Ruminant Flashcards
What percentage of beef cattle are bred naturally? What percent are bred AI?
Natural ~93%, AI ~7%
What percentage of dairy cattle are bred naturally? What percent are bred AI?
Natural ~25%, AI ~75%
What are the advantages of natural service breeding?
Doesn’t require specialized training, doesn’t require heat detection/hormone manipulation, has improved conception rate, creates less narrowing of genetic base, allows animals to express natural behaviors
What are the advantages of AI?
Rapid genetic improvement, allows access to “proven sires”, reduces genetic defects and disease transmission, removes the need for male management, provides prolonged use of sires
What are signs that may help detect estrus?
Standing to be mounted (occurs 12 hours prior to ovulation), mounting other cows, increased activity, vocalizing, clear mucoid vaginal discharge
What aids can be used in estrus and mating detection?
Tail paint/chalk, color indicators, pedometers, surgically altered bulls, other activity monitors
What is the estrus detection rate?
cows inseminated / # cows expected to be cycling every 21 days (should be 60-70%)
What factors may impact heat detection?
Housing, footing, lameness, heat stress, and employee accountability
Describe the process of artificial insemination
Semen collected at bull studs with artificial vagina -> diluted with extended -> frozen in 0.5mL straws -> stored in liquid nitrogen -> intrauterine deposition through rectovaginal approach
Define conception rate
cows pregnant / # cows bred (goal is 50-60%)
What are potential reasons for poor conception rates?
Improper semen handling, poor heat detection, poor insemination technique, poor fertility in cow herd
What is the goal of estrus synchronization?
To induce estrus without impacting fertility (reduces the amount of time needed for estrus detection but doesn’t eliminate the need for it)
What would you use to induce estrus?
Prostaglandin F2a- 2/3 will come into heat 2-5 days after injection; give second injection in 2 weeks and 80% will come into heat (works by lysing the CL). Can also add in progesterone (MGA in feed) but not common anymore. Now commonly use a CIDR- mimics CL, pull it out and they go into heat.
Describe the OvSynch protocol
Day 0- GnRH (ovulates any dominant follicle, recruits next wave); Day 7- PGF-2-alpha (luteolysis); Day 9- GnRH (ovulation); Breed 12-16 hours later
When might someone use embryo transfer in a cow? How would it be done?
Used for high genetic value animals. Perform trans-cervical deep intrauterine deposition of frozen thawed or fresh 7 day embryo (7 days after her observed heat)
What percent of dairy cattle are bred off of observed heat (as opposed to timed AI)?
55% off observed heat, 45% off timed AI
What are the reproductive goals for dairy cattle?
Breed heifers by 13 months old. Calf every 13 months. Heat detection rate 60-70%, conception rate 50-60%, pregnancy rate 30% (per heat cycle)
What time of the year are dairy cattle bred?
Year round
Are beef cattle bred year round?
No- have a defined breeding season
What is the goal pregnancy rate for beef cattle during breeding season?
90-95%
What happens to dairy cattle that don’t breed successfully? Beef cattle?
Dairy- try re-breeding. Beef- probably culled
At what point can you detect pregnancy via rectal palpation?
Day 35+
At what point can you detect pregnancy via trans-rectal ultrasound?
Day 24+
At what point can you perform fetal sexing with trans-rectal ultrasonography?
Days 55-85ish
What could you successfully use radioimmunoassays to detect pregnancy? How do these work?
Day 24+, they detect pregnancy specific protein, may have some false positives if recent abortion
What are the 4 positive signs of pregnancy on rectal palpation and at what times do they occur?
Amniotic vessel- day 35-65. Membrane slip- day 35- term. Fetus- day 65 to term. Placentomes- day 85 to term.
What are supporting signs of pregnancy on rectal palpation?
Asymmetry of uterine horns, uterine fluid, fremitus/enlargement of middle uterine artery, presence of a CL
What are the advantages and disadvantages of pregnancy detection via rectal palpation?
Advantages- low cost, accurate, can diagnose pathology (pyometra, ovarian cyst, lymphosarcoma, uterine abscess, adhesions). Disadvantages- physically demanding, requires training, potentially detrimental (abortion, atresia ani), not pleasant for cow.
What are the advantages and disadvantages of pregnancy detection via trans-rectal ultrasound?
