EFFECT OF RUMEN FILL ON VOLUNTARY FOOD-INTAKE AND PATTERN OF EATING IN HOLSTEIN STEERS

The influence of rumen capacity on voluntary food intake and eating pa ttern were determined using three Holstein steers (683 kg, 744 kg and 850 kg) fitted with large rumen cannulae. They were fed ad libitum on hay (degradation characteristics a = 35.2, b = 0.0397) in a 3 x 3 chan ge-over Latin square design comprising seven periods of five days each . Periods 1, 3, 5 and 7 were controls while 2, 4 and 6 were treatments during which rumen was totally emptied once daily, and (i) 15% (add), (ii) 25% (remove) or (iii) 100% (return of the digesta to the rumen). Fresh food teas served at 08.30h daily and rumen digesta manipulated at 11.30h. Mean hay daily dry matter intake (DMI) during control perio ds was 9.3kg/d Addition of 15% digesta significantly decreased (P<0.01 ) DMI while 25% digesta removal had no (P>0.05) influence. That these observations were not due to digesta manipulation was demonstrated by digesta return treatment, when all emptied digesta was replaced with n o significant effect on both intake and eating pattern of the Holstein steers.