Sources of Variation in Subcutaneous Fat Colour of Beef Carcasses

Yellow fat in beef carcasses incurs price penalties in many domestic and export markets. Sources of variation in subcutaneous fat colour of beef carcasses was investigated by objective measurements on 622 carcasses of various classes of cattle. Fat colour was subjectively assessed using a six point photographic colour chart . The majority of carcasses sampled (80.6%) had creamy-white to cream fat. The objective measurement of the yellowness of the subcutaneous fat (b* value) explained 46% of variation in subjective fat colour scores (r *=0.46, r.s.d.=5.35; P<O.OOl). Multiple regression analysis of the results for British breeds of cattle showed significant effects of nutrition, age and sex and interactions between sex x age and age x hot carcass weight on the b* value of the subcutaneous fat (P<0.001 for all). Grassfed cattle and milk vealers had yellower fat than feedlot cattle. The subcutaneous fat of female cattle was yellower than that of steers across all age categories. Aged cattle (8 permanent incisors) had yellower fat. Breed also influenced the b* value of the subcutaneous fat (P<O.OOl) dairy cattle breeds had yellower fat than British and European breeds.