Response of lactating cows to supplemental rumen protected methionine and Niacin

• 来源期刊: 中国高等学校学术文摘·农学
• 关键词: lactating cows RPMet niacin milk yield milk composition
• 年，卷（期）: 2008,（1）
• 页码范围: 121-124
• 页数: 4页
• 语种: 英文
• DOI: 10.1007/s11703-008-0021-7

摘要

Eight Chinese Holstein cows were used in a 4×4 Latin square design to determine the effects of rumen protected methionine (RPMet) and Niacin on milk yield and milk composition of lactating cows with 14 d adaptation and 6-d sampling periods. The cows were fed the control diet or the control diet plus RPMet tion in the diet increased 4% fat corrected milk (FCM) yield (P<0.05) and milk fat percentage (P<0.05). However, supplemental RPMet had no effect on the solid non fat (SNF) (P > 0.05) and lactose percentage (P>0.05). Dietary niacin supplementation increased milk yield (P < 0.05), milk protein percentage (P < 0.05) and lactose percentage (P<0.05), but had no effect on milk fat percentage (P>0.05) and SNF (P>0.05). RPMet supplementation in the diet of lactating cows significantly decreased serum urea nitrogen (P<0.01) and glucose contents (P<0.05), but had no effects on nonesterified fatty acids (NEFA), total cholesterol and triglyceride (P>0.05). Niacin supplementation influ-enced the contents of glucose and NEFA in serum, but had no effects on the urea nitrogen, total cholesterol and triglyceride (P>0.05).