Feed intake, selectivity and ap p a ren t digestibility coefficients of dry m atte r, protein and d etergent fib er fractions w ere d eterm in ed in groups of four yearling bison, yak and cattle. Diets of co n trastin g q u ality for th ese cam parisons w ere provided by native sedge m eadow hay, brom efescue grass hay and alfalfa hay. Feed intakes fo r bison and cattle w ere sim ilar b u t considerably h igher on a p er u n it body w eight basis th a n for yak. A p p aren t digestibility coefficients fo r dry m a tte r an d deterg en t fiber fractions tended to be highest in bison follow ed by yak th en cattle, a digestive su p e rio rity w hich was m ost m ark ed on th e grass h ay diet. H ow ever, off-settin g the digestive advantage of bison in rela tio n to the other tw o species w as an a p p a re n t higher digestible dry m a tte r re q u ire m ent for m aintenance. G ains and feed conversion for cattle exceeded those of yak and bison on sedge and grass hays b u t not on alfalfa.[Dept. Anim. Sci., Univ. A lberta, E dm onton, C anada T6G 2E3].

Muscle distribution was studied in 109

ABSTRACT

Video image analysis (VIA), carcass shape and colour data were collected for 1211 lambs of known gender, breed type and carcass weight over a 1-week period using the VIAscan® system developed by the Australian Meat Research Corporation. Classification data (thickness of soft tissue over the 12th rib (GR measurement) and subjective conformation scores on a five-point scale of the leg, loin and shoulder) were assessed by an Agriculture and Agri-Food Canada grader after carcasses had chilled at 5°C for 3 to 6 h. Dissections into saleable meat yield (no. = 58) were performed after carcasses had chilled an additional 24 h. The timing of this study, which was dependent on availability of the VIA equipment, influenced the age and type of lambs available for analysis. The majority of lambs evaluated were wool-breed wethers, age > 10 months, of average GR (15-7 (s.d. 0-2) mm) and muscle conformation (3-0, s.d. 0-1). VIA improved the prediction of saleable meat yield (R 2 = 0-71, residual s.d. = 14g/kg) compared with the current classification system (R 2 = 0-52, residual s.d. = 18 glkg). Although prediction ofGR measurement by VIA resulted in a large residual error (residual s.d. = 2-4 mm), the proportion of waste fat (perirenal and subcutaneous) and bone dissected from the carcass was accurately predicted (R 2 = 0-62, residual s.d. = 11 glkg). Proportions of leg (R 2 = 0-71, residual s.d. = 7 glkg) and shoulder (R 2 = 0-62, residual s.d. = 9 glkg) primals were also accurately predicted by VIA, although there were no significant predictors for the proportion of the loin (P > 0-15). VIA improved the prediction of saleable meat yield compared with the current classification system. However collection of additional data including some from extremely lean or well muscled animals would be required before VIA could be recommended to classify lamb carcasses

JoNss,S. D. M.,RrcutroND,R. J.,Pntce,M. A. e.NoBsnc,R' T' 1980' Effects ofbreed and sex on the patterns offat deposition and distribution in swine. Can. J. Anim. Sci .o*purironr. No significant differences were detected for coefficients among breeds and Letween sexes using both total muscle and total side fat as independent variables. Significant breed and sex-type differences were found in the fat depots at a constant *.ight of rid" muscle. This would indicate that breed differences in fatness seemed to be more influenced by the initiation of fattening at different muscle weights than by any inherent differences in rate of fattening. Significant breed differences were also found in the fat depots at a constant fat weight, indicating that breed may influence fat distribution. Sex-type had no effect on fat distribution when the evaluation was made at constant fatness.