2-4 months
169
How is trichomoniasis diagnosed in cattle?
Identification of organism in vaginal discharge, penile and preputial scrapings
170
How is trichomoniasis controlled?
Females acquire resistance and untreated bulls will remain carriers, so use AI
171
What are the non-infectious causes of bovine abortion?
- Genetic factors or teratogens
- Twin pregnancy
- Trauma/stress
- Insemination/intra-uterine infusion
- High fever and endotoxins
- Nutritional deficiency
- Hypothyroidism (goitrogens)
- Drug induced: PGF2α, corticosteroids, oestrogen, xylazine
- Exotoxins (poisonous plants), mycotoxins, nitrates
- Shock/ fright
172
What is the rule of thumb concerning administration of prostaglandins?
If any doubt, do not administer PGs
173
Where is progesterone produced from during bovine pregnancy?
By the CL and also by the placenta between about days 120-175 in cattle.
174
How does the foetus hormonal control over bovine parturition?
- Increased corticotrophin releasing factor
- Increased adrenocorticotropin
- Increased cortisol
175
How does the placenta have hormonal control over bovine parturition?
- Decreased progesterone
- Increased oestrogen – stimulate oxytocin receptors
- Increased prostaglandin – uterus
176
How does the mother's uterus have hormonal control over bovine parturition?
- Increased softening of cervix, relaxin from ovary
- Increased gap junctions in myometrial cells
- Increased myometrial contractions
- Increased pressure on cervix and vagina
177
How does the pituitary gland have hormonal control over bovine parturition?
Increased oxytocin
178
What are the signs of impending calving?
- Increased udder development
- Oedema of the udder and ventral abdominal wall
- Relaxation of pelvic ligaments
- Sinking of the sacrosciatic area
- Relaxation of the perineum and vulva
- Liquefaction of mucous cervical seal which appears as a cloudy mucoid vulval discharge
179
How long is the first stage of bovine parturition?
6 hours (average)
180
What are the signs of the first stage of bovine parturition?
Restlessness
Inappetence
Desire for isolation
Tail twitching
Paddling of feet
181
What happens in the second stage of bovine parturition?
Allantochorion/water beg ruptures with the escape of watery allantoic fluid.
182
What is the average duration of the second stage of bovine parturition?
70 mins
183
What happens in the third stage of bovine parturition?
Expulsion of foetal membranes. Average duration of 6 hours. Normal detachment of the placenta as a result of:
- Uterine contractions
- Ripening and maturation of the placenta
- Rupture of the umbilicus with rapid ‘bleed out’ of the foetal side of the placenta with shrinkage of the foetal placental villi.
- Distortion of the caruncle by the myometrial contractions causing detachment of the cotyledon
- Gravitational pull
184
What hormones can be used to induce premature calving?
- Water soluble, short-acting corticosteroid
- Medium-acting corticosteroid
- Prostaglandin F2α or analogues
- Combinations
185
What are the indications for premature induction of parturition?
- Misalliance
- Reduce possibility of dystocia
- Tighten a seasonal calving pattern – not ethical
- Advance time of calving in a cow suffering from disease or injury
- Excessive oedema
- Hydrallantois
- Mummified foetus
186
What should you use to induce parturition before 100 days of gestation?
Prostaglandin PGF2α
187
What should you use to induce parturition between 250 and 275 days of gestation?
Medium acting corticosteroid or medium acting plus short acting corticosteroid
188
What should you use to induce parturition over 275 days of gestation?
Medium plus short-acting corticosteroid or
medium acting corticosteroid plus PGF2α
189
What should you use to induce parturition after 282 days of gestation?
- Medium acting corticosteroid
- Short acting corticosteroid
- PGF2α
190
What should be done if corticosteroids are used to induce premature parturition?
Cows or heifers should be examined to eliminate the presence of infectious disease.
191
What are the possible problems with inducing premature parturition?
- Sufficient softening and relaxation of the vulva, perineum and pelvic ligaments does not always occur following the use of prostaglandins
- Placental retention is common
- Uterine involution may be delayed with risk of metritis and chronic endometritis
192
Why is clenbuterol used in bovine parturitions?
- Delay heifer deliveries to allow full preparation of the soft birth canal
- To relax the uterus as an aid to obstetrical manoeuvres in dystocia
- To relax the uterus for caesarean section
- In embryo transfer to ensure less traumatic manipulation of the uterus
- To delay and therefore programme delivery to permit observation of parturition
193
What are the specific signs of dystocia?
- Prolonged non-progressive first stage labour
- The cow standing in an abnormal posture during first stage labour – in cases of uterine torsion the cow may stand with a dipped back
- Straining vigorously for 30 minutes without the appearance of a calf
- Failure of the calf to be delivered within 2 hours of the amnion appearing at the vulva
194
Why may there be expulsive force problems during calving?
Uterine inertia
Ca/Mg deficiency
Fatty deposits
Environmental disturbance
Abdominal pain
195
Why may there be bitch canal problems during calving?
Inadequate pelvis
Breed
Immaturity
Diet
Cervix fails to dilate
Torsion
Rupture
196
Why may there be oversizing problems in calving?
