Singh Sultan, Kushwaha Badri Prasad, Maity Subendu Bikas, Singh Krishan Kunwar, Das Nityanand
Plant Animal Relationship Division, Indian Grassland and Fodder Research Institute, Jhansi, 284003, UP, India,
Trop Anim Health Prod. 2015 Jan;47(1):213-20. doi: 10.1007/s11250-014-0713-3. Epub 2014 Nov 19.
Fifteen Bhadawari buffalo heifers of 207 ± 9.78 kg mean body weight were randomly distributed into three dietary groups to evaluate the effect of protein level on nutrient utilization, nitrogen (N) balance, growth rate, blood metabolites, and puberty. All animals were offered wheat straw-berseem diets supplemented with concentrate mixtures of similar energy (2.7 Mcal/kg) and different protein levels (14.3-22%). Animals of standard-protein group (SPG) were offered protein and energy as per requirement, while animals of low-protein group (LPG) and high-protein group (HPG) were fed 20% less and 20% more protein, respectively, than SPG. Feed dry matter (DM) and metabolizable energy (ME) intake (% body wt. and g/kg w(0.75)) were similar for all three diets; however, the crude protein (CP) and digestible crude protein (DCP) intake on percent body weight and per kilogram metabolic weight was higher (P < 0.05) in HPG than in SPG or LPG. Digestibility of CP, cellulose, and hemicellulose was higher (P < 0.05) in HPG versus LPG. Fecal N excretion was similar, while urinary N excretion was highest (P < 0.05) in HPG (74.83 g/day) compared with SPG (50.03 g/day) and LPG (47.88 g/day), which resulted in lower N retention in HPG than in the other dietary groups. Level of dietary N had no effect on blood metabolites viz. glucose, urea, and N. Digestible energy (DE) and ME contents of diets were identical, while DCP contents were higher (P < 0.05) in HPG than in LPG. Feed and nutrient (CP and ME) conversion efficiency to produce a unit kilogram weight gain was identical among the dietary groups. Dietary protein level had no effect on the heifer's weight and age at puberty. The mean growth rate of heifers at 240 days was higher (P > 0.05) in SPG (330.8 g/day) than in LPG (296.7 g/day), while the animals gained more weight in January to March months and the lowest weight in May to July months. Protein level had no effect on conception rate of heifers. Results revealed that 20% higher or less protein than the ICAR requirement had no significant (P > 0.05) on feed intake, nutrient conversion efficiency for weight gain, heifer growth, and puberty; however, 20% more protein increased urinary N loss.
选取15头平均体重为207±9.78千克的巴达瓦里水牛小母牛，随机分为三个日粮组，以评估蛋白质水平对营养物质利用、氮（N）平衡、生长速率、血液代谢物和青春期的影响。所有动物均饲喂小麦秸秆-埃及三叶草日粮，并补充能量相似（2.7兆卡/千克）但蛋白质水平不同（14.3%-22%）的精料混合料。标准蛋白质组（SPG）的动物按需求供给蛋白质和能量，而低蛋白质组（LPG）和高蛋白质组（HPG）的动物分别比SPG少喂20%和多喂20%的蛋白质。三种日粮的饲料干物质（DM）和代谢能（ME）摄入量（%体重和克/千克体重0.75次方）相似；然而，HPG组按体重百分比和每千克代谢体重计算的粗蛋白（CP）和可消化粗蛋白（DCP）摄入量高于SPG组或LPG组（P<0.05）。HPG组的CP、纤维素和半纤维素消化率高于LPG组（P<0.05）。粪便氮排泄量相似，而HPG组的尿氮排泄量最高（P<0.05）（74.83克/天），相比之下，SPG组为（50.03克/天），LPG组为（47.88克/天），这导致HPG组的氮保留量低于其他日粮组。日粮氮水平对血液代谢物（即葡萄糖、尿素和氮）没有影响。日粮的消化能（DE）和ME含量相同，而HPG组的DCP含量高于LPG组（P<0.05）。各日粮组生产单位千克体重增加的饲料和营养物质（CP和ME）转化效率相同。日粮蛋白质水平对小母牛青春期的体重和年龄没有影响。240天时，SPG组小母牛的平均生长速率（330.8克/天）高于LPG组（296.7克/天）（P>0.05），而动物在1月至3月体重增加较多，在5月至7月体重增加最少。蛋白质水平对小母牛的受孕率没有影响。结果表明，比印度农业研究理事会（ICAR）要求高20%或低20%的蛋白质对采食量、增重的营养转化效率、小母牛生长和青春期没有显著影响（P>0.05）；然而，多20%的蛋白质会增加尿氮损失。
