The treatment of anoestrus and suboestrus in dairy cattle using a progesterone releasing intravaginal device (PRID) or gonadotrophins.

Dairy cows and heifers which had not shown any detectable oestrus were divided into three treatment groups. Animals with active ovaries (suboestrus) were treated with PRID, whereas those with inactive ovaries (true anoestrus) were treated with either PRID or gonadotrophin injections. When comparing the results of the treatment, the criterion used was the pregnancy (%) achieved within forty days after the commencement of the treatment. Furthermore, the rate of pregnancy after first insemination, the number of inseminations per pregnancy, and the time of conception after treatment, as well as the return interval of the animals not conceiving at first insemination were surveyed.