刈割期及青贮时长对饲草青贮品质的影响

Effects of Mowing Period and Silage Duration on Quality of Forage Silage

以4个小黑麦(Triticosecale Wittmack)品种(黑麦3241、黑麦1048、冀饲1号和冀饲2号)和1个黑麦(SecaleL.)品种(冬牧70)为材料,研究不同刈割期(4月26日、5月8日和5月19日)及不同青贮时长(30、45d和60d)对饲草营养指标、青贮品质的影响。结果表明:刈割期显著影响所有品种的营养和品质指标(P<0.05),与4月26日相比,随着刈割期的推迟,其水分和粗蛋白含量降低,而中性和酸性洗涤纤维含量增加,综合认为5月8日—19日为较适刈割期。青贮时长对所有品种的粗蛋白含量、氨态氮/总氮、pH值、乳酸和乙酸含量影响显著(P<0.05),而对总磷含量影响较小,只有T4、T5差异显著(P<0.05);随青贮时长增加,除水分含量呈增加趋势、粗蛋白含量呈先增加后降低趋势外,总磷、中性洗涤纤维、酸性洗涤纤维含量呈下降趋势,乳酸、乙酸含量和氨态氮/总氮比值呈上升趋势。综合考虑认为各项指标青贮30d基本能达到相关品质指标要求,青贮30d和45d之间投喂最佳。

Four triticale(Triticosecale Wittmack) varieties(Rye 3241, Rye 1048, Jisi 1 and Jisi 2) and one rye(Secale L.) variety(Dongmu 70) were used to study the effects of different mowing periods(April 26, May 8 and May 19) and silage duration(30, 45 d and 60 d) on the nutritional indexes and silage quality. The results showed that the mowing period significantly affected the nutrition and quality indexes of all varieties(P<0.05). With the delay of mowing period, the contents of water and crude protein decreased and the contents of neutral and acid detergent fiber increased compared with April 26. It was considered that the best cutting time was from May 8 to May 19. Silage time had significant effects on crude protein content, ammonia nitrogen/total nitrogen, pH value, contents of lactic acid and acetic acid(P<0.05), but it had little effect on total phosphorus, only T4 and T5 treatments had significant difference(P<0.05). With the increase of silage time, the moisture content increased and crude protein content increased first and then decreased;the contents of total phosphorus and neutral and acid detergent fiber decreased, the contents of lactic acid and acetic acid and the ratio of ammonia nitrogen to total nitrogen increased. The results showed that silage for 30 days could basically meet the requirements of related quality indexes, and it was the best in the range of 30~45 days.