Absolute – sire breed, prolonged gestation, developmental defects
Relative
197
Why may there be positional problems in calving?
Presentation – anterior, posterior
Position – dorsa, ventral, lateral
Posture – flexed limbs, head back
198
What are the general principles when dealing with dystocia cases?
1. Treat all dystocia cases as emergencies
2. Be prepared
3. Obtain history
4. If possible, perform a rapid general examination in case the cow is suffering from peracute mastitis or another life-threatening illness – TPR/Milk Fever
5. Never underestimate the risk factor with dealing with a calving cow
6. Vaginal examination
7. Uterine relaxant
8. Epidural anaesthesia
199
Why must the position of the cow be considered when administering epidural anaesthesia in cows?
Do not have them facing downhill, do slightly uphill when giving epidural – to prevent going further up the spinal cord.
200
What drugs may be needed on dystocia/calving cases?
Local anaesthetic
Xylazine (Rompun)
NSAID
Clenbuterol
Oxytocin
Calcium/Phosphorus
Antibiotic
201
Distinguish cranial and caudal presentations.
If cranial presentation – head and legs in pelvis, and space or head. Should deliver.
If caudal presentation – hocks already out of vulva. Should deliver
202
When should cesarean be considered?
If delivery by traction is not successful within 10 minutes, it should be abandoned in favour of a caesarean. If no progress, stop. A successful caesarean depends on an early decision – the viability of the calf and the health of the cow will be compromised if traction is prolonged.
203
When is an epistiotomy done?
Anterior presentation. Only if the vulva is restricting passage of the head
204
What is a foetotomy?
- Deviated head
- Hip lock
- Decapitation in retained forelimb
- Hip flexion/breech
205
Why could uterine torsion be a medical emergency?
Duration, hydration, shock. Consider fluid therapy before attempting delivery
206
How do you manage uterine torsion?
- Rocking calf with cow standing
- Rolling cow with/without plank – plank fixes the uterus while the cow’s body is turned slowly
- Caesarean
- Laparotomy and correction
207
What are the 3 suitable conditions for maintenance of bovine pregnancy?
- A normal uterus
- Appropriate hormonal status
- Freedom from uterine infection
208
When can prenatal death occur during bovine pregnancy?
At any stage of gestation
209
What happens in early embryonic death in bovine pregnancy?
- Dies before day 15
- Returns to oestrous at a normal interval
- Impossible to differentiate it from fertilisation failure
- Animals present as repeat breeders if this occurs multiple times
210
What happens in late embryonic death in bovine pregnancy?
- Embryo dies between day 15 and 42
- Returns to oestrous after a prolonged and irregular interval
- May be a slight vulval discharge due to slightly larger conceptus so some material may be lost with this
211
What are the possible causes of embryonic death?
- Genetic factors
- Stress, including heat stress
- Infection resulting in pyrexia
- Fatty liver disease
- Nutritional deficiencies and excesses
- Endocrine deficiencies, asynchrony and imbalance
- Non-specific infectious agents
- Small embryo
212
What happens in foetal death?
- Between day 43 and term
- Early foetal death can be followed by expulsion of foetal fluids, autolysis of foetal tissue and membranes which are voided and are sometimes not detected
213
What may accompany foetal death?
Resorption
Abortion
Mummification
Foetal maceration
Stillbirth
214
What happens in foetal mummification?
- Foetus dies and becomes dehydration
- Corpus luteum persists and cow fails to calve at expected time
- There is no udder development.
215
How is foetal mummification detected on rectal palpation?
Hard mass in uterus, no placentomes, fluid or fremitus. Corpus luteum maintained and cervix is closed.
216
How is foetal mummification treated?
PGF2a, causing them to essentially come into oestrous, cervix will open, large amounts of mucus is produced in the uterus and vagina and they will expel the foetus. Corticosteroids not effective.
217
What is papyraceous mummification?
Any breed. All foetal fluids slowly resorbed. Aetiology is rarely ascertained. Mostly due to infections of BVD, leptospirosis, neospora and genetics/certain sires.
218
When does foetal maceration occur?
Sequel to foetal death. Occurs in cows after the 3rd month of gestation and is a sequel to incomplete process of abortion
219
What happens in foetal maceration?
Corpus luteum regresses, parturition process begins but not completed. Partial dilation of cervix allows bacteria into uterus that infect the dead foetus and break down soft tissue sleaving just bony tissues, embedded deep into endometria.
220
What is hydrops?
Excessive accumulation of foetal fluids
221
What is hydramnios?
Rare, usually co-exists with a foetal abnormality. Due to failure of swallowing by the foetus
222
What are the clinical signs of hydramnios?
- No external signs in the cow
- Examination per rectum
- Excessive uterine enlargement due to excessive fluid
- Placentomes usually palpable
223
What is hydrallantois?
More common, not normally associated with foetal abnormality. Excessive fluid is in allanto-chorion. Postulated that foetal/maternal incompatibility is the basic root cause. Thought to be due to the failure of the selective reabsorption of electrolytes from the allantois.
224
What are the clinical signs of hydrallantois?
