| Objective: Pine needles contain antibacterial substances.Pine needles are added to fresh alfalfa grass to make mixed silage to obtain good quality mixed alfalfa silage.However,the research on the feeding effect and feeding safety of pine needle and alfalfa mixed silage has not been reported yet.To this end,this study used Kazakh male lambs as experimental animals,and added different proportions of pine needles and alfalfa mixed silage to the lamb diet to fatten lamb feed intake,daily gain,slaughter performance indicators,blood biochemical parameters and diets The index of nutrient digestibility is determined,and the effect of pine needle and alfalfa mixed silage feeding on fattening lambs is discussed,which provides a scientific reference basis for the application of pine needle and alfalfa mixed silage in the production of sheep.Methods: The specific test methods of the experimental content of this paper are as follows:In this study,50 Kazakhstan male lambs with similar body weight were randomly divided into five groups,with the ration of concentrate to crude being 50: 50 and the mixed silage accounting for 70% of the crude.The proportion of pine needles in mixed silage(fresh weight basis)was 0(group I),5%(group II),10%(group III),20%(group IV)and 30%(group V),respectively.The fasting body weight of fattening sheep was weighed continuously before morning feeding 2 d before the start of the positive trial and the end of the trial.The daily dry matter intake(DMI)of the lamb was measured once a week after the start of the feeding trial,and the average daily weight gain(ADG)and feed-weight ratio(F/g)were calculated.After the feeding test,three fattening lambs with the live weight close to the average value of the group were selected from each group.Feed was stopped 24 h before slaughter,and water was stopped 12 h before slaughter and the body weight before slaughter was measured.The slaughter performance indexes of the lambs were measured after slaughter within 24 hours.At the end of the feeding trial,blood was collected from the jugular vein of lambs in each group.Collect whole blood for measuring blood hemoglobin;At the same time,blood was collected to prepare serum.After the blood sample was allowed to stand at room temperature for 30 min,it was centrifuged at 3000r/min for 10 min.The centrifuged serum was collected and subpackaged in a 1.5ml centrifuge tube,and stored frozen at-20℃ for subsequent use.The contents of total protein,serum urea nitrogen,creatinine,aspartate aminotransferase and alanine aminotransferase were determined by kit method.In the last three days of the experimental period,three lambs were randomly selected from each group.Feed samples and feces samples were collected by the total feces collection method to determine the apparent digestibility of dietary nutrients.Results:(1)The average daily weight gain of lambs was gradually decreased with the increase of the proportion of pine needles in alfalfa mixed silage.The average daily weight gain of groups I and II were significantly higher than that of group V(P<0.05),and the differences were not significant between groups III and IV and group V(P>0.05).There was no significant difference in dry matter intake among the five test groups(P>0.05).The feed to weight ratios in the experimental groups Ⅰ and Ⅱ were significantly lower than that in the experimental group V(P<0.05),and the differences between the experimental groups Ⅲ andⅣ and the experimental group V were not significant(P>0.05).The carcass weight,slaughter rate,net meat weight,net meat rate and meat/bone ratio were not significantly different among the groups Ⅰ,Ⅱ,Ⅲ and Ⅳ(P>0.05),and they were all significantly higher than those in group V(P<0.05).The eye muscle area of lambs was not affected among groups(P>0.05).(2)There were no significant differences in blood hemoglobin content,serum total protein,albumin,aspartate aminotransferase,alanine aminotransferase,creatinine,and urea nitrogen content of fattening lambs among the five test groups(P>0.05).There was no significant difference in the digestibility of dry matter,crude protein and neutral detergent fiber among the groups Ⅰ,Ⅱ,Ⅲ and Ⅳ(P>0.05).The digestibility of dry matter in diet of groups Ⅰ and Ⅱ were higher than that of group V(P<0.05),the digestibility of crude protein in diet of group Ⅰ was significantly higher than that of group V(P<0.05),and the digestibility of neutral detergent fiber in groups Ⅰ and Ⅱ was significantly higher than that of group V(P<0.05).The digestibility of acidic washing fiber was not significantly different among the groups Ⅰ,Ⅱ,and Ⅲ(P>0.05),but it was significantly higher in group Ⅰ than in groups Ⅳ andⅤ(P<0.05),and the differences were not significant among the groups Ⅱ,Ⅲ,Ⅳ,and Ⅴ(P>0.05).There was no significant difference in the digestibility of calcium and phosphorus in the diet of fattening lambs among different groups(P>0.05).Conclusion:Under the conditions of this experiment,it was feasible to feed the lambs with mixed silage of pine needles and alfalfa,but the proportion of pine needles in the mixed silage should not exceed 20%,and the mixed silage of pine needles and alfalfa had no effect on the blood biochemical indexes of the lambs.The nutrient digestibility of the lambs diet was significantly reduced by feeding 30% mixed silage of pine needles and alfalfa. |
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