Environmental influences on frequency of estrous cycles
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Environmental influences on frequency of estrous cycles by R. E. Erb

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Published by State College of Washington, Agricultural Experiment Station in Pullman, Wash .
Written in English


  • Dairy cattle -- Reproduction,
  • Estrus

Book details:

Edition Notes

StatementR.E. Erb, M.H. Ehlers, and R.A. Morrison.
SeriesBulletin / State College of Washington. Agricultural Experiment Station -- no. 583., Bulletin (State College of Washington. Agricultural Experiment Station) -- no. 583.
ContributionsEhlers, M. H. 1918-, Morrison, R. A.
The Physical Object
Pagination[30] p. ;
Number of Pages30
ID Numbers
Open LibraryOL17817072M

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The endocrinology of the estrous cycle involves a balance between hormones produced by the pineal gland, hypothalamus, pituitary gland, ovaries, and endometrium. Growth of antral follicles in the ovary occurs in wave-like patterns, and is influenced by several factors such as stage of the estrous cycle,Cited by: 7. Cheryl A. Frye, in Vitamins & Hormones, Estrous cycle/sperm motility. Estrous cycle duration in females and sperm motility in males can be used as a marker of sexual maturity/gonadotropin responsiveness (see Table ).Female rats typically cycle every 4–5 days (Asdell, ).Both estrous cycle length and sperm motility are altered by exposure to EDCs.   In fact, measurements of behavior se- quence structure revealed that estrous cycle stage was of lesser importance to sequence consistency than either indi- vidual or environmental influences. The females tested in this study were at the age when close to peak differences between estrous and diestrous ac- tivity levels were to be expected [26].Cited by: 3. The duration of the normal estrus cycle in the cow is days. It consists of two-phase, a luteal phase ( days) and a follicular phase ( days) [4]. The estrus occurs at the end of the.

  The onset of estrous cycles occurs at the time of puberty. In heifers puberty occurs at 6–12 months of age, generally at a weight of – kg. The normal duration of an estrous cycle in cattle is 18–24 days. The cycle consists of two discrete phases: the luteal phase (14–18 days) and the follicular phase (4–6 days). The ANOVA for VER over estrous cycle stages showed a highly significant (Pof estrous cycle on VER in buffaloes. The percent decrease in VER was more pronounced from diestrus. The estrous cycle can be divided into four stages: proestrus, estrus, metestrus, and diestrus. During proestrus the CL regresses (progesterone declines) and a preovulatory follicle undergoes its final growth phase (estradiol increases). Ovulation usually occurs during estrus (cows ovulate during metestrus). The Normal Canine Estrous Cycle. Canine Puberty. p p Normal puberty can occur at months. Larger dogs tend to reach puberty at an older age than smaller dogs. First estrus tends to be irregular. Do not base fertility on what happens during the first heat. LH has an increased frequency. FSH is suppressed.

Estrus, also spelled Oestrus, the period in the sexual cycle of female mammals, except the higher primates, during which they are in heat—i.e., ready to accept a male and to mate. One or more periods of estrus may occur during the breeding season of a species. Prior to ovulation the endometrium (uterine lining) thickens, in preparation for holding the fertilized ova. The events of the cycle are strongly influenced by lighting periodicity. A set of follicles starts to develop near the end of proestrus and grows at a nearly constant rate until the beginning of the subsequent estrus when the growth rates accelerate eightfold. Ovulation occurs about .   However, in latitudes nearer from the equator, the presence of estrus will depend on the availability of nutrients and the environment. On average, the goat’s estrus cycle is 21 days, and the high frequency of short estrual cycle is characteristic and tends to occur at the beginning of the reproductive season and in young animals [1, 2].   The Bovine Estrous Cycle The cow is a non seasonal polyestrus species. In other words she continually has estrous cycles all year around. The entire estrous cycle averages 21 days long, but can be as short as 18 days and as long as 24 days. The stages of the bovine cycle are. proestrus, estrus.