摘要
The recent trend in the dairy industry towards elevated planes of milk feeding of young calves requires reconsideration of calf milk replacer (CMR) formulations. The fat:lactose ratio in CMR is typically lower than that of whole milk and effects of increasing fat inclusion at the expense of lactose in CMR on nutrient metabolism and gut function of rearing calves are not sufficiently understood. Therefore, the current study aimed to determine the effect of increasing replacement of lactose by fat on growth performance, nutrient digestibility and metabolism, and glucose/insulin sensitivity. A total of 40 male calves (1.7 ± 0.10 days of age, 46.7 ± 0.76 kg BW) were blocked based on arrival date and randomly assigned to one of four treatments containing differing levels of fat and lactose (18F: 18.8% and 47.6%; 22F: 22.3% and 42.8%; 26F: 26.0% and 38.6%; 30F: 30.1% and 33.8%, fat and lactose DM, respectively). Calves were individually housed for the duration of the 11 week study and received their CMR (150 g/L) twice a day (0700 and 1600 h) from a teat bucket. The CMR feeding schedule consisted of 6 L/d from d 2 to 14, 7 L/d from d 15 to 56, and then 4 L/d during gradual weaning from 56 to 63 days. Pelleted starter, chopped straw, and water were available ad libitum throughout the study. Measurements included feed intake, growth, nutrient digestibility, fecal composition, and blood parameters. A glucose tolerance test (GTT) was performed between 28 and 32 days of age. By design, metabolizable energy intake from CMR increased linearly with fat level, but this did not result in a difference in BW, ADG, or concentrate intake. Fecal composition remained unaffected by treatment except for higher fat content in 22F compared to 26F. Also, plasma non-esterified fatty acids and total bilirubin differences were limited to 22F having the highest values whereas 26F had the lowest values. Regarding the GTT, total area under the curve (AUC) for glucose was highest in 22F and 26F and lowest in 18F whereas the AUC between 30 and 60 min for glucose was highest in 26F and lowest in 18F and 22F. Overall, altering the lactose:fat ratio in CMR did not affect growth performance while having minor effects on nutrient metabolism, but future investigation should focus on physiological consequences and effects in adult life to understand biological impact of fat and lactose levels in CMR for rearing calves.
摘要译文
最近乳制品行业迈向牛奶饲养飞机的趋势需要重新考虑小牛牛奶替代品（CMR）制剂。脂肪：CMR中的乳糖比通常低于全乳的乳糖比，并且在CMR中牺牲乳糖的脂肪夹杂物的脂肪夹杂物的效果不充分理解饲料牛犊的营养代谢和肠道功能。因此，目前的研究旨在通过对生长性能，营养消化率和代谢的脂肪增加更换乳糖的效果，以及葡萄糖/胰岛素敏感性。基于到达日期，总共40只雄性小牛（1.7±0.10天，46.7±0.76kg BW），并随机分配到含有不同水平的脂肪和乳糖水平的四种治疗方法中的一种（18°F：18.8％和47.6％; 22F：22.3％和42.8％; 26F：26.0％和38.6％; 30F：30.1％和33.8％，脂肪和乳糖DM）。小牛被单独饲养11周的研究，并从奶油桶中每天（0700和1600h）两次接受CMR（150g / L）。 CMR进纸时间表由D 2至14,7L / D的6L / D组成，然后在56到63天的逐渐断奶期间4L / D。在整个研究中可获得颗粒式起动器，切碎的稻草和水。测量包括进料摄入，生长，营养消化率，粪便组合物和血液参数。葡萄糖耐量试验（GTT）在28至32天之间进行。通过设计，CMR的可代谢能量进气量随脂肪水平线性增加，但这并未导致BW，ADG或浓缩物摄入的差异。除了22F中的脂肪含量相比，粪便组合物仍未受到治疗的影响，除26F相比22f。此外，血浆非酯化脂肪酸和总胆红素差异限于具有最高值的22F，而26F具有最低值。关于GTT，葡萄糖的曲线（AUC）下的总面积在22F和26F中最高，18°F中最低，而在26F和18F和22F中最低的葡萄糖的AUC在最高的情况下最高。总体而言，改变乳糖：CMR中的脂肪比在对营养代谢产生轻微影响的同时不影响生长性能，但未来的调查应关注成年生命中的生理后果和影响，以了解CMR在CMR中饲养脂肪和乳糖水平的生物学影响。
T.T. Yohe[a];H. Berends[b];L.N. Leal[b];J.N. Wilms[b];M.A. Steele[a];J. Martín-Tereso[b]. Metabolic and performance responses to the replacement of lactose by fat in milk replacer formulations for dairy calves[J]. animal, 2021,15(1)