Bovine Reproduction Flashcards
How many follicular waves does the average cow have in a follicular cycle?
2-3
What is luteolysis determined by?
Prostaglandin receptors
What does AI success depend on?
Reliable oestrus detection
Use of fertile/proven sires
Is it better to inseminate too early or too late?
Too early
How many sperm are there in a straw?
12 million
When does endometritis tend to occur?
21 days + post-calving
When does metritis tend to occur?
Up to 21 days post-calving
Give some differentials for vulval discharge in a cow
Pyelonephritis RFM Endometritis Metritis Cystitis Vaginitis
How would you diagnose pyelonephritis in a cow with vulval discharge?
Catheterisation of bladder
Palpate kidneys per rectum (will be painful if inflamed)
Which antibiotics tend to concentrate in the urine?
Give a condition this could be used for
Penicillin (hence useful for pyelonephritis)
Why is it worth cleaning a cows tail when investigating vulval discharge?
So you can identify any further discharge
If not, can’t tell whether discharge is new or old
How can you administer tetracyclines?
Liquid suspension (injection) Tablets to be inserted into the uterus (pessaries) (milk withhold of 4 days)
Do 1st gen cephalosporins have a milk withhold?
No
Why may iodine be used in cases of vulvular discharge?
Releases prostaglandin from uterus
What are the 4 stages in the follicular cycle?
Emergence -> selection -> dominance -> atresia
What do the umbilical arteries become in calves?
Lateral ligaments of bladder
What does the umbilical vein become in calves?
Round ligament of liver
What does the urachus become in calves?
Median umbilical ligament
Where does the umbilical vein lead to in calves?
Liver
What should you check when diagnosing umbilical swelling in calves?
Suck reflex Joint ill Spread/source of infection Lungs CNS
If an umbilical swelling in a calf is reducible into the abdomen what kind of hernia is it?
Simple hernia
If an umbilical swelling in a calf is partially reducible into the abdomen, what kind of hernia is it?
Hernia and abscess
If an umbilical swelling in a calf is irreducible into the abdomen what kind of hernia is it?
Abscess
Hernia complicated by incarceration/strangulation/adhesions
What would a pitting oedema signify in a calf with an umbilical hernia?
Urolithiasis (bladder stones) and urethral rupture
How can you identify discharging tracts in a calf with umbilical hernia?
Pass a blunt probe (eg bitch urinary catheter) to see which direction it goes/how far etc
Inject radio-opaque contrast medium and take radiographs with US
What is fibrinogen an indicator of?
Chronic inflammation
What is the usual cause of simple hernias in calves?
Genetic
How big must a simple umbilical hernia be for you to perform surgery?
Larger than one finger diameter
How should a calf be treated after umbilical hernia surgery?
Must have minimum 1 month box rest and not be turned out for 3 months after surgery to avoid wound breakdown
Add calf to a group of smaller animals to prevent bullying
What sedative should you use when performing surgery on a calf with a simple umbilical hernia?
Xylazine
What local anaesthetic should you use when performing surgery on a calf with a simple umbilical hernia?
Procaine
Which incision should you make when performing surgery on a calf with a simple umbilical hernia?
Elliptical incision
Describe the surgical approach to surgery on a calf with a simple umbilical hernia
Dissect down the edges of the hernia ring using Metzenbaum dissection scissors to free the peritoneum
Hernial sac will fall back into the abdomen, allowing the edges to be drawn together
(Do not open sac unless incarcerated/adhesions)
What is the cause of an infected umbilicus/abscess outside the body wall in a calf with umbilical hernia?
A.Pyogenes or E.Coli
How would you treat an infected umbilicus/abscess outside the body wall in a calf with umbilical hernia?
Antibiotics eg amoxicillin +/- open abscess cavity and flush with saline/disinfectants twice daily
Need several weeks treatment to prevent recurrence
How would you treat a patent/infected urachus in a calf with an umbilical hernia?
Flush and give antibiotics
May require surgery to remove urachus and infected umbilical arteries 1 or 2 stage process
How would you treat an infected umbilical vein in a calf with an umbilical hernia?
If doesn’t extend to liver, treat as for urachus (flush/antibiotics/surgery)
If tracks to liver, can try surgery if no systemic signs-partial hepatectomy
Maruspialisation of vein out of body wall to drain abscess
Poor prognosis
Give some complications of umbilical hernia surgery in calves
Seroma
Re-herniation
Infection
Why might a cow not have come into oestrus?
