Semina: Ciências Agrárias (Oct 2016)

Evaluation of grazing beef cows receiving supplements with different protein contents

  • Sidnei Antônio Lopes,
  • Mário Fonseca Paulino,
  • Edenio Detmann,
  • Luciana Navajas Rennó,
  • Ériton Egídio Lisboa Valente,
  • Carla Heloísa Avelino Cabral,
  • Victor Valério de Carvalho,
  • Josilaine Aparecida da Costa Lima,
  • Marcos Rocha Manso,
  • Hugo Colombarolli Bonfá

DOI
https://doi.org/10.5433/1679-0359.2016v37n5p3361
Journal volume & issue
Vol. 37, no. 5
pp. 3361 – 3372

Abstract

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The aim of this study was to evaluate the effects of supplementation with different crude protein contents on the productive performance of grazing beef cows during post-calving. Thirty-six beef cows, with age and average body weight of 5 years and 490±17.9 kg, respectively, were used. The experimental design was completely randomized. The treatments were: control = cows received only mineral mixture ad libitum; supplemented = cows received 1 kg d-1 of supplement containing 80, 200, or 320 g crude protein (CP) kg-1. There was no effect (P ? 0.16) of supplementation on voluntary intake. A linear effect (P < 0.02) of the CP content in the supplements was observed among supplemented cows, only for the CP intake. Supplementation did not affect (P ? 0.20) the total digestibility of organic matter, neutral detergent fiber corrected for ash and protein, and CP. Among supplemented cows, a positive linear effect (P < 0.01) of the CP content in the supplement was observed for the CP digestibility. Intestinal flow of microbial nitrogen compounds and efficiency of synthesis microbial were not affected (P ? 0.18) by treatments. Performance, milk yield and composition were not also affected (P ? 0.11) by treatments. Supplementation did not affect (P ? 0.52) non-esterified fatty acids, urea nitrogen and progesterone serum concentrations. It is concluded that supplementation of grazing beef cows during post-calving does not affect nutritional and productive performance.

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