Andrew S M, Tyrrell H F, Reynolds C K, Erdman R A
Ruminant Nutrition Laboratory, Livestock and Poultry Sciences Institute USDA Beltsville, MD 20705.
J Dairy Sci. 1991 Aug;74(8):2588-600. doi: 10.3168/jds.S0022-0302(91)78437-3.
The NEL of calcium salts of long-chain fatty acids from palm oil was determined in mature Holstein cows. Twelve lactating (fed for ad libitum intake) and six nonlactating (restricted to near maintenance intake) Holstein cows were fed 0 or 2.95% fat supplement in diets formulated to contain 16 or 20% CP in a 2 x 2 factorial arrangement of treatments in a single reversal design within protein level. The fat supplement was substituted for ground corn and minerals. Two 6-d total collection balance trials were conducted during which cows were in open circuit respiration chambers. Intake of OM was lower for lactating cows fed the fat supplement (18.1 vs. 19.1 kg/d), but energy intake did not differ (93.2 Mcal/d). Total long-chain fatty acid intake was increased from 477 to 820 g/d with fat feeding. Apparent digestibility of long-chain fatty acids was increased 11.1 percentage units with increased dietary CP for lactating cows with no difference in fatty acid digestibility for the dry cows. Milk yield was higher (34.3 vs. 32.0 kg/d) with fat feeding, but milk energy yield did not differ (22.6 Mcal/d). The NEL of the fat supplement was estimated from the incremental differences in energy values within cows, assuming NEL of corn replaced by fat to be 1.96 Mcal/kg DM, and was determined to be 6.52 Mcal/kg DM (SE = 1.74). The efficiency of the use of metabolizable energy for lactation from dietary fat was 77.2%. The energy in calcium salts of long-chain fatty acids is utilized efficiently for lactation in mature cows.
在成年荷斯坦奶牛中测定了棕榈油长链脂肪酸钙盐的净能值。采用2×2析因设计，在蛋白质水平内进行单次反转设计，将12头泌乳（自由采食）和6头非泌乳（限制采食至维持水平）的荷斯坦奶牛分为两组，分别饲喂添加0或2.95%脂肪补充剂的日粮，日粮粗蛋白含量分别为16%或20%。脂肪补充剂替代了玉米粉和矿物质。进行了两次为期6天的全收粪收尿平衡试验，试验期间奶牛置于开路呼吸室中。饲喂脂肪补充剂的泌乳奶牛有机物质摄入量较低（18.1对19.1千克/天），但能量摄入量无差异（93.2兆卡/天）。饲喂脂肪后，长链脂肪酸总摄入量从477克/天增加到820克/天。泌乳奶牛日粮粗蛋白增加时，长链脂肪酸的表观消化率提高了11.1个百分点，干奶牛的脂肪酸消化率无差异。饲喂脂肪时牛奶产量较高（34.3对32.0千克/天），但牛奶能量产量无差异（22.6兆卡/天）。脂肪补充剂的净能值根据奶牛体内能量值的增量差异估算，假设被脂肪替代的玉米净能为1.96兆卡/千克干物质，测定为6.52兆卡/千克干物质（标准误=1.74）。日粮脂肪用于泌乳的代谢能利用效率为77.2%。长链脂肪酸钙盐中的能量在成年奶牛泌乳中得到有效利用。
