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báo cáo khoa học: "Relationships feed between growth rate, carcass composition, intake, feed conversion ratio and income in four biological types of cattle "

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Relationships feed between growth rate, carcass composition, intake, feed conversion ratio and income in four biological types of cattle (1) | Génét. Sél. Evol. 1987 19 2 225-248 Relationships between growth rate carcass composition feed intake feed conversion ratio and income in four biological types of cattle 1 R. HANSET c. MICHAUX and A. STASSE Chaừe de Génétique Faculte de Médecine Vétérinaire U. Lg 45 rue des Vétérinaires B-1070 Bruxelles Belgique Ministère de I Agriculture Station de Selection Bovine 12 rue des Champs-Elysees B-5300 Ciney Belgique Summary The relations between growth rate carcass composition feed intake feed conversion ratio and income are investigated on bulls entered in Station at the age of one month and tested from 7 to 12 months of age belonging to four biological types 1 Belgian Blue bulls of the double-muscled type DM n 622 2 crossbred sons of DM sires out of Friesian dams DM X FR n 94 3 similar SOTS but out of MRY dams DM X MRY n 20 4 Belgian Blue bulls of conventional type CONV n 236 . . For.the biological as for the economical traits considered the double-muscled type was quite distinct from the other types. In comparison with the conventional animals the double-muscled ones had their feed intake reduced by 6.5 p. 100 their feed conversion ratio reduced by 8.7 p. 100 their dressing-out percentage increased by 8 p. 100 their percent lean in the 7th ribcut increased by 20 p. 100 their percent fat in the same ribcut lowered by 42 p. 100. For the year 1980 the selling price of the double-muscled exceeded that of the conventional by 57 p. 100 and their net income was 3.25 times higher. The coefficients of determination R2 of feed intake and of feed conversion ratio by initial weight daily gain and carcass composition criteria were computed within each biological type. These traits were considered singly and in combination. It was found that within biological types the carcass traits were of minor importance in the determination of feed intake or of feed conversion. A covariance analysis showed that mean feed intake adjusted for initial weight and daily gain was significantly .