Advantages- determines pregnancy status at earlier fetal age, better determination of health/viability of fetus, diagnosis of sex, twins, or fetal abnormalities, better assessment of ovarian and uterine structures, less physically demanding for practitioner. Disadvantages- high equipment cost, technical training required, still not pleasant for cow.
When do short-day breeders kid/lamb?
Spring
Is the breeding management of small ruminants more similar to dairy or beef cattle?
Beef- natural cover
How many offspring can you expect from small ruminants a year?
1-3, varies based on breed, increases with age. Goal average is 1.5-2/year
Describe artificial insemination in small ruminants
Synchronization less dependable than in cattle, transcervical AI is more difficult, laparoscopic AI can be used.
True/False- twins are most commonly dizygotic
True
Twinning increases the risk of…
Abortion, dystocia, postpartum complications (retained placenta, metritis, displaced abomasum), freemartinism (male and female twin, male hormones make female twin sterile)
Describe uterine torsion
Rotation of uterus on long axis- pregnant horns move up and over non-gravid horn
What are the risk factors for uterine torsion?
Hilly pastures, use of tilt tables in pregnant cows, tie-stall housing
What are the clinical signs of uterine torsion?
Prolonged stage 1 or stage 2 labor, rarely painful, +/- twist in vagina
How is uterine torsion corrected?
Vaginally, with detorsion rod, using a C-section, or using the “plank in flank” method (press plank into cow, rotate cow while keeping plank still)
How does a fetal mummy occur?
When fetal death occurs after ossification and the uterus remains sterile. The fluid is resorbed, the CL is maintained, and the cervix stays closed. Presents with firm mass in uterus. Treat with PGF2a.
Which is more common- hydrallantois or hydramnion?
Hydrallantois ~85% of cases, hydramnion only ~10%
What are predisposing factors for vaginal prolapse?
Genetics, obesity, multiple fetuses, poor feed quality
How are vaginal prolapses treated/repaired?
Epidural, clean and replace, can replace retention device or suture (remove at time of lambing/calving). Affected animals may also be culled.
How does hydrallantois occur?
Abnormal placentation w/ too few caruncles. Typically will have rapid abdominal distension late in gestation and fetus and placentomes won’t be palpable.
How is hydrallantois treated/managed?
Salvage slaughter, induce parturition with dexamethasone and PGF2a. Dystocia and uterine inertia are common in these cases, expect retained placenta.
How does hydramnion occur?
Failure of fetus to swallow amniotic fluid. Appears with gradual abdominal distension during the 3rd trimester. Fetuses and placentomes will typically be palpable.
What is the treatment/management of hydramnion?
Focus on keeping dam healthy, induce parturition. Future fertility may be reduced.
Describe when you might see a uterine prolapse and how it may appear
Occurs within 24 hours postpartum. Will see eversion of uterus through open cervix. Present with hypocalcemia, associated with dystocia.
How would you treat uterine prolapse?
Epidural, elevate uterus and clean it/evaluate it for trauma. Compress uterus and treat with topical sugar. Manually replace it starting at vulva. Fill uterus with dilute betadine. Administer oxytocin, antibiotics, and calcium.
When are fetal membranes considered retained?
If present more than 12 hours postpartum
How would you treat retained placental membranes?
Gently remove manually, provide systemic antimicrobials and NSAIDs if systemically ill. May practice benign neglect.
What are predisposing factors for retained fetal membranes?
Induction of parturition, unsanitary calving conditions, dystocia, C-section, twins
Describe metritis and its treatment
Bacterial infection of uterus 2-3 weeks postpartum. Often present systemically ill with open cervix and foul uterine discharge. Treat with uterine lavage, systemic antibiotics, and NSAIDs
Describe pyometra and its treatment
Uterine infection with a closed cervix and dominant CL, typically > 2 weeks postpartum. If presenting during anestrus then they won’t be systemically ill. Treat with PGF2a, antibiotics not needed.
What is the standard bull:cow ratio?
1:25
What is the equation for figuring out how many cows a bull can breed?
Starting at 12 months- 1 cow/month of bull age maxing out at 48
What is the standard buck/ram:doe ratio?
1:75
What should you examine on a bulls breeding soudness exam?
