Equine Reproduction Review Questions
1. Define teasing. What are the signs of a mare in heat? What are the signs of a mare out of heat?
2. What environmental factor controls reproductive seasonality in the horse? This is mediated through the
gland which secretesduring darkness.
3. What are the 4 basic reproductive seasons in the mare? Approximately in what months does each occur? In which is the mare ovulating, and in which does she not ovulate?
4. During anestrus most mares presented to a stallion will, however, some will, and others will .
5. During anestrus, follicles are in size, the cervix is and the uterus is.
6. A mare in transition shows what kind of behavior when approached by a stallion?
7. A foal is born February 1 , 1997. Another foal is born in August 1997. How old will both these foals be on Jan 1, 1998 according to breed registries. Which foal will have the advantage if they compete against each other as 2 year olds? Why? What implications does this have for when people want to breed their horses? Why are mares commonly put under lights in the winter?
8. What is the impact of season on semen output and libido in the stallion?
9. What is the length of the estrous cycle in the mare?
10. What is the length of diestrus? Does it vary?
11. What is the length of estrus? Does it vary?
13. When does the mare ovulate relative to estrus?
14. True or false-A mare only produces follicles during estrus, and never ovulates in diestrus.
15. Are multiple ovulations common in mares? Are twins?
16. How long can sperm cells survive in the mare? How long before ovulation can you breed a mare?
17. How long does the oocyte survive? How long after ovulation can you breed a mare?
18. When does the fertilized egg enter the uterus?
19. When does the equine CL become responsive to prostaglandin?
20. Under the influence of estrogen a mare's uterus and cervix will become, but under the influence of progesterone they become . This is the (same or different ) as a cow.
21. After entry into the uterus the spherical embryo migrates up and down both horns and the uterine body until day, the day of fixation. Whether the embryo fixes in the left or right horn is (dependent/independent) of the side of the corpus luteum (like/unlike) the cow.
22. At about day chorionic girdle cells invade the endometrium. They produce structures called , which secrete the hormone .
23. After day 36 follicles develop on the ovaries, some of these follicles then, and form functional , which secrete the hormone .
24. What hormone (hormone X) starts to decline after day 80 of pregnancy in the mare? What hormones biochemically similar to X then continue to increase throughout pregnancy? What tissue produces this second group of hormones?
25. Equine pregnancy is also characterized by high levels of the hormone , (produced by the fetal gonads) which spills into urine after day150. Fetal gonads are largest at about day, exceeding in size.
26. What is the average gestation length of a mare? Does gestation length vary in the mare?
27. Milk in the udder indicates foalng in. Foaling can most accurately be predicted using .
28. Define "waxing" relative to impending parturition in the mare.
29. Parturition (rapid /slow) in the mare and occurs mostly at what time of day?
30. The placenta is normally released withinhours of birth. A placenta retained for is considered a medical emergency.
31. The first post-partum estrus is called, and occurs about day in the mare.