| In this study,we chose the weaned Holstein calves as the research object,thirty healthy45 day old weaned Holstein calves were randomly divided into three treatment groups(control、test1 and test2)which were fed with complete formula calf pellet diet and complete formula straw pellet diet respectively(16% and 25% straw were added to trial 1and trial 2 respectively).Each group was divided into five repetitions,two calves for each repetition.The pre feeding period was 7 days,and the normal feeding period was 40 days.The results showed that : 1.There was no significant difference in the production performance of calves in each treatment group(P > 0.05),compared with the control,the average daily intake and average daily gain of each experimental group were higher than those of the control group,and the average daily gain of experimental group 1 increased by25.8%;2.There was no significant difference in apparent digestibility of nutrients between the three groups;3.There was no significant difference in serum indexes related to liver function,such as AST、ALT、γ-GT 、ALP、TP、ALB、GLOB、A/G between the three groups(P > 0.05);Serum CR,UA,UREA levels are within the normal reference range of calves;4.Calves fed with complete formula straw pellet diet can significantly change the rumen and intestinal microflora structure,and have a positive correlation with the level of straw addition.At the phylum level,the dominant bacterial groups in the rumen microorganisms of each treatment group were Firmicutes and Bacteroidetes,The proportion of rumen flora Firmicutes in the control was significantly higher than that in the two tests(P<0.05),and the proportion of Bacteroidetes was significantly lower than that in the test 2(P<0.05),The test results show that as the proportion of dietary straw increases,the proportion of Bacteroidetes in the rumen flora tends to increase;At the family level,the proportion of Lachnospiraceae in the rumen of the control is significantly higher than that of the two tests(P<0.01),The proportion of Prevotellaceae was significantly lower than that of test 2(P<0.05),The results show that as the proportion of straw in the diet increases,the proportion of rumen flora Prevotellaceae has an increasing trend and the proportion of Lachnospiraceae has a decreasing trend at the family level;At the phylum level,the dominant bacterial groups in calf intestinal flora of each treatment group were Firmicutes and Bacteroidetes,The proportion of Firmicutes in the intestinal flora of the calves in the test 2 was significantly higher than that in the control(P<0.05),while the proportion of Bacteroidetes was significantly lower than that in the control(P<0.05);At the family level,the percentage of predominant bacteria such as Ruminococcaceae,Porphyromonadaceae,Lachnospiraceae,Bacteroidaceae,Prevotellaceae in the intestinal flora is not significantly different,but it can be seen that as the proportion of dietary straw increases,Ruminococcaceae and Lachnospiraceae tend to increase,Porphyromonadaceae tends to decrease5.The economic benefit analysis shows that compared with the control,the test1 and the test 2 can save 38.14% and 41.34% of the cost per ton of complete formula straw pellet diet.In the summary: feeding weaned calves with complete formula straw pellet diet has the tendency to increase the average daily feed intake and average daily weight gain of weaned calves;at the same time,it can significantly improve the microbial community structure of the rumen and intestine of the calf and promote the calf Digestion and metabolism and gastrointestinal health;for weaning and fattening calves,the use of complete formula straw pellet feed can reduce feed costs and improve breeding efficiency,and can efficiently use crop straw resources.According to the comprehensive analysis,the effect of 16% corn straw in the complete formula straw pellet feed of calves is better. |
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