Research On Early Pregnancy Diagnosis Procedure By Ultrasonography In Scaled Dairy Farm

In this experiment,the technical procedure of early pregnancy diagnosis of cows is studied.The accuracy,faster examine speed and efficiency of three diagnostic methods were compared to attempt find the most suitable early pregnancy diagnostic method in large-scaled diary farms.By comparing different ultrasonographic scanning methods to attempt finding out the ultrasound diagnostic procedures that can ruduce misdiagnosis,and evaluate the effect after the procedures were applicated.Three early pregnancy diagnostic methods were tested for 281 dairy cows inseminated 28～34 days.The results were showen as follow:by transrectal ultrasonography,PAG detection and rectal palpation,the average time-consuming of each cow was 0.47 minutes,1.58 minutes and 0.88 minutes,respectively;the minimum time for a single diagnosis was 3 seconds,1652 seconds and 7 seconds,respectively;the rate of suspected but uncertain was 2.49%and 1.07%,respectively.By comparation of the rusults of three diagnostic methods,the transrectal ultrasonography had the advantages of higher accuracy,shorter time-cosuming,easier to management,lower biosecurity risk and no medical gabage.In pregnancy diagnosis for 8673 cows inseminated after 28～34 days,the results of single section scanning and continuous cross section scanning combined with mucus expelling were compared.It was shown the misdiagnosis rate was 1.86%(161/8673)and 0.01%(1/8673).The misdiagnosis rate of countinous cross section scanning was lower than single section scanning extremely significant.From September,2019 to November,2020.A survey of early pregnancy diagnosis of total numer of 44652 cows 28～34 days after insemination in four scaled dairy farms was carried out.The misdiagnosis rate was 1.45%(270/18454),1.72%(23/1337),1.92%(32/1663)and 2.08%(9/433),respectively,before using the procedure of continuous cross section scanning combined with mucus expelling.After application of the procedure,the misdiagnosis rate was reduced to 0.06%(12/19095),0.14%(2/1422),0.06%(1/1721)and 0.25%(1/397),respectively,in four farms.There were significant differences between the results befor and after using the procedure by statistic analysis.The main abnormal pregnancy imagines found at 28～32 days after Al in this study included unidentified fetal heartbeat and umbilical artery pulsation in 79 cows,and separated chorioallantoic membrane in 85 cows,these situations may lead the rate of 100%pregnacy loss as recheck at 90 days after Al,so these cows should be treated immediately.Another condition was cloudy fetal fluid imagines found at 28～32 days after Al in 732 cows,which determined as unpregnancy rate was 64.34%(471/732)as re-examination at 90 days after Al.This condition indicated that as cloudy fetal fluid imagines appeared it shouldn’t make a certain dicision whether the fetus to be dead,it is necessary to take a further inspection.By comparing three different early pregnancy diagnosis methods,it indicated that the transrectal ultrasonography is the most suitable method for the scaled dairy farms.Application the procedure of continuous sectional scanning combined with mucus expelling can reduce the misdiagnosis rate significantly.The results obtained in this study can provide some important basis for process operation of early pregnancy diagnosis in large-scaled dairy farms.