- Abdominal distension is the main sign
- Per rectum – huge fluid filled mass palpable plus bilateral fremitus
- Placentomes and foetus often impalpable
- The animal may become recumbent and die with huge abdomen and difficulty to eat
225
How is hydrallantois treated medically?
Induce abortion with PGF2α or Dexamethasone. There may be dystocia, so need to assist as cervix may not open correctly
226
How is hydrallantois treated surgically?
2 stage drainage of allanto-chorion using a large gauge needle inserted low in right flank or via catheterisation of cervix. 30 litres of fluid is removed followed by caesarean section or drug induced abortion. Unlikely to have viable calf and cow that is in poor body condition, welfare is risked when removing such an amount of fluid.
227
Name 3 other abnormalities of foetal fluids.
Hydrocephalus
Foetal anasarca
Foetal ascites
228
When does vaginal prolapse occur?
Usually occurs after 7th month of pregnancy
229
Why may vaginal prolapse occur?
Due to relaxation of the soft tissues around the pelvis – pelvic ligaments, the vagina and vulva and later dilation of the cervix.
230
What is the aetiology of vaginal prolapse?
Multifactorial
Breed (Hereford)
Parity
Overfeeding
Lack of exercise
Sloping surface to stand on
Previous prolapse
231
How is vaginal prolapse treated?
Epidural and clean and repair any damage
232
How is vaginal prolapse retained?
Trusses and harnesses.
Sutures – purse string using Buhner’s technique using tape/mattress sutures
233
What must be considered before undertaking reproductive surgery in ruminants?
Handling and restraint facilities
Environment
Surgical procedure
Patient and assistant(s)
Under cover/outdoors
Sheltered from the prevailing wind/rain
Protection from dust
Lighting
234
When should a ruminant be transported to a more appropriate environment before undertaking reproductive surgery?
- Surgical site is heavily contaminated pre-op
- Preparation is time-consuming
- High likelihood of contamination
- Need for perioperative antibiotics
235
What anaesthesia can be used for ruminant reproductive surgery?
- Local infiltration
- Paravertebral (T13 to L2 +/- L3)
Epidural (L6-S1 or C1-2)
- Procaine with adrenaline
236
What is the speed of onset of local anaesthetic techniques for ruminant reproductive surgery?
5-15 mins (local infiltration, paravertebral, epidural)
237
What analgesia is used in ruminant reproductive surgeries?
Pre-emptive NSAIDs. Carprofen, flunixin meglumine, ketoprofen, meloxicam licensed in cattle.
No licenced opioids in food producing animals
238
Describe responsible use of antibiotic therapy for ruminant reproductive surgery.
- Infection status
- Risk of contamination
- Likely bacteria present mean we need a broad spectrum to cover all basis
- Resistance
- Culture/sensitivity – unlikely
- Route of administration
- Duration of treatment
239
What are the 1st generation antibiotics that can be given to ruminants for reproductive surgery?
For 3-5 days
- Aminopenicillins
- Early generation cephalosporins
- Tetracyclines
240
How do you prepare ruminants for reproductive surgery?
- Secure the tail in cattle
- High level of contamination so wide clip area - consider whether externalisation of viscera will be necessary, generally a 25cm margin sufficient
- Surgical scrub – 2 bucket rule
241
Why can access be challenging in ruminant reproductive surgery?
- Large abdominal size
- Cranial extension of the abdominal cavity beneath the rib cage
- Short mesenteries and omenta
- Rumen obstructs left flank
242
What must be considered for caesarean sections?
- Contamination risk – calf dead/alive
- Previous surgeries
- Timing of intervention
- Reason for surgery
243
Why may a caesarean section be needed in ruminants?
- Foetomaternal disproportion
- Malpresentation
- Insufficient dilation of cervix
- Elective
244
What anaesthesia is used in ruminant caesarean sections?
Paravertebral – anaesthetises the whole straining, allows extension of the incision if required
Caudal epidural optional extra – reduces abdominal straining but risk of ataxia, 2ml LA max
245
What are some possible additional pre-operative considerations for ruminant caesarean sections?
- Clenbuterol relaxes uterus for better access and manipulation
- Preparation for resuscitation
- Tie a long rope to the contralateral HL
- Use of sedation – but xylazine cause uterine contraction so can make the uterus harder to handle
246
Describe the approach to the left sided paralumbar fossa laparotomy in cattle.
- Rumen easier to manipulate than distal GIT
- Minimises egress of viscera and abdominal contamination
247
Describe the approach to the paralumbar fossa laparotomy in cattle.
- Incise ½ way between last rib and stifle
- Large dorsoventral incision 40 cm to avoid trauma to the incision while manipulating the uterus
248
Outline the process of a paralumbar laparotomy in cattle.
1. Identify and incise muscle layers individually
2. The transverse abdominal muscle and peritoneum should be tented with a forceps and a cut made carefully into the abdomen.
3. A sharp hiss heard
4. Extend the incision dorsally and ventrally
5. Determine calf position and identify the closest HL in anterior/FL in posterior presentation
6. Incise uterus outside abdomen to decrease contamination over plantar metatarsus and hock
7. Pull calf dorsally and caudally
8. Check for second calf
249
How is a calf revived?
