Bovine Flashcards
Define a fertile bull
Impregnate naturally 60% and 90% in normal females in 3 and 9 weeks
Define sub-fertile bull
Can impregnate naturally but below fertile levels. Or, cant impregnate naturally but can by AI
Define infertile bull
Cannot achieve pregnancies
What to check for on physical exam
Lesions, congenital defects, papillomas, persistent frenulums, posthitis
What is a fibropapilloma?
A penile wart that self resolves with sexual rest
What is balanoposthitis
Due to BHV
What could swelling of the prepuce be caused by?
Penile haematoma (rupture of tunica albuginea), cellulitis (laceration on prepuce with penile oedema), trauma, ruptured urethra
How do we treat preputial prolapse?
Systemic AB, anti-inflammatories, hydrotherapy, topical antibiotics
Surgery
What is part of a conformation exam?
Legs, joints, head, length of prepuce, sheath structure/score
what do we report about swollen joints in young bulls?
Q or F classification
Re-evaluate if necessary
Avoid growing bulls too rapidy between 6-12 months
What do we examine with the scrotum?
Measure and palpate - puberty >27cm
Circumference -> outside 90% CI for breed and weight may indicate fertility issues
If close to threshold - may be right as he grows so record as Q and retest
What is scrotal circumference related to?
Daily sperm production
High semen quality
Onset of pubery in heifers and bulls
Pregnancy rate
What do we assess semen for?
Motility + mass activity
Volume and concentration
Colour, texture + contaminants
What progressive motility % is a fail or a pass?
Fail <30%
Pass >60%
What concentration is a fail or pass?
Fail <200 million/ml
Pass >200 million/ml
How do we examine progressive motility?
Dilute - recommend using pipette to draw into Eppendorf tube with phosphate buffered saline and examine at 100x
How do we assess libido?
Serving ability test - 10 minute test record successful services
Restrain females in breeding crates and 10 min stimulation of bulls first, then 10 minutes of serving
Record interest, mounts (not including serves), serves
at least 1 serve = pass
How do we assess semen morphology?
High power microscopy
Use stained smear or preserved in formol buffered saline (examine under phase contrast)
Examine at 1000X and count 100
Need at least 70% normal sperm
How long is spermatogenesis?
61 days -> 13.5d for one cycle and need 4.5 cycles for spermatogenesis
What is the epididymal transport time in bulls?
11-14 days
When does puberty occur in cows?
8-19 months
What influences onset of puberty?
Bodyweight, breed, age, nutrition, sire scrotal circumference, season of birth, management (growth implants)
What weight do we breed cows?
55-65% BW for heifers
350kg for holstein-friesian
15-20 months for dairy heifers
15 months for beef heifers
What age are bulls fertile?
10 months (not Brahman)
Oestrus cycle length
18-24 days
When does ovulation occur
12h after the end of oestrus
Oestrus length
18 hours
How long is the oocyte viable for?
6 hours
How long can fresh sperm survive?
24-48 hours
How long is the luteal phase?
14-18 days
Where does fertilisation occur?
Ampullary-isthmic junction
What is the average pregnancy rate per cycle?
60%
What are the energy requirements of an adult cow for maintenance, lactation, or pregnancy?
Maintenance -> 10% BW + 5-10MJ
Lactation -> Maintenance + 5MJ ME/L
Pregnancy -> maintenance + 5MJ ME/month of pregnancy starting at 6 months
What day does attachment occur and what does this cause?
Day 28
Stops PGF2a production from endometrium to stop lysis of the CL
What is the role of interferon Tau and when is it produced?
Produced day 16 from the trophoblast - stops lysis of CL
When do the first villi form during pregnancy?
30 days and attach to carcuncle up to 36 days
Main functions of placenta
Metabolic exchange, temporary endocrine organ (progesterone, placental lactogen, IGFs)
Where are binucleate giant cells located and what do they produce?
In the placenta
Produce placental lactogen and pregnancy specific protein B
What is the amnionic fluid made of?
