Shortening of the oestrous cycle and repeated induction of heat as a method of treatment of repeat breeder cows
Abstract. Fifty-four repeat breeder cows were divided into 4 groups (GI to GIV), each one contained 14 cows with the exception of the 1st one which contained 12 cows. The oestrous cycle was shortened in cows of GI and GII by means of injection of 0.5 mg of cloprostenol in GI on day 10 of the cycle and by single intra-uterine infusion of 100–150 ml of Lugol's Iodine from day 3 to 5 of metoestrous in cows of GII. Cows in GIII were infused by Norofloxacin on day 1 to 3 of the 1st and 2nd cycle only. Cows in group IV were left as non-treated affected control and just rested for 3 successive cycles. Insemination was performed at the 3rd induced heat in cows of GI, after 3 cycles (2 shortened and one with normal length) in cows of GII and after 3 cycles with normal length in cows of both GIII and GIV. The post-treatment conception rates were determined. There were significant differences (P < 0.005) in the total and first service conception rates between cows in GI and GIII compared with that of those in GIV and GII. Also, there was a significant difference (P < 0.001) for C.R. between cows in GII and those in GIV. From the results of this study, it could be concluded that shortening of oestrous cycle and repeated induction of heats using PGF2 α analogue (cloprostenol) is better than i.u. infusion of antibiotic together with sexual rest for treatment of repeat breeder cows.