Straw up nose, cold water down ears, acupuncture site – small needle in nasal septum
250
How is a paralumbar laparotomy closed in cattle?
Uterine closure - continuous inverting in 2 layers, 5/6 metric synthetic absorbable, remove clots from wall to minimise adhesions
Abdominal closure - layers 1 to 3 simple continuous suture with absorbable, skin with ford interlocking non-absorbable
251
What is the aftercare necessary for the mother after a paralumbar laparotomy in cattle?
- Continue NSAIDs
- Continue antibiotic
- Oxytocin to allow uterus to contract again
- Give oral fluids if required
- Phone or visit the next day/day after to see how getting on – beware peritonitis occurs at least 3 days later
- Stitches out 14 days
252
What are the possible post-operative complications of paralumbar laparotomy in cattle?
- Retained foetal membranes
- Metritis, peritonitis, wound infection
- Severe adhesions
- Reduced fertility
253
When is a left ventrolateral laparotomy indicated?
Useful for dead emphysematous foetus
254
What are the benefits of a left ventrolateral laparotomy?
Improved uterine exposure and reduced contamination of abdomen
255
What is the approach to a left ventrolateral laparotomy?
- Requires right lateral recumbency and elevated left hind limb
- Closure is more involved and prolonged
- Assistance preferred as it is more difficult
256
Why is disbudding preferred to dehorning?
- Less stressful for the calf and the vet
- Improved local anaesthesia
- Fewer complications
- Reduced risk of horn regrowth
257
What is the legislation of dehorning?
- Only a vet may carry out the procedure in cattle over 2 months of age
- Only a vet can dehorn or disbud a sheep or goat – except the trimming of the insensitive tip of an ingrowing horn
- Local anaesthetic (LA) must be used
258
What anaesthesia is used for dehorning?
Cornual nerve block with/without accessory nerve for a minimum 10 minutes. NSAIDs recommended
259
What does a disbudding iron do?
Haemostasis, destroy horn producing tissue
260
What are the complications of dehorning?
- Inadequate anaesthesia
- Haemorrhage
- Sinusitis
- Fly strike
- Regrowth
261
What anaesthesia is used for castration?
- Local infiltration
- Epidural – lumbo-sacral L6-S1
- Sedation (xylazine) – mature bulls, aggressive or difficult to handle animals, safe handling
- GA – adult boars or pot-bellied breeds. Restraint and allow closure of the inguinal ring to prevent herniation
262
How do you administer local anaesthetic for castration into the testes?
1. Inject 5 to 10 ml of 5% procaine directly into the stroma of the testicles using a 19 gauge, 2.5 cm needle
2. Due to the inelastic vaginal tunic that surrounds the stroma, this method is potentially painful to the patient
263
How do you administer local anaesthetic for castration into the spermatic cord?
1. Inject 5 to 10 ml of 5% procaine into each spermatic cord at the neck of the scrotum using a 19 gauge, 2.5 cm needle
2. Draw back needle to check you are not in the blood vessels there
3. This method is less painful and the anaesthetic acts more quickly
264
How is castration done with bloodless castration using elastrator rings?
Calves/lambs < 7days old. Place ring at the neck of the scrotum
265
What are the possible complications of bloodless castration using elastrator rings?
Unilateral or failed castration due to retraction
Failure of the elastrator ring
Dehiscence
Infection
266
When is bloodless castration using burdizzo indicated?
Poor environmental hygiene or in fly season, farms with history of complications with open castration,
267
How is a bloodless castration done with a burdizzo?
- Apply proximal to testes
- Clamp 4 times and hold for at least 10s
- 2nd application made proximal to the first
- Each cord should be crushed separately with the crush lines staggered to prevent interruption of blood supply to the scrotal skin
268
What are the possible complications of bloodless castration using a burdizzo?
Incomplete castration due to failure to occlude vas deferens
Accidental crushing of urethra (fatal)
Sloughing of the scrotal skin
269
How can surgical castration be done?
Using traction and torsion or using emasculators
270
What method of castration is used for cattle under 6 months, 6-12 months and over 12 months of age?
Under 6 months - torsion and traction
6-12 months - torsion and traction, emasculators
Over 12 months - emasculators with/without ligation
271
Outline how to surgically castrate using torsion and traction?
1. Make a bold J shaped incision through the scrotal skin
2. Carefully cut the vaginal tunic
3. Digitally break down the ligament attaching the vaginal tunic to the testis distally leaving only the vascular attachments
4. Twist the testicle ensuring the twists move up the vascular cord around 25-50 times
5. Care not to entrap hair or vaginal tunic into cord
6. Pull firmly on the cord until it breaks
272
Outline how to surgically castrate using emasculators.
1. Make a bold J shaped incision through the scrotal skin
2. Apply emasculator to spermatic cord either open vaginal tunic or close vaginal tunic
3. Apply “nut to nut” for a minimum of two minutes so that lamp is above cutting edge
4. Crush the vasculature separately from the vas-deferens, with/without proximal ligature
273
What are the possible complications of surgical castration?
Haemorrhage
Infection
Abscessation
Fly strike
Tetanus
Eventration - abdominal contents coming through vas deferens, big risk in pigs so treat like SA and close up inguinal ring in pigs
Adhesions
274
What is a vasectomy and when it is done?
