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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #231354
Title: Nutrition during mid to late gestation affects growth, adipose tissue deposition, and tenderness in cross-bred beef steers

Author
item UNDERWOOD, K - UNIVERSITY OF WYOMING
item TONG, J - UNIVERSITY OF WYOMING
item PRICE, P - UNIVERSITY OF WYOMING
item Roberts, Andrew
item GRINGS, E - CGIAR
item HESS, B - UNIVERSITY OF WYOMING
item MEANS, W - UNIVERSITY OF WYOMING
item DU, M - UNIVERSITY OF WYOMING

Submitted to: Meat Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/12/2010
Publication Date: 9/9/2010
Citation: Underwood, K.R., Tong, J.F., Price, P.L., Roberts, A.J., Grings, E.E., Hess, B.W., Means, W.J., and Du, M. 2010. Nutrition during mid to late gestation affects growth, adipose tissue deposition, and tenderness in cross-bred beef steers. Meat Science. 86:588-593.

Interpretive Summary: Gestating beef cows grazing western rangelands can experience extended periods of low quality forage during late summer into fall, especially in drought conditions. Nutrient restriction of the dam during this period can cause fetal adaptations affecting the animal later in life. Adipocyte differentiation occurs during mid to late gestation, and therefore nutrition during this time could alter adipose tissue development resulting in changes in carcass composition at slaughter. Thus, the objective of this study was to examine if cow nutrition by pasture management during mid to late gestation, would affect growth, carcass composition, and tenderness of steer offspring produced by crossbred beef cows that grazed either improved pasture (IP, n = 8) or native range (NR, n = 7) for a 60-days period from about 135 to 195 days of gestation. Steers were weaned at 191 days of age and were fed as a single group until slaughtered at 15 months of age. At slaughter, steers born to mothers grazed on IP had heavier live body weight and hot carcass weight than NR steers. Longissimus muscle area, semitendinosus weight, marbling score, kidney, pelvic and heart fat, and yield grade were similar between NR and IP steers. Steers from cows that had grazed IP had greater fat thickness over the 12th rib and tended to have more adipose cells than NR steers. Steaks from IP steers had greater crude fat content and were more tender than steaks from NR steers. These data show pasture quality available to cows during mid to late gestation affects growth and adipose tissue deposition in their fetuses, which carries over into growth performance, fat deposition and meat quality of offspring.

Technical Abstract: Nutrient restriction of the dam during gestation can have detrimental effects on the progeny. Adipocyte differentiation occurs during mid to late gestation, and therefore nutrition during this time is expected to affect adipose tissue development and resulting carcass composition of steers. Thus, the objective of this study was to examine if cow nutrition by pasture management during mid to late gestation, would affect growth, carcass composition, and tenderness of steer offspring. Fifteen crossbred beef cows were randomly placed on improved pasture (IP, n = 8) or native range (NR, n = 7) from 120 to 150 through 180 to 210 d of gestation. Then, both groups of cows were placed together and allowed to calve. Steers were weaned at 191 d of age and were fed in a single pen until slaughtered at 15 mo of age. Longissimus muscle and adipose tissue samples were collected. Carcass characteristics were measured at 48 h postmortem. Subcutaneous adipose tissue was fixed, sectioned, stained and used for analyses of cell number and cell diameter. Weight at 315 d of age when steers were placed on a finishing ration did not differ (P = 0.71) between treatments. At slaughter, steers born to mothers grazed on IP had heavier live BW (P = 0.04) and HCW (P = 0.01) than NR steers. Longissimus muscle area, semitendinosus weight, marbling score, kidney, pelvic and heart fat, and yield grade were similar (P > 0.12) between NR and IP steers. Crude fat content (6.00 ± 0.49% vs. 4.82 ± 0.53%, P = 0.06) and tenderness (P = 0.01) were greater in rib steaks from IP than NR steers. Twelfth rib fat thickness (P = 0.05) and adjusted 12th rib fat thickness (P = 0.02) were greater for IP steers than for NR steers. Adipose tissue cell number per field tended (P = 0.09) to be greater for IP steers than for NR steers. These data show improving pasture quality available to cows during mid to late gestation affects growth and adipose tissue deposition in steers.