Electronic-pressure-sensing-systems for the detection of oestrus in cattle: possibilities and limits.

Inacurate and/or inefficient detection of oestrus result in a decrease in t he economical performances of diary herds where almost all pregnancies are obtained following artificial insemination. Different methods have been pro posed to help breeders to detect oestrus but if some of them do provide an aid to identify cows in oestrus, they need to be associated with visual obs ervation for being fully effective. These last years, different sensing systems for the detection of oestrus ha ve been developed. Their two main interests reside in the fact that they ar e based on the only specific behaviour associated with oestrus (standing to be mounted) and that they provide a 24h surveillance v.s. periodic breeder s' observations. These devices have been evaluated on many aspects includin g the relationships of oestrus as detected with these techniques and ovaria n as well as hormonal events and it appears that their efficiency (proporti on of oestrus detected among those possible) is in the range of what can be obtained in situations where oestrus detection by visual observation is op timum; moreover, the fertility of cows is similar whether they are insemina ted according to oestrus detected by visual observation or by these systems . However, they do not detect all situations where a cow can be successfully inseminated and some problems can be encoutered with the fixation of the de vice on the rump of the animals. These systems are expensive and their inte rest, on an economical point of view, remains to be evaluated.