Location: Forage and Livestock Production ResearchTitle: The effects of protein supplement on leptin concentrations in lambs and meat goat kids grazing Bermudagrass pastures in Central Oklahoma Author
Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/21/2010
Publication Date: 8/4/2010
Citation: Walker, E.L., Nusz, S.A., Keisler, D.H., Brown, M.A. 2010. The effects of protein supplement on leptin concentrations in lambs and meat goat kids grazing Bermudagrass pastures in Central Oklahoma [abstract]. American Society of Animal Science Annual Meeting, July 11-15, 2010, Denver, CO. Available on-line: http://adsa.asas.org/meetings/2010/toc.asp Interpretive Summary: Abstract Only.
Technical Abstract: Lambs and kids weaned and pastured on bermudagrass (BG; Cynodon dactylon) may not receive enough protein to reach maximal growth during mid to late summer when protein in BG pastures declines. As an indicator of physiological status, leptin is an adipocyte-derived hormone that increases as body condition increases and is involved in body temperature regulation. Our objective was to determine the affects of protein supplementation on leptin status in lambs and meat goat kids grazing on summer BG pastures. In 2007, 10 Boer type (BT) and 13 Spanish type (ST) kids were used (start bwt = 14±5 kg) and 23 Katahdin (KK), 14 Katahdin×Suffolk (KS), 14 Suffolk×Katahdin(SK), and 21 Suffolk (SS) lambs were used (start bwt = 30±5 kg; start age = 100±10 d). In 2008, 27 BI and 28 SP kids were used (start bwt = 18.8±0.6 kg) and 11 KK, 15 KS, 21 SK, and 25 SS lambs were used (start bwt = 25.8±0.7 kg; start age = 100±5 d) were used. Animals were allotted by weight, breed, and gender to one of two treatments: 1.22 hectares of BG with no protein supplement (NP; n=2) or with 21% molasses-based protein blocks (PT, n=2). Animals were weighed and blood samples collected every 2 weeks. In 2007, serum concentrations of leptin did not differ by treatment (P = 0.94) or between species (P = 0.60) or genders (P = 0.29). There was a breed within species interaction (P = 0.01)and serum leptin values tended to decline from June to August (P = 0.10). In 2008, serum leptin tended to be greater in PT than NP animals (P = 0.08) and greater in kids than lambs (P = 0.001). No breed within species interaction was observed (P = 0.49) nor did gender affect serum leptin (P = 0.33). There was a strong association between date and serum leptin concentrations (P = 0.001) and there was a breed by date within species interaction (P = 0.009). In both trials, serum leptin values declined from June to August as forage quality decreased throughout the summer.