Effect of gestation stage on milk yield and composition in Holstein Friesian dairy cattle

摘要: The effect of gestation stage on daily milk production and composition was investigated using first lactation weekly test day records 325 Holstein Friesian cows in one herd. Gestation had a significant (P < 0.05) all traits, accounting for 1.38 to 1.69% reduction total sum squares yield traits less than 0.4% content traits. Decline due pregnancy began from the month increased non-linearly about 3.0, 0.08, 0.12 0.14 kg/day respectively milk, fat, protein lactose 8th gestation, corresponding 7–12% mean yield. There little change but fat significantly 6th gestation. A interaction between observed, indicating that adverse higher mid late lactation. Lactation estimated decline by 21, 1.5, 0.9 1.4 kg were pregnant three months during If eight months, losses 207, 8.1, 8.7 10.7 directly pregnancy.