Effect of coefficient of inbreeding on breeding efficiency and body measurements of Japanese Black cows

概要

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Data on study were pedigree information and breeding records of 319 cows which were born in 1969-1982 and had been culled by March of 1987 in Ie Is. Okinawa Prefecture. Main effects and covariates were sire (random), hard, period and season of birth, linear regression on age at body measurement and quadratic regression on coefficient of inbreeding. Traits analyzed were age at first calving, no. of calving, age at final calving, body type score, withers height, chest girth, chest depth, rump length, hip width and thurl width. Regression equations, for which x was independent variable of coefficient of inbreeding and y were dependent variables, were y=4.305-0.080x for no. of calving, y=177.8-2.601x+0.100x<SUP>2</SUP> for chest girth and y=63.9-0.782x+0.028x<SUP>2</SUP> for chest depth. From these results, inbreeding depression against no. of calving was suggested, however no clear conclusion was obtained for chest girth and chest depth because of the unreliable body measurements due tp pregnancy.
日本暖地畜産学会の論文