Early supplementation of alfalfa to starter diets improves the pre- and post-weaning performance of lambs

Abstract Text: The objective of this study was to determine the effects of alfalfa supplementation to starter diets of artificial reared lambs on pre- and posting performance. Twelve Hu lambs at the age of 10 days, with an initial body weight of 3.87±0.564 (SD) kg , were randomly divided into two equal groups and allocated to two dietary treatments: cereal feeding (CF, milk replacer and pelleted starter) and forage feeding (FF, milk replacer, pelleted starter and alfalfa). All animals were fed the same milk replacer at 880 ml/d on day 1, and milk replacer was then reduced at a rate of 30 ml/d until day 24. The lambs were then fed at 180 ml milk replacer per day from day 24 to 28 (weaning). During this period, the pelleted starter (16.8% NDF) was offered to all animals, but alfalfa (38.6% NDF) was only to group FF ad libitum. After weaning, the animals were offered with 300 g/d cereal powder (21.5% NDF) and had free access to alfalfa. Feed offered and refused, and body weights were recorded for two consecutive days at 0800 am every week during the 4-week feeding trial after weaning. On day 57, blood samples were obtained to determine serum concentration of glucose and β-hydroxybutyrate. After slaughtered, rumen pH and weight of carcass and forestomachs were determined immediately. Average alfalfa intake was 118 g/d before weaning, and 345 and 289 g/d (P=0.365) for FF and CF after weaning, respectively. Starter intake was not affected by early supplementation of alfalfa (P=0.195), but intake of cereal powder tended to be higher in FF group than in CF (258 vs 209 g/d, P=0.051). Average daily gain was 69% (P=0.001) and 12% (P=0.006) higher in FF than that in CF before and after weaning, respectively. Forage feeding before weaning resulted in higher carcass weight compared to cereal feeding (5.76 vs. 4.57 kg, P=0.005). No significant difference was observed in abomasum and reticulum weight between CF and FF (P>0.05), but rumen weight tended to be higher in FF than in CF (292 vs. 247 g, P=0.059), and omasum weight increased by 24% (P<0.05) in FF than in CF. Differences in rumen pH and serum concentration of glucose and β-hydroxybutyrate were not observed between two treatments (P>0.05). From the present study, it is inferred that supplementation of alfalfa in starter diets is beneficial to growth performance and forestomach development in weaned lambs. 

Keywords: alfalfa, lamb, starter