Physiology and Endocrinology: Hormonal Regulation of the Estrous Cycle in Beef Cattle
نویسندگان
چکیده
J. Anim. Sci. Vol. 88, E-Suppl. 2/J. Dairy Sci. Vol. 93, E-Suppl. 1/Poult. Sci. Vol. 89, E-Suppl. 1 T264 Effects of 72-h temporary calf removal prior to fixed-time AI on pregnancy rates and subsequent calf performance in suckled beef cows. G. H. L. Marquezini*1, V. R. G. Mercadante1, S. L. Bird2, B. J. Funnell2, and G. C. Lamb1, 1University of Florida, Marianna, 2University of Minnesota, Grand Rapids.
منابع مشابه
Hormonal Profile of Ovarian Follicular Fluid and Blood Plasma during Different Stages of Estrous Cycle in Holstein Cattle
The aim of this study was to evaluate the concentrations of reproductive hormones in blood plasma and in follicular fluids of different sized follicles during various stages of the estrous cycle in Holstein cattle. Jugular blood samples from 42 adult Holstein cattle were collected immediately after the slaughter. Antral fluids from small (4-5 mm), medium (6-9 mm) and large (10-20 mm) follicles ...
متن کاملPhysiology and Endocrinology: Hormonal Regulation of the Estrous Cycle in Dairy Cattle
J. Anim. Sci. Vol. 88, E-Suppl. 2/J. Dairy Sci. Vol. 93, E-Suppl. 1/Poult. Sci. Vol. 89, E-Suppl. 1 W277 Effects of treatments with hCG or GnRH on serum progesterone (P4) and conception rates (CR) in lactating dairy cows submitted to timed artificial insemination (AI) or embryo transfer (ET). P. Justolin*1, P. Morelli1, M. Reis1, O. Sá Filho1, F. Aragon2, M. Veras2, S. Soriano3, and J. L. Vasco...
متن کاملPhysiology and Endocrinology: Hormonal Control of Estrus in Beef Cattle
The objective of the experiment was to compare follicular dynamics, ovulatory response to GnRH, steroid hormone concentration patterns, and synchrony of estrus and ovulation among estrous-cycling and anestrous postpartum beef cows following treatment with long-term progestin-based protocols. Beef cows (n = 40) were assigned to treatments based on age, days postpartum, BCS and estrous cyclicity ...
متن کاملPhysiological Principles Underlying Synchronization of Estrus
Reproductive efficiency is the most important factor impacting the economics of a cow calf operation. The economic value of reproduction for commercial beef producers was reported to be five times greater than calf growth (Trenkle and Willham, 1977). Maximizing reproductive efficiency depends upon the successful completion of the following events: a heifer must reach puberty before the start of...
متن کاملProduct Development for Estrous Synchronization : Beef Cattle
Physiological principals underlying synchronization of estrus identified 1) hormones naturally controlling the estrous cycle of cattle, 2) hormones commercially available, 3) mode of action of the hormones commercially available, and 4) when/how they might be used to manage estrus and breeding of beef cattle. The products available are progestogens (melengestrol acetate (MGA) and progesterone d...
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