摘要
Most milk replacers (MR) contain a higher lactose:fat ratio compared to whole milk, potentially affecting nutrient absorption and use by the calf. This study evaluated how body composition and intestinal development were affected when lactose was replaced with fat in MR. Thirty-four calves (43.3 ± 0.8 kg) were blocked (BW and dam parity), and randomly assigned to a high-lactose (43.8% lactose and 17.1% crude fat) or high-fat (37.9% lactose and 23.4% crude fat) MR. Calves were fed pooled colostrum within 2 h (18% of metabolic body weight (MBW)) and 12 h (9 %MBW) postnatal, followed by MR feeding (18 %MBW) twice daily. Calves were weighed pre-prandially at birth and on d 7. Calves were euthanized on d 7 to sample intestinal tissue and analyze body composition using dual-energy x-ray absorptiometry. Samples of intestinal segments were processed to evaluate histomorphology using bright-field microscopy. Data were analyzed using PROC MIXED in SAS software. Total gain (3.90 vs. 2.29 ± 0.38 kg, P = 0.01) and gain:ME intake (44.64 vs. 28.61 ± 4.32 kg, P = 0.02) were greater for high-fat compared to high-lactose calves, whereas body composition was unaffected (P = 0.13). Proportionally, the large intestine was 0.11 ± 0.02 %BW heavier (P = 0.03) in high-fat calves compared to high-lactose calves, while their small intestine tended to be 0.16 ± 0.06 %BW heavier (P = 0.09). Small and large intestine length did not differ (P = 0.96). High-fat calves had wider villi (125.41 vs. 96.58 μm, P = 0.05) in the jejunum but shorter villi (414.17 vs. 470.96 μm, P = 0.02) in the ileum compared to high-lactose calves. Macronutrient composition affected intestinal histomorphology and improved efficiency of ME use for BW gain. Understanding how fat (including its source) influences nutrient efficiency in dairy calves may improve nutritional strategies on farm.
摘要译文
与全脂牛奶相比，大多数代乳牛奶（MR）所含的乳糖：脂肪比率更高，可能会影响小牛的营养吸收和使用。这项研究评估了在MR中用脂肪代替乳糖后，身体成分和肠道发育受到的影响。封锁了三十四只犊牛（43.3±0.8公斤）（体重和水坝体重），并随机分配给高乳糖（43.8％乳糖和17.1％粗脂肪）或高脂肪（37.9％乳糖和23.4％粗脂肪） ） 先生。在产后2小时（代谢体重（MBW）的18％）和产后12小时（9％MBW）的小牛中喂初乳，然后每天两次MR喂养（18％MBW）。在出生前和第7天，对小牛进行称重。在第7天，对小牛进行安乐死，以取样肠道组织并使用双能X线吸收法分析身体成分。使用明视野显微镜对肠段样本进行处理以评估组织形态。使用SAS软件中的PROC MIXED分析数据。高脂犊牛的总增重（3.90比2.29±0.38 kg，P = 0.01）和增重：ME摄入量（44.64 vs. 28.61±4.32 kg，P = 0.02）大于高乳糖犊牛，而身体成分不受影响（P = 0.13）。与高乳糖犊牛相比，高脂犊牛的大肠比重高0.11±0.02％BW（P = 0.09），而高脂犊牛则大肠比重高乳糖（0.16±0.06）。小肠和大肠长度无差异（P = 0.96）。与高乳糖犊牛相比，高脂犊牛的空肠绒毛较宽（125.41 vs. 96.58μm，P = 0.05），而回肠肠绒毛较短（414.17 vs. 470.96μm，P = 0.02）。大量营养素成分影响肠道组织形态，并提高了ME用于获得体重的效率。了解脂肪（包括其来源）如何影响奶牛的营养效率可能会改善农场的营养策略。
Anna C Welboren [1]; Bayissa Hatew [2]; Leonel Leal [3]; Javier Martin-Tereso [3]; Michael A Steele [1]. 80 Effects of macronutrient composition of milk replacer on body composition and intestinal development in neonatal dairy calves[J]. Journal of Animal Science, 2019,97(Sup3): 70-71