Cattle Reproduction Flashcards
What is the length of a cow oestrus cycle?
21 days
What continues to produce progesterone after ovulation?
Corpus luteum
What are the Cotyledons?
What are the Caruncles?
The foetal side of the placenta
The maternal side of the placenta
What shape are placetomes in the cow and sheep?
Cow: Convex
Sheep: Concave (doughnuts)
In which ovary do 60% of ovulations occur?
Right
How long does involution of the uterus take?
3-4 weeks
How does resumption of cyclicity after calving occur?
2 weeks post-partum FSH increases, which stimulates the first follicular wave
What does suckling do?
Inhibits resumption of cyclic activity
What is the gold standard for oestrus detection?
Progesterone monitoring (blood test every day)
What time period is a retained foetal membrane classed as in a cow?
Over 12 hours after delivery of the calf
What are the 3 consequences of uterine infections?
- Damage uterus
- Suppress hypothalmic GnRH and pituitary LH secretion
- Localised effects on ovarian function
What are 4 main pathogens involved in uterine infections?
Are they gram +ve or -ve
- E. coli (-ve)
- Truperella pyogenes (+ve)
- Dichelobacter nodosus
- Fusobacterium necrophorum (-ve)
What is the biggest risk factor of uterine bacterial infection?
RFM
What is metritis?
Abnormal enlargement of uterus and purulent vaginal discharge within 21 days of parturition
What are the grades of metritis?
1: Enlarged uterus and purulent discharge but no pyrexia/illness
2. Systemic illness and pyrexia
3. Toxaemia
What is the treatment for pyometra?
PGF (Prostaglandin F2 alpha)
How do you differentiate between metritis and endometritis?
Metritis is within 21 days of calving
Endometritis is 21 days or MORE after calving
What are the 3 biggest effects on fertility?
i.e. days from calving to pregnancy
- Caesarean
- Lameness
- Endometritis
What are two clinical signs of cystic ovarian disease?
When is it most common?
- Nymphomania
- Anoestrus
< 60 DIM
How does Cystic Ovarian Disease affect milk production?
High milk production
What are the main differences between follicular and luteal cysts?
Follicular cysts are thin walled and fluid filled
Luteal cysts are thick walled and may have trabeculae inside
Follicular cysts are larger in diameter than luteal
How do follicular cysts cause continuous oestrus?
Produce oestrodial (oestrogen)
What is the best way to treat COD if unsure what type of cyst is present?
What should you do if the cow comes into oestrus after treatment?
Progesterone device (PRID/CIDR)
DONT inseminate, oocyst will be old or unhealthy
Wait for next cycle
What is so important about Brucellosis?
How is it monitored?
It is zoonotic and reportable
Monthly routine bulk milk sampling
What are 5 non-infectious causes of abortion?
- NEB
- Selenium deficiency
- Iodine deficiency
- Alfatoxins
- Nitrite/nitrate toxicity
What cell type does BVD target?
What does this cause?
Neuroglial cells
Cerebellar hypoplasia
How can primary abortive agents cause abortion?
Damages placenta and foetus, allowing invasion of opportunistic pathogens
How do secondary (opportunistic) pathogens cause abortion?
Prostaglandin synthesis
Prostaglandin inhibits progesterone
Progesterone maintains pregnancy, without it luteolysis occurs
What are the three routes of infection for abortive agents?
- Commensal flora of reproductive tract
- Transplacental
- Haematogenous
How does the complexity of the antigen produced by abortive pathogens affect foetal antibody response?
The more complex the antigen, the more time it takes for the foetus to recognise the antigen as “non-self” and mount an immune response (antibody production)
What is the most commonly diagnosed cause of abortion?
Which groups of animals are at highest risk?
Neospora
Congenitally infected heifers in first gestation
What virus causes IBR?
BHV-1
How does horizontal and vertical transmission of Neospora occur?
Horizontal (exogenous)
Ingestion oocyts, naive animals, abortion storms
Vertical (daughter-daughter)
Slow succession
What is the most common outcome of Neospora infection during gestation?
Birth of clinically normal persistently infected calf
What is cytopathic BVD associated with?
Mucosal disease in PI animals
What type of virus is BVD?
Pestivirus
At what stage (in days) of gestation does BVD infection cause a PI (persistently infected) foetus?
95-120 days
What antigen and antibody status are PI calves?
Antibody negative
Antigen positive
When should you vaccinated for BVD?
When is the earliest PI calves can be diagnosed?
Before AI (first breeding)
Protects the pregnancy
1 month
Before this, MDA interferes
What disease in sheep does BVD have link with?
What is the prevention?
Border disease
Avoid co-grazing
Which 3 abortive agents can result in a latent state? (i.e. no clinical signs)
BHV-1
Neospora caninum
Leptospira hardjo
Which is the most common serovar associated with bovine abortion?
What should be done upon diagnosis of infecton?
S. dublin
ZOONOTIC
Reportable to APHA and inform milk buyer
Why is calving significant to Salmonella infection?
Stressful period
Stress increases shedding
Which strain of Campylobacter causes abortion?
What is it often mistaken for?
How is it diagnosed?
Campylobacter fetus fetus
Apparent failure to conceive/poor fertility
As causes very EARLY abortion
Culture of vaginal mucosa or preputial washes
Which two abortive agents are spread venereally (i.e. natural service)
Trichomonas fetus
Campylobacter spp
Which 4 abortive agents can you use Bulk milk screens for? (antibody)
What is the next step if this comes back positive?