BSC, lameness, prepuce, eyes, scrotum (testes freely movable, equal in size, consistent, good epididymis)
Why do you want to examine bull scrotum and testes?
Larger scrotal circumference means increased fertility, reach puberty earlier
Which accessory sex glands do bulls/bucks/rams have?
Prostate and vesicular glands
What should you look for on gross semen evaluation? How is it rated?
Look for swirl speed. Rated very good (>70%), good (50-70%), fair (30-49%), or poor (<30%)
What are some primary sperm abnormalities? What are they associated with?
Associated with testicular pathology. Head abnormalities, proximal cytoplasmic droplets, tightly coiled tails, double forms, swollen midpieces, abaxial attachment of the tail and midpiece to the head, spheroids
What are some secondary sperm abnormalities? What are they associated with?
Associated with pathology of extra-testicular ducts and secondary glands; can be due to poor semen hadnling techniques. Detached head, distal cytoplasmic droplets, bent tail.
What important breeding factor for a male is not evaluated in a BSE?
Libido
What is the cause of fibropapillomas in bulls?
Bovine papilloma virus
How do fibropapillomas interfere with breeding?
Cause bleeding during breeding which reduces fertility
How are fibropapillomas treated?
Removed with surgery, cautery, or cryotherapy; immune-response stimulated
Describe a persistent frenulum in a bull
Prevents extrusion of the penis. Cut to break the attachment. This is a heritable trait, should only be used as a terminal sire.
How do you treat hair rings in bulls?
Remove, treat the wound, rest. Prevent by trimming preputial hairs.
Describe a penile hematoma
Rupture of the tunica albuginea, presents with swelling cranial to the scrotum. DON’T aspirate. Treat with antibiotics to prevent abscessation, hydrotherapy, and sexual rest.
Who are preputial lacerations most common in? How are they treated?
Brahma or Brahma-crosses. Treat with topical antibiotics, hydrotherapy, and bandaging to erduce edema
What are the different types of penile deviations and how are they treated?
Corkscrew, ventral, S-shaped; can be iatrogenic from electroejaculator. Requires surgery to fix. Prevents breeding.
What is vesiculitis? What is its causative agent?
Bacterial infection of the seminal vesicles, caused by Trueparella pyogenes (Arcanobacterium)
How does vesiculitis present? How is it treated?
Usually very young or old bulls with enlargement, loss of lobulation, adhesions, and neutrophils in semen. Treat with long-acting antibiotics or cull older bulls.
What are the causes of orchitis/epididymitis?
Systemic infection, often Brucella ovis in rams (venereal spread)
How is orchitis/epididymitis treated?
Unilateral castration or cull. Antibiotics ineffective.
What are the clinical signs of Brucella abortus?
Abortion in 3rd trimester of first pregnancy, otherwise asymptomatic; subsequent pregnancies produce weak calves. Placental lesions include necrotic placentitis of cotyledonary and intercotyledonary zones. Fetal lesions include autolysis, acute fibrinopericarditis, and pleuritis.
How is Brucella abortus diagnosed?
Isolation of organism in chorioallantois, fetal tissue, or stomach contents. Can run PCR, culture, or do serology of dam.
How is Brucella abortus spread?
Transmitted via direct contact. Biosecurity important. REPORTABLE AND ZOONOTIC.
Describe treatment/control of Brucella abortus?
RB51 modified live vaccine (can’t give if pregnant), cull infected animals. REPORT!!
What are the clinical signs and lesions of Leptospirosis?
Sporadic abortion in last trimester, weak calves, lethargy and fever, retained membranes. Placenta- intercotyledonary zones thickened and yellow with brown necrotic cotyledons. Fetus- mummified or still-birth, autolysed, can have interstitial nephritis and tubular necrosis.
How is Leptospirosis diagnosed?
IHC on fixed tissue, FA on frozen tissue, microscopic agglutination serology on fresh tissue. Obtain kidney, pericardial fluid, abomasal fat.
How is Leptospirosis spread? How is it treated/controlled?
Spread through direct or indirect contact. Controlled with a killed vaccine, keeping wildlife away from herd. Treat carriers with antimicrobials- use caution- ZOONOTIC.
What are the clinical signs of Tritrichomonas fetus?
