EFFECT OF FOOD ALLOWANCE ON DIET SELECTIVITY AND INTAKE OF PEARL-MILLET (PENNISETUM-GLAUCUM) STOVER LEAVES BY SHEEP

The influence of food allowance or level of food excess on diet select ivity and intake by sheep given pearl millet stover leaves, and the po tential feeding value of the food leftovers (not eaten) (L) were studi ed. Animals were given food at four levels of L (100, 300, 500 and 700 g dry matter (DM) per day). All sheep received different food allowan ces (A, g DM per day) and had different L/A and A/M (g DM per kg M) ra tios. An additional treatment consisted of feeding the leftovers from the two highest levels of food excess to six rams to have 300 g DM of L per day. A diet supplement was given to provide sufficient rumen deg radable protein and sulphur to sustain microbial activity. Variances o f organic matter (OM) digestibility (OMD, g/kg) and intake (g/kg M0.75 ) of both DM (DMI) and digestible OM (DOMI) of the original millet lea ves were analysed using L, L/A, A/M and A/M0.75 as independent variabl es. Variation accounted for was highest when OMD was analysed as a fun ction of L/A (R2 = 0.34) and when DMI was analysed as a function of A/ M (R2 = 0.79) or A/M0.75 (R2 = 0.80). The response in OMD to varying L /A was best described by the equation OMD = 457 (s.e. 16) + 157 (s.e. 48) L/A. As L/A or A/M increased, L had a lower concentration of acid- detergent fibre and a higher in sacco OM disappearance. As A/M increas ed, DOMI and L/A increased following a diminishing return pattern. How ever, when A/M fell below 31.1 (s.e. 0.9) g DM per kg M, DOMI decrease d linearly. No differences (P > 0-33) were observed for OMD between th e original food (505 (s.e. 8) g/kg) and the re-fed leftovers (489 (s.e . 15) g/kg), but DOMI was lower with the latter (22.4 (s.e. 0.4) v. 20 .3 (s.e. 0.8) g/kg M0.75, P < 0.03). Results suggest that DOMI of mill et stover should be determined at L/A much higher than the traditional ly recommended (0-15), and support the hypothesis that farmers could b enefit from feeding millet stover at high allowances to animals of hig h economic value and give the leftovers to less valuable or less selec tive stock.