Relationship of fertility to ovarian follicular waves before breeding in dairy cows

Cows with two waves of follicular growth during the estrous cycle yield follicles that are older and larger at ovulation compared with cows having three waves. The objectives of the current research were 1) to compare fertility in cows with two or three follicular waves and 2) to examine association...

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Bibliographic Details
Published in:	Journal of animal science Vol. 80; no. 4; pp. 1053 - 1058
Main Authors:	Townson, D. H, Tsang, P. C, Butler, W. R, Frajblat, M, Griel, L. C., Jr, Johnson, C. J, Milvae, R. A, Niksic, G. M, Pate, J. L
Format:	Journal Article
Language:	English
Published:	Savoy, IL Am Soc Animal Sci 01-04-2002 American Society of Animal Science Oxford University Press
Subjects:	Animal productions Animals Biological and medical sciences Breeding Cattle Cattle - physiology Estradiol - blood Estrus - physiology Female Fertility Fertility - physiology Fundamental and applied biological sciences. Psychology Hormone metabolism and regulation Hormones Insemination, Artificial - veterinary Male Mammalian female genital system Ovarian Follicle - physiology Ovulation - blood Ovulation - physiology Pregnancy Pregnancy Rate Progesterone - blood Terrestrial animal productions Vertebrates Vertebrates: reproduction Farming animal Ruminant animal Dairy cattle REPRODUCTIVE PERFORMANCE Experimental study Sexual reproduction Ovulation Female sexual function Vertebrata Mammalia Fertility Rearing Artiodactyla Estrous cycle Progesterone Ovarian follicle Ungulata
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Summary:	Cows with two waves of follicular growth during the estrous cycle yield follicles that are older and larger at ovulation compared with cows having three waves. The objectives of the current research were 1) to compare fertility in cows with two or three follicular waves and 2) to examine associations between luteal function, follicular development, and fertility after breeding. Follicular waves were monitored by ultrasonography during the estrous cycle before insemination in 106 dairy cows. Fewer cows had three follicular waves before next estrus and ovulation than two waves (P < 0.01; 30% vs 68%, respectively), but pregnancy rate was higher (P = 0.058; 81 vs 63%, respectively). Cows with two waves had shorter estrous cycles (P < 0.01), with the ovulatory follicle being both larger (P < 0.05) and older (P < 0.01). In cows with three waves, luteal function was extended (P < 0.05) and the peak in plasma progesterone occurred later (P < 0.05) in the estrous cycle compared to two wave cows. Considering cows that became pregnant, luteal phase length was shorter (P < 0.05) during the estrous cycle preceding insemination than for nonpregnant cows. In conclusion, fertility was greater in lactating cows inseminated after ovulation of the third-wave follicle that had developed for fewer days of the estrous cycle as compared with two-wave cows.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0021-8812 1525-3163
DOI:	10.2527/2002.8041053x