Bulls are asymptomatic, cows have early embryonic death before day 20, infertility, long inter-estrous intervals, and pyometra. Placental lesions include edematous stroma and chorionic necrosis.
How is Tritrichomonas fetus diagnosed?
Diagnosed on preputial scrapings or wash, culture and PCR of cervicovaginal secretions with modified diamonds meda
How is Tritrichomonas fetus controlled/treated? How is it spread?
Spread through bodily fluids (venereal). Cull carriers and vaccinate cows with TrichGuard to decrease fetal loss. Test bulls before breeding.
List infectious agents that cause reproductive disease
Chlamydia, Coxiella burnetti, Foothill abortion, Listeria, Campylobacter, Salmonella
List viral agents that cause reproductive disease
BVDV, Bluetongue, IBR-1, Cache Valley
List protozoal agents that cause reproductive disease
Neospora caninum, Toxoplasma gondii
List fungal and environmental agents that cause reproductive disease
Aspergillus and various chromosomal and toxigenic plants
What are the clinical signs and lesions of Brucella melitensis and ovis?
Infertility and epididymitis in rams, abortion in last 2 months of gestation, necrotizing placentitis with yellow, thickened intercotyledonary zones. Fetal- petechial hemorrhage, hepatomegaly, blood-tinged peritoneal fluid.
How are Brucella melitensis and ovis spread? Diagnosed?
Transmission occurs via direct contact, inhalation, and ingestion of contamianted material. Diagnosed with culture and serology of fetal membranes or PCR.
How are Brucella melitensis and ovis treated/controlled?
Vaccination (Rev-1 killed vax), cull infected animals, REPORT- ZOONOTIC
What is the number one cause of abortion in sheep?
Campylobacter fetus subsp. fetus and subsp. venerealis
What are the clinical signs and lesions of Campylobacter fetus
Abortion in last trimester, abortion storms in naive herds, infertility. Placenta- edematous, leathery, thickened with brown/red cotyledons. Fetus- red-tinged body fluid, white plaques on liver, hepatitis, pneumonia, serositis, and encephalitis.
How is Campylobacter fetus diagnosed?
Culture of stomach content and fetal membrane. Ziel-Neilson stain on IHC and cytology.
How is Campylobacter fetus treated/controlled?
Vaccinate (first dose before breeding, booster 60-90 days later, annual vaccination). ZOONOTIC
What are the clinical signs and lesions of Chlamydia abortus (psittaci)?
Early gestational infection- abort late gestation. Late gestation infection- abort next pregnancy. Healthy lambs and kids serve as carriers. Causes ~30-60% abortion rate in naive herds. Placenta- red/brown cotyledonary exudate and necrosis with leathery intercotyledonary zones, trophoblastic loss, and suppurative inflammation. Fetus- coagulative necrosis of liver and spleen.
How is Chlamydia abortus (psittaci) diagnosed?
Impression smear of placenta- will see elementary bodies when using Gimenez stain, ELISA serology with complement fixation titers 1:12-1:32, PCR
How is Chlamydia abortus (psittaci) controlled/treated?
Attenuated vaccine 1B for sheep (may cause placentitis). Inactivated abortogenic serovar vaccine (1st dose 60 days pre-breeding, 2nd dose 30 days later). Tetracyclines used for pregnant ruminants to reduce fetal loss and shedding.
What are the clinical signs and lesions of Coxilla burnetti?
Late term abortion (naive herds 50-70%, endemic herds 5%), infertility, endometritis, retained membranes. Placenta- fibrinonecrotic placentitis- “Moroccan leather” appearance, intercotyledonary and cotyledonary necrosis with red/brown exudate. Fetus- no lesions or bronchopneumonia.
What is another name for Coxilla burnetti?
Q fever or “query fever”
How is Coxilla burnetti diagnosed?
IHC or FISH on placental and fetal tissues. ELISA and complement fixation on serology. IgM and IgG phase II Ab detection, PCR on fresh tissue.
How is Coxilla burnetti treated/controlled?
No vaccine available in the US, tetracyclines used to reduce shedding, cull. REPORTABLE- ZOONOTIC
What plants are toxigenic to small ruminants?
Veratrum californicum, locoweed, hemlock, juniper, nitrates
What medications cause reproductive issues in small ruminants?
PGF, dexamethasone, benzimadoles
