Short communication: Heritability of methane production and genetic correlations with milk yield and body weight in Holstein-Friesian dairy cows.

Greenhouse gases originating from the dairy sector, including methane (CH), contribute to global warming. A possible strategy to reduce CH production is to use genetic selection. This requires genetic parameters for CH production and correlations with production traits. Data were available on 184 Holstein-Friesian cows. Methane production was measured in the milking robot during milking from December 2009 to April 2010. In total 2,456 observations for CH production were available. Milk yield (MY) and body weight (BW) were obtained at every milking from November 2008 to October 2010. In total 4,567 observations for milk yield and 4,570 observations for BW were available. Restricted maximum likelihood, using random regression models, was used to analyze the data. Heritability (standard error given in parentheses) for CH production ranged from 0.12 (0.16) to 0.45 (0.11), and genetic correlations with MY ranged from 0.49 (0.12) to 0.54 (0.26). The positive genetic correlation between CH production and milk yield indicates that care needs to be taken when genetically selecting for lower CH production, to avoid a decrease in MY at the animal level. However, this study shows that CH production is moderately heritable and therefore progress through genetic selection is possible.