Cattle reproductive performance in the Paiaguás subregion of the Brazilian Pantanal. III. Effect of mineral supplementation on cow's reproductive and weight variables

Avaliou-se o efeito da suplementação de sal comum (SC), SC + fosfato bicálcico (SP) e SP + enxofre + Co, Cu, I e Zn (SPM) sobre o intervalo entre partos (IP), peso ao parto (PP), peso à desmama (PD) e peso à concepção (PC) de vacas de cria azebuadas, na sub-região dos Paiaguás. O experimento, um fatorial 3 x 3, em delineamento inteiramente casualizado, foi iniciado em julho/79, com 300 vacas em 990 ha de pastagem nativa, e foi concluído em maio/84. A análise de variância evidenciou efeito significativo (P < 0,05) da suplementação com SP e SPM sobre PP, PD e PC, mas não sobre IP. Não houve diferenças entre SP e SPM. O consumo médio de P nos tratamentos SP e SPM foi de c. 7 g/UA/dia. Concluiu-se que a resposta ao fosfato bicálcico, em termos de desempenho reprodutivo, foi limitada por deficiências de nitrogênio e/ou estacionalidade das pastagens. The effects of supplementation of common salt (CS), CS + dicalcium phosphate (SP) and SP + sulphur + Co, Cu, I and Zn (SPM) on the calving interval (CI), calving weight (CaW), weaning weight (WW) and conception weight (CcW) of zebu cows were studied in native pastures of the Paiaguás subregion in the Pantanal Mato-grossense, Brazil. The experiment, a 3 x 3 factorial arrangement, in a completely randomized design, was iniciated in July, 79, with 300 cows on 990 ha of native pastures, and was concluded on May 84. The analysis of variance showed significative (P < 0.05) effects of suplementation with SP and SPM on CaW, WW and CcW, but not on CI. There were no differences between SP and SPM. Phosphorus average intake in treatments SP and SPM was of 7 g/AU/day. It was concluded that the cows' reproductive performance response to dicalcium phosphate was limited by nitrogen deficiencies and/or pasture seasonality.