Use of bovine somatotropic hormone (bST) for increased milk production has been widely investigated in dairy cattle, whereas very little work has been done in buffaloes. To observe the effect of bST on buffalo for long term duration study was planned with the objectives to investigate the effects of long term use of bST on milk production, milk composition, reproduction, hematological and biochemical parameters in Nili-Ravi buffaloes. For this study 30 lactating Nili-Ravi buffaloes with similar milk production and stage of lactation were selected and randomly divided in to two groups A and B with 15 animals in each group. The group A (0 bST) served as control while animals in group B (+bST) were given injection of bST (250 mg Boostin-250/animal) at 14d interval. Nutritional requirements of experimental animals were met through available green fodder (45-50kg/day) supplemented with concentrate ration @ half of milk production. The milk production was significantly (P<0.05) increased by 18.04 % in treated group compared with control. The results showed that there was no significantly variations in parameters like milk composition, dry period and lactation length, calving interval in both the groups. The postpartum estrous period and service period were significantly (P< 0.05) improved which reflected positive effect of bST on reproductive parameters. However, the difference in services per conception was non-significant. Small variations were found in the prevalence of contagious and non contagious diseases in both experimental groups during the study period. The differences among body weights, hematological and biochemical parameters were also non-significant expect blood urea nitrogen (p< 0.05). The proceeds over a lactation period of 305 days was PKR. 4227.0 with the use of bST.

Second trial was conducted to study the effect of dose interval of bST in Nili-Ravi buffaloes. For the proposed study 21 Nili-Ravi lactating buffaloes with similar milk production and stage of lactation were randomly divided into three groups A, B and C with 7 animals in each group. The group A was injected with full dose of bST hormone (250 mg/animal) with trade name of Boostin-250 at an interval of 14 days, while animals in group B were given injection on alternate days with divided dose of 36 mg/animal. Group C was kept as control. Duration of study was 5 months and the animals were kept on green fodder supplemented with concentrate ration half of milk production. The concentrate ration had 17.2% CP and 72.0% TDN. The milk production increased by 18.35% and 15.27% in-group A and B compared with group C (control) but increase was non-significant (P>0.05) . Similarly data revealed that dose interval had no affect on milk contents, reproductive and hematological parameters in all the experimental groups.

In a third trial feed digestibility and efficiency for milk production was studied. For the study fourteen Nili-Ravi buffaloes at their mid lactation with almost same level of milk production were randomly divided into two groups A and B with seven animals in each group. The group A was kept as control, while group B was injected bST hormone (250 mg/animal) at an interval of 14 days and continued for 60 days. The nutritional requirements of animals in both the groups were met through TMR according to NRC recommendations. The milk production was increased by 7.0% in. treated group (B) as compared with control group (A) and the increase was statistically non-significant (P>0.05). However, the feed efficiency for milk production was significantly improved (P< 0.05) in treated group. The differences in milk composition (Fat, SNF, TS and Protein percent) body weight gain digestibility of dry matter and other nutrients in treated and control groups were found non-significant (P>0.05).

The fourth trial was conducted to determine the effect of energy on milk production and its quality under the influence of bST hormone in Nili-Ravi buffaloes. Multiparous (n12) buffaloes with mid lactation and similar level of milk yield were selected and randomly divided in to three groups i.e. A, B and C with four animals in each group. All the experimental animals were injected bST with trade name of Boostin - 250. The dose level was 250 mg per animal and injection was given at fortnightly interval during study period. The nutritional requirements of three groups animals were met through TMR with varying levels of energy (15% low and 15% above the recommendations of NRC). The milk yield was significantly higher (pO.O5) between medium and low energy diets. The milk components and body weight gain were similar on all rations, while feed efficiency and nutrient intake (except ether extract) in low energy diet was significantly higher (p
Conclusion

On the over all there was consistency of results for milk production and milk composition with reference to available literature. However, some reproductive parameters including postpartum estrus and service period were significantly improved with the use of bST hormone. This effect has not been reported in the previous literature which needs to be further investigated and verified. Similarly the dose level in buffaloes needs to be further studied.