Oestrus control in cattle in Tunisia: application of progesterone or progestagen-PMSG combined treatments

Abstract

The aim of the present study was to test fertility in cattle in Tunisia after oestrus control treatment. This field study was performed in 3 distinct regions on 1 249 females of either Holstein or Friesian breeds (n = 554) or in local pure or crossbreds (n = 695). They were treated with vaginal coils + PMSG (700-1 000 IU; groups I and II) or subcutaneous implants + PMSG (500 IU; group III). The synchronized females were inseminated at pre-determined times, namely 48 and 72h after coil or implant removal. The overall conception rate on induced heats in females submitted to rectal palpation 90 days after AI (n= 1 042) was 54.7 %. There were no significant effects of the type of treatment or of the physiological status prior to treatment (P > 0.05). By contrast, the local, pure or crossbred-females had a higher conception rate than Holstein-Friesian cows (P < 0,01) (47.8 and 59.6 %, respectively). Among 132 cows of group I which were subjected to an early non pregnancy diagnosis based on milk progesterone concentration and found positive i.e. presumably pregnant, 72 were confirmed pregnant by rectal palpation (54,5 %) 90 days after AI. The mean cumulative conception rate (1st and 2nd AI) was 71.6 %. It was concluded that such oestrus control treatments were very effective, particularly in local animal breeds in favor of a larger use of AI.