- Performed to produce teaser males
- Removal of a segment of the ductus deferens
275
What local anaesthesia is used for a vasectomy?
Lumbosacral epidural – preferred, provides good analgesia and relaxation
Local infiltration – line block along neck of scrotum
276
Outline the approach to a vasectomy.
1. 3 cm skin incision is made in cranial scrotum over the spermatic cord
2. Spermatic cord is bluntly dissected and exteriorised
3. Place closed artery forceps to isolate spermatic cord
4. Identify the ductus deferens – medial aspect of the spermatic cord, white and glistening
5. The ductus deferens is clamped and ligated
6. 3-4 cm is resected and removed
7. Routine skin closure with absorbable sutures
8. Repeated for the other side
277
What should you warn the farmer about with vasectomisation?
- Not a 100% procedure and re-canalisation occasionally occurs
- Allow minimum 2 weeks to relapse before the bull/ram is introduced to any fertile females
278
How do you treat post partum haemorrhage in cattle?
Ligate, clamp, pack or oxytocin
279
How may a cow get post partum vaginal or uterine tears?
Associated with dystocia, excessive traction, large calves. May be associated with profuse post-calving arterial haemorrhage from vulva
280
How are post partum vaginal and uterine tears treated?
- Identify bleeding vessel and clamp with artery forceps
- Stitch vaginal tears
- If large uterine tear, consider salvage slaughter or repair via laparotomy
281
How can post partum vaginal and uterine tears be prevented?
- Avoid foeto-maternal disproportion, over-fat cows at calving and excessive traction
- Consider episiotomy
282
What may uterine prolapse be associated with?
Prolonged parturition
Straining
Hypoglycaemia, as this causes uterine inertia and uterus doesn’t contract and cervix doesn’t close
283
Why might a cow be down post partum?
Exhaustion
Shock
Hypocalcaemia
Pelvic nerve damage
284
How should you manage and treat a uterine prolapse?
- Intravenous calcium
- Sternal recumbency with hind legs pulled back which tilts pelvis forward
- Caudal epidural
- Clean uterus and remove placenta and put on a plastic feed back
- If there is a tear, suture up first before putting back in
- Replace uterus using firm manual pressure with closed fist, fingers will go through
- Fully invert
- Consider giving antibiotics for 3-4 days
- Give NSAID, oxytocin and Ca injections
285
What must be considered with Buhner's sutures?
Do not tie so tight that they can’t urinate or pass foetal membranes. Do not rely on this keeping uterus in.
286
What does gluteal nerve paralysis present as?
Weakness in hind limbs or inability to stand after calving
287
What does obturator nerve paralysis present as?
Legs tend to splay laterally when weight-bearing. Involuntary abduction of limb
288
What does sciatic nerve paralysis present as?
Dragging leg
289
What does tibial nerve paralysis present as?
Hock is lowered and over-flexed
290
What does peroneal nerve paralysis present as?
Digit is knuckled over onto dorsum
291
How long do uterine contractions last post partum?
A few days
292
How long does it take for uterine involution post partum?
4-6 weeks
293
What happens to the cervix post partum?
Constricts rapidly
294
What are the factors affecting normal uterine involution?
Parity
Retained placenta
Uterine infection
Twins
Hypocalcaemia
Selenium deficiency
Suckling frequency
Dystocia
Climate (especially heat stress)
Hydrops
295
What events occur post partum in the cow's cycle?
1. Uterine involution
2. Regeneration of endometrium
3. Elimination of bacterial contamination of uterus
4. Return of cyclical ovarian activity
296
What is LOCHIA?
Discharge for 7-10 days, reddish brown and odourless
297
Why is there an opportunity for bacterial contamination at calving?
At calving and immediately post-partum the vulva is relaxed and the cervix is open, so there is an opportunity for environmental bacteria to colonise the uterus.
298
How does acute metritis or chronic endometritis interfere with fertility?
- Directly killing gametes or conceptus
- Altering the uterine ‘milk’
- Causing endometritis (generating toxic products, inducing luteolysis)
- Causing chronic histological lesions (metritis, pyometra, salpingitis)
- Delaying onset of ovarian cyclicity (with or without the formation of ovarian cysts)
299
How is acute metritis treated?
Broad spectrum antibiotic (local and/or systemic)
IV fluids and NSAIDs if toxic
Removal of RFM with great care (contraindicated here)
300
What can happen in sequalae to post partum acute metritis?
Secondary ketosis
Hypocalcaemia
Displaced abomasum
Chronic endometritis
Salpingitis
Adhesions
Bacteriaemia leading to endocarditis and pulmonary abscessation
301
What are the clinical signs of post partum acute metritis?
Anorexia
Milk drop
Pyrexia
Foul smelling vulval discharge
302
What does endometritis present as?
Mucopurulent vaginal discharge, 21 days or more after calving and associated with delayed uterine involution. The cow is not ill. Farmers call it “whites” - a purulent discharge
303
What are the predisposing factors of chronic endometritis?
