The use of groundnut hay as a supplement for sheep consuming poor quality natural pasture hay

A 5 × 5 latin square design experiment using five male sheep (60–70 kg live weight) was carried out to assess the effects of supplementing poor quality veld hay with groundnut hay on intake, digestibility, rumen environment and digesta kinetics. Five diets were formulated in which veld hay with 1% urea was fed alone (Control) or together with 100 g, 200 g or 300 g groundnut hay (100Gnut, 200Gnut or 300Gnut, respectively) and groundnut hay fed alone (Gnut). The forages were coarsely chopped prior to feeding. The groundnut hay supplements increased total feed intake and in vivo digestibility of the diets (P < 0.05). Intake of veld hay tended to decline with increasing levels of groundnut hay in the diet. This decline in veld hay intake was however less than anticipated if there had been simple substitution. Supplementation increased the concentration of ammonia and volatile fatty acids in the rumen fluid, but had no significant effect on in sacco degradation of veld hay. Measurements using chromium-mordanted hay and Co-EDTA, showed that rumen digesta volume/pool size were not affected by supplementation, while digesta outflow rate was increased. In the absence of positive associative effects on digestion of the poor quality forage, the increase in digesta outflow rate was probably the mechanism facilitating an increase in feed intake.