Investigation On The Incidence Of Calf Diarrhea In A Large-scale Dairy Farm In Heilongjiang Province And The Preventive Effect Of Compound Probiotics

As one of the diseases causing serious harm to the health of calves,calf diarrhea seriously affects the normal growth and development of calves in the early stage,as well as the reproductive capacity and lactation performance in the later stage,and brings huge economic losses to cattle producers all over the world.Due to the high morbidity and mortality,and the complicated causes of the disease,the disease is prevalent in different countries and regions to varying degrees,which is recognized as one of the urgent problems to be solved in the cattle industry worldwide.In this study,the incidence of diarrhea disease in calves in a large-scale dairy farm in Heilongjiang province was investigated,and the experiment of compound probiotics affecting the growth of calves and preventing diarrhea was carried out.Combined with the regularity of calf diarrhea and the results of prophylaxis test of compound probiotics,for the grazing pasture and surrounding areas of calf diarrhea disease prevention and control to provide scientific and effective experimental basis and theoretical guidance,in order to minimize grazing economic losses,improve breeding efficiency,at the same time for the composite effect of clinical application of probiotics to provide data support.This study on August 5,2021 the zap 0 to 6 months of calf diarrhea incidence has carried on the investigation statistics,the investigation period,the daily observation of calf diarrhea incidence,record the onset time,onset age,birth weight and duration of diarrhea,diarrhea,stool color,texture,tire inferior related data of excrement and urine,diarrhea rate calculation,At the same time,fecal samples of diarrhea calves were collected and detected by real-time PCR for Bovine rotavirus,Bovine coronavirus,E.coli K99~+and Cryptosporidium.At the same time,45healthy newborn Holstein calves were selected to carry out the prophylaxis test of compound probiotics.They were randomly divided into two groups:control group(n=23)and experimental group(n=22).The experiment lasted for 60 days.The experimental group was fed with the compound probiotics at 3-5 days of age,and the compound probiotics was added to the drinking milk of calves at a feeding rate of 10 g/cow/day,while the control group was not treated with any treatment.Weight was recorded at birth and weaning at 60 days of age and average daily gain,diarrhea rate and duration of diarrhea were calculated.A total of 705 diarrhea cases(115 males and 590 females)were collected,and 331 calves(58males and 273 females)had diarrhea.The results showed that the diarrhea rate of calves was41.6%during the survey period,and the diarrhea rate of female calves was higher than that of male calves.The onset time of calves was mainly in May(32%)and June(29%).The onset age of calves was 11-30 days(51%).The birth weight of diarrhea calves was 30-40 kg(77%).A total of393 feces samples of diarrhea calves were collected,46 samples were randomly selected for detection,and 26 samples(57%)were positive.The highest detection rates of pathogens were rotavirus and cryptosporidium(37%).Single infection was dominant(58%),and mixed infection was mainly rotavirus and cryptosporidium(91%).The results of compound probiotics showed that the weaning weight of calves in experimental group was significantly higher than that in control group(P<0.01),and the average daily gain of calves in experimental group was significantly higher than that in control group(P<0.05).During the experiment,different degrees of diarrhea occurred in both the control group and the experimental group.The diarrhea rate of calves in experimental group and control group was46.1%and 51.0%,respectively.The diarrhea rate and duration of calves in experimental group were significantly lower than those in control group(P<0.01).In conclusion,the calves were fed with compound probiotics can significantly increase weaning weight and average daily gain,and improve growth performance of calves.It can effectively reduce the diarrhea rate of calves,significantly reduce the duration of diarrhea,and has good effect on preventing the occurrence and development of diarrhea of calves.