Sath K, Pauly T, Holtenius K
Centre for Livestock and Agriculture Development (CelAgrid), P.O. Box 2423, Phnom Penh, Cambodia.
Asian-Australas J Anim Sci. 2013 Jan;26(1):59-64. doi: 10.5713/ajas.2012.12355.
Eight male cattle of the Local Yellow breed with an average live weight of 121 kg and an average age of 18 months were used to evaluate the effects of different levels of sun-dried cassava (Manihot esculenta) foliage supplementation on mineral metabolism in growing cattle fed rice straw and para grass as basal diet. Rice straw ad libitum and para grass (Brachiaria mutica) at 1% DM of BW comprised the basal diet. The study was arranged as a 4×4 double Latin square design, with cassava foliage contributing 0, 0.8, 1.6 or 2.4 g CP/kg BW. The cassava foliage intake was lower than the planned levels. DM consumption was significantly affected by cassava foliage supplementation, with the largest intake observed at the two highest levels of cassava foliage supplementation. Rice straw intake showed the opposite pattern, with lower intake at higher cassava foliage supplementation. No refusals occurred for para grass in any of the treatments. Ca, P, Mg, K, S and Mn intake increased significantly with increasing intake of cassava foliage, but Na intake was not affected by treatment. Faecal excretion of Ca, Mg, S and Mn increased significantly with increasing cassava foliage intake. There were no differences between P, K and Na excretion in faeces. There was a significant diet effect on Mg, S and Mn digestibility. Mg and Mn digestibility increased with increasing cassava foliage supplementation, while S digestibility decreased. Ca, P, K and Na digestibility was not affected by diet. There was a significant effect of treatment on P retention, with the highest value observed for supplementation with 1.6 g CP/kg BW cassava foliage. Ca and Mg showed similar trends, with the highest retention again for supplementation with 1.6 g CP/kg BW cassava foliage. There were weak but significant positive correlations between nitrogen retention and the macro minerals Ca, P and Mg. Furthermore, retention of all these minerals was positively correlated. Mineral losses in urine were not affected by dietary treatment with the exception of P excretion, which was affected by treatment. In conclusion, cassava foliage is a good Ca source which compensates for the low Ca content in rice straw and para grass, but P deficiency appears to be exaggerated in cattle with higher cassava intake. The results suggest that under these conditions growing cattle on a high cassava intake would benefit from P and S supplementation.
选用8头本地黄牛公牛,平均体重121千克,平均年龄18个月,用于评估在以稻草和臂形草为基础日粮的生长牛中,不同水平的木薯干叶补充料对矿物质代谢的影响。以随意采食的稻草和占体重1%干物质的臂形草作为基础日粮。本研究采用4×4双拉丁方设计,木薯叶的添加量为每千克体重0、0.8、1.6或2.4克粗蛋白。木薯叶的摄入量低于计划水平。木薯叶补充料显著影响干物质采食量,在木薯叶补充料的两个最高水平下观察到最大采食量。稻草采食量呈现相反的模式,在木薯叶补充料水平较高时采食量较低。在任何处理中,臂形草均无剩余。随着木薯叶摄入量的增加,钙、磷、镁、钾、硫和锰的摄入量显著增加,但钠的摄入量不受处理影响。随着木薯叶摄入量的增加,粪便中钙、镁、硫和锰的排泄量显著增加。粪便中磷、钾和钠的排泄量没有差异。日粮对镁、硫和锰的消化率有显著影响。镁和锰的消化率随着木薯叶补充量的增加而增加,而硫的消化率降低。钙、磷、钾和钠的消化率不受日粮影响。处理对磷的保留有显著影响,在每千克体重补充1.6克粗蛋白的木薯叶时观察到最高值。钙和镁呈现相似趋势,同样在每千克体重补充1.6克粗蛋白的木薯叶时保留量最高。氮保留与常量矿物质钙、磷和镁之间存在微弱但显著的正相关。此外,所有这些矿物质的保留呈正相关。除了磷的排泄受处理影响外,尿液中的矿物质损失不受日粮处理影响。总之,木薯叶是一种良好的钙源,可弥补稻草和臂形草中钙含量低的问题,但木薯摄入量较高的牛中磷缺乏似乎更为严重。结果表明,在这些条件下,高木薯摄入量的生长牛补充磷和硫会有益处。