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
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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.