Ordem de parto da matriz sobre o desempenho de bezerros e eficiência produtiva de vacas da raça Nelore

Abstract

The aim of this study was to investigate the Nelore cows age effect on her productive efficiency and performance of calves. Data were obtained from a commercial herd, raised in Pontes e Lacerda city, state of Mato Grosso. The age of cow were analyzed by the Average Daily Gain (GMD), weight at 205 days pre-weaning (P205) and the number of days to gain 160kg (D160), using information from 1,122 male calves and 1,009 female calves. The analyses of productive efficiency was obtained using the Weaning Weight Ratio (RPD) in g kg-¹ calf/cow, from information of 1,948 cows and their males (1018) and females (930) calves. The cow were ranked by similar cow calving order, using cluster analysis through the Tocher and hierarchical methods. Cluster analysis does not indicate what the best group, which is defined as average performance estimates. The GMD, P205 and D160 variables showed values of 702,2511+12,3, 180,0717+46,4 and 230,8887+25,3 for males, and 667,3264+109,2, 171,0011+23,2 and 246,4618+41,7 for females calves, respectively. The effect of cow’s age using the Tocher method for calves demonstrated that the best performing group was composed of calves of cows from 1º to 10º calving order. In hierarchical clustering, the best performing group was formed by the calves from 3º to 6º calving order. The Tocher method showed the best performance for animals in the first group, consisting of the female calves of cows from 1º to 13º cows calving. In hierarchical clustering the best performing group was represented by the female calves of cows 3º, 4º, 5º, 6º and 8º parturition. The values to the productive efficiency variable were 398,9927+73,4 and 371,7487+59,8 and g kg-1 for males and females respectively. The productive efficiency of cow how calved male calves, by Tocher method, were most effective in the first calving. However, using the hierarchical method de productive efficiency remain until the 6º calving. The Tocher method for females showed similar results to the males. On the other hand, the hierarchical method for females calves showed productive effective until the 13º calving. For males calves, the performance begins to decrease from the sixth cow calving and for females from the eighth. The youngest cow has the best productive efficiency, since the relationship of weaning weight is higher due the low cow weight