Enteric Methane Emission Intensity of Lactating Cows Fed Soy-hull

BURASCHI, L.; PALLADINO, R.A; TIERI, MARÍA PAZ; WILLIAMS, R.; RICCI, P.

Orlando

Conferencia; 8th International Greenhouse Gas and Animal Agriculture Conference; 2022

Buraschi L., Palladino A.R., Tieri M.P., Williams S.R.O., Ricci P. 2022. Enteric methane emission intensity and nitrogen excretion of lactating cows fed soy-hull. Soy hull (SH) is an important by-product of the Argentinean crop industry. Including it in ruminant?s diets will increase Carbon circularity of mixed crops-livestock systems, yet it may increase enteric CH4 production. The aim of this study is to evaluate if this by-product can be used as partial replacement of maize grain (MG) in the diet of lactating cows without negatively affecting their feed use efficiency and emissions. We hypothesized that the use of a high degradable fiber will improve energy and nitrogen use efficiency through higher fiber digestibility and rumen stability, allowing a better performance, lower CH4 emission intensity and Nitrogen excretion. Six Holstein lactating cows were fed a 50:50 (DM basis) corn silage:concentrate TMR (18% CP, 2.9Mcal ME) during two-25 days periods. Three replicated 2x2 Latin Squares were used to evaluate 2 concentrates, containing either 45% SH or 45% MG, in 2 periods at 60±7 and 84±7 DIM. Cows were housed in individual pens, and fed and milked twice daily. From day 18 to 21 samples of milk, urine, and feces were collected and blood was obtained on day 20 for further analysis of total Nitrogen, urea and creatinine. From day 22 to 25 cows were housed individually in 2 respiration chambers to determine enteric CH4 production. Feeds were sampled and DMI measured (offered ? refused) from day 18 to 25. Rumen content was collected through esophageal tubing on day 25 once cows leaved the chambers and at least 4 hours after feeding. Milk production from each milking was measured (weighted) throughout the experiment and sampled on days 24 -25 for further analysis. As preliminary results, we expect to observe 5% higher DMI of cows fed SH compared to MG diets, resulting in higher milk production and without impact on enteric CH4 emission intensity and Nitrogen excretion.