Economic weights for dairy cattle selection

[摘要] - Economic weights for important economic characteristics in the "Milk Production System" of the Santa Rita Experimental Farm, EPAMIG, located in the municipality of Prudente de Moraes, MG were calculated. The economic weights were defined as the partial derivative of profit with respect to each trait, in method (1), and as the partial derivative of the receipts/cost ratio, in method (2), evaluated at the mean value of all other traits. The economic weights, expressed in milk equivalents, for milk yield with 3.1% fat, fat yield above 3.1%, mastitis, milk flow, services/conception, age at first calving, herdlife and dry cow metabolic weight, were respectively 31.73/kg, -23.92/kg, -3341.90/case, 1531.26/kg/min, -1005.08/service, -22.30/day, 2184.38/year and -368.33/kg for the first method (1) and 1.52/kg, -1.76/kg, -179.50/case, 82.33/kg/min, -53.97/service, -1.25/day, 117,30/year and -29.00/kg, for the second method (values multiplied by 10-4 in the latter case). As expected, the relative economic weights were similar with both methods, but the absolute weights were very different.

[学科分类] 兽医学

[关键词] dairy cattle;selection objectives;economic weights     IntroduçãoO Brasil possui um dos maiores rebanhos bovinos do mundo;porém índices zootécnicos muito abaixo dos alcançados em regiões de clima temperado