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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Slack, N. H. Articles by Rankin, A. D. Search for Related Content PubMed Articles by Slack, N. H. Articles by Rankin, A. D.

Progestogen Treatment in Relation to Time of Insemination and its Effect on the Breeding Efficiency of Dairy Cows¹

New Jersey Agricultural Experiment Station, New Brunswick

V. Hurst

South Carolina Agricultural Experiment Station, Clemson

A. D. Rankin

The Squibb Institute for Medical Research, New Brunswick, New Jersey

ABSTRACT

The effect of routine therapy with 500 mg of progesterone caproate (PC) alone or in combination with 0.5 mg of estradiol valerate (PC + EV) on breeding efficiency was determined with 594 Holstein and 282 Guernsey female reproductive cycles. In three controlled trials the drug was injected intramuscularly at 0, 2, 10, or 14 days after artificial insemination on the first and (if necessary) the second insemination during a reproductive cycle.

In the first trial, when PC was administered at zero day, breeding efficiency values were 20.7% lower for Holsteins and 13.5% lower for Guernseys than for the controls. When PC was administered two days after insemination, the breeding efficiency of the Holsteins was almost equal (3.1% lower) to that of the controls, though it was markedly lower (15%) for the Guernseys. Such early treatments showed a detrimental effect on breeding efficiency.

When PC was administered alone or in combination with EV at ten days in Trial II to both breeds and at 14 days in Trial III to Holsteins, breeding efficiency values were only slightly below those of the control group, except for the PC + EV group in Trial II, in which the Holsteins averaged 17.7% below their controls. No beneficial effects were seen in any of the treatment groups. Other comparative analyses of the data yielded no conclusive evidence that the treatments were causing prolonged injurious effects on the reproductive system.

¹ Paper of the Journal Series, New Jersey Agricultural Experiment Station, Rutgers—The State University, New Brunswick, and technical contribution 456 of the South Carolina Agricultural Experiment Station, published by permission of the director. This study was part of NE-41 (revised), Endocrine Factors Affecting Reproduction in the Bovine Female, a regional study by the agricultural experiment stations in the Northeast, and the Dairy Cattle Research Branch, Animal Husbandry Research Division, USDA.