刈割期及添加剂对甜高粱青贮发酵品质的影响

Effects of Cutting Time and Additives on Fermentation Quality of Sweet Sorghum Silage

【目的】研究刈割期与添加剂对甜高粱青贮饲料发酵品质和营养成分的影响。【方法】以新高粱3号、新高粱9号为供试品种,选择乳熟期、蜡熟期、完熟期3个时期刈割,并以不添加,添加尿素、青贮添加剂进行青贮制作,在青贮60 d后取样分析其发酵品质及营养价值。【结果】随着甜高粱刈割期的后移,粗纤维、酸性洗涤纤维、中性洗涤纤维含量逐渐减少,在完熟期时达到最低,新高粱3号分别为13. 58%、23. 51%、16. 35%,新高粱9号分别为16. 74%、29. 55%、21. 34%,与乳熟期相比分别降低了15. 3%～32. 85%、20. 87%～57. 31%、21. 4%～24. 76%;完熟期时新高粱3号的体外消化率与粗蛋白含量可达到65. 35%、8. 16%,比乳熟期时提高了48. 4%、0. 86%。在青贮过程中,加入青贮添加剂和尿素后蛋白质含量分别比空白组提高了3. 34%～4. 4%、6. 5%～11. 4%;体外消化率分别比空白组提高了7. 17%～23. 22%、1. 22%～17. 06%;同时降低了青贮饲料的p H值,有效减少了干物质及可溶性碳水化合物的损失。【结论】种植于新疆北疆地区的甜高粱宜在完熟期刈割制作青贮,且青贮时加入添加剂可改善青贮饲料的发酵品质和体外消化率。

【Objective】The purpose of this study is to investigate the effect of cutting time and additives on the fermentation quality and nutrient composition of sweet sorghum silage.【Method】The new sorghum No.3 and new sorghum No.9 were used as the tested varieties in this experiment.Milk ripening stage,the dough stage and complete ripening stage were selected for cutting,and the silage was made by adding urea and silage additive without adding,adding urea and silage additive.After 60 days of silage,the fermentation quality and nutritional value were analyzed.【Result】With the cutting period of sweet sorghum moving backward,the contents of crude fiber,acid detergent fiber,and neutral detergent fiber gradually decreased and reached the lowest level during the ripe stage,XT-2 was 13.58%,23.51%,and 16.35%,respectively,and T601 was 16.74%,29.55%,and 21.34%,respectively,which were reduced by 15.3%to 32.85%,20.87%to 57.31%,and 21.4%to 24.76%,respectively,compared with the milky stage.At the ripe stage the in vitro digestibility and crude protein content of XT-2 could reach 65.35%and 8.16%,which were 48.4%and 0.86%higher than those of the milk stage.During silage,after adding silage additive and urea,the protein content increased by 3.34%-4.4%and 6.5%-11.4%respectively compared with the blank group;the in vitro digestive rate increased by 7.17%to 23.22%and 1.22%to 17.06%,respectively,compared with the blank group;at the same time,the silage pH was reduced,which effectively reduced the loss of dry matter and soluble carbohydrates.【Conclusion】Considering the index of in vitro digestibility,protein content,dry matter content and pH value of silage,sweet sorghum planted in northern Xinjiang should be mowed to produce silage at the ripening stage,and silage added with additives can improve silage fermentation quality and in vitro digestibility.