- Negative energy balance/ketosis
- Dystocia/assisted calving
- Retained foetal membranes
- Dirty calving environment
- Premature calving-twins, induced calving
- Delay in return of post-partum cyclicity
- Overfat at calving/fatty liver
- Nutritional deficiency e.g. Selenium
304
How can chronic endometritis be diagnosed?
- Persistent purulent vulval discharge “whites” evident at 3-4 weeks post calving
- Tacky discharge stuck to tail
- May be seen following oestrus when cervix opens
- Vaginal examination manual or speculum
- Rectal examination confirmed by ultrasound
305
How can chronic endometritis be treated?
- Prostaglandin injection (PGF2α) – repeat treatment in 10-14 days if “whites” persist.
- Intra-uterine antibiotics
- Saline washout
- Antiseptic wash-out (not licensed) Lugol’s iodine or Chlorhexidine
- Oestrogens (no longer licensed and illegal in EU)
- Self-cure
306
How can chronic endometritis be prevented?
- Minimise dystocia
- Good general calving hygiene
- Avoid overfat cows/fat mobilisation syndrome
- Ensure adequate mineral/vitamin supplementation
- Amounts to good dry cow management
307
What is pyometra associated with?
Persistent CL and closed cervix
308
How does pyometra present in cattle?
Distended uterine horn
Uterine wall is thick, but no membrane slip, no placentomes and no foetus palpable
309
What is the aetiology of pyometra?
- Failure of normal separation of foetal cotyledonary villi from maternal caruncles
- Primary or secondary uterine inertia
- Failure of breakdown of the acellular layer between the foetal and maternal epithelial layers, which is a chemical change but is assisted by uterine motility
310
What are the predisposing factors of pyometra?
- Premature parturition – twin births, late abortions, induced births
- Oedema of chorionic villi caused by dystocia, caesarean or following uterine torsion
- Placentitis cause by abortion agents
- Uterine inertia due to hypocalcaemia or twins
311
What are the clinical signs of pyometra?
- Putrid placenta hanging from vulva but, may be retained in cervix/ vagina and not obvious from outside
- Cow may strain
- Usually not ill unless acute metritis develops
312
What can happen in sequalae to pyometra?
Spontaneous expulsion in 5-10 days with no treatment
313
What is cystic ovarian disease in cows?
A cystic follicle is defined as an anovulatory follicle-like structure (greater than 2 cm in diameter) that may persist on the ovary (usually for more than 10 days) with or without the presence of a corpus luteum.
314
How can cysts be further classified?
- Follicular cyst - thin-walled, non-progesterone-producing
- Luteinised/luteal cyst - thicker-walled, progesterone-producing
- Non-hormone producing cyst
315
How can cysts and corpus lutea be distinguished on ultrasound?
Many normal CLs have fluid filled centres/lacunae visible on ultrasound scan – these are not cysts.
316
What is the consequence of luteal cysts?
Luteal cyst producing progesterone so administer PG to destroy luteal tissue.
317
What is the consequence of follicular cysts?
Produce oestrogen = keep having oestrous behaviour/nymphomania
318
Why might an LH surge fail?
- Stress – cortisol can block or delay normal LH surge or may alter LH receptor activity at follicular level.
- Metritis/endometritis – endotoxin production from uterus can cause cortisol release which interferes with ovulation
- Other dietary deficiencies plant-based oestrogens in diet (probably not in UK)
319
What are the predisposing factors of cystic ovarian disease?
- Arises as an interaction between an hereditary predisposition, stress, milk yield, age, season of the year and plane of nutrition
- Ketosis, dystocia, twin births, RFM and MF
320
Distinguish the clinical signs of follicular and luteinised cysts.
Follicular – irregular or recurrent oestrous behaviour or anoestrus
Luteinised cysts – anoestrus
321
How is cystic ovarian disease diagnosed?
- Rectal Palpation – if thick walled structure, likely to be luteinised cyst
- Milk/blood Progesterone Analysis: follicular cyst leading to low milk progesterone, luteinised cyst leading high milk progesterone
- Ultrasound
- Behaviour
322
How is GnRH/hCG used to treat cystic ovarian disease?
GnRH given exogenously should result in FSH and LH release, but doesn’t bring ovulation about with cysts but brings about follicular to luteal tissue change and then given PGF2a to destroy luteal tissue.
323
How is PGF2-a used to treat cystic ovarian disease?
Exogenous IM, short half-life as it goes through lung, uses counter current uterus to ovary and destroys luteal tissue. Also cause smooth muscle constriction in the lung in humans and can cause abortions in pregnant people, so handle carefully. Only luteal cysts.
324
How is progesterone used to treat cystic ovarian disease?
PRID/CIDR for 12 days, release progesterone to mimic a CL, feeds back to hypothalamus to switch of GnRH release. Removing the device then removes the negative feedback which allows GnRH release and then FSH and LH and ovulation will occur. Can treat both follicular and luteal cysts.
325
When does the first post partum ovulation occur in dairy and beef suckler cattle?
Dairy - 1st pp ovulation normally occurs within 20-30 days
Beef suckler - 1st pp ovulation normally occurs within 20-60 days
326
What happens if the dominant follicle fails to ovulate?
It will become atretic or occasionally become cystic
327
Why is there is a delay in first ovulation between dairy and beef suckler cows?
