HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Haughian, J. M. Articles by Wiltbank, M. C. Search for Related Content PubMed PubMed Citation Articles by Haughian, J. M. Articles by Wiltbank, M. C.

Extending the Postpartum Anovulatory Period in Dairy Cattle with Estradiol Cypionate

J. M. Haughian^*, R. Sartori, J. N. Guenther, A. Gümen and M. C. Wiltbank^*,

^* Endocrinology-Reproductive Physiology Program and
Department of Dairy Science, University of Wisconsin, Madison, WI 53706

Corresponding author:
M. C. Wiltbank; e-mail:
wiltbank{at}calshp.cals.wisc.edu.

Estradiol cypionate (ECP), a long-acting estrogen, has been used therapeutically in early postpartum (PP) dairy cows. In experiment 1, effects of ECP on circulating reproductive hormones, cyclicity, and ovarian function in early PP dairy cows were investigated. Lactating Holsteins received 10 mg of ECP (ECP; n = 17) or placebo (CON; n = 16) on d 7 PP. Serum and ultrasound data were acquired from 5 to 90 d of lactation. Compared to CON, ECP cows had greater serum estradiol for 10 d and lower serum FSH for 15 d posttreatment. After ECP, the appearance of follicles 10 mm and time to first ovulation were delayed. Nevertheless, by 90 d PP, normal estrous cycles were found in only 50% of CON versus 88% of ECP cows. Primiparous, but not multiparous, cows receiving ECP had higher milk yields. Experiment 2 investigated effects of ECP on reproduction and milk production on a commercial dairy. Cows were blocked by parity and randomized to three treatments: 0 (n = 85), 4 (n = 85), or 10 (n = 86) mg of ECP on d 5 to 8 PP. Data included cycling status (two ultrasound examinations at 30 to 33 d PP and 7 d later), individual reproduction records, and daily milk yields from 10 to 90 d PP. In primiparous cows, ECP had no significant effects on ovulatory status or milk yields. By 40 d PP, a greater percentage of multiparous cows receiving 10 mg of ECP remained anovulatory compared with those receiving 0 or 4 mg. Milk yields were highest for multiparous cows receiving 4 mg of ECP, intermediate for the 10-mg dose, and lowest for controls. Lower conception was observed in multiparous cows receiving 4 mg of ECP. In summary, ECP delayed time to first ovulation particularly in multiparous cows, an effect associated with observed inhibition of circulating FSH. Milk yield responses to ECP were inconsistent within parity groups across the two experiments.

Abbreviation key: CL = corpus luteum, , CON = control, , DA = displaced abomasum, , ECP = estradiol cypionate, , PP = postpartum

Key Words: estradiol cypionate • anovulation • milk yield • dairy cattle

This article has been cited by other articles:

				C. A. Blevins, J. E. Shirley, and J. S. Stevenson Milking frequency, estradiol cypionate, and somatotropin influence lactation and reproduction in dairy cows. J Dairy Sci, November 1, 2006; 89(11): 4176 - 4187. [Abstract] [Full Text] [PDF]