RELATIONSHIP OF BODY-COMPOSITION OF MATURE EWES WITH CONDITION SCORE AND BODY-WEIGHT

Fourteen mature, ovariectomized, western-range ewes with an initial me an BW of 72 +/- 4.5 kg and mean condition score (CS) of 7.5 +/- .3 wer e used to evaluate the relationship between CS and body composition. D iets of chopped straw and alfalfa hay were formulated to provide eithe r maintenance energy or less than maintenance energy (100 or 60% of ME ) to induce changes in BW and CS. After 180 d, ewes were weighed, scor ed for body condition, and slaughtered. All carcass components, viscer a, and organs were analyzed for lipid, DM, and ash, and protein was de termined by difference. Body weight and CS values were related by regr ession analysis to percentage of composition and weights of carcass co mponents, carcass, and empty body. Body weight and CS were highly corr elated (r = .89) and analysis indicated that each increase in CS resul ted in an increase of 5.1 kg of BW. Condition score accounted for more variation of percentage of lipid in the empty body (R2 = .95) and car cass (R2 = .90) than did BW (R2 = .84 and .80, respectively). In contr ast, BW accounted for more of the variation in carcass weight (R2 = .9 7) and empty BW (R2 = .99). Inclusion of both BW and CS in regression models did not increase the variation accounted for with the single be st predictor. With mature western-range ewes in this study, CS was hig hly related to carcass lipids and could be used to describe energy res erves available to ewes.