Abstract 127

Suarez,-S; Rubio,-J; Franco,-C; Vera,-R; Pizarro,-EA; Amezquita,-MC

Cent. Nacional de Investigaciones de Cafe, Chinchina, Colombia.

PasturasTropicales. 1987, 9: 2, 11-17; 11 ref.

In grazing trials in Chinchina, Colombia, 3- to 4-year-old Brown Swiss cows were grazed on Digitaria decumbens swards given 48.6 or 238.5 kg N/ha annually with or without either 2-hour access to L. leucocephala or daily supplementation with 6 kg concentrates/head. Grazing continued for 17 days with 34-day rest periods. On the pasture given only 48.6 kg N, liveweight rapidly decreased and lactation terminated after 176 days. The highest milk yield averaging 8.56 kg over 263 days was given by supplementing the diet with concentrates compared with 6.29 kg over 228 days from grazing alone and 7.70 kg over 248 days from supplementation with L. leucocephala. It was concluded that supplementation with L. leucocephala could economically increase milk production, CIAT lines 17481, 17482, 17491 and 17492 being the most productive, persistent and tolerant to grazing of 32 ecotypes compared in this region of Colombia.