Delay in sufficient LH pulse frequency rather than FSH problem. Suckling effect
328
What are the nutritional effects of anoestrous?
- Inadequate energy intake in late pregnancy/early ppp, due to suppression of LH pulse frequency
- Negative energy balance affects levels of
- Insulin and growth hormone
anoestrus due to excess molybdenum or sulphur in the diet
329
How does suckling cause anoestrous?
Frequency and duration of suckling affects LH output via opioid release interfering with GnRH output in hypothalamus.
330
What could cause anoestrous?
Nutritional
Suckling
Seasonal effects
Delayed uterine involution
Cystic ovarian disease
Persistent corpus lutea - uterine infection
High yielding dairy cow
Heifers still under nutritional stress
331
What is needed to diagnose anoestrous?
- Palpate/scan 2 small hard ovaries with no CL or large follicles, with similar rectal finding in 10-14 days
- Have 2 low milk progesterone values recorded 10 days apart
332
How is anoestrous treated?
- Management changes
- Progesterone releasing devices
- Single dose of GnRH
333
How is a single prostaglandin injection used to treat oestrous not observed?
If a CL, give PG. When CL is destroyed is predictable but ovulation is not due to where they are in the follicular phase.
334
How is a double prostaglandin injection used to treat oestrous not observed?
To synchronise oestrous. About half may have a CL so PG will induce oestrous, those who don’t will have no effect. 11 days later, all will be in luteal phase. You can synchronise ovulation without observing oestrous
335
How is Ovsynch used to treat oestrous not observed?
1st injection in GnRH for effect on follicular wave. If there are dominant follicles, they will ovulate and follicular waves will be synchronised. Then give them PGF2a to destroy CL, so all come back into oestrous close together by synchronising follicular wave and luteolysis. 56 hours later, another GnRH to induce ovulation to synchronise further
336
How are CIDR and PRID plus PGF2a used to treat oestrous not observed?
If you put in a device and there is a still a CL present 10 days later, PGF2a then given 2 days before you remove it, so that there is no natural progesterone.
337
What is the effect of GnRH given on the day of service (holding injection)?
- Some cows may have delayed ovulation relative to standing oestrus
- GnRH given at oestrus also improves subsequent luteal function
338
What is the effect of GnRH given at day 11-12 post service?
At day 11-12 post AI or more economically can be targeted on cows that are stressed or return to service
339
What is given at 12 days post service to improve fertility?
Chorionic gonadotrophin
340
How are CIDR and PRID used to enhance fertility?
Inserted at day 5 and removed at day 12 enhances fertility in some cases
341
What is a repeat breeder cow?
Cow that fails to become pregnant following 3 or more consecutive serves at normal inter-oestrus intervals
342
What are the causes of repeat breeders?
- Statistical chance related to herd pregnancy rate
- Failure of fertilisation
- Early embryonic death
- Failure of sufficient bTP-1 production from embryo leading to failure of maternal recognition of pregnancy
343
How are repeat breeder cows treated?
- If thin improve condition
- If lame treat
- Try experienced inseminator or put in with a bull to reduce reliance on oestrous signs
- Try ‘holding injection’ (GnRH) – at beginning of standing oestrus and also day 11 post insemination.
344
What are the possible causes of stillbirths in cattle?
Dystocia/anoxia
Hypocalcaemia
Twinning
Iodine deficiency
Vitamin E/selenium
345
How can dystocia be recognised as the cause of stillbirth?
Head and tongue is swollen due to affected venous return by constriction round the head so is a sign of dystocia/anoxia
Infection pre-partum
346
What causes corneal opacity following stillbirths?
Water being absorbed from the amnion through the cornea leading to oedematous cornea
347
How are stillbirths prevented against?
- Multifactorial
- Bull selection
- Cow nutrition
- Supervision of labour
- Exercise dams
- Induction or delay of parturition
- CCTV
348
Distinguish neonatal effect of normal and abnormal delivery.
Normal delivery results in temporary acidosis
Abnormal delivery results in severe acidosis
349
What are the characteristics of acute neonatal respiratory distress syndrome?
- Decreased surfactant, severe respiratory distress
- Broken ribs or other trauma
- Inhalation of meconium
- Congenital defects
350
How is acute neonatal respiratory distress syndrome treated?
- Increase oxygen via a nasal tube
- Doxapram – respiratory stimulant
- Careful nursing including administration of colostrum
351
What causes alveolar collapse in neonatal acute respiratory distress syndrome?
Proteinaceous deposit in lungs
352
What is ventricular septal defect?
Most common shunting left to right
353
What are the clinical signs of ventricular septal defect in calves?
- Decreased exercise tolerance
- Listlessness
- Systolic murmur on both sides of chest
- Acute heart failure and pulmonary oedema
354
Distinguish smaller and larger cardiac defects.
Smaller defect is more likely to give you the louder murmur. A very small VSD may close and can have them without any issue to health. Larger ones will have affect on functionality.
355
What are the factors affecting transfer of colostral antibodies?
Poor maternal nutrition
Parity
Pre-partum leakage/milking
Premature calving
Movement of dam in late pregnancy
Interval from calving to removal of calf
Maternal and calf behaviour
Inadequate mothering
Failure of calf to suck
356
What is the duration of action of colostrum in calves?
