The Effect of Progesterone Intravaginal Devices (CIDRS), P.G. 600 and RAM Effect on Hastening the Onset of Cyclicity of Transitional Targhee Ewes

Sheep are seasonally polyestrous breeders, cycling in late summer and early autumn. Breeding out of season or as early as possible in the season has many management and economical benefits. Efforts to hasten the transition period of ewes into cyclicity involve the use of vasectomized rams to induce the "ram effect"(RE) and progesterone devices.

The objective of the study was to compare the use of a recently-approved intravaginal progesterone device (CIDR; EAZI-BREEDTM CIDR® Sheep Insert, Zoetis, Florham Park, NJ) with the ram effect (vasectomized rams), a combination of CIDR and ram effect and the addition of P.G.600® (eCG+hCG; Merck Animal Health/Intervet, Madison, NJ) to determine their contribution to induce the onset of cyclicity and alter reproductive efficiency. [...]