Potential Of Sorghum Silage As A Roughage Source In Sheep Diets

Dry season conditions are a major constraint to ruminant production in the Caribbean region, limiting both pasture quantity and quality. Preservation of forage as silage under favorable growing conditions is one means of stockpiling forage for dry season use. This pilot study compared growth and intake by hair sheep lambs fed sorghum silage with those fed native pasture green chop (predominantly Panicum maximum and Leucaena leucocephala). The silage samples were pooled from a sorghum variety/alley cropping trial, which were ensiled either with (3%) or without the addition of molasses. Fifteen wether lambs were assigned to the 3 treatment groups (n=5) and group-fed daily a diet of either green chop (GC), silage (S) or silage with molasses (S+H) and coconut meal (CH) at 5 and 2% of body weight on an as fed basis for 24 d following a 4-d adjustment period on a composite diet. Refusal of feedstuffs was recorded daily. Average daily gain was 110, 52 and 84 g/d for GC, S and S+H diets, respectively, and differences approached significance (P~0.15). Roughage dry matter intake was similar between treatment groups (263 to 287 g/d), but supplement intake varied from 232 g/d (S) to 364 g/d (GC). Total dry matter intake was 651, 495 and 550 g/d for CC, S and S+H, respectively. Despite the increased CH intake by GC, the gain/feed ratio was higher (0.169) compared Ito S (0.105) and S+H (0.152). Plasma urea nitrogen (PUN) increased by 9.3, 5,9 and 6.6 mg/dl from d 1 to d29 of the study for animals on GC, S and S-t·H diets, respectively. These preliminary data indicate that lambs receiving sorghum ensiled with molasses, but not plain sorghum silage, approached the growth rate of lambs receiving green chopped pasture.