Resumo

FARIA MARMOLL, Jesús; CHIRINOS, Zuleima  e  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.

Palavras-chave : Leucaena leucocephala; milk production; milk properties; cattle feeding; liveweight gain; bovine feeding.

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