- Cysts
- Persistent CL
- Nutritional anoestrus (NEB)
- Cycling but oestrus not observed/no behavioural changes
What would it mean if you found the following when doing a vaginal exam:
- Pus
- Clear mucous
- Blood
- Pus: endometritis
- Clear mucous: oestrus
- Blood: metoestrus
How big is a follicular cyst?
25mm+ diameter
Give the 2 types of commercial prostaglandin
- Estrumate (GnRH analogue; Cloprostomol)
- Dinoprost (synthetic)
Where are prostaglandin drugs metabolised?
Give a possible side effect
- Lungs
- Asthma, Blackleg
How soon after calving does the first follicular wave occur?
5-10 days
How would you describe the nature of the first ovulation after calving?
Silent
How long does oestrus last (ie how long will a cow stand to be mounted)?
12 hours
Give some signs of a cow in oestrus
- Standing to be mounted (best indicator)
- Chin resting
- Licking
- Bunting
- Mounting head to head
- Sniffing vulva
What could you recommend to a farmer to be able to tell whether or not a cow is in heat?
- Pain/chalk/ Kamar (changes colour when mounted by another cow)
- Pedometers
- Record keeping
- Teaser bull
- Monitor progesterone
How long does the oestrus cycle last?
18-24 days
How long does it take for involution of the uterus to occur after calving?
3-4 weeks
What stimulates the first follicular wave post-calving?
Increase in FSH
How long after calving does the first oestrus occur?
2-3 weeks (unless ill/NEB)
Give some negative factors for using natural service over AI
- Lack of genetic variation
- Potential for injury to both cow and bull
Define metritis
- Inflammation of all layers of uterus (abnormally enlarged uterus and purulent uterine discharge detectable in the vagina)
- Occurs within 21 days after calving
What are the 3 grades of metritis
1) Enlarged uterus, purulent uterine discharge, no pyrexia/illness
2) ‘Puerperal metritis’: overt systemic illness (decreased milk yield, fever >39.5oC, reduced appetite)
3) ‘Toxaemic metritis’: signs of toxaemia (cold extremities, dullness)
Define pyometra
Accumulation of purulent material within the uterine lumen, in the presence of a CL and a closed cervix
Define endometritis
Inflammation of functional wall of uterus (purulent uterine discharge detectable in the vagina)
Occurs after 21 days post-partum
Give some risk factors for uterine bacterial infection
-RFM
-Abortion
-Dystocia
-Twins
(also induction, multiparous, milk fever)
Which pathogens are most likely to cause uterine disease?
- E coli
- Trueperella pyogenes
- BHV-4 (endometritis)
- Dichelobacter nodosus
- Fusobacterium necrophorum
Give some symptoms of cystic ovarian disease
- Anoestrus
- Nymphomania (due to a pathological expression of oestrus)
- Extending calving interval
- More common <60 days post-calving
Describe follicular cysts
- Thin walls (<3mm)
- Fluid-filled
- Internal diameter >25mm
- Last for 10 days
Describe luteal cysts
- Luteinised follicular cyst
- Thick walls (>3mm; indicates progesterone production)
- External diameter >25mm
- Fluid-filled lacuna
- Last for 10 days
How can you diagnose uterine cysts?
- Palpation
- US
- Milk progesterone?
Which drug is most successful in treating endometritis?
Oxytetracycline
Which abortion-causing microbes have vaccines?
- Brucella
- Lepto
- BHV-1
- BVDV
What is the difference between a primary and secondary abortion pathogen?
- Primary: cause damage to and cross the fetomaternal barrier (eg Brucella)
- Secondary: need another agent to create damage so it can cross the fetomaternal barrier (eg salmonella)
When in gestation do most pathogens cause abortion?
4 months +
Give some primary infectious agents that cause abortion
- Brucella abortus
- BVDV
- BHV-1
- Leptospira borgpetersenii (commensal in repro tract)
- Neospora
- Parainfluenza 3
Give some secondary infectious agents that cause abortion
Gram +ve: streps and staphs, Staph aureus, Trueperella pyogenes, Listeria monocytogenes
Gram -ve: E coli, Fusobacterium necrophorum, Histophilus somni, Leptospira borgpetersenii, Salmonella
Give the 3 routes of infection for abortion
- Resident flora of repro tract during pregnancy
- Transplacenral
- Haematogenous (ie viruses)
What is the most common cause of abortion in cattle?
