Effect of stimulation with a gonadotropin mixture onreproductive outcome in nulliparous ewes bred duringseasonal anestrus and early breeding season

Project Type: Research and Education
Funds awarded in 2014: $134,152.00
Projected End Date: 12/31/2016
Region: Northeast
State: West Virginia
Project Leader:
Marlon Knights
West Virginia University
Breeding replacement ewes to lamb for the first time at 1 year of age increases lifetime productivity of the ewe and overall productivity. Ewe lambs born to fall lambing systems reach the age at which they should attain puberty during spring/summer when reproductive activity is suppressed. As a consequence few ewe lambs can be successfully bred during seasonal anestrous. In this study we demonstrated that gonadotropic stimulation with a gonadotropin mixture containing 240 IU of eCG and 120 IU of hCG following progesterone pre-treatment improved reproductive outcome in fall-born ewe lambs bred during the mid-anestrous period with estrous response and pregnancy rate to the first service period comparable to that observed in adult females. Further, Progesterone pre-treatment alone was sufficient to induce fertile estrus and advance the breeding season in yearlings bred during mid- and late-anestrus.
Marlon Knights, West Virginia University
Adam Redhead, West Virginia University
Kellie D'Souza, West Virginia University
Quinn Baptiste, Berea College
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.