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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #122392
Title: A POSSIBLE ROLE OF THE LEPTIN ASSAY IN ASSESSING CARCASS FAT AND COMPOSITION IN BEEF CATTLE

Author
item Geary, Thomas
item MCFADIN-BUFF, E - UNIVERSITY OF MISSOURI
item Macneil, Michael
item FUNSTON, RICK - MAES
item Short, Robert
item Grings, Elaine
item KEISLER, D - UNIVERSITY OF MISSOURI

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 4/3/2001
Publication Date: 6/1/2001
Citation: GEARY, T.W., MCFADIN-BUFF, E.L., MACNEIL, M.D., FUNSTON, R.N., SHORT, R., GRINGS, E.E., KEISLER, D.H. A POSSIBLE ROLE OF THE LEPTIN ASSAY IN ASSESSING CARCASS FAT AND COMPOSITION IN BEEF CATTLE. JOURNAL OF ANIMAL SCIENCE SUPPLEMENT. 2001. v. 79(Suppl. 2). p. 125.

Interpretive Summary: The hormone leptin is produced by adipocytes and is positively correlated with body fatness. In cattle, fat makes up approximately 36% of an animal's empty body weight. Approximately 70% of this fat is stored as either intermuscular, intramuscular, or kidney fat, which are all difficult to accurately estimate in the live animal. Our objective was to determine if a newly developed leptin radioimmunoassay (RIA) could be used to predict carcass merit in fed cattle. Two different groups of crossbred Bos taurus steers and heifers were managed under feedlot conditions in Miles City, MT. The first group (CGC) consisted of 88 1/2Red Angus, 1/4Charolais, and 1/4Tarentaise composite steers harvested at the Con Agra processing facility in Greeley, CO. The second group (LB) consisted of Limousin, Hereford, or Piedmontese crossbred steers and heifers harvested at a local processing facility in Miles City. Blood samples were collected 24 h before harvest (CGC) or 3-5 d before and at harvest (LB). Circulating leptin concentrations were positively correlated (P<0.01) to fat depth in both CGC (r=0.34) and LB cattle (r=0.38). Leptin concentrations were also positively correlated (P<0.01) to marbling score (r=0.35 and 0.37) and KPH (r=0.42 and 0.46) in CGC and LB cattle, respectively. Ribeye area was not correlated to leptin in CGC steers (r=0.12, P=0.3), but was negatively correlated to leptin in LB cattle (r=-0.25, P=0.02). Leptin concentration was correlated to yield grade in both CGC and LB groups (r=0.23, P<0.05 and r=0.36, P<0.01, resp.). Leptin has a significant association with fat deposition in feedlot cattle and may prove to be a powerful and accurate tool in assessing fat content in feedlot cattle.

Technical Abstract: The hormone leptin is produced by adipocytes and is positively correlated with body fatness. In cattle, fat makes up approximately 36% of an animal's empty body weight. Approximately 70% of this fat is stored as either intermuscular, intramuscular, or kidney fat, which are all difficult to accurately estimate in the live animal. Our objective was to determine if a newly developed leptin radioimmunoassay (RIA) could be used to predict carcass merit in fed cattle. Two different groups of crossbred Bos taurus steers and heifers were managed under feedlot conditions in Miles City, MT. The first group (CGC) consisted of 88 1/2Red Angus, 1/4Charolais, and 1/4Tarentaise composite steers harvested at the Con Agra processing facility in Greeley, CO. The second group (LB) consisted of Limousin, Hereford, or Piedmontese crossbred steers and heifers harvested at a local processing facility in Miles City. Blood samples were collected 24 h before harvest (CGC) or 3-5 d before and at harvest (LB). Circulating leptin concentrations were positively correlated (P<0.01) to fat depth in both CGC (r=0.34) and LB cattle (r=0.38). Leptin concentrations were also positively correlated (P<0.01) to marbling score (r=0.35 and 0.37) and KPH (r=0.42 and 0.46) in CGC and LB cattle, respectively. Ribeye area was not correlated to leptin in CGC steers (r=0.12, P=0.3), but was negatively correlated to leptin in LB cattle (r=-0.25, P=0.02). Leptin concentration was correlated to yield grade in both CGC and LB groups (r=0.23, P<0.05 and r=0.36, P<0.01, resp.). Leptin has a significant association with fat deposition in feedlot cattle and may prove to be a powerful and accurate tool in assessing fat content in feedlot cattle.