Genetic and Non-Genetic Factors Affecting Lactational Milk Constituents and Yield Traits in Karan Fries Cattle

摘要

The present study was carried out on lactational milk constituents, their yields and milk yield traits from 1487 lactation records of 706 Karan Fries (Tharparkar x Holstein Friesian) cows, calving from 1989 to 2000, maintained at NDRI. Overall least-squares means for lactational percentages. Lactational yields (overall least squares means) of fat, protein, SNF, total solids, 305 days milk yield, total lactation milk yield, 4 per cent fat corrected milk yield were 120.02±4.06, 105.98±6.76, 262.56±8.92, 38262±12.96, 2819.02±81.35, 3002 98± 101.55 and 3001.46±101.24 kg, respectively. Analysis of variance revealed significant variation due to sire for all the traits, except protein percentage. Except protein percentage, SNF percentage and proteinyield, all the other traits were significantly affected by Friesian inheritance level. While fat, protein, total solids percentages and protein yield did not show any seasonal variations, other traits did. The effect of period was significant on the other traits except on fat percentage, fat yield, total lactation milk yield and 4 per cent fat corrected milk yield. Barring protein yield all the traits showed significant lactational variation. The sufficient variation existed in the traits can be exploited for improvement of milk quality and quantity through planned breeding programmes and proper managemental practices.