Abstract

FARIA MARMOLL, Jesús; CHIRINOS, Zuleima  and  MORILLO, David E. Effect of partial substitution of concentrate feed by grazing with Leucaena leucocephala on the production and characteristics of milk, and liveweight change of crossbred cows. Zootecnia Trop. [online]. 2007, vol.25, n.4, pp.245-251. ISSN 0798-7269.

At “La Esperanza” farm of the University of Zulia, located in Zulia state, Venezuela, 24 non-pregnant predominantly Holstein crossbred cows in the first 45 to 60 days of their third or fourth lactation were used to evaluate the effect of substituting 50 to 75% of concentrate feed (C) with 17% crude protein by grazing of a leucaena bank during 2 h/day (LB) on milk production and properties and liveweight (LW) gain. There were used 12 cows in the dry (DS) and wet (WS) season, respectively. The treatments during DS were: T₁: 1 kg of C/cow/day + LB; T₂: 2 kg of C/cow/day + LB, and T₃: 4 kg of C/cow/day. An additional treatment T₄, 2 kg of C/cow/day + LB during 2 h on alternate days, was evaluated during WS. A switch-back design was used in both seasons, with four (DS) and three (WS) cows per treatment and three 4-week periods. Basal diets were Brachiaria humidicola hay (DS) and grazing on Panicum maximum (WS) plus water and minerals ad libitum. Milk productions (kg/cow/d) for T₂ (10.5 and 10.8) and T₃ (10.8 and 11.1) were higher (P≤0.05) than those for T₁ (9.9 and 9.7) in DS and WS, respectively. During WS, T₄ (10.2 kg/cow/d) was higher than T₁, but similar to T₂ and T₃. Treatments were similar (P>0.05) for LW gain (360 and 423 g/cow/d), milk fat (3.5 and 3.6%), and protein content (3.3 and 3.4%), acidity (16.5 and 16.6 mL NaOH 0.1N/100 mL) nor density (1.030 and 1.029 g/mL) during DS and WS, respectively.

Keywords : Leucaena leucocephala; milk production; milk properties; cattle feeding; liveweight gain; bovine feeding.

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