No abstract

This study was carried out to determine the effect of repeated injections of cloprostenol sodium during the early luteal phase on luteolytic capacity and  hormonal changes of Large white x Pietrain in Otukpo. A total of ten (n = 10) oestrus Large white x Pietrain sows were randomly divided into two groups. experiment and a control. Group I (n = 5) no synchronizing agent was administered Group II (n = 5) received 6 doses of 500 µg of cloprostenol sodium at  days 5, 6, 7, 8, 9 and 10 of the oestrous cycle and was monitored for natural oestrus twice daily from 0700 – 1000 and 1500 – 1800h. The fertility parameters determined in this study were: Time to onset of oestrus (TOO), duration of oestrus (DOO), total litter size (TLS), total born alive (TBA) average  body weight (Av. BW). Five (5) milliliters of blood was collected via the posterior vena cava before PGF2α injections on at day 1 and 5, 6, 7, 8, 9, 10 and every other day afterwards till next observed oestrus. The extracted serum from the collected blood was assayed using competitive ELISA for Oestradiol  (E2) progesterone (P4) concentrations. Variables such as TOO, DOO, TLS, TBA, Av. BW and data on E2 and P4 profile were expressed as mean ± SEM.  Student ttest and Tukey’s post-hoc test were used to compare the percentages and mean values between the groups. A value of P ≤ 0.05 was considered  significant. Results TOO was 484.80 ± 13.99 h, and 484.80 ± 15.92 h; DOO was 86.40 ± 5.88 h and 76.80 ± 4.80 h; TLS was 10.00 ± 0.84 and 10.20 ± 0.66;  TBA was 10.00 ± 0.84 and 10.00 ± 0.55 and Av. BW was 1.26 ± 0.09 kg and 1.06 ± 0.05 kg in groups I and II respectively. However, the fertility parameters  showed no statistically (P ≤ 0.05) significant differences between the control and the treated groups. The serum E2 concentrations of the samples  collected from the first day which is the first day oestrus, fifth day which is the first day of cloprostenol sodium (PGF2α) to 23rd day