双低菜籽粕与玉米蛋白粉对奶牛生产性能、经济效益及瘤胃微生物区系的影响OA

The experiment aimed to investigate the effects of replacing part of soybean meal with a combination of canola meal and corn gluten meal on the production performance,economic benefits,and rumen microbiota of dairy cows in mid-to-late lactation.A total of 240 healthy Holstein dairy cows in mid-to-late lactation with similar parity and milk yield were randomly divided into two groups,with 120 replicates per group and one cow per replicate.The control group was fed a basal diet,while the experimental group received the basal diet with part of the soybean meal substituted by canola meal and corn gluten meal.The pre-trial period was 10 days,and the formal test period was 45 days.The results showed that compared with the control group,the average daily dry matter intake(ADMI)in the experimental group was extremely increased(P<0.01),while the average daily milk yield showed no significant difference(P>0.05),with a net economic benefit of 0.41 yuan/(head·d).The rumen ammonia nitrogen(NH3-N)content in the experimental group was extremely increased(P<0.01),while the rumen microbial richness showed no significant change(P>0.05).The relative abundance of Firmicutes in the rumen of the experimental group was significantly decreased(P<0.05),while the relative abundance of Paludibacter was extremely increased(P<0.01).Functional prediction results revealed that the experimental group was significantly enriched in pathways related to the biosynthesis of neomycin,kanamycin,and gentamicin,as well as protein digestion and absorption(P<0.05),whereas the control group was significantly enriched in pathways related to pyruvate metabolism and methane metabolism(P<0.05).The study shows that replacing part of soybean meal with canola meal and corn gluten meal can maintain production performance of dairy cows in mid-to-late lactation while improving economic benefits,without causing adverse effects on the rumen microbiota.