体外法评价日间不同刈割时间和茬次对初花期紫花苜蓿青贮品质的影响

为明确日间不同刈割时间和茬次对初花期紫花苜蓿青贮饲料品质的影响,对两茬紫花苜蓿于初花期同一天08:00、13:00和18:00刈割并调制青贮饲料,室温下保存45d后,取样分析并采用体外法评价其饲用价值。结果表明,不同日间刈割时间和茬次对紫花苜蓿青贮饲料的干物质含量,相对饲喂价值及干物质体外消化率有显著差异(P<0.05)。随着刈割时间从早上推迟到下午,紫花苜蓿青贮饲料的粗蛋白质含量、中性洗涤纤维体外消化率及体外发酵总挥发性脂肪酸、产气量显著增加(P<0.05),中性洗涤纤维和酸性洗涤纤维含量显著降低(P<0.05)。第1茬紫花苜蓿青贮饲料的干物质、粗蛋白质含量、相对饲喂价值、干物质体外消化率及产气量均显著高于第2茬(P<0.05),中性洗涤纤维和酸性洗涤纤维含量显著低于第2茬(P<0.05)。因此,在调制初花期紫花苜蓿青贮饲料时,应优先考虑第1茬且推迟刈割时间至午后。

Effects of diurnal shift and clipping stubbles on fermentation characteristics of alfalfa silage in the initial flowering stage by in vitro

The effects of diurnal shift and clipping stubbles on alfalfa silage quality in the initial flowering stage were studied.Initial flowering stage alfalfa was harvested twice at 08:00,13:00,and 18:00 on a sunny day.Silages were prepared using a laboratory scale system without wilting,and stored at ambient temperature for 45 days.Then the samples were collected and in vitro method was used to evaluate their feeding value.The results showed that the effect interaction of different diurnal harvest times and clipping stubbles on dry matter content,relative feed value and in vitro DM digestibility of alfalfa silages were significant(P<0.05).With delaying the harvest times to afternoon,alfalfa silages had higher(P<0.05)crude protein content,in vitro neutral detergent fiber digestibility and the in vitro total volatile fatty acids concentrations and gas productions,but lower(P<0.05)NDF and acid detergent fiber concentrations.Compared to the second cutting alfalfa silages,the DM and CP contents,RFV,IVNDFD,and gas productions of the first cutting alfalfa silages were significantly higher(P<0.05),with the lower(P<0.05)NDF and ADF concentrations.These results suggested that during the initial flowering stage,alfalfa harvest for silage should take precedence over the first cutting and delaying the harvest time to the afternoon.