Gunha Thidarat, Kongphitee Kanokwan, Binsulong Bhoowadol, Sommart Kritapon
Department of Animal Science, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand.
Renewable Energy and Environmental Engineering Program, Institute of Interdisciplinary Studies, Rajamangala University of Technology Isan, Nakhon Ratchasima 30000, Thailand.
Animals (Basel). 2023 Jul 13;13(14):2296. doi: 10.3390/ani13142296.
The objectives of this research were to (1) determine the feed intake, digestibility, and energy utilization and (2) estimate the net energy value of cassava chips consumed by lactating dairy cows. Four multiparous Holstein-Friesian crossbred cows at 139 ± 33 (mean ± SD) day in milk were assigned according to a 4 × 4 Latin square design with four periods. The four treatments included a diet substituted with cassava chips on a 0%, 12%, 24%, and 36% dry matter (DM) basis in the basal diet. Indirect calorimetry with a head cage respiration system was used to determine nutrient and energy utilization. Increasing the number of cassava chips in the diet resulted in a linear increase ( < 0.05) in nutrient intake and digestibility but a linear decrease ( < 0.01) in crude protein (CP) and fiber. The enteric methane yield and intensity were not affected ( > 0.05), while energy was lost as feces and urine reduced linearly ( < 0.05). Milk yield and milk composition (protein, fat, lactose) also increased linearly ( < 0.05). The net energy requirement for the maintenance of the lactating cows was estimated as 327 kJ/kg of metabolic body weight, and the efficiency of metabolizable energy used for lactation was 0.66. The estimated net energy value of cassava chips for lactation was 8.03 MJ/kg DM.
（1）测定采食量、消化率和能量利用率；（2）估算泌乳奶牛所采食木薯片的净能值。选用4头处于泌乳139±33（均值±标准差）天的经产荷斯坦-弗里生杂交奶牛，按照4×4拉丁方设计，分为4个阶段。4种处理包括在基础日粮中分别用木薯片替代0%、12%、24%和36%的干物质（DM）。采用头部呼吸笼系统的间接测热法来测定养分和能量利用率。日粮中木薯片数量增加，养分摄入量和消化率呈线性增加（P<0.05），但粗蛋白（CP）和纤维呈线性下降（P<0.01）。肠道甲烷产量和强度不受影响（P>0.05），而粪便和尿液中的能量损失呈线性减少（P<0.05）。产奶量和乳成分（蛋白质、脂肪、乳糖）也呈线性增加（P<0.05）。泌乳奶牛维持需要的净能估计为327 kJ/kg代谢体重，用于泌乳的可代谢能量效率为0.66。木薯片对泌乳的估计净能值为8.03 MJ/kg DM。
