作者: JR da Glória , JAG Bergmann , RB Reis , MS Coelho , MA Silva
DOI: 10.1590/S0102-09352006000600024
关键词: Animal science 、 Genetic composition 、 Milk yield 、 Lactation 、 Milk production 、 Crossbreed 、 Ice calving 、 Biology
摘要: The effects of genetic composition (GC) and environmental factors on milk production (MP), lactation length (LL) yield per day calving intervals (P/I) (n=2,016) 822 crossbred (1/2, 3/4 7/8) Holstein-Gyr cows, raised in the West Minas Gerais State, Brazil, were evaluated using least squares methodology. effect predicted transmitting ability (PTA) Holstein sires MP their daughters was also evaluated. three traits an important source variation. MP, LL P/I increased with increase contribution. Season variation for cows 1/2 cows. highest observed lactations starting at end rainy season. age linear 1//2 curvilinear 7/8 For On PTA not different from zero. Estimated repeatability .72, .69 .63, respectively, 1/2,