Effect of Dietary Energy Supplementation on Feed Intake, Growth and Reproductive Performance of Sheep under Grazing Condition

Abstract: Six female sheep were used in a 90 day trial to study the effect of dietary energy supplementation to grazing on feed intake, growth and reproductive performance of female sheep. Animals were blocked according to live weight and blocked groups were assigned at random into two feeding regimes i.e. low and high energy (10.02 and 11.98 MJ ME/kg DM). Each sheep received 250 grams of supplemental diet in addition to grazing. Results showed that, feeding of sheep with increased levels of dietary energy supplementation did not have significant (P>0.05) differences for daily average dry matter and crude protein intake. However, daily average ME intake significantly (P<0.05) increased in a linear fashion and the mean values were 4.67 and 5.76 MJ/d for low and high energy supplemented diets respectively. The digestibility of dry matter (DM), organic matter (OM) and crude fibre (CF) significantly (P<0.05) increased as the level energy supplementation was increased. However, the digestibility of crude protein (CP), nitrogen free extract (NFE) and ether extract (EE) was similar (P>0.05) for all dietary energy regimes. Average daily live weight gain significantly (p<0.05) increased from 34.8 to 48.5 g/d as the level of supplement energy increased from 10.02 to 11.98 MJ ME/Kg DM. The birth weight of lambs was highest i.e. 0.71 kg fed high energy diet and lowest i.e. 0.50 kg fed low energy diet. These results indicate that, increasing levels of supplemental energy improve growth and reproductive performance of female sheep. Therefore, supplementation of higher level of dietary energy (11.98 MJ ME/kg DM) may be suggested for optimizing growth and reproductive performance of female sheep under grazing condition. Key words: Sheep, energy supplementation, digestibility, live weight gain, reproductive performanc