Colostrum has an in utero immune response from 120 days. Colostrum derived immunoglobulin, transfer from plasma to colostrum over 2 months.
357
What are the humoral immune factors in colostrum?
Complement
Lysozyme
Lactoferrin
Interferon
Acute phase protein
Lactoperoxidase
358
What are the dam factors affecting immunoglobulin concentration yield in colostrum?
- Increases yield causing decreased quality of parity heifers
- Decreased quality and quantity of breed
- IgG transfer starts earlier in heifers (older cows increase IgG2 levels) quarter increased quality in hind quarters
359
What are the management factors affecting the immunoglobulin concentration of colostrum?
- Time after parturition is greater than 9 hours
- Length of dry period
- Prepartum milking
- Vaccination
- Induction
- Feeding – no effect on Ig concentration, effects yield, B.C.S. poor condition causing poor quality and quantity
360
How much colostrum should calves receive?
10% body weight in first 6 hours of life
361
What is the outcome of under 10, 10-20 and over 20 zinc sulphate turbidity test units?
< 10 = septicaemia/diarrhoea, high mortality
10-20 = diarrhoea, variable mortality
>20 = healthy/transient diarrhoea
362
What is bovine neonatal pancytopaenia?
Thrombocytopaenia
Alloimmune syndrome caused by vaccine-induced alloreactive antibodies
363
What are the clinical signs of colisepticaemia?
Sudden death – or dull, stiff, reluctant to rise and feed
Subnormal – pyrexia 40.5C, collapse, diarrhoea (terminal), CNS signs , swollen joints, death in less than 12 hour or leading to septic polyarthritis, multiple abscesses, meningitis. Elevated heart rate
Calves that get this tend to get endotoxic shock leading to DIC C.V. collapse hypogammaglobulinaemic causing decreased immunoglobulins
364
While usually ineffective, how is colisepticaemia treated?
- IV fluids
- NSAIDs – flunixin has an antiendotoxic effect
- Antibiotics – don’t have time to figure out which bacteria is causing infection and calves are succumbing to environmental bacteria. So use those that are good at getting through BBB – florfenicol, amoxicillin/clavulanic acid, trimethoprim/sulphonamide, enrofloxacin.
365
How is colisepticaemia controlled?
Colostrum
Cleanliness
Reduce obstetrical problems
Dip navel
Management of cow and calf
366
When does bacterial meningitis occur in calves?
Sequel to bacteraemia in hypogammaglobulinaemic calves
367
What are the CNS signs of bacterial meningitis in calves?
- Depressed
- Hypopyon – pus in anterior chamber of the eyes (eyes are the extension of the brain so if pus in eye, likely in brain), not be confused with cataract (cloudiness in lens)
- Opisthotonus – rigid and have head right back
- Blindness
- Paddling/convulsions
- Coma
368
How is bacterial septicaemia treated in calves?
- Antibiotics
- Anticonvulsants
- Drugs must cross blood CSF barrier
- Nursing
- Good colostral transfer to prevent
369
Which bacteria could cause bacterial polyarthritis in calves?
Trueperella pyogenes
Fusobacterium necrophorum
Staphylococcus species
Streptococcus species
Escherichia coli
Salmonella
370
How can bacterial polyarthritis lead to paraplegia in calves?
If gets into joints/vertebral discs, can get into bone, spine can collapse = paraplegic calf/lamb
371
What are the clinical signs of omphalophlebitis/polyarthritis?
- Hot, painful, swollen joints
- Lameness, recumbent
- Dull, pyrexic, anorexic
- Swollen painful navel/purulent discharge
372
How is omphalophlebitis/polyarthritis diagnosed?
- Synovial fluid culture and analysis
- Radiology
373
What is the aim of treatment when treating omphalophlebitis/polyarthritis?
Often ineffective due to welfare implications. Aim is to remove destructive enzymes, eliminate infectious agents, decreased inflammation and pain.
374
Why is rapid treatment required for polyarthritis?
- Synovitis and necrosis leading to destructive enzymes
- Decreased glycosam inoglycans and proteoglycans
- Cartilage destruction and osteomyelitis
375
How is polyarthritis treated in calves?
- Broad spectrum antibiotics for at least 2 weeks, must have good tissue perfusion, acid intra-articular environment
- Joint drainage – arthrotomy/arthroscopy
- Joint rest via NSAIDs
376
What is the aetiology of navel and joint ill in calves?
Bacteraemia/septicaemia arising from navel or chronic neonatal septicaemia
377
List the possible clinical scenarios of navel and joint ill in calves.
- Abcessation of navel only
- Spread from navel into falciform ligament
- Spread along urachus
- Peritonitis
- Haematogenous spread to single or multiple joints
378
How should you treat navel and joint ill calves?
- Broad spectrum antibiotics until culture results available
- In navel-ill surgical excision
- Large abscesses can be lanced, flushed and allowed to granulate
- Joint lavage often useful
379
How should navel and joint ill be prevented against?
Adequate colostrum
Treatment of navel at birth
Separate navel suckers from other calves
