Animal Science: Reproduction, Genetics, and Lactation

Vocabulary practice flashcards covering animal reproduction anatomy, endocrine control, estrous cycles, pregnancy, parturition, lactation, and basic genetic principles.

Gonad

The primary reproductive organ (ovary in females, testis in males) responsible for steroidogenesis and gametogenesis.

Steroidogenesis

The physiological process of producing sex steroid hormones within the gonads.

Gametogenesis

The biological process of producing gametes (ova in females and spermatozoa in males) within the gonads.

Cryptorchidism

A developmental condition in males where one or both of the testes fail to descend from the abdominal cavity into the scrotum.

Epididymis

The male reproductive duct structure responsible for the concentration, storage, maturation, and transport of spermatozoa.

Types of Uteri

Anatomical uterine configurations across species, including Duplex (two cervices; marsupials, rabbits), Bicornuate (poorly to highly developed uterine horns; mares, cows, sows, bitches), and Simplex (no uterine horns; primates).

Accessory Sex Glands

Male glands comprising the seminal vesicles, prostate gland, and bulbourethral (Cowper's) glands that add fluid volume, nutrients, and buffers to spermatozoa to form semen.

GnRH (Gonadotropin Releasing Hormone)

A neuropeptide hormone produced by the hypothalamus that acts on the anterior pituitary to stimulate the release of LH and FSH.

LH (Luteinizing Hormone)

A glycoprotein hormone secreted by the anterior pituitary that stimulates testosterone production in males, and induces ovulation, corpus luteum formation, and progesterone production in females.

FSH (Follicle Stimulating Hormone)

A glycoprotein hormone secreted by the anterior pituitary that promotes Sertoli cell function in males, and stimulates follicular development and estradiol synthesis in females.

Estradiol

A steroid hormone produced by ovarian follicles, the placenta, and Sertoli cells that regulates mating behavior, secondary sex characteristics, uterine motility, and GnRH release.

Progesterone

A steroid hormone produced by the corpus luteum (CL) and placenta that maintains pregnancy, inhibits GnRH release, and promotes mammary development.

PGF2α (Prostaglandin F2α)

A C-20 fatty acid hormone produced by the uterine endometrium and vesicular glands that induces luteolysis of the corpus luteum, uterine contractions, and ovulation.

Freemartin

A sterile female calf born twin to a male bull calf due to the fusion of placental membranes and vascular exchange during fetal development.

Placentome

The point of tissue attachment between the fetal placenta and maternal uterus in cotyledonary placentation, formed by a fetal cotyledon and a maternal caruncle.

Cotyledon

The specialized fetal component of the placentome attachment in cotyledonary placentation.

Caruncle

The maternal uterine site of attachment that pairs with the fetal cotyledon to form a placentome in ruminants.

Dystocia

Any abnormal, prolonged, or difficult delivery of a fetus during parturition.

Retained Placenta

A condition occurring when the placenta is not expelled within the normal time frame after parturition, significantly increasing the risk of postpartum uterine infection.

Colostrum

The initial fluid secreted by the mammary gland post-parturition, rich in proteins, vitamins, minerals, and antibodies that convey passive immunity to the newborn.

Postpartum Interval

The duration of time between parturition and the subsequent conception in a female animal.

Flushing (Embryo Transfer)

The non-surgical process of collecting fertilized embryos from the uterus of a superovulated donor female for evaluation and transfer into recipient females.

Mammogenesis

The structural development and growth of the mammary gland occurring from birth through pregnancy and lactation.

Lactogenesis Stage I

The phase of mammary differentiation before parturition characterized by immunoglobulin uptake and the formation of colostrum.

Lactogenesis Stage II

The phase following parturition marked by copious milk secretion and the transition from colostrum to milk of normal composition.

Mammary Gland Gross Anatomy

The anatomical path of milk synthesis and collection, including alveoli, lobes, primary and secondary ducts, gland cistern, teat cistern, sphincter muscle, and streak canal.

Prolactin

A hormone released from the anterior pituitary prior to parturition that acts synergistically with other hormones to initiate and maintain milk secretion.

Oxytocin

A hormone released by the posterior pituitary that stimulates uterine contractions during parturition and myoepithelial cell contractions for the milk ejection reflex.

Mastitis

An inflammation of the mammary gland, most commonly caused by a bacterial infection of the teat canal.

Animal Breeding

The branch of animal science that applies principles of genetics to selectively improve traits of economic value in livestock.

Phenotype

Any physical property, appearance, or measurable performance trait of an animal determined by its genotype and environment.

Genotype

The complete genetic constitution of an animal, determined by equal contributions from sire and dam, consisting of breeding value and non-additive value.

Genetic Model

The mathematical and conceptual representation showing that Phenotype is determined by Genotype (Breeding Value and Nonadditive Value) and Environment (Known and Unknown factors).

Breeding Value

The portion of an individual's genotype for a specific trait that is due to additive gene effects and is passed directly from parent to offspring.

Non-additive Value

The portion of an individual's genotype determined by the unique combination of genes in that specific individual, which is not transmitted to progeny.

Contemporary Group

A group of animals of similar age, sex, and breed that have been raised under identical environmental and management conditions to enable accurate genetic comparisons.

Heritability

The proportion of total phenotypic variation among animals for a specific trait that is due to additive genetic variation and can be transmitted to offspring.

Selection Differential

The average superiority or inferiority of selected breeding animals compared to the overall herd or flock average for a given trait.