Refractoriness of Porcine Corpora Lutea to Cloprostenol Sodium and Dinoprost Tromethamine Treatments at Day 7 of Oestrous Cycle

This study was carried out to evaluate the refractoriness of porcine corpora lutea to exogenous prostaglandins (Cloprostenol sodium and Dinoprost tromethamine). Twenty (n = 20) apparently healthy sows were randomly assigned to 4 treatment groups. Group 1 (n=5) received two injections of Cloprostenol sodium (Synchromate ® ) (500µg) (days 0 and 13). Group 2 (n=5) received three injections of Synchromate ® (Day 0, 7, 13). Group 3 (n=5) received two injections of Dinoprost tromethamine (Lutalyse ® ) (12.5mg) (days 0 and 13). Group 4 (n=5) received three injections of Lutalyse ® (Day 0, 7, 13). Five (5) milliliters of blood was collected via the posterior vena cava before PGF 2α injections on day 0, 7, and 13 and once weekly afterwards till pregnancy was established. Data on progesterone profile were expressed as mean ± SEM. One-way ANOVA and Tukey’s post hoc test were used to compare the mean values between the groups. Graphpad Prism ® data package for windows (2009) was employed for all statistical analyses. A value of P 2α in groups 2 and 4 and following first injections in groups 1 and 3. Complete luteolysis was seen with behavioural oestrus after the second injection of PGF 2α at day 13 in groups 1 and 3 and after third injection of PGF 2α in groups 2 and 4. It was therefore concluded that the corpora lutea was refractory to both Cloprostenol sodium and Dinoprost tromethamine at Day 7. Further work should be done to find out the reason for lack of response of porcine CL to PGF 2α between days 7 and 12.