Hay treatments used in our study (Exp 1 and 2) were of the same grass species with their quality differing as a result of treatment with urea only, although, there was a possibility of slight differences in organoleptic properties between these treatments, intake rates for IRQ, SIRQ
, and PRQ hays were expected to be similar.
In-vivo digestibility of IRQ (n = 6), SIRQ (n = 6), and PRQ (n = 6) were determined over a 7-day period.
The model for rumen fill was: [RF.sub.ijk] = [mu]+[R.sub.i]+[P.sub.j]+BW+[[epsilon].sub.ijk], where: RF, rumen fill (wet matter, DM, NDF); [mu], overall mean; [R.sub.i], roughage quality effect (i = IRQ; PRQ; SIRQ); [P.sub.j], period of sampling effect (j = 0; 6; 12; 24 h or j = morning, afternoon and evening); BW, body weight; [e.sub.ijk], experimental error.
However, digestibility were +0.089 (IRQ) and +0.074 g/g DM (SIRQ) greater than for goats fed PRQ.
Dry rumen load was highest for goats fed SIRQ. Rumen load for NDF took values of 2.2 [+ or -] 0.32 kg/100 kg BW for all roughage qualities.