Behavioral, endocrine, and ovarian relationships during the estrous cycle of the Nubian goat

Behavioral, endocrine and ovarian cyclicity were studied for 2-3 cycles in a group of 10 multiparous Nubian does. Serum samples were collected and analyzed for extradiol 17-B (E2), luteinizing hormone (LH), and progesterone (P). Laparoscopic examination of the ovaries was conducted 1, 5, 11 and 17 days after the onset of estrus II and 2 days after the onset of estrus III. Changes in luteal morphology were photographed and recorded. The percentage of ruptured follicles observed 1, 2-5, or 6-11 days after the LH peak was 14.3, 71.4 and 14.3 percent, respectively, and the mean ovulation rate was 3.1. Corpora lutea ranged from 4.9 - 9.8 mm in size at maturity. Of 48 estrous cycles followed, 21 exhibited a mean cycle length of 6.6 days, and the highest proportion (86 percent) of these short cycles were noted during the first month of the experiment. Of these cycles, 55 percent were anovulatory. The remaining 27 cycles exhibited a mean cycle length and estrus duration of 21.5 and 2.8 days, respectively. All of these cycles were ovulatory. Mean serum hormone concentrations of individual animals were normalized to the day of the LH peak (Day 0). Initiation of estrus in 67 percent of normally cycling does coincided with the day of the preovulatory LH surge. Mean serum E2 (pg/ml) and P (ng/nl) concentrations during the preovulatory period (POP, Days - 3 to + 2), early luteal period (ELP, Days 3 to 9), and late luteal period (LLP, Days 10 to 17) were: POP, (E2 equal 28.6, P equal 0.81); ELP, (E2 equal 20.2, P equal 2.4); LLP, (E2 equal 25.7, P equal 4.2). Mean serum LH concentration on Day 0 was 32 ng/ml. LH peaks of low amplitude and elevated levels of estradiol 17-B were observed coincident with the onset of estrus in short estrous cycles. These data indicate that short estrous cycles observed early in the goat breeding season are predominantly anovulatory and associated with preovulatory LH peaks of markedly reduced magnitude

Bibliographic Details

Main Authors:	53326 Camp, J.C., 131490 Wildt, D.E., 78822 Howard, P.K., 122077 Stuart, L., 56297 Chakraborty, P.K., 6757 Dairy Goat Journal Publishing Co., Scottsdale, AZ (EUA), 33022 3. International Conference on Goat Production and Disease Tucson, AZ (EUA) 10-15 Ene 1982
Format:	Texto biblioteca
Language:	eng
Published:	Scottsdale, AZ (EUA) 1982
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