Effect of phosphorus supplementation on the reproductive performance of beef cows grazing Brachiaria humidicola

The objective of this experiment was to observe and quantify the effect of two mineral mixtures, as free-choice feeding, one without (M) and other with phosphorus supplement (MP), an the productive and reproductive performance of Nellore beef cows grazing Brachiaria humidicola. This work was conducted at the Fazenda Modelo (Embrapa-Centro Nacional de Pesquisa de Gado de Corte), located in Terenos, MS, Brazil, in two phases, 1(st) from 1988/92 and 2(nd) from 1992/94. During the 2(nd) phase, stocking rate, for the dry period, and suckling days were reduced (from 1.0 to 0.5 cows/ha and 210 to 90 days, respectively). Mineral intake (M = 76 and MP = 112 g/had/day), forage phosphorus level (wet season = 0.16%; dry season = 0.11%), liveweight (1(st) phase: M = 363+/-3.3 and MP = 371+/-3.8 kg; 2(nd) phase: M = 407+/-5.7 and MP = 417+/-6.5 kg), birth percentage (1(st) phase: M = 67+/-3.3 and MP = 66+/-3.5; 2(nd) phase: M = 75+/-6.3 and MP = 80+/-5.7) and weaning of cakes (1(st) phase: M = 86+/-5.0 and MP = 91+/-5.3; 2(nd) phase: M = 55+/-6.4 and MP = 67+/-5.7) were measured. Beef cattle is not responsive to P supplementation.