Department of Animal Science, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
Animal Science Research Institute of Iran, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran.
J Anim Physiol Anim Nutr (Berl). 2021 Nov;105(6):1034-1045. doi: 10.1111/jpn.13548. Epub 2021 Apr 16.
This study compared ensiled sorghum (ES) from two varieties (first and second cuts) with corn silage (CS) for chemical analysis, total-tract nutrient digestibility, ruminal variables and blood biochemistry metabolites in sheep. Five experimental silages representing first cut ES var. Pegah (PS1), second cut ES var. Pegah (PS2), first cut ES var. Speedfeed (SS1), second cut ES var. Speedfeed (SS2) and CS were assessed for chemical analysis, silage fermentation and anti-quality compounds. Diets consisted of lucerne hay, silage and a premix (at the ratio of 53.5:46:0.5 on a dry matter [DM] basis). Feed consumption, total-tract nutrient digestibility, microbial nitrogen supply (MNS), ruminal variables and blood biochemistry metabolites were determined in a Latin square design of five periods with five male sheep. Compared to sorghum, CS had lower (p < 0.01) concentrations of ash, water-soluble carbohydrates and crude protein, but higher starch, lignin (sa), non-structural carbohydrates and apparent nutrient digestibility. The measurements of pH, lactic acid, NH -N and volatile fatty acids (VFA) confirmed that all silages were well-preserved. The anti-quality compound levels in the silages were below the safe limits for ruminants. No differences were observed in feed consumption (p > 0.05) and total-tract digestibility of DM and nutrients (p > 0.05). Rumen pH, NH -N, VFA concentrations and acetate to propionate ratio showed no difference among treatments (p > 0.05). Sheep fed on sorghum silage showed a decrease (p < 0.01) in total protozoa, and particularly in the Entodiniae population. There were no differences in cellulolytic bacteria counts (p > 0.05) among treatments. Urinary N, MNS and blood biochemistry metabolites showed no difference among treatments (p > 0.05). Silages from both cuts of sorghum had comparable total-tract nutrient digestibility to CS, therefore, these varieties could be used as a more drought resilient silage source in the feeding of sheep.
本研究比较了来自两种品种（第一茬和第二茬）的青贮高粱（ES）与玉米青贮（CS）的化学分析、全肠道养分消化率、瘤胃变量和绵羊血液生化代谢物。评估了五种实验青贮饲料，分别为第一茬 ES 品种 Pegah（PS1）、第二茬 ES 品种 Pegah（PS2）、第一茬 ES 品种 Speedfeed（SS1）、第二茬 ES 品种 Speedfeed（SS2）和 CS，以进行化学分析、青贮发酵和抗质量化合物分析。日粮由紫花苜蓿干草、青贮饲料和预混料（以干物质[DM]为基础的比例为 53.5:46:0.5）组成。采用 5 个雄性绵羊的拉丁方设计进行了饲料采食量、全肠道养分消化率、微生物氮供应（MNS）、瘤胃变量和血液生化代谢物的测定。与高粱相比，CS 的灰分、水溶性碳水化合物和粗蛋白浓度较低（p<0.01），但淀粉、木质素（sa）、非结构性碳水化合物和表观养分消化率较高。pH、乳酸、NH 3 -N 和挥发性脂肪酸（VFA）的测量结果证实所有青贮饲料均保存良好。青贮饲料中的抗质量化合物水平低于反刍动物的安全限量。饲料采食量（p>0.05）和 DM 及养分的全肠道消化率（p>0.05）无差异。瘤胃 pH、NH 3 -N、VFA 浓度和乙酸与丙酸比在处理间无差异（p>0.05）。饲喂高粱青贮饲料的绵羊总原虫数量减少（p<0.01），尤其是 Entodiniae 种群。处理间纤维分解菌计数无差异（p>0.05）。尿液 N、MNS 和血液生化代谢物在处理间无差异（p>0.05）。两种茬口的高粱青贮饲料的全肠道养分消化率与 CS 相当，因此，这些品种可作为绵羊饲料中更耐旱的青贮饲料来源。