Neospora (12.5% of UK abortion)
What is the most likely outcome of pregnancy in a cow infected with Neospora?
Birth of clinically normal, PI calf
What kind of virus is BVDV?
Pestivirus
In which organ can Leptospirosis reside?
Kidney
How do you treat Leptospirosis?
- Antibiotics: prolonged course of dihydrostreptomycin or oxytetracycline
- Can control with vaccination
Which Salmonella serovar is most associated with bovine abortion?
S. Dublin
What increases shedding of Salmonella?
Stress eg around calving
When do you vaccinate against Salmonella?
2 months pre-calving
Should also vaccinate youngstock
How would you diagnose a calf persistently infected with BVDV?
Can detect in blood from 1 month old (if <30 days, MDAs interfere)
Ear notch tissue test when tagged
You can do bulk milk screens for which abortion-causing pathogens?
- BVDB
- Lepto
- Neospora
- BHV-1
How can you identify Campylobacter as a cause of abortion?
- Preputial washing of bulls (use warm phosphate-buffered saline)
- Vaginal mucus collection (minimum of 12 samples)
When during pregnancy does Neospora cause abortion?
Between months 4 and 6
How can you use radiography to see if an aborted calf died from BVD?
Radio-opaque lines will be present on bones
Give a developmental lesion associated with BVD in calves
Cerebellar hypoplasia
When does T cell recognition of the calf’s own self occur during gestation?
90-120 days gestation
In which ways can Neospora cause abortion?
- Cattle ingest oocytsts -> transplacental transmission -> PI calf or abortion or uninfected weak calf
- PI cow recrudesces during pregnancy -> PI calf or abortion or uninfected weak calf
How can you diagnose neospora in an aborted calf?
Brain histopath
How can you control Neospora?
Keep dogs away from cattle feed and water and don’t allow to eat placentas
Cull seropositive animals and offspring? (often not practical as high prevalence)
Breed to beef and do not keep or sell as replacement heifers
Use sexed semen to get more heifers from uninfected animals
What is the incubation period for BVD?
5-7 days
Give the likely outcomes of infection with BVD at the following gestations:
0-95 days
95-120 days
120-285 days
0-95 days: abortion or resorption
95-120 days: PI calf
120-285 days: sero-positive foetus +/- congenital lesions. Abortions may occur due to placentitis
Give some effects of BVD on cows
Lowered pregnancy rates (affects the epithelia lining the repro tract)
Abortion
PI calves
Congenital abnormalities (of calves affected after day 120 of gestation)
Mucosal disease
Give some clinical signs of mucosal disease (caused by BVD)
Ulcerations of mucosa (particularly tongue, soft palate, ginigiva & oesophagus)
Ill thrift
Diarrhoea
+/- Concurrent respiratory disease (immune suppression)
How is leptospirosis excreted by cows?
In urine
Give some clinical signs of leptospirosis in cows
Cow often in latent state Abortion, stillbirth, weak calves Infertility RFM Milk drop (uncommon)
How do you diagnose leptospirosis in cows?
Bulk milk antibody testing gauges level of infection in herd
Serology
Identification of leptospires from aborted tissue, blood or urine by IF or PCR
How is Camplylobacter fetus venerealis spread?
Venereally
How does Camplylobacter fetus venerealis cause infertility?
Early embryonic loss within first 3 weeks of conception
What is the difference between Camplylobacter fetus venerealis and Campylobacter fetus fetus?
Camplylobacter fetus venerealis causes early embryonic loss within first 3 weeks of conception
Campylobacter fetus fetus causes abortion
Give the clinical signs of Trichomonas fetus
Occasionally causes abortion
More commonly causes poor pregnancy rates
Pyometra and endometritis
How is Trichomonas fetus spread?
Natural service
How can you estimate gestational age of aborted foetuses?
Crown-rump length
Which sample would you need from an aborted calf when investigating BVD?
Spleen (PCR)
How do you treat Campylobacter in bulls?
Systemic: Streptomycin 10mg/kg
Sheath lavage: 100ml pen/strep
How long does oestrus last in the cow?
24 hours
When does a cow ovulate?
12 hours after the end of oestrus
Which hormone is essential for embryo growth?
Progesterone
How do you calculate submission rate?
