New Research Journal Article Available
April 15, 2016

A peer-reviewed article has been added to the 2015-Volume 30 edition of the Sheep and Goat Research Journal available online at www.sheepusa.org/ResearchEducation_ResearchJournal.

The article, Effects of Photoperiodic Manipulation on Growth Rate and Ability to Breed Fall-born Ewe Lambs in Spring, authored by M.L. Deacon, M. Knights and E.K. Inskeep, examines the effects of photoperiod in winter on puberty and growth in fall-born ewe lambs. Dorset, Suffolk and Texel lambs were randomized within age, weight, breed and type of birth and rearing, to be exposed to either natural photoperiod or both natural and supplemental light to produce a photoperiod of 16 hours of light to eight hours of dark for 14 weeks.

At completion of the supplemental lighting, each treated lamb received an ear implant of melatonin. Lambs were weighed at weaning, light completion and insertion of controlled-internal, drug-releasing devices containing progesterone (CIDR) to synchronize estrus. Serum progesterone was measured at light completion and one week before and at CIDR insertion. CIDRs were removed and fertile rams introduced for 27 days or 33 days.

The study found that estrous response and pregnancy rate did not differ with treatment. At the ages tested, photoperiodic manipulation did not hasten puberty or response to progesterone and ram introduction in fall-born ewe lambs.

Read the entire article to get the complete details of this study.