Use of Leucaena leucocephala in a silvopastoral context for cattle production

Jesús Manuel Iglesias Gómez
Estación Experimental de Pastos y Forrajes Indio Hatuey, Central España Republicana 44280, Matanzas, Cuba

ABSTRACT
Two trials were conducted at the Pasture and Forage Research Station “Indio Hatuey”, located in the Matanzas province, Cuba, on a Ferralitic Red soil, without irrigation, in order to evaluate the utilization of Leucaena leucocephala in protein bank systems and association with pastures for beef production and as alternative in the rearing of growing heifers for replacement. The fattening trial was conducted between April 25, 1988 and May 11, 1989; and the second experiment was carried out three years later, in the period between April 7, 1992, and June 7, 1993. Two continuous fattening periods (initial and final) were evaluated, in which the following experimental treatments were compared: A) Association of Leucaena leucocephala cv. Cunningham with Panicum maximum cv. Likoni and creeping legumes in the whole area; B) Protein bank of leucaena, creeping legumes and Guinea grass Likoni in 25 % of the area + Guinea grass Likoni fertilized with 80 Kg of N/ha in the remaining 75 % of the area, and C) Traditional grazing system with Guinea grass Likoni in the whole area, fertilized with 80 Kg of N/ha. A completely randomized design was used, with 10 Zebu young bulls of 147 kg of live weight per treatment. For the initial fattening a stocking rate of 0,73 LAU/ha (2,5 bulls/ha) was used and in the final fattening, 2 animals/ha (1,2 LAU/ha). The live weight gains in the initial fattening were 0,820; 0,760 and 0,800 kg/animal/day for treatments A, B and C, respectively; in the final fattening the gains were 0,426; 0,301 and 0,276; while the cumulative gain of both periods was 0,623; 0,530 and 0,538, respectively; for which the live weight gains of the association in the final fattening and the cumulative gains were significantly higher (P˂0,05). In the dry season the echeloned pruning of leucaena was applied, which maintained its population stable; the same occurred with the botanical composition of the grasses and creeping legumes. In the second experiment the performance of the pastureland and of growing heifers since 12 months of age in two treatments: A) Association of leucaena with Guinea grass Likoni and herbaceous legumes and B) protein bank of leucaena and other herbaceous legumes plus Guinea grass Likoni as base pasture in 75 % of the area. A completely randomized design was used with 10 heifers, ¾ Holstein x ¼ Zebu, of 100 Kg of LW, per treatment and a stocking rate of 2,5 animals/ha (0,5 LAU/ha). The live weight tended to be higher at incorporation for the animals of the association (310,4 Kg), although it did not differ significantly from the one reached in the protein bank (292,3 Kg). The live weight gain until incorporation to reproduction was 488,3 and 449,1 g/animal/day, respectively, without significant differences. Leucaena kept its population practically stable, although a decrease was observed in the botanical composition of the grass; while the creeping legumes tended to increase. The results obtained in both trials confirm the possibility of using leucaena in silvopastoral systems of protein bank and association in the whole area for beef production and the rearing of replacement heifers, although it was proven that its use in associated systems is more feasible from the productive and economic as well as the management point of view in general.