Effects of different rations of hybrid Pennisetum americanum×P. purpureum cv. Minmu 6 in Leymus chinensis hay on production performance and milk quality of dairy cows

The effects of different rations of fresh hybrid P. americanum × P. purpureum cv. Minmu 6 in Leymus chinensis hay on production performance and milk quality of dairy cows were studied using a randomized block experiment with 24 Holstein dairy cows which were first birth with similar milk production(15 kg). The experiment had 6 different ratios of fresh Minmu 6 forage (CK, 0; Group Ⅰ, 7.50 kg; Group Ⅱ, 15.00 kg; Group Ⅲ 22.50 kg; Group Ⅳ,30.00 kg; and Group Ⅴ, 37.50 kg) with 4 cows in each group and had 40 days treatment period including 10 days for pre-trial period and 30 days for regular trial period. In summer around 30~37 ℃, there was no differences (P>0.05) between treatments fresh Minmu 6 forage for dry matter intake and milk production. The milk production of the experimental group with fresh forage was more stable than that of the control group. The α-linolenic acid (ALA) content of milk in Group Ⅲ with 22.50 kg fresh Minmu 6 forage was 15.88 mg·100 g-1 which increased by 43.1% compared with CK (P<0.05). In conclusion, fresh Minmu 6 forage in hay was helpful to stable the milk production and can improve ALA content of milk.