Study On Automatic Detection And Variation Of Body Temperature And Activity In Dairy Cows During Reproductive Cycle

Estrus identification is very important to the economic production of dairy cattle,and it is gradually developing from traditional manual identification to automatic estrus identification.The rules of variation of physiological parameters of estrus is the basis of automatic estrus monitoring technology.Therefore,it is of great significance to explore the rules of variation of physiological parameters in estrus of dairy cows.The research showed that the temperature of cow's bodies has a significant change during estrus,which indicates its important potential in the research and development of automatic estrus identification technology in dairy cows.At the same time,the amount of activity has been applied to the automatic identification of estrus in dairy cows,but the results of different studies vary greatly and the efficiency of identification needs to be improved.Therefore,by using self-developed pedometer and vaginal parameter detection device to collect cow activity and vaginal temperature data,and then comparing and analyzing the data during estrus and diestrus,it can reveal rules of variation of the two parameters,which services in the reproduction management of dairy cattle.First,one hundred and fifty-seven randomly selected dairy cows(150 postpartum healthy lactating dairy cows and 7 primiparous ones)in a Beijing dairy farm were analyzed in this study.The activities of the experimental cows pre-and post-estrous were measured by the pedometer and the estrous status was confirmed by the rectal examination.Then,the activity alteration of dairy cows and influence of parities,season,and type of estrus treatment in estrus were explored.The detection of pedometer showed that the activities of cows after the onset of estrus(>1 500)were significantly higher than those during diestrus(<500)(P<0.05).The maximum activities(2 179±1 073)was observed at 4.5 h after the onset of estrus and gradually decreased till the end of the estrus to the level of diestrus.The amount of increased activities and the duration of cows estrous were markedly influenced by parity,season and type of estrus treatment(P<0.05).Then,the estrus detection threshold(the amount of activities increased 2.5 times higher than the amount at the same time point 7 days earlier,and lasted for 2.5 h)was applied to the automatic detection system of estrus,and its identification efficiency was compared with the artificial observation of estrus.The results showed that the efficiency of pedometer monitoring was greater than that of artificial observation,and the self-developed pedometer could be used for cow pregnancy diagnosis.In addition,the body temperature monitoring was carried out by the self-developed vaginal parameter detection device,and the cyclic temperature changes of cows estrous were explored.The effects of natural estrus,synchronous estrus and different seasons on body temperature were studied.The results showed that body temperature was determined to be in circadian rhythm,which was in day higher than that in night,and there were seasonal differences that were significantly higher in summer than those in either autumn or winter(P<0.05).After PG injection,the body temperature of the cow gradually decreased,then gradually rose to the lowest point,until about 44 hours to return to the normal body temperature,which was significantly lower(0.15-0.35 °C)from 9 h to 33 h after the drug administration than the average body temperature at the same time 7 d earlier(P<0.05).Body temperature gradually increased,reaching a peak of 0.53±0.22 °C 3.5 h after estrus,and then decreased 4 h before the end of estrus until body temperature returns to normal.The body temperature of cows in estrus and the duration of their estrus were significantly affected by seasons and estrus types(P<0.05).Therefore,it is crucial to take the 3 above mentioned factors and the specific conditions of a certain farm into consideration to determine the estrus prediction threshold of Holstein cows using the pedometer to detect estrus automatically.Rules of Circadian and seasonal body temperature and the estrous cycle provide theoretical guidance for evaluating the physiological status of cows and developing an effective automatic estrus identification technique.