No of cows served / no of cows eligible
How do you calculate pregnancy rate?
No of cow pregnant / no of cows served
When can you detect a calf’s heartbeat in a pregnant cow?
Day 28
Which endocrine changes are associated with ovarian cyst formation?
Reduced LH surge
Persistently increased oestrogen levels
Give some effects of milk fever
RFM
Endometritis
Difficulty calving
When is a cow’s peak milk yield after calving?
8 weeks after calving
How do follicles and CLs feel when doing a rectal examination?
Follicles: blister-like
CL: firm sponge
What are the 3 accessory sex glands of a bull?
Seminal vesicles (cranial to prostate) Prostate Bulbourethral gland (caudal to prostate)
How do you score endometritis based on vaginal mucus appearance?
0= clear/translucent mucus 1= mucus containing flecks of white or off-white pus 2= <50ml exudate containing <50% white/off-white mucopurulent material 3= >50ml exudate containing purulent material, usually white or yellow, occasionally serosanguinous (containing blood), very unpleasant odour
What does the calf embryo secrete to signal its presence? How is this different from a foal?
Calf embryo secretes interferon tau
Foal embryo moves around the uterus
How do you diagnose pyoderma?
Enlarged uterus
CL
Check ultrasound for pus
How do you treat pyoderma?
Prostaglandin
Give some predisposing factors of cystic ovarian disease
High milk production NEB and ketosis; raised NEFAs Twinning and periparturient problems Genetic predisposition Higher parity Excess BCS at drying off
What effects do follicular cysts have on the oestrus cycle?
Secrete oestradiol for the first half of their lifespan -> other follicles can’t develop, and prolonged oestradiol inhibits the LH surge
What % of cows should a fertile bull get pregnant?
Should get 90% of 50 normal, cycling, disease free, females pregnant within 9 weeks
60% should become pregnant within the first 3 weeks of the breeding period
What BCS should a bull be at the start of the breeding period?
3 or 3.5
What are the treatment options for penile haematoma in a bull?
Cull
Medical: sexual rest for 2 months. Cold hosing for 4 days followed by warm hosing and massage for 3 weeks. ABs to stop abscess formation & NSAIDs
Surgical: removal of blood clot and suturing of tunica albuginea where possible. Followed by medical treatment.
What causes penile fibropapilloma in bulls?
Bovine papilloma virus
Most common in young bulls
How do you treat penile fibropapillomas in bulls?
Removal can be done standing under a pudendal nerve block
What are the main venereal diseases that can be transmitted by bulls?
Campylobacter fetus venerealis
Trichomonas foetus
BHV 1
Give some clinical signs of Campylobacter fetus venerealis in cows
Endometritis after service
Failure to conceive
Late embryonic death (irregular return to service)
Abortion (usually 4-5 months)
Do cows and bulls develop immunity to Campylobacter fetus venerealis?
Cows develop immunity after a few months and can get pregnant again but may shed for up to 1 year
Bulls do not develop immunity
How do you diagnose Campylobacter fetus venerealis in cows and bulls?
Cows: vaginal mucus culture
Bulls: sheath washing and culture
What is the voluntary waiting period?
How long should it be?
Time between calving and first service
50 days
Give some differentials for a cow that calved last night and is dull, unwilling to stand, off her food, tachycardic, with no rumen turnover
Hypocalcaemia (usually occurs within 72 hours of parturition) Toxic mastitis (E.coli, Klebsiella) Trauma at calving Hypomagnasaemia Ketosis (would usually happen 21 days post-calving) Metritis Fracture Poisoning Haemorrhage Nerve/muscle damage Hyperphosphataemia DA (would usually happen 21 days post-calving)
Give some differentials for a cow that is 80 days post-calving and has not been seen in oestrus
Cystic ovary (follicular or luteal cyst) Missed heats (poor heat detection) Endometritis (unlikely if no vulval discharge) Mastitis DA Hypocalcaemia Persistent CL Nutritional anoestrus (eg in NEB)
How do you treat a follicular or luteal cyst?
GnRH followed by prostaglandin 7 days later
Can use an ovulation synchronisation programme (eg GnRH, then prostaglandin 7 days later, then a second administration of GnRH 48hr later, and finally TAI 0–24 hr later)
Give a differential for a cow that calved 28 days ago with white muco-purulent vulval discharge
Endometritis
