Study On Nutrition Dynamics And Silage Quality Of Different Maize Varieties And Fattening Hu Sheep With Maize Silage

In this study,the nutrient dynamic and silage fermentation quality of 23 silage maize varieties were measured during the growth period,and the effects of the ratio of maize silage on the fattening Hu sheep were studied.It provides theoretical basis for selection of silage maize varieties and utilization of silage maize.In experiment 1,23 varieties of silage maize were selected and samples were collected on the 92 d,97d,102 d,107d,112 d,125d,130 d and 135 d day after sowing to determine nutrient changes,and the yield of the whole plant was determined on the 120 d after planting.The results showed that the growth time had a significant effect on the stem,leaf,ear and initial water content of silage maize(P<0.01),the content of DM,Ash,CP,NDF and ADF in the whole silage maize with different growth times were significantly different(P<0.01).The results showed that J27,J10 and J67 had the highest yields of 4926.17 kg/mu,4822.46 kg/mu and 4822.46 kg/mu,respectively,and their starch content in DM were the highest at 125,130 and 130 days after planting,respectively,at 41.37%,40.26% and 43.99%.Experiment 2 according to experiment 1,14 varieties of silage maize with high yield were selected for silage fermentation test.A portable near infrared spectrometric analyzer was used to determine the nutrient composition for com parative analysis after 90 days of fermentation.The results showed that the co ntent of J1824 DM was 33.13%,which was significantly higher than that of oth er varieties(P<0.01),the content of J1825 CP was 9.39%,which was significan tly higher than that of other varieties(P<0.01);The EE content of J1814 was significantly higher than that of other varieties(P<0.01),it was 2.90%.The sta rch content of J1819 was significantly higher than that of other varieties(P<0.01),30.47%.After Fermentation,the lactic acid content of J67 was 64.46 g/kg,which was significantly higher than that of other varieties(P<0.01),J1824 pH was significantly higher than that of other varieties(P<0.01).The relative feedi ng value(RFV)of each species from high to low is J1804(149.33)>Z29(142.79)>J1824(140.95)>J1819(140.54)>J1814(139.35)>J10(139.10)>J1818(138.84)>J17(137.22)>N1506(136.42)>J1820(135.47)>J1825(133.97)>J67(132.90)>J27(130.99)>J1815(129.62).In the third experiment,72 three-month-old Hu sheep males with the same genetic background,age,healthy,disease-free,and good growth conditions were selected.According to the principle of similar birth weight between the experimental groups,the experimental animals were randomly divided into 4 groups and fed separately PTMR with different proportions of maize silage in 4 kinds of roughage: 100% of roughage is corn stalk(CS),33% of roughage is whole maize silage(33MS),66% of roughage is whole maize silage(66MS),100% of roughage is whole maize silage(MS).The fattening experiment lasted for 9 weeks.The experimental results showed that:(1)there was no significant effect on the growth and fattening performance and slaughtering performance of Hu sheep in different ratios of corn stalk and corn silage in the roughage(P>0.05);(2)Dietary NDFD and ADFD increased linearly with the increase in the ratio of corn silage to roughage(P<0.05),MS group DNFD(69.71 %)and ADFD(58.11%)were significantly higher than other groups(P<0.05).The ratio of corn silage to roughage in the diet significantly affects CP digestibility(P<0.05),and the 33 MS group is the highest,which is 76.17%;(3)The muscle pH 45 min and drip loss of 66 MS group were significantly higher than those of other groups(P<0.05).The valeric acid content of 66 MS group was significantly higher than that of CS group(P<0.05),and the lightness of rumen was significantly lower than other groups(P<0.05).Under the test conditions,based on the comprehensive consideration of yield and harvest quality,Minqin is recommended to plant J27,J10 and J67,and the appropriate harvest time is 125,130 and 130 days after planting,respectively.Considering the RFV of the whole corn after 90 days of silage,planting J10 is preferred.Comprehensive production efficiency and feed processing efficiency,in pellet total mixed ration with a concentrate-to-forage ratio of 85:15,it is recommended that the appropriate ratio of maize silage in the roughage is 1/3.