Evaluation of grazing beef cows receiving supplements with different protein contents

Abstract

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. Key words: Beef cows. Intake. Nellore. Non-esterified fatty acids. Supplementation. ResumoObjetivou-se avaliar os efeitos da suplementação com diferentes teores de proteína sobre o desempenho produtivo de vacas de corte em pastejo durante o pós-parto. Foram utilizadas 36 vacas de corte com idade e peso corporal médio de 5 anos e 490±17,9 kg, respectivamente. O delineamento experimental foi inteiramente casualizado. Os tratamentos foram: controle = vacas receberam somente mistura mineral ad libitum; suplementados = vacas receberam 1 kg dia -1 de suplemento contendo 80, 200 ou 320 g de proteína bruta (PB) kg -1 . Não houve efeito (P ≥ 0,16) da suplementação sobre consumo voluntario. Entre os animais suplementados, o consumo de proteína aumentou linearmente (P < 0,02) com o teor de PB no suplemento. A suplementação não afetou (P ≥ 0,20) a digestibilidade total da matéria orgânica, fibra em detergente neutro corrigida para cinza e proteína (FDNcp) e da proteína. Entre os animais suplementados, houve efeito linear positivo (P < 0,01) dos teores de PB nos suplementos sobre a digestibilidade da PB. O fluxo intestinal de compostos nitrogenados microbianos e a eficiência de síntese de proteína microbiana não foram afetados (P ≥ 0,18) pelos tratamentos. O desempenho, produção e a composição do leite não foram afetados (P ≥ 0,11) pelos tratamentos. A suplementação não afetou (P ≥ 0,52) as concentrações séricas de ácidos graxos esterificados, ureia e progesterona. Conclui-se que a suplementação de vacas de corte em pastejo durante pós-parto não afeta o consumo e ...

Energy-protein supplementation before and after parturition of Nellore primiparous cows in the Brazilian tropical savannah

“…Feed supplementation can reduce the nutritional stress and enhance the onset of ovarian cyclicity after calving. Bos indicus cows have a greater ability to retain and deposit energy, and supplementation of grazing cows improves the nutrient utilization (Lopes et al 2016). The combination of cow and calf performance in a Zebu herd in Africa management under similar conditions of the present study showed the best results when the dams were treated before and after calving with supplement content cottonseed cake and molasses (Sidibé-Anago et al, 2008).…”

Performance, metabolic and hormonal responses of grazing Nellore cows to an energy-protein supplementation during the pre-partum phase

“…In this study, NEFA concentrations were not affected by supplementation and these levels at calving indicate a higher adipose tissue rate of lipolysis [29,30]. The NEFA post-partum concentrations were lower compared to parturition, and remained at basal concentrations throughout the experimental period, which suggests the recovery of animals' nutritional status.…”

Performance, metabolic and hormonal responses of grazing Nellore cows to an energy-protein supplementation during the pre-partum phase

“…In this study, NEFA concentrations were not affected by supplementation and these levels at calving indicate a higher adipose tissue rate of lipolysis [43,44]. The NEFA post-partum concentrations were lower compared to parturition, and remained at basal concentrations throughout the experimental period, which suggests the recovery of animals' nutritional status.…”