Fetal salivary and amnionic membrane secretion
What is the allantoic fluid made of?
Fetal kidney secretions via urachus
Allantoic membrane secretions
What type of placenta do cows have?
Synepitheliochorial
Cotyledonary
Gestation of pregnancy?
283 days - Cl present for duration
When does the placenta produce significant levels of P4?
From 120 days
When is the uterus involuted?
By 35-45 days
When does the first PP ovulation occur?
16-18 days
What is lochia?
Normal PP discharge - should not smell foul
What 3 things occur during Puerperium
Uterine involution
- Decreases in size over 40 days
Lochia
Re-epithelialisation of caruncles
When should the involuting uterus stop being contaminated?
21d
How is clinical endometritis defined?
> 50% purulent uterine discharge past 21 days PP
How is subclinical endometritis defined?
> 8% neutrophils in cytology between 21 and 30 days
How is subclinical endometritis defined?
> 8% neutrophils in cytology between 21 and 30 days
What is pyometra?
Purulent material in lumen of uterus with closed cervix and persistent CL
What is metritis?
Inflammation of the full thickness of the uterine wall within 21 days with fetid purulent uterine discharge in the vagina
What is puerperal metritis and when does this usually occur?
Metritis coupled with systemic signs -> tachycardia, hyper/hypothermia, decreased milk yield
Usually occurs <10d PP
Explain the difference between luteal and follicular cysts in cystic ovarian disease
Follicular cyst - does not ovulate
Luteal cyst - luteinises and does not ovulate - edge of follicle thickens to become this that produces progesterone
2 pathogens causing infertility (failure to conceive whilst still cycling)
Campylobacteriosis (Vibriosis) - campylobacter fetus var venerealis
Tritrichomonas foetus
What is vibriosis - what does it cause, describe organism and where is it found on a bull
Venereal disease transmitted through copulation causing 3-5 month infertility and occaisonal abortion
Gram negative rod - bulls asymptomatic (permanent or transient infection found in penis + prepuce)
What does vibrio produce in the female?
Endometritis and local immune response of mainly IgA antibodies - in vaginal mucous
Signs of vibriosis
Embryonic death - longer interoestrus intervals and delayed conception
Occaisonal abortion
Vaginal and cervical erythema
Control of vibriosis
Vaccine - double dose 4-6 weeks apart (2nd dose 1 month before joining) do bulls and sometimes heifers
Have a clean and dirty herd
Pathogenesis of Vibriosis
Bacteria on bull penis and prepuce - fertilisation followed by EED due to endometritis and no subsequent conception at next breedings
Recovery in 3-5 months
Older bulls - chronic carriers
How do we diagnose Vibriosis?
Bacteriology of aborted fetus, vaginal mucous IgA ELISA, smegma from bull
What is tritrichomonas foetus?
A protozoan venereal pathogen
What does tritrichomonas cause?
Infertility, occaisonal early abortion + pyometra
Is there a vaccine for tritrichomonas?
No
Where is tritrichomonas foetus found? What signs does it cause and when?
Vagina, uterus + uterine tubes - discharge 3-4 days later and vulvovaginitis on day 4-9
Bulls penis and prepuce
Is there an IgA test for tritrichomonas?
NO
When does tritrichomonas foetus cause fetal death?
day 50-100
How do we diagnose tritrichomonas fetus?
Herd and preg test records, preputial culture of older bulls - 3-6 samples at weekly intervals
Culture from pyometra
How do we control Tritrichomonas?
No vaccine or antibiotic
Clean & dirty herd - cull dirty
sexually rest clean herd for 3 months after calving
Keep bull herd young
Name 2 other bacterial causes of infertility
Mycoplasma Bovigenitalium
Ureaplasma diversum
What is ureaplasma diversum and mycoplasma bovis? What does it cause in cows and bulls? What control measures are there?
associated with mucous membranes causing vulvovaginitis, cervicitis, endometritis, infertility, EED and LFL
Seminal vesiculitis in bulls
No control measures
Name 6 diseases that cause epidemic abortion
- Leptospirosis
- Infectious bovine rhinotracheitis
- Campylobacteriosis
- Bovine Pestivirus (BVDV)
- Brucellosis
- Neosporosis
Clinical signs of lepto
How is it transmitted
Placentitis, mastitis, abortion in last trimester
Transmitted in urine and products of abortion
How do we diagnose lepto?
