饲粮NDF/NFC对泌乳后期奶牛瘤胃甲烷排放量、营养物质表观消化率及生产性能的影响

为研究不同中性洗涤纤维/非纤维性碳水化合物(NDF/NFC)饲粮对泌乳后期奶牛甲烷排放量、营养物质消化率和生产性能的影响,试验选用体重(777.46±27.31)kg、胎次(1.5±0.15)胎、泌乳天数(242.92±15.28)d、产奶量(18.75±0.62)kg/d的奶牛12头,随机分配到3组,每组4头。各组饲粮NDF/NFC分别为2.10(精粗比为42:58)、1.96(精粗比为37:63)、1.52(精粗比为30:70),采用六氟化硫(SF_6)示踪技术测定自然状态下泌乳奶牛甲烷排放量。预试期14 d,正试期9 d。结果表明:饲喂不同NDF/NFC饲粮的泌乳后期奶牛甲烷排放量、甲烷能、单位干物质采食量的甲烷排放量以及单位总能摄入量的甲烷能均有显著差异;随着NDF/NFC降低,奶牛生产性能、饲料转化率和营养物质消化率无显著差异。综上,在不影响奶牛健康和生产性能的前提下,NDF/NFC为1.52的低NDF组饲料能显著降低泌乳后期奶牛瘤胃甲烷排放量。

Effects of Dietary NDF/NFC on Rumen Methane Emissions,Nutrient Apparent Digestibility and Production Performance of Dairy Cows during Late Lactation Period

Methane emissions from lactating cows under natural production condition were determined by sulfur hexafluoride(SF_6) tracer technique in order to study the effects of different neutral detergent fiber/non-fiber carbohydrate(NDF/NFC)diets on rumen methane emission,nutrient apparent digestibility and production performance of dairy cows during late lactation period. Twelve Holstein lactating cows were selected with similar body weight(777.46±27.31)kg, parity(1.5±0.15)parities, lactating days(242.92±15.28)d and milk yield(18.75±0.62)kg/d and were randomly allocated to 3 groups with 4 lactating cows in each group. Dietary NDF/NFC was 2.10, 1.96 and 1.52, respectively, and concentrate to forage ratio was 42:58, 37:63 and 30:70. The whole experiment lasted for 23 d with 14 d of pre-test and 9 d of test. The results showed that there was significant difference(P<0.05) in methane emissions, methane energy, methane emissions per unit of DMI, and methane energy emissions per unit of gross energy intake in lactating dairy cows, With the decrease of NDF/NFC; there was no significant difference(P>0.05) in the production performance, feed conversion rate and nutrient apparent digestibility. In conclusion,without affecting the health and production performance of dairy cows, low NDF group with NDF/NFC of 1.52 could significantly reduce rumen methane emissions during middle lactating period of dairy cows.