Reproductive Terms

Prostaglandins

unsaturated fatty acids responsible for the control of the estrous cycle and timing of parturition

Open Mare

a mare that was either not bred or did not conceive in the previous season

Corpus Luteum

a gland formed on the ovary following ovulation that produces the hormone progesterone

Winking

the mares exposure of the clitoris during the heat or receptivity to the stallion

Estrous

the period of sexual inactivity between two estrous cycles

Lactation

the production of milk by the mammary glands

Silent Heat

an estrous cycle with no outward signs of estrus or receptivity to the male

Estrus

the short period of sexual excitement when the female will accept the male in the act of mating

Dystocia

a retained placenta in the mare or difficulty giving birth

Diestrous

the extended period of time when a mare does not cycle or have a heat period

Colostrum

antibody-rich milk secreted by a mare just before and the first day after foaling

Relaxin

causes relaxation of the pelvic ligaments and the cervix at parturition

Placenta

the organ lining the uterus and holding the fetus which is attached via the umbilical cord

Amniotic fluid

the substance contained within the innermost of the fetal membranes, just outside the fetus

Foal Heat

a heat that occurs after parturition that is often not fertile

Anestrous

the time at which a mare does not cycle or have a heat period; usually in the winter

Semen

sperm cells plus fluid from the accessory glands

Waxed teats

when drops of sticky, clear, or amber-colored fluid excreted prior to parturition become dried and hard, coating the ends of the teats and giving them a waxy appearance

Artificial insemination

introducing sperm cells into the female reproductive tract by means other than natural service

Ovulation

the release of the egg from the mature follicle on the ovary

Polyestrous

having many heat cycles during the year, mares have more regular cycles at the peak of breeding season when there is more light and no cycles at all during the winter months.

Puberty

sexual maturity

Gestation

pregnancy

Oxytocin

stimulates uterine contractions and milk letdown

Testosterone

develops and maintains accessory sex glands; stimulates secondary sexual characteristics; regulates sexual behavior and sperm production

Follicle

a saclike structure within the ovary that gradually enlarges and, with one burst, releases an egg into the oviduct. following this rupture, CL is formed

Barren Mare

a mare that is in heat and bred but does not produce a foal

Photoperiod

refers to the number of hours of light in a day