Abstract 479

Rivero,-R; Perez,-G; Sosa,-N; Combellas,-J

Inst. de Produccion Anim., Univ. Central de Venezuela, Maracay, Venezuela.

Tropical-Animal-Production. 1984, 9: 2, 114-121; 23 ref.

In 2 trials 18 Holstein-Friesian and Brown Swiss heifers with av. initial weight 215 kg were offered sorghum silage to appetite with (i) ground sorghum (+ 2% minerals and 1% salt) at 1, 2 or 3 kg, or (ii) concentrate (15.7% crude protein) at 2, 3 or 4 kg daily. The silage contained about 8% crude protein and organic matter digestibility was about 58%. In the 1st trial av. daily weight gain increased from 0.09 to 0.26 and 0.42 kg as the amount of ground sorghum increased; in the 2nd trial av. daily gain increased from 0.67 to 0.87-0.94 kg as the amount of concentrate increased from 2 to 3-4 kg. In both trials silage DM intake fell by 0.4-0.5 kg for every kg increase in concentrate. In a 3rd trial 24 cows were offered sorghum silage with concentrate (22.8% crude protein) at 9 or 5 kg/day, or elephant grass with concentrate at 9 kg/day. Daily milk yield averaged 13.6, 10.9 and 12.2 kg resp., with a significant difference between silage treatments; weight gains were similar on all treatments. Roughage intakes were low on all treatments; increasing concentrate intake by 1 kg decreased roughage intake by 0.62 kg. The results underline the importance of adequate supplementation when feeding heifers or medium-yielding cows with sorghum silage.