History
Serology -> bleed herd sample of 10-15 twice and look for seroconversion - low titres present in cattle (hardjo)
Urinary examination -> excretion starts 2 weeks after infection lasting from 4 months - years
How do we treat lepto?
25mg/kg streptomycin single dose - DPI authorisation hard to get
Erythromycin and oxytetracycline also effective with multi doses
How do we control lepto?
Use bivalent vaccine in heifers twice 4-6 weeks apart
annual booster late gestation
Vaccinate males
What does IBR cause and what group does it belong to?
Bovine herpes group
Abortion btwn 4-9 months
Fetus retained 2 days = autolysis
Recrudescence
What are other symptoms of IBR?
Can also cause rhintotracheitis, conjunctivitis, meningoencephalitis
Abortion not reported in Australia
What type of virus is bovine pestivirus, how many herds are affected?
Enveloped positive sense SS RNA virus
>80% herds affected
variety of clinical manifestations depending on biotype
Name the two strains of BVDV
BVDV1 - AUS
BVDV2 - US more virulent
Describe the two biotypes of BVDV
Cytopathic -> mucosal damage to cells, causes disease, can become this from non-cytopathic in PI calf
Non-cytopathic -> acute and causes PI animals, causes disease but no damage to cells
Describe the pathogenesis of BVDV - what does it cause?
erosive lesions to epithelial and endothelial tissue
Abortions 3-5 months after acute stages in dam
Epitheliotrophic and Lymphotrophic - decreases immune response
Often acute and subclinical
What are the clinical signs of BVDV
Acute - little signs
Pyrexia, lethary, leukopaenia, oral erosions, ulcers, diarrhoea, immunosuppresion and pneumonia
EED/LED/EFL/Abortion - mummification and maceration
PI calves
Control of BVDV
Vaccinate at risk animals
Identify and remove PI animals
Biocontainment + bioexclusion
Describe Brucellosis - what is it shed in, how do we diagnose, when does it cause abortion and what are high risk operations?
Dystocias and castrations pose high zoonotic risk Abortions after 5 months Fetus retained for 2 days Shed in milk, vaginal discharge + blood Fetal stomach contents for diagnosis
What is Neosporosis?
Neospora caninum
Protozoan with worldwide distribution
Pathogenesis of Neosporosis (transmission, life cycle stages)
Abortion (3-8mths) + neonatal mortality, pareisis + paralysis - take fetal brain sample
Transplacental transmission
Sexual stage completed in dog
Bradyzoits (tissue cysts) and tachyzoits
Risk of abortion decreases with next pregnanies if they did not abort the first time
Neosporosis - when does it cause abortion?
Between 3-8 months - well autolysed or mummified
How do we diagnose Neosporosis?
Immunohistochemical labelling of protozoan
Histological lesions
Prevention of neosporosis
Limit canine faecal contamination of water
Cull aborting cows
Dispose abortions hygeinically
List 4 causes of sporadic bovine abortions
- Mycotic placentitis
- Listeriosis
- Trueparella pyogenes
- Salmonellosis
Pathogenesis of mycotic placentitis - two types, tranmission method, what it infects and what it causes
Septate fungi - no autolysis
Non-septate fungi - autolysis common
Ingested/inhaled
Settles at junction of fetal & maternal placenta
Causes severe placentitis with necrosis of cotyledons
Diagnosis + control of mycotic placentitis
Upper eyelid fetal skin, fetal lung, hyphae in fetal or placental lesions
Avoid wet hay
Pathogenesis of listeriosis (where is it, when is abortion and what signs)
In soil + discharge from aborting cows
Abortion at any time
Pyrexia and anorexia near time of abortion
Diagnosis and treatment of listeriosis
Advanced autolysis of fetus, tetracyclines in feed for 2 weeks
What is trueperella pyogenes - when does it cause abortion, what causes the abortion, how do we diagnose?
