THE EFFECT OF DIET AND FREQUENCY OF WATERING ON RUMEN DEGRADABILITY AND OUTFLOW RATE OF LOW-QUALITY VELD HAY AND DRY-MATTER APPARENT DIGESTIBILITY IN STEERS GIVEN FOOD AT MAINTENANCE

The effect of water restriction on rumen degradability and outflow rat e of low quality veld hay and dry-matter apparent digestibility was in vestigated in four rumen cannulated Tuli x Friesian steers (mean weigh t 329 (s.d. 36.6) kg) given food at maintenance (metabolizable energy allowance (maintenance) (MJ) = 8.3 + 0.091 M). Two diets with 20: 80 ( low, L) and 80 : 20 (high, H) roughage to concentrate ratios were used in combination with free access to water for 2.5 h once daily or once every 3rd day. A 4 x 4 Latin-square design with a 2 (diets) x 2 (wate ring frequencies) factorial arrangement of treatments was used. The de gradation pattern of vein hay was Mot affected by the type of diet and the watering frequency. Although the effective degradabilities of hay in steers given the two diets were low (177 and 258 g/kg for L and H, respectively), they were significantly different (P < 0.05) from each other. However, watering frequency did not affect the effective degra dability of hay (218 and 217 g/kg). While the low roughage diet had a higher rumen outflow rate for Cr-mordanted hay than the high roughage diet (0.047 per h and 0.031 per h), this was not statistically signifi cant. The same outflow rate was obtained for the two watering frequenc ies (0.039 per h).