Relationships between fat depots and body condition score or tail fatness in the Rasa Aragonesa breed

Abstract

ABSTRACTThe relationships between body fat depots and body condition score (BCS) were determined in 52 adult Rasa Aragonesa ewes aged 10 (s.d. 2) years and ranging in BCS from 1·5 to 4·5. BCS of each ewe was assessed by three people, the repeatability within individuals being 90% and between individuals 80%. The ewes were weighed before slaughter. After slaughter the omental, mesenteric, kidney and pelvic fat were separated and weighed. The fat of the left side of the carcass was separated into subcutaneous and intermuscular depots. The relationship between live weight and BCS was semilogarithmic and those between fat depots and BCS were logarithmic. Regression analysis was also used to describe the relationships between the various fat depots and BCS or live weight. Of the variation in total fat weight, proportionately 0·90 was accounted for by variations in BCS, while 0·84 was accounted for by variations in live weight. For individual fat depots proportionately 0·86 to 0·90 of the variation was accounted for by variation in BCS and 0·69 to 0·79 by variation in live weight. BCS was a better predictor than live weight of the weight of both total body fat and the individual fat depots.A curvilinear regression between BCS and live weight showed that the increases in live weight for a unit change in BCS was 7, 10, 12 and 16 kg for each one point increase in BCS from 1 to 5 respectively.The tail fat depot (tail fatness score) was assessed in the same ewes by score on a three-point scale. Of the variation in the weight of individual fat depots, proportionately 0·79 to 0·86 was accounted for by variation in tail fatness score. Thus the tail fatness score could be used as an additional method of assessing body condition in the Aragonesa breed.