SUBSTITUTION OF UREA BY HOME-MADE PROTEIN MOLASSES (HPM) AS A SUPPLEMENT FOR DAIRY-COWS FED SUGAR-CANE - EFFECT ON MILK-YIELD AND SUGAR-CANE FIBER DIGESTIBILITY

Three experiments were carried out with I crossbred Holstein cows fed whole sugar cane (S. officinarum) plants as a basal diet for studying of sugar cane on supplementing A) 9 kg of IIPM; B) the effect on milk production and fibre digestibility 4.5 kg of IIPM + 100 g of urea and C) 200 g of urea. In the first experiment, 9 stabulated cows with a daily yield of 12 kg received 1% of their liveweights as forage (DB) and concentrates from 8 kg, of milk onward (0.46 kg/kg). In the second, 18 cows with a daily yield of 8 kg of milk and on star grass (C. nlemfuensis) grazing, received 0.5 kg of concentrates. In the third, 3 dry rumen cannulated cows, stabulated in individual cubicles were fed ad libitum forage in the morning. A Latin square design replicated in the first two experiments and a split plot in a Latin square in the third one was used. Milk yield (Exp. I) was higher (11.6 kg) when I IPM was supplied instead of urea alone (10.7 kg/lg) while the combination of both had an intermediate position (10.8 kg). There were no differences between treatments in experiment II(7.1, 7.0 and 7.0 kg for A, B and C, respectively). Total DM consumption (Eup. I) was higher when IIPM was supplemented. The same did not occur with cannulated cows (14.7; 15.0; 13.6 and 14.3; 14.1; 14.2, kg for A, B and C, respectively). Fibre digestibility of sugar cane increased with incubation time but did not differ between treatments. The cost of the additional kg of milk on supplementing IIPM instead of urea (15.6 Cuban cents) was economically Favourable. The substitution of urea by HPM as a supplement for dairy cows with a milk yield of 12 kg fed whole ground sugar cane is considered advantageous.