Determination of suitable oestrus synchronization protocols of ewes for lamb production in coastal areas of Bangladesh

The aim of this study was to produce lambs through hormonal synchronization of oestrous cycle in 1.5 to >3.5 year-old ewes. From coastal region of Bangladesh, a total of 45 ewes were selected and grouped as treatment (n=30) and control (n=15) group. Based on synchronization protocol, the treatment group was again divided into sub-group A (n=15) and B (n=15). In subgroup A, the ewes were injected intramuscularly with 2 ml of Ovuprost(R) (PGF2α) 9 days apart from first injection whereas in sub-group B, the ewes were injected intramuscularly with 2.5 ml Ovurelin(R) (GnRH) once. Though, sub-group A showed higher oestrus (93.33%) than control (60%), the differences were not significant (p>0.05). The pregnancy rate in treatment group (80%) was significantly (p<0.007) higher than control (40%). In two different treatment groups, oestrus and pregnancy rates were not significantly (p>0.05) different. The ewes between 2.6 and 3.5 yr aged showed comparatively higher oestrus and pregnancy than 1.5 to 2.5 and >3.5 yr. The mean litter size and average birth weight of lambs were 1.13±0.41, 1.46±0.31, 1.27±0.34 and 1.17±0.04, 1.32±0.03, 1.29±0.04 kg in control, sub-groups A and B, respectively. It was concluded that the hormonal synchronization of oestrous cycle in ewes of coastal region of Bangladesh increased pregnancy rate.