Bovine Infertility & Pregnancy Wastage Flashcards
What is the pregnancy risk/rate? Why can they be especially low at certain farms?
function of service risk (detecting estrus) and conception risk (breeding) over 21 days
misinterpretation of estrus signs
How is conception rate calculated? How does it compare in beef and dairy cattle with pregnancy exams at days 26 and 45?
(females pregnancy at exam)/(females inseminated) x 100 = %
- DAY 26 - beef = 70%; dairy = 40% (higher in heifers)
- DAY 45 - beef = 65%; dairy = 30-40% (higher in heifers)
What is the difference between embryonic death, abortion, stillbirth, and neonatal loss?
death before the fetal period within 42 days (75% of pregnancy waste!)
death of fetus prior to age of viability
death of fetus in utero that would have been viable extra uterine
death of newborn
What are 5 causes of anestrus without a corpus luteum?
- ovarian agenesis/aplasia
- Freemartin - heifer twin to bull, resulting in a chimera
- post-partum anestrus
- cystic ovarian disease
- post-partum complications
What are 3 post-partum complications associated with anestrus without a CL?
- metritic delays
- retained fetal membranes
- ketosis
What cattle has a genetic predisposition for developing ovarian agenesis/aplasia
Danish Red cattle —> no ovaries
What is a Freemartin heifer?
chimera twin of a male resulting from placental vascular anastomoses by 30 days of gestation, where anti-mullerian hormone, testosterone, and male-derived hematopoietic progenitors flow from the male to the female twin
What are 5 typical phenotypes of Freemartin heifers?
- normal to small vulva
- increased anogenital distance
- enlarged clitoris
- prominent tuft of hair @ ventral commissure
- varying degrees of internal development
How is a Freemartin heifer diagnosed?
- history of heterosexual multiple birth
- palpation/vaginal probe (short tract)
- PCR
What is postpartum anestrus? What are the most common causes in beef and dairy cattle?
no cycling following the 60-day voluntary waiting period taken to avoid high metabolic imbalances and healing of the reproductive tract
- BEEF = rarely separated from calf, which is continually suckling = negative energy balance
- DAIRY = poor nutrition, continual milking = negative energy balance
What is cystic ovarian disease? What are the 2 classifications?
presence of follicle(s) with a diameter of at least 20 mm at one or both ovaries in the absence of active luteal tissue —> interferes with normal ovarian cyclicity
- FOLLICULAR = estrogen secretion, nymphomania
- LUTEAL = progesterone secreted
In what cattle is cystic ovarian disease most common? When is it especially seen?
dairy cattle
- interval between calving and first service
- interval between calving and conception
- increases with parity
What causes the development of cysts seen in cystic ovarian disease?
absence of a preovulatory surge due to a functinal breakdown in the positive estradiol feedback loop
Cystic ovarian cysts, pathogenesis:
What are the 4 major options for treating cystic ovarian disease?
- GnRH, hCG - induces other follicles to become dominant and ovulate
- PGF2α
- synchronization protocols
- progesterone (CIDR)
cysts unable to ovulate!
How does the CL lifespan compare with intact and missing uterus?
- INTACT = 15-17 days, normal cycle
- TOTAL UTERECTOMY = 148 days, normal gestation length
- PARTIAL UTERECTOMY = 15-17 day normal cycle if CL is present on the intact side; 35 days if CL is on the missing side due to countercurrent exchange taking longer to take effect
What is a mechanical cause of a cycling cow that is not getting pregnant?
segmental aplasia - “white heifer syndrome” in white Shorthorns + uterus unicorns, imperforated hymen
single recessive sex-linked gene that causes an arrest in the development of the Mullerian duct —> if ovulation occurs on the missing side, there is nowhere for the sperm to meet for insemination
How do bulls and cows present with Tritrichomonas foetus infection?
BULLS = typically asymptomatic +/- mild balanoposthitis localized in the prepuce and distal urethra
COW = loss of conceptus (15-80 days), inflammation of the reproductive tract, post-coital pyometra, extended calving syndrome, irregular estrous cycles
Causes of bovine infertility:
