Medroxyprogesterone priming and response to the ram effect in Corriedale ewes during the nonbreeding season

Abstract

The "ram effect" (RE) is an inexpensive technique that allows farmers to obtain out-of-season lambs. Five hundred and ninety-six Corriedale ewes were used in three experiments to determine the effectiveness of different medroxyprogesterone (MAP) treatments associated with the ram effect during the nonbreeding season. The aim of the first experiment was to evaluate the effectiveness of short-term (6-day) MAP priming. We obtained similar results in estrus incidence and fertility after using MAP sponges for 6, 9, and 13 days. In the second experiment, we compared the effect of sponges containing 20, 40, or 60 mg of MAP used in 6-day priming. Estrous behavior and fertility were not affected by dosage. In the third experiment, 2.5 mg of MAP was administered in single treatments 0, 1, 3, or 5 days before the introduction of the rams. Medroxyprogesterone administration 1, 3, or 5 days before the introduction of the rams concentrated estrus in ewes 17 to 20 days later. (C) 2002 Elsevier Science Inc. All rights reserved

Keywords

estrus induction; ram stimulus; seasonal anestrus; sheep

Published in

Theriogenology
2003, Volume: 60, number: 1, pages: 35-45
Publisher: ELSEVIER SCIENCE INC

SLU Authors

• Forsberg, Mats

  • Department of Clinical Sciences, Swedish University of Agricultural Sciences
    

Publication identifier

DOI: https://doi.org/10.1016/S0093-691X(02)01302-X

Permanent link to this page (URI)

https://res.slu.se/id/publ/64