沙地恢复草场放牧绵羊体增重及瘤胃发酵参数动态变化

本研究选择浑善达克沙地腹地内蒙古自治区正蓝旗正在围封恢复中的沙地草场,进行毛肉兼用细毛羊暖季自由放牧和划区轮牧试验,结合放牧绵羊增重及瘤胃发酵参数动态变化指标评价恢复阶段沙地草场牧养能力。结果表明,暖季(6-10月)放牧绵羊增重明显,3个放牧区绵羊平均月增重分别为2.46,5.08,5.52和2.29kg,而不同放牧方式对绵羊增重效果没有显著影响;在7-8月放牧绵羊瘤胃发酵水平较好,空腹到采食后7h内发酵参数动态变化表现为:瘤胃pH7.01-6.38-6.47-6.77、NH₃-N浓度6.02-9.26-10.75-10.82mg/100mL、总VFA浓度31.37-42.99-58.55-65.28mmol/L。因此在围封恢复5~6年的沙地退化草场上进行绵羊的暖季适度放牧,可以产生较好的增重及瘤胃发酵效果。

Dynamic changes of grazing sheep body gains and ruminal fermentation parameters on sandy recovering grassland

A sheep grazing experiment was carried out at the Inner Mongolian, Zhenglan banner, Hunshandake sandy recovering grassland in the warm season to determine body weight gains and ruminal fermentation parameters under rotational grazing and continuous grazing. Sheep body weight gains were evident at 4 months, and averaged 2.46, 5.08, 5.52, and 2.29 kg/month, respectively in the three experimental groups. There was no obvious difference between sheep weight under continuous grazing and rotational grazing. Sheep had high rumen fermentation levels from July to August, from fasting to intake after 7 h the rumen pH, NH₃-N concentration and TVFA (total volatility fatty acid) concentration range were changed as 7.01－6.38－6.47－6.77, 6.02－9.26－10.75－10.82 mg/100 mL and 31.37－42.99－58.55－65.28 mmol/L, respectively. Therefore, sheep can produce higher body gains and better rumen fermentation when grazed on sandy recovering grassland after a 5-6 year fenced recovery period.