Exam #2- Animal Repro   

Terminology

Estrus−Estrus- heat or sexual receptivity ( showing signs)

Estrous−Estrous- the length of the estrus cycle

Semen−Semen- viscous secretion of the male reproductive tract

Spermiation−Spermiation- the process by which spermatozoa is released into the lumen of the seminiferous tubules

Stages of the estrous cycle

concentration is increasing = Metestrus

estrogen concentration is increasing= proestrus

Corpus hemorrhagicum is being transformed into a corpus lute= Metetrus

Graafian follicle reaches maximal diameter at beginning of this stage= estrus

Progesterone reaches its highest concentration= Diestrus

This stage starts with ovulation= Metestrus/ ovulation

Maximal follicular diameter= estrus

Feedback during periods in relation to puberty that estradiol exerts on GnRH

Prior to puberty

  • negative feedback

After puberty occurs during a normal estrous cycle

  • positive feedback
Average length of the estrous cycle, in days, & age when they reach puberty

%%cow%%

estrous cycle: 21 days

Puberty: 8-13 months

%%Ewe%%

estrous cycle: 17 days

Puberty: 7-20 months

%%Sow%%

estrous cycle: 20 days

Puberty: 5-7 months

%%Mare%%

estrous cycle: 21 days

Puberty: 15-24 months

List one sign that a female has reached puberty
  • First estrus
2 phases of the estrous cycle where progesterone level is elevated
  1. Diestrus
  2. Metestrus
Signs and hormonal events during the estrous in species

%%Cow%%

  • irritability, restless
  • vocalization
  • clear mucus

%%Mare%%

  • Allows stallion to smell & bite
  • elongated & swollen vulva
  • visible mucous
  • extends hind legs & lifts tail to side

%%Sow%%

  • Swollen vulva
  • no visible mucus
  • pressure on loin
  • some homosexual behavior

%%Doe%%

  • moderate visible vulva
  • MAYBE mucus
  • tail wagging/ urination near buck

%%Ewe%%

  • No signs of heat
List the phase where corpus luteum is regressing & what structure it becomes

Phase: Proestrus

Structure : Corpus albicans

Major source of energy in semen
  • fructose
  • sorbitol
Species and characteristics of the ejaculate

Highest volume

  • Boar

Highest total # of sperm

  • Boar

Highest concentration of sperm per ml

  • Ram
Hormone that stimulates Sertoli cells to secrete androgen binding protein
  • testosterone and FSH
3 phases of spermatogenesis
  1. spermatocytogenesis
  2. Meiosis
  3. Spermiogenesis
Sperm cells & chromosomal numbers

Spermatozoa

  • haploid (1N)

Primary spermatocyte

  • diploid (2N)

Spermatid

  • haploid (1N)

A3 (Active) spermatogonium

  • diploid (2N)
Male species puberty and length for spermatogenesis

Bovine

  • puberty = 10-12months
  • Length = 56-63 days

Equine

  • puberty = 13-18 months
  • length = 55-59 days

Swine

  • puberty= 4-8 months
  • length= 36-40 days