animal reproductive cycles
Post on 22-Oct-2014
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DESCRIPTION
This presentation outlines the estrus cycle of livestock animals. It also outlines common ages of puberty in livestock animals.TRANSCRIPT
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Estrus and Menstruation
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Estrus – Time of ovulation and sexual receptivity in most mammals; known as heat
Menstruation – the shedding of the thickened lining of the uterus in humans and some primates
Animals in estrus mate whenever with whomever when in estrus vs. animals with a menstrual cycle choose when and with whom to mate.
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Cows 21 daysPigs 21 daysMares 21 daysEwes 16 days
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The estrus cycle is the period of days between coming into “heat”
“Heat” is the term used to describe estrus or sexual receptivity in livestock
Estrus is brought on by a drop in progesterone levels and an increase in estrogen levels
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Cows 12-24 hrsPigs 24-36 hrsMares 4 daysEwes 24 hrs
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period following estrus when cattle and goats ovulate LH is released when the follicle
ruptures and stimulates the remaining follicle tissue to form the Corpus Luteum
Corpus Luteum produces progesterone which maintains pregnancy
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period when the system assumes pregnancy
longest phase of estrus cycle
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If pregnancy is not established the CL begins to regress
Progesterone levels dropThe body prepares for estrus again
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Day 1 – first day of menstruationDay 5 – Last day of menstruationDay 14 – Ovulation ** Unpredictability of human body
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Time at which animals reach a level of sexual maturity that will sustain reproduction
Not best time to breed animal, not fully mature
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Cows 1-1½ yearsPigs 5-10 moHorses 1½-2 years
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Cows 2-2½ yearsPigs 1-1½ yearsHorses 2½-3 years