NR 13. Milk production and liveweight change of crossbred cows with partial substitution of concentrate feed by leucaena (Leucaena leucocephala) meal

Abstract

A study was conducted in a farm located at El Laberinto, Zulia state, Venezuela (10° 50’ N and 71° 49’ W; tropical dry forest) to evaluate the effect of substituting 50 % of a 12 % crude protein (CP) concentrate feed (C) by leucaena meal 15 % CP on milk and liveweight change of twelve nonpregnant crossbred cows (6 predominantly Holstein and 6 predominantly Brown Swiss) the first 45 to 60 days of their third or fourth lactation and grazing Guineagrass pastures during a wet season (June to August). Supplementation treatments were: T1: control (no supplement); T2: T1 + C (1 kg/cow/day); T3: T1 + C (0.5 kg/cow/day) + leucaena meal (0.5 kg/cow/day). A latin square change-over experimental design blocked by predominant phenotypes was used. Milk productions (kg/cow/day) for T1 (8.6) and T2 (9.0) were similar (P>.05) but lower (P<.01) than T3 (9.7). LW gain (kg/cow/day) for T3 (0.344) was higher (P<.01) than those for T1 (0.235) and T2 (0.308), while T1 and T2 did not differ (P>.05). Brown Swiss phenotype cows had higher (P<.01) milk production (9.4) than Holsteinphenotype cows (8.8) LW gains (0.330 and 0.360, respectively) did not differ (P>.05).