Bovine reproduction Flashcards
What is the definition of fertility?
The ability of a cow to give birth to a live calf at approximately 12 month intervals
What is the definition of sterility?
The total inability of a cow to become pregnant/give birth to a live calf
What is infertility/subfertility?
Cow can become pregnant and give birth to a live calf but the interval may be longer than 12 months
What are some main reproductive difficulties?
Failure to cycle Failure to be mated Failure to conceive Dystocia Stillbirths Neonatal mortality
What are the two things that can happen to a follicle?
Ovulates or atreses
How long is a normal cow oestrous cycle?
21 days
What is a normal post partum cyclicity pattern?
3 weeks post partum - small rise in progesterone due to an short lived corpus luteum
Then goes into a normal 3 week cycle
What other post partum cyclicity patterns are there?
Long anoestrus - suckling calf
Persistent luteal phase - abnormal
What is involution of the uterus?
Repairing the uterus
How long do you have to get the cow back pregnant for the 12 month cycle?
85 days
When is puberty in heifers?
7-18 months
35-40% of mature body weight
What is the age that cows are first served?
14-22 months
Best to calve at 2 years
What is the average duration of oestrus?
6 hrs
How and when do cows ovulate?
Spontaneously 9-15hrs after the end of standing oestrus
When is it best to inseminate a cow?
6 hrs
At mid oestrus
What is a common cause of poor reproductive performance?
Poor oestrus detection
What are the most reliable signs of oestrus?
Standing to be mounted
Mounting the head and neck of other cows
When is the first post partum oestrus?
15-30 days after calving
What is the first post partum oestrus like?
Behavioural oestrus is absent bcos brain needs to be primed with progesterone
What should the BCS be at calving?
3 so it doesnt drop below 2.5 at service
What is the average length of gestation?
285 days
How long is the gestation period to be considered abortion?
Shorter than 270 days
Why should you perform a breeding soundness exam on a bull?
Can cause major financial impact on a farm
Welfare
When should you perform a breeding soundness exam?
Pre purchase
Pre breeding season
For an infertility investigation
What are the steps of a breeding soundness exam?
Take history Clinical exam Semen collection/evaluation Test mating Prognosis
What are the 4 different categories of inability to mate?
Good libido but hesitant about mounting
Failure to exteriorise penis
Penis exteriorised but no intromission
Intromission but no thrusting
What can cause no thrusting?
Damage to the dorsal nerve of the penis - dont know penis is in vagina
How can you examine the penis safely without causing damage?
Xylazine - relax retractor penis muscle
Before/after mating - deviate to one side and look
What is the most common traumatic condition of the bovine penis?
Penile haematoma
What can cause penile haematoma?
Sudden angulation of penis/miss thrust
Tears tunica albuginea of corpus cavernosum at sigmoid flexure
What are the signs of penile haematoma?
Swelling cranial to scrotum
reluctance to serve, cant extrude penis
What is a complication of penile haematoma?
Abscessation
Damage to dorsal nerve of penis
Cant raise blood pressure in penis and get erection
What occurs to the penis normally during intromission?
Deviates ventrally and to the right
What is the main sign of spiral deviation of the penis?
Failure to extrude penis
What is phimosis?
Stricture of the preputial orifice
What does phimosis cause?
Failure to extrude the penis
What can cause phimosis?
Injury or infection
What is paraphimosis?
Can get the penis out of the prepuce but cant withdraw it
What does paraphimosis lead to?
Strangulation
What is balanoposthitis?
Inflammation of the penis and prepuce
What can cause balanoposthitis?
Infection
Trauma
BHV 1
Mycoplasma
What is the name of warts on the penis?
Fibropapilloma
What are signs or papilloma?
Bleeding at service
Pain at intromission
Phimosis/paraphimosis
What is impotence?
Cant get an erection
What are the two reasons for impotence?
Shunt for the blood
Blockage of proximal penis
What are some causes of impotence?
Congenitally large veins draining penis
Traumatic injury
Blockage by fibrous tissue/thrombus/haematoma
How do you assess the musculoskeletal system of bull?
Observe gait and posture
Lameness
Conformation
What change to the testes can cause infertility?
If held high/too close to body they will be too hot
What should testes be?
Similar in size
Round
Not too close to body
Symmetrical
What can cause testicular hypoplasia?
Inherited defect
XXY chromosome
What is a feature of testicular degeneration?
Failure of spermatogenesis
What can cause testicular degeneration?
Systemic infection
Trauma
Hot/cold
Autoimmunity
What are the 4 main causes of an enlarged testicle?
Orchitis
Abcess
Haematoma
Neoplasia
What can cause orchitis?
Wound
Ascending infection
Truporella pyogenes
What are the main features of orchitis?
Usually unilateral
Often accompanied by periorchitis/epididymitis
What is epididymal occlusion?
Blocked epididymis
What can epididymal occlusion cause?
Spermatocoele - cystic dilation
Sperm granuloma after rupture of epididymal wall
Testicular degeneration
What is seminal vesiculitis?
Normal penis and testes but abnormal ejaculate with not enough seminal fluid
What are the signs of acute seminal vesiculitis?
Severe pain
Purulent discharge
Pus in semen
Enlarged
What are the signs of chronic seminal vesiculitis?
Pus in semen
Fibrosis
Loss of lobulations
No pain
How do you collect semen?
Electroejaculation
Artificial vagina
Massage ampulla per rectum
What should you assess in semen evaluation?
Volume Colour Wave motion Motility - linear Live:dead ratio
What does semen evaluation show?
Potential to sire calves
Only true test is calves on the ground
How do you sex sperm?
Sort using flow cytometry - female sperm contain more DNA than male
What is the definition of abortion?
Production of one or more calves less than 271 days after service/AI
They are dead or alive for less than 24 hours
When is the level of abortion frequency an issue?
When it exceeds 3-5%
How are infectious agents of abortion classified?
Sexually transmitted
Non sexually transmitted
Primary - act directly on the repro tract
Secondary - cause systemic disease