Estratégias de suplementação em bovinos como alternativa para mitigação da produção de metano por fermentação ruminal

Abstract

The Brazilian beef cattle industry has world prominence due to its expressive productivity. The current scenario discusses how the activity contributes to the increase in the emission of greenhouse gases, such as methane. This concern affects the consumer market, which demands production that minimizes environmental impacts. Thus, the experiment was carried out with the objective of evaluating the ruminal fermentation parameters of cattle kept on pasture, using different supplementary strategies for methane mitigation. Five (5) crossbred cattle, with an average weight of 520 kg, equipped with permanent ruminal cannulas, were randomly distributed in a Latin square design (5x5). The animals were kept in individual paddocks in Urochloa brizantha, cv. Marandu (Syn Brachiaria), receiving daily supplementation in the morning, following the amounts (% BW) indicated on the product label (SP1=0.04; SP2=0.08; SP3=0.13; SP4=0.25 ; SP5=0.11). In total, the experiment was segmented into five periods lasting 12 days, with the collection of ruminal fluid on the 11th day, for evaluation of pH, N-NH3 and determination of the concentration of short-chain fatty acids, which served as to estimate enteric methane production following the methodology of Moss et al. (2000), where he calculated the generation of CH4 based on the proportions of acetic, propionic, and butyric acid, using the following equation: CH4= 0.45 (C2) – 0.275 (C3) + 0.4 (C4). The data obtained were submitted to SAS (Version 9.1.3, SAS Institute, Cary, NC 2004), checking the normality of the residues and the homogeneity of the variances by PROC UNIVARIATE. The experimental supplements did not show significant results for pH (P = 0.132), N-NH3 (P = 0.927) and for methane production (P = 0.148). However, there were significant results when we consider the time after supplementation for the variables pH (P = 0.004) and N-NH3 (P = 0.026), indicating interaction with the ruminal microbiota, which caused reductions in the production of acetic acid (P= 0.002). Supplements with higher NDT contents are the most suitable for the enteric methane mitigation strategy.