Evaluation Of Behavior Monitor In Technology And Behavior Development Of Holstein Calves

The behavioral changes of calves are induced by their corresponding health statuses to some extent,the behaviors of calves are closely related to factors such as feed intake,growth performance,and disease.However,the traditional methods on behavior observations are time-consuming and labor-intensive,while the accuracy of automatic monitoring equipment needs to be determined.In this experiment,we conducted a continuous and longitudinal observation on calves,aiming at the rhythm of behavior changes and 24-hour behavioral rhythms,which provided the most efficient method for calf behavior sampling.We also conducted independent analyses on feed intake,growth performance and rumen fermentation factors with data of calf behavioral changes from scaled farms separately to reveal the correlation between behavioral changes and health and welfare,furthermore to determine the underlying physiological mechanism,which provides the theoretical basis for calf management in future.A total of 18 newborn Holstein female calves of similar weight（42.1±5.4 kg）were selected to be independently reared to day 84.The ruminating,non-nutritive oral,lying,and standing behaviors of calves during this 12-week period continuously recorded by video on a daily basis and the daily feeding intake was recorded.The parameters related to growth performance were measured every 2 weeks,and the rumen fermentation parameters were determined on 1 d,35 d and 84 d respectively.To find out the optimal sampling days and sampling intervals,we analyzed the data of 8 calves in week 6 with different sampling days（6,5,4,3,2,1 d）and different sampling intervals（5,10,15,30s,and 1,3,5,10,15,30,60 min）.R²≥0.75（P>0.05）was used as the criteria for the effectiveness.The results showed that data from observations with 3 or more days could be used for accurate predictions of4 kinds behaviors in a particular week.When both sampling days and sampling intervals are taken into consideration,the optimal observation method are:ruminating with 3 sampling days and 5-minute sampling interval（R²=0.781）;lying with 2 sampling days and 10-minute sampling interval（R²=0.812）;non-nutritive oral with 3 sampling days and 5-minute sampling interval（R²=0.773）;standing with 3sampling days and 10-minute sampling interval（R²=0.750）.And the accuracy of prediction increases along with increase in sampling days and deceases in sampling intervals.This method will contribute to the effectiveness and accuracy in data collection in the future.Additionally,according to the results of the above experiments,the 3-day observational data of Tuesday,Thursday and Saturday per week can accurately estimate the behaviors of calves in the corresponding week,so this method will be applied to observe the behavior of calves at weeks 1,3,6,9 and 12 to analyze the 24-hour rhythm of calves’behaviors before and after weaning.The accuracy of monitoring ear tag flex rumination monitoring was evaluated by video recording,and the accuracy of monitoring ear tag flex health system for calf disease was evaluated by disease records.The results showed that the probability distributions of the ruminating behaviors recorded by the video and the monitoring ear tag flex were not similar（P<0.01）,but there was a significant correlation（ρ=0.744;P<0.001）,and the monitoring ear tag flex health index has a higher accuracy for calf disease monitoring（sensitivity is 70.37%,specificity is 94.50%,accuracy is 93.50%）,and the monitoring ear tag flex health index can reflect the disease occurrence.This supports the potential application of monitoring ear tag flex used in calves in the future research.The correlations between calf behaviors,feed intake and nutrients in feed were analyzed,and the results showed that the intakes of DM（r=0.768）,NDF（r=0.749）,pe NDF（r=0.752）were significantly positively correlated（P<0.01）with the ruminating duration.It was concluded that the development of calf rumination behavior was influenced by the total DMI,and DMI of solid feed,NDF and pe NDF that are the key factors for rumen development and ruminating behavior establishment of calves.At the same time,the data of ruminating activity of 18 calves were collated in this experiment,9 calves with the highest rumination activity and 9 calves with the lowest ruminating activity were screened out,and the effects of calf rumination activity on feed intake,growth performance and rumen fermentation parameters were investigated.The results showed that the interaction between high and low treatment and time of rumination activity had a significant influence on the forage intake（P<0.05）,but there was no significant effect on the growth performance,rumen p H,VFAs concentration,NH₃-N concentration and MCP content of calves（P>0.05）.