Avaliação do desempenho produtivo e reprodutivo de vacas leiteiras puras e mestiças da raça holandesa na Região do Alto do São Francisco-MG / Evaluation of the productive and reproductive performance of pure bred and crossbred Holstein dairy cows in the Alto do São Francisco-MG

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

The data used in this work were obtained from individual records on production and reproduction of black and white Holstein dairy cows, Holstein-Gir, Holstein- Gir, 7/8 Holstein-Gir, 15/16 Holstein-Gir and Holstein-Jersey, from 23 farms located in the region of Alto do São Francisco-MG. All the farms applied a very similar semiintensive management system. The period assessed was from 2003 to 2007. This study aimed to compare cattle herds presenting different degrees of blood and their productive and reproductive efficiencies as well as environmental condition effects. A total of 2.872 lactations, calving intervals and service periods were studied. The data were analyzed by the SAS program (1999) at 5% probability. All the effects studied influenced (P <0.05) the characteristics analyzed. In other words, milk production, crossbreed, and calving interval were influenced by the genetic group, farm, year and parity. In this study, the reproductive indices were found to be satisfactory, with the mixed bred animals with a higher degree of Zebu blood presenting the lowest productive indices and the animals with the highest degree of Holstein blood, the lowest reproductive efficiency, likely due to the higher sensitivity to climate and management conditions. The characteristic service period interfered both in the reproductive and productive indicators. The best results for service and calving intervals were obtained during the dry period and in the beginning of the rains, time when the forage supplied presents a higher quality. The effect of age of cow at calving on total dairy production was linear, with increase being observed in the milk production per year of increased age of cow at calving. Such increase was observed up to the fifth lactation; from the sixth order on, the effect was inverted. This fact can likely be explained by the physiological development of the animal s organism during the first lactation periods and by posterior old age and senility.

ASSUNTO(S)

holstein cows producao animal vacas holandesas desempenho reprodutivo desempenho produtivo productive performance reproductive performance

ACESSO AO ARTIGO

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