- BVD
- IBR
- L Hardjo
- Neospora
First lactation screen
In testing for BVD, what is the next step if the first lactation milk screen comes back positive?
Bulk tank PCR to test for antigen
What is the treatment for Campylobacter in bulls?
What age do bulls have to be in order for it to be effective?
Streptomycin preputial washings
< 4 years old
What type of abortive agent is Selenium/Vitamin E deficiency?
Why?
Primary non-infectious
Anti-oxidants
Cause myocardial degeneration and allow invasion of secondary agents (e.g. Streptococci)
Which abortive agent is associated with cerebellar hypoplasia?
What 2 other foetal lesions does it cause?
BVDv
- Fatal foetal myocarditis
- Radio opaque lines
What foetal lesions are associated with Ureaplasma diversum?
Conjunctivitis
Bronchopneumonia
Which foetal abortive agent causes pericarditis?
B. lichenformis
What does Truperella pyogenes cause in calves?
Bronchopneumonia
What does iodine deficiency cause?
Thyroid hyperplasia
Which virus causes liver necrosis?
BHV-1 (IBR)
What is a circular chart used to monitor lactation and fertility called?
What does circular once round represent?
Bray chart
1 lactation
What does the calving to conception interval produce?
As animals conceive, what happens to the ratio?
Predicted calving index
Gets WORSE as animals conceive
What is the conception (pregnancy) rate?
How many more cows conceive than actually calve? (%)
% pregnant (at PD) of those served
50-80%
Which is more predictive of actual calving, a later or earlier PD?
Later
Allows for losses due to abortion/resorption
What is the definition of abortion?
Calving that occurs < 270 days of gestation
How is a Cu-sum used to track conception rate over time?
Positive PD moves up
Negative moves down/horizontal
What are two autosomal recessive diseases of cattle?
Bovine Leucocyte Adhesion Deficiency
Complex Vertebral Malformation
What clinical signs present with Bovine Leucocyte Adhesion Deficiency?
Ulcers on oral mucosa
Chronic pneumonia
Recurrent/chronic diarrhoea
Death < 1 year old
What is arthrogryposis?
What congenital disorder can cause this?
Multiple joint contractures of limbs at birth
Complex Vertebral Malformation
What is the best way to measure efficiency in suckler herds?
Calves weaned/cows to bull
What is the target age at first calving in a suckler herd?
2 years old
What are 3 ways of heifer management in a suckler herd?
- Selected replacements from early born calves - maximum growth and age at time of breeding
- Wean her calf early
- Calve heifers 3-4 weeks before PSC for herd - gives extra time before next breeding
How can you control BCS in a suckler herd?
Wean early: increase BCS
Wean late: If cow is overconditioned
What are the targets for a fertile bull?
90% of females pregnant within 9 weeks
60% should become pregnant within first 3 weeks
When put with a cow on heat, should serve within 20 minutes (ideally 10)
What measurement of scrotal circumference in bulls is associated with reduced fertility?
< 34cm
What BCS should bulls start the breeding period at?
3-3.5
What 3 things do you assess in semen evaluation?
- Gross motility
- Linear progressive motility
- Morphology
What causes penile haematoma?
What is the clinical sign?
Sudden bending to erect penis
Rupture of tunica albuginea
Why is surgical removal indicated in penile fibropapilloma in bulls?
Bleeding reduces semen quality
Interferes with serving
In campylobacter fetus venerealis, why is it harder to eradicate in older bulls?
Lives in crypts of prepuce
Increased size of crypts as bulls age
What causes IPVV?
Infectious Pustular Vulvovaginitis/Balanoposthitis
BHV-1
DIFFERENT strain from the one that causes IBR
What are 3 causes of fertility problems in cattle?
- Lameness
- Low BCS
- High yield
What 3 effects can milk fever have?
- Difficult calving
- RFM
- Endometritis
What 3 effects on oestrus does lameness have?
- Lower intensity of oestrus
- Affects oestrus behaviour (e.g. mounting)
- First CL and first oestrus occurs later
What are the 3 stages of calving?
- Cow separates from rest of herd, dilation of cervix, beginning of strain
- Waterbag (membranes) appear and rupture, delivery of calf
- Expulsion of placenta
Give 3 reasons to proceed with assisted calving
- No progress after 1 hour of waterbag showing
- Extreme discomfort
- Excessive bleeding from vulva
How does Clenbuterol (Planepart) assist with dystocia?
Relaxes uterus which give more space in uterus to manipulate calf Reduces contractions
Increases perfusion to calf
What anaesthetic technique would you use for an episiotomy?
What cattle is this nearly always used in?
Caudal epidural
Heifers
What are 3 complications of an episiotomy?
- Wound infection and breakdown
- Distorted vulva confirmation, reduces fertility
- Rectovaginal fistula (if cut at 12 noon)
What are 2 indications for full embryotomy?
- Large dead calf
2. Foetal monster
Which direction do the majority of uterine torsions occur in?
Anti-clockwise (stood behind the cow
In which direction do you roll a cow to untwist a uterine torsion?
From left lateral recumbency
To back
To right lateral recumbency
What are the 3 forced indications for a caesarian section?
- Foetal oversize/foetal-maternal disproportion
- Irreducible uterine torsion
- Insufficient cervical dilation
What must you avoid using when performing a caesarian and why?
Sedation! Will cross placenta and decrease viability of calf
What two methods of anaesthesia could you use in a C section?
- Caudal epidural
2. Paravertebral nerve block
What should be given post-op after a C section?
Oxytocin +/- calcium
