Effect of fluorogestone acetate (FGA) sponge with oestradiol benzoate (OB) on oestrus response and behaviour in Dorper cross ewes.

The purpose of this experiment was to identify the most suitable oestrus synchronisation protocol using 30 mg fluorogestone acetate (FGA) sponges with oestradiol benzoate (OB) for sheep. Thirtyfour Dorper crosses ewes, randomly allocated into three groups. Ewes in each group are either received FGA with i) corn oil (Control; n=11); ii) 0.05 mg OB (OB-L; n=11) or iii) 0.25 mg OB (OB-H; n=12). A day before FGA removal, one ml of prostaglandin (PG) was injected into each ewe regardless of their treatment groups. Oestrus behaviours observation was conducted with the involvement of four alternate fertile rams after 24 hours post-FGA removal and OB injection. Data of oestrus response and behaviour was analysed using one-way ANOVA. Results showed that all ewes in OB-L and OB-H groups had oestrus within 60 hours of observation, while only 36.4% in the Control group. Meanwhile, ewes with standing oestrus in OB-L and OB-H groups had a shorter interval compare to Control group. Moreover, ewes in OB-L and OB-H groups showed a significantly higher (p<0.05) percentage of ewes express their oestrus behaviour compared to ewes in Control group. The results suggested that synchronisation using intravaginal FGA with OB either low or high dose improve the oestrus response of Dorper crosses ewes compared to synchronisation with non-administration of OB. [ABSTRACT FROM AUTHOR]