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Learn about the male and female reproductive organs, endocrine functions, fertilization, gestation, and more to understand animal reproduction processes.
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Animal Reproduction Chapter 10
Objectives • Identify and describe the male and female reproductive organs • Describe the function of the endocrine glands and hormones in reproduction
Objectives (cont.) • Describe reproductive failures that may occur • Define fertilization, gestation, parturition, and estrus cycle
Reproduction • May be sexual vs. asexual • All common farm animals reproduce by sexual reproduction • Copulation • Male mates with a female and sperm is placed into the female reproductive tract
Reproduction (cont.) • Fertilization • Sperm penetrates the egg cell • Embryo • The new animal, grows inside mother • Parturition • Act of giving birth
Male Reproductive System • Mammals • Reproductive organs of male mammals are similar to those of a bull • Scrotum • Testicles • Vas deferens, urethra • Seminal vesicles • Penis
Male Reproductive System (cont.) • Mammals (cont.)
Male Reproductive System (cont.) • Poultry • Testicles, inside the body, produce sperm • Vas deferens carries seminal fluid and sperm cells to the cloaca • Papilla is organ in the wall of the cloaca, which puts sperm cells into hen’s reproductive tract
Male Reproductive System (cont.) • Poultry (cont.)
Female Reproductive System • Mammals • Female farm animals have two ovaries, which produce the ova and sex hormones • Fetus grows within the uterus • Cervix is lower outlet of uterus • Vagina is the passage between cervix and vulva
Female Reproductive System (cont.) • Mammals (cont.)
Female Reproductive System (cont.) • Mammals (cont.)
Female Reproductive System (cont.) • Poultry • Has two ovaries and two oviducts • Funnel receives yolk from ovary • Sperm cells stored in funnel • Magnum secretes thick white of egg • Once thick white is placed around yolk, it moves to isthmus and uterus for shell • Eggs laid in about 25-27 hours
Female Reproductive System (cont.) • Poultry (cont.)
Estrus Cycle • Estrus, also known as heat, is the period of time in which a female will accept a male for breeding • Estrus periods begin when female mammals are old enough to be bred
Estrus Cycle (cont.) • Signs of estrus in cattle include • Standing when mounted by another cow • Nervousness • Swelling of vulva • Signs of estrus in swine include: • Frequent mounting of other sows • Swelling in vulva, restless activity
Estrus Cycle (cont.) • Signs of estrus in goats include • Nervousness • Shaking tail, swelling of vulva • Signs of estrus in horses include: • Raised tail • Relaxation of vulva • Frequent urination, teasing of mares
Ovulation • Release of egg cell from the ovary • Eggs are contained in follicle prior to ovulation • When follicle breaks, egg is released into one of the oviducts • If sperm is present, egg may be fertilized
Ovulation (cont.) • After ovulation, corpus luteum forms on ovary and releases progesterone, causing • Fertilized egg implantation in uterus • Other eggs to stop forming • Pregnant condition to be maintained • Development of mammary glands
Ovulation (cont.) • If egg is not fertilized, the corpus luteum atrophies • When animals have several young at birth, the offspring are fraternally related • Occasionally, one egg cell divides to form two identical offspring
Fertilization • During copulation, male deposits sperm in female reproductive tract • If an egg cell is present, sperm cell may penetrate and fertilize it • Sperm and egg cells do not live long • If animal doesn’t become pregnant, estrus cycle will repeat
Gestation • Period of time when animal is pregnant • Fetus develops in uterus • Nutrients and oxygen supplied, and waste carried off, by umbilical cord • Food, oxygen, and wastes exchanged by diffusion through placenta • Most fetal growth in final third of gestation
Parturition • Process of giving birth to new animals • Buildup of estrogen causes contractions, beginning process of birth • First water bag appears and breaks • Second water bag appears and presentation of fetus begins • Difficulty in birthing is called dystocia
Parturition (cont.) • After birth, mother produces colostrum • Rich in antibodies, vitamins, minerals • Important during 12to 24 hours after birth • Regular milk produced thereafter • Afterbirth should be expelled several hours after birth
Reproduction in Poultry • Sperm are placed into cloacal wall of female by papilla of male • Sperm move up oviduct to funnel • Egg is fertilized • Egg yolk moves through female reproductive tract
Reproduction in Poultry (cont.) • Thick white, shell membranes, thin white, and shell are added • Egg is laid, embryo grows inside shell • Embryo fed by contents of the egg • Incubation period is 21 days in chickens, 28 days in ducks and turkeys • After incubation, chicken hatches
Reproductive Failures • Physical condition • Infections • Hormones • Cysts • Cryptorchidism