Sporadic abortions 4 months onwards
Fetus retained 1-2 days
Placentits
Diagnose by fetal stomach contents, tissues or placenta
What is salmonellosis?
Zoonosis - var dublin host adapted
What is the diagnosis rate for abortion?
35% where fetus and placenta submitted
Characteristics of prenatal death
No signs of life - lungs not aerated, no colostrum in stomach, autolysis
Characteristics of neonatal death
Aerated lungs, clot in umbillical artery, curd in abomasum, used hooves
In a randomly cycling group, how many are in oestrus each day?
5%
How long does CL lysis take?
36-60 hours
When is the CL responsive to PGF2a?
between day 5-18
What does progesterone do?
Block GnRH surge
What does prostaglandin do?
Decrease progesterone - lyse CL
How many hours is acceptable for oestrus synchtonisation?
within 72h of each other
How can we manipulate oestrus using prostaglandin? (2 ways)
Inject it to lyse CL
Inject progesterone to keep high until prostaglandin releases endogenously
Name 3 prostaglandin programmes
- Moody system -> 5 day one injection
- The two injection programme
- The one injection programme
How long should a progesterone IVI be in for?
18 days - stale follicle syndrome and vaginitis potential problems
Oestrogen shortens CL lifespan allowing shorter progesterone treatment (7-12 days)
How can we enhance progesterone treatment?
Combine with eCG - FSH and LH like activity
Ovsynch program
Day 0 - 100ug GnRH (LH surge + ovulation)
Day 7 - Prostaglandin 25mg (lyse CL and reduce progesterone)
Day 9 - GnRH (causes ovulation in recruited follicles)
Day 10 - Inseminate in morning 20hrs after GnRH
Scott Norman’s Old faithful method
Day 0 - CIDR and 2mg ODB (oestradiol benzoate)
Day 8 - 25mg lutalyse (prostaglandin)
day 10 - remove CIDR at 8am and apply mount detectors
Day 12 - Fixed time AI at 52 and 58 hours
How many cows should we be breeding (max) each day?
No more than 100 with 2 techs
How many days PP should a cow be when she is bred?
60 days (90 if Bos. Indicus)
What capacity are semen straws?
0.25=-0.5ml
What is the dose for frozen sperm?
20million/ml
What temperature are sperm thawed at and for how long (for 0.25 and 0.5ml straw)
37 degrees
- 25 -> 15 seconds
- 5 -> 30 seconds
What is shanging?
48 hour calf removal to increase GnRH and LH - small increase in pregnancy rates
Where is semen depostited?
Intrauterine insemination - body of uterus
NOT in horns
What are bulls tested for before entering AI centres?
TB (bovine tuberculosis), EBL (enzootic bovine leukosis), Vibriosis, BVD and Johnes
How long is the oocyte viable for?
6-12 hours
What age should bulls be for selection for AI?
between 15 months and 4 years old
What are low risk, medium risk and high risk bull breeds for dystocia?
Low -> Jersey
Medium -> Holstein Friesian, Angus
High -> Charolais
When is pregnancy diagnosis conducted?
From 30 days post insemination/mating
What three layers can be inflamed in endometritis?
Epithelium
Stratum compactum
Stratum spongiosum
(2marks) What is the cause of freemartinism in heifers and when would this condition be likely to cause economic loss?
Result of the fusion of the chorioallantoic portions of the twin placentas, which usually is established between days 28 and 30 of gestation. Causes economic loss as the heifer will most likely be infertile
4 steps for diagnosing the cause of abortion
- Differentiate between fetal and neonatal death
- Get a close approximation of the fetal age
- Estimate the duration of time the fetus has been in utero prior to expulsion
- Specimens for lab. examination
