PS5-23. Mitigation of Enteric Methane Emissions Using a Bromoform-based Feed Additive in Finishing Nellore Cattle.
Thaynara Paolla da Silva Freitas, Luiz Guilherme Santos de Oliveira, Bárbara Martins Brixner, Eduardo Fonseca, Augusto Marques Nardi, Pedro Souto Lamas, Igor Fávero, Ana Claudia D Exposti, André Garcia, Maria Bassani, Natalia Fernandes, Felipe Varella, Maria Prado, Luiz Oliveira, Guilherme Arnandes, Murilo Lima, Gerson Barreto Mourão, Diogo Fleury Azevedo CostaAbstract
The objective of this study was to evaluate the efficacy of a bromoform-based feed additive on enteric methane emissions and animal performance in finishing Nellore cattle fed a typical Brazilian feedlot diet. The experiment was conducted at ESALQ/USP (Piracicaba, Brazil) using 80 Nellore bulls (Bos indicus; 335 ± 19.2 kg BW) allocated to a randomized complete block design with two treatments: CONTROL (total mixed ration; TMR) and ADDITIVE (TMR supplemented with a bromoform-based additive). Animals were individually housed to allow precise measurements of intake and methane emissions. The feeding trial lasted 120 d (36 d adaptation and 84 d treatment). Methane emissions were measured using a GreenFeed system during three measurement periods. Performance variables included dry matter intake (DMI), average daily gain (ADG), and feed efficiency. Data were analyzed using mixed models with treatment as a fixed effect and initial BW as a random block (α = 0.05). The additive substantially reduced methane emissions. Methane production decreased by 50.4%, from 104.6 to 51.9 g CH4/d (P < 0.0001). Methane yield decreased from 12.59 to 6.63 g CH4/kg DMI (P < 0.0001), and methane intensity decreased from 77.18 to 39.55 g CH4/kg ADG (P < 0.0001). Hydrogen production increased from 0.41 to 2.55 g H2/d (P < 0.0001), whereas carbon dioxide production was not affected (P = 0.78). Animal performance was not negatively affected by the additive. Dry matter intake did not differ between treatments (P = 0.267), whereas feed efficiency improved by 5% (P = 0.043), with a tendency for greater ADG (P = 0.081). These results demonstrate that the bromoform-based feed additive is an effective strategy to substantially reduce enteric methane emissions in feedlot Nellore cattle without compromising productivity. Additionally, the improvement in feed efficiency suggests a dual benefit of mitigating the environmental impact of beef production while enhancing production efficiency.