Resumo

GOMEZ ROSALES, Sergio; ANGELES, María de Lourdes; ROMANO MUNOZ, José Luis  e  RUIZ CORRAL, José Ariel. Estimation of enteric methane production in family-run dairy farms in the south of the State of Querétaro, Mexico. Rev. mex. de cienc. pecuarias [online]. 2020, vol.11, suppl.2, pp.18-33.  Epub 30-Jun-2020. ISSN 2448-6698.  https://doi.org/10.22319/rmcp.v11s2.4685.

The objective was to estimate the emission factor (EF) of methane (CH4) and the daily losses of gross energy (GE) converted to CH4 (LCH4), by means of prediction equations of the Level 2 method of the Intergovermental Panel of Climate Change (IPCC) or based on technical information from the family-run dairy farming system. The study was carried out in 10 farms, obtaining technical information on the type and quantity of the ingredients offered to the herd during three visits in different periods of the year. The technical information -body weight, milk production and amount of each ingredient consumed, together with laboratory analysis of dry matter (DM) and GE content of the sampled ingredients- was used to calculate the DM and GE intake; the EF and the PCH4 were estimated using the IPCC methodology. The same variables were estimated using the prediction equations of the IPCC. In cows in milking conditions, the EF (81 and 70, kg CH4 yr-1) and the LCH4 (2.95 and 2.56, Mcal d-1) obtained using the IPCC equations were similar to those obtained through the observations in the farms; the weighted EF per farm was similar (49.06 and 54.09, kg CH4 yr-1), but the LCH4 estimated using the IPCC equations was lower than that obtained through farm observations (1.11 and 1.97, Mcal d-1; P<0.01, respectively). In general, the use of technical information from the farms, made it possible to estimate the EF and to show a higher LCH4 per farm, and, consequently, a lower energetic efficiency, compared to the IPCC methodology.

Palavras-chave : Stable; Subsistence production; Ruminal fermentation; Environmental contamination; Energy loss.