The objective of this study was to evaluate the effect of inclusion of an extruded high-fat pellet mixed with a conventional pelleted calf starter on energy intake and performance around weaning in calves. To this end, 75 female Holstein newborn calves (41.0 ± 4.98 kg) were randomly assigned to 1 of 5 iso-nitrogenous solid feed treatments consisting of 4 levels of fat inclusion by mixing a low-fat highly fermentable control pellet with 3 different levels of inclusion of an extruded high-fat pellet [control (100:0), 90:10, 80:20, and 70:30], and a high-fat single pellet (HFSP). The HFSP was equivalent iso-energetic and iso-nitrogenous, although it had almost 1 percentage point difference in fat relative to the 80:20 treatment, to contrast the effect of the dual-component pellet mixture. The extruded high-fat starter feed contained a high proportion of fat (38%), mainly from hydrogenated palm fatty acids. Calves were offered a milk replacer up to 900 g/d, and then pre-weaned at 49 d of age by halving milk allowance until 56 d when calves were weaned. Calves had ad libitum access to the starter diets, chopped straw, and water. Individual milk replacer and starter intakes were recorded daily and BW was determined weekly. A glucose tolerance test was performed at 49 and 84 d of age to evaluate blood glucose homeostasis. Apparent total-tract digestibility was determined from 70 to 75 d of age. Calves on the 90:10 treatment had greatest starter feed intake mainly due to a marked increase in solid feed intake around weaning. Metabolizable energy intake was increased when the extruded pellet was included in the starter. No differences were present in digestibility of ether extract among solid feed treatments. The area under the curve of blood glucose concentration after the glucose tolerance test was greatest in 80:20; intermediate in 70:30, HFSP, and control; and lowest in 90:10 calves. No differences were observed for insulin or other parameters related to blood glucose homeostasis. Delivering dietary fat by mixing an extruded high-fat pellet with a conventional highly fermentable pellet to reach a total fat content of 7% results in increased starter intake, energy intake, and body weight gain until 84 d of age compared with a conventional low-fat pellet, or a single pellet with increased fat content.

这项研究的目的是评估将挤奶的高脂肪颗粒与常规的粒状小牛发酵剂混合在一起对小牛断奶时能量摄入和生产性能的影响。为此，通过将低脂高发酵度对照颗粒与3种不同水平的高脂饲料混合，将75只雌性荷斯坦新生犊牛（41.0±4.98千克）随机分配到5种同氮固形物饲料处理中的1种，其中包括4种脂肪含量水平。包括挤出的高脂肪颗粒[对照（100：0），90：10、80：20和70:30]和高脂肪单颗粒（HFSP）。尽管与80:20处理相比，HFSP在脂肪上几乎有1个百分点的差异，但它是等量的等能量和等氮的，以对比双组分颗粒混合物的效果。挤出的高脂发酵剂饲料中脂肪的比例很高（38％），主要来自氢化棕榈脂肪酸。给犊牛提供最高900 g / d的代乳品，然后在49 d时通过将牛奶津贴减半直至断奶56 d来预断奶。小牛可以随意采食初学者饮食，切碎的稻草和水。每天记录单独的代乳品和发酵剂的摄入量，每周测定体重。在49和84 d年龄进行了葡萄糖耐量试验，以评估血糖稳态。从70到75 d年龄确定表观总消化率。90:10处理的犊牛的起始饲料采食量最大，这主要是由于断奶前后固体饲料采食量显着增加。当挤出的颗粒被包含在起始剂中时，可代谢的能量摄入增加。在固体饲料处理中，醚提取物的消化率没有差异。葡萄糖耐量试验后的血糖浓度曲线下面积最大为80:20。70:30的中级，HFSP和控制；在90:10的犊牛中最低。没有观察到胰岛素或其他与血糖动态平衡有关的参数的差异。通过将膨化的高脂颗粒与常规的高度可发酵颗粒混合以达到7％的总脂肪含量来提供膳食脂肪，与常规的低脂肪颗粒相比，直到84 d年龄，其起始摄入量，能量摄入和体重增加均增加了。脂肪颗粒或脂肪含量增加的单个颗粒。葡萄糖耐量试验后的血糖浓度曲线下面积最大为80:20。70:30的中级，HFSP和控制；在90:10的犊牛中最低。没有观察到胰岛素或其他与血糖动态平衡有关的参数的差异。通过将膨化的高脂颗粒与常规的高度可发酵颗粒混合以达到7％的总脂肪含量来提供膳食脂肪，与常规的低脂肪颗粒相比，直到84 d年龄，其起始摄入量，能量摄入和体重增加均增加了。脂肪颗粒或脂肪含量增加的单个颗粒。葡萄糖耐量试验后的血糖浓度曲线下面积最大为80:20。70:30的中级，HFSP和控制；在90:10的犊牛中最低。没有观察到胰岛素或其他与血糖动态平衡有关的参数的差异。通过将膨化的高脂颗粒与常规的高度可发酵颗粒混合以达到7％的总脂肪含量来提供膳食脂肪，与常规的低脂肪颗粒相比，直到84 d年龄，其起始摄入量，能量摄入和体重增加均增加了。脂肪颗粒或脂肪含量增加的单个颗粒。