Avaliação nutricional e metabólica de vacas nelore suplementadas ou não no periparto

The objective of this study was to evaluate the effect of supplementation during pre- and/or post-calving on performance, nutritional and metabolic characteristics of Nellore cows grazing Brachiaria decumbens. The experiment lasted 120 days from July to November, during dry season and dry – to – rainy transition period. For the experiment, 48 multiparous Nellore cows were used, with an average aged of 6 years. The average body weight (BW) and body condition score (BCS) at the beginning of the experimental period was 501±55 kg and 5.4±0.65, respectively. The experiment was carried out according to a completely randomized design, following a 2 × 2 factorial arrangement, where two supplementation strategies were tested, supplementation (1 kg/d of 20% of crude protein, CP) and no supplementation, during two periods, pre- and post-calving. Therefore, there were four treatments: supplementation during pre- and post-calving (PrePost), supplementation during pre-calving but not during post-calving (Pre), no supplementation during pre-calving but during post-calving (Post), and no supplementation during pre- or post-calving (Control). During the pre-calving, supplemented cows showed a higher intake of dry matter (DM), organic matter (OM), and CP, compared to cows without supplementation (P0.10), neither digestibility of neutral detergent fiber. Supplementation during post-calving showed an effect on intake of DM and OM when expressed as g/kg of BW (P0.10). Supplementation during pre- and/or post-calving did not affect (P>0.10) serum concentration of glucose, total proteins, albumin, globulins, blood urea nitrogen (BUN), non-esterified fatty acids (NEFA) and β-hydroxybutyrate (βHB). Similarly, there were no significant interaction between treatments and time when these variables were measured (P>0.10). However, the concentration of these variables changed significantly depending of the sampling day (P0,10), nem a digestibilidade da fibra em detergente neutro. A suplementação durante o pós-parto mostrou um efeito na ingestão de MS e MO quando expresso em g/kg de PC (P0,10). A suplementação durante pré e/ou pós-parto não afetou (P>0,10) a concentração sérica de glicose, proteínas totais, albumina, globulinas, nitrogênio ureico no sangue (BUN), ácidos graxos não esterificados (NEFA) e β-hidroxibutirato (βHB). Da mesma forma, não houve interação significativa entre tratamentos e tempo em que essas variáveis foram medidas (P>0,10). No entanto, a concentração dessas variáveis mudou significativamente dependendo do dia da amostragem (P