| Neonatal calf diarrhea is the main source of economic losses in the dairy industry and the main cause of calf death before weaning in most countries.Therefore,the treatment of calf diarrhea is crucial for the breeding industry.Probiotics are a class of substances that regulate intestinal microbial flora by adhering to the digestive tract,protect the stability of the intestinal ecosystem,improve animal health,increase productivity,and improve host immunity.However,there are few reports on the use of probiotics in newborn calves.Based on this,this experiment studied the effects of adding three different compound probiotics on the growth performance,nutrient apparent digestibility,diarrhea rate,fecal pathogenic microorganisms,serum indexes and fecal microbial flora of newborn calves.The aim is to lay a foundation for the rational application ofcompound probiotics.In this experiment,40 healthy newborn female calves with similar body weight were randomly divided into 4 groups with 10 calves in each group.The control group（C group）was fed with milk and starter,and the Duzhuangzhuang group（LF group）was fed with 10 g/d of normal milk per calf after 1 day of colostrum intake and 2-15 days of age.Calves in the Bimulac Extra+Calf Protector group（BP group）were given 30ml Calf Protector immediately after colostrum intake,and 10g of Bimulac Extra was added to milk from the 2nd to 11th day of age.The calves in Weiliru group（YC group）were given 30 g/d of Weliru after colostrum intake and 2-60 days of age.The experiment lasted for 60 days,during which the body weight,body size,feed intake and diarrhea days of calves were recorded.Blood was collected at 1,30,60 days of age,and feces were collected at 15,30,45 days of age for index detection.The test results show that:1.Compared with C group,the 30-day-old weight of BPgroup was significantly increased（P<0.05）,the ADG of BP group and YC group was significantly increased（P<0.05）,and the feed efficiency of YC group was significantly increased（P<0.05）.2.Compared with C group,the diarrhea rate of LF group,BP group and YC group decreased by 34.5%,44.6%and 50%respectively from 1 to 30 days of age;the diarrhea rate decreased by29.1%,32.0%and 36.9%at 1-60 days of age,respectively.The fecal score of LF group was significantly decreased（P<0.05）,and the fecal score of BP group and YC group was significantly decreased（P<0.01）.3.Compared with C group,the apparent digestibility of DM,CP,EE and ADF in BP group and YC group was significantly increased（P<0.05）,and the apparent digestibility of EE and ADF in LF group was significantly increased（P<0.05）.4.Compared with C group,the GLU serum content of YC group at 30 days of age was significantly increased（P<0.05）,at 30 days of age,the ALP content of BP group and YC group increased by 2.2%and 5.7%（P<0.05）,at 30 and 60 days of age,the BUN content of BP group and YC group was significantly different（P<0.05）,the T-AOC content of BP group at 30 days of age was significantly increased by 5.0%（P<0.05）,and the TNF-αcontent of YC group at 60days of age was significantly decreased（P<0.05）.The serum Cor content of 30 days old in BP group and YC group was significantly decreased（P<0.05）,the serum T3content of 30 days old in YC group was significantly increased（P<0.05）,and the serum T4content of 60 days old in YC group was significantly increased（P<0.05）.5.Compared with C group,the infection rates of rotavirus,coronavirus and Cryptosporidium in calves before weaning in LF group,BPgroup and YC group decreased.6.Compared with C group,the relative abundance of Bacteroidetes and Actinobacteria in15-day-old YC group increased（P<0.05）,the relative abundance of Phocaeicola in 15-day-old BP group and YC group increased（P<0.05）,and the relative abundance of Bifidobacterium in LF group and YC group increased（P<0.05）.In summary,the addition of three different groups of compound probiotics can promote the growth of calves before weaning,increase daily gain,reduce the diarrhea rate,diarrhea days and diarrhea score of calves,improve the apparent digestibility of nutrients,improve the immunity and antioxidant capacity of calves,reduce the infection rate of rotavirus,coronavirus and Cryptosporidium in calves,increase the relative abundance of fecal microflora,and improve the composition of fecal microflora in calves.The YC group had the best effect. |
