Browsing by Subject "jalostusohjelmat"

The main objective of this thesis was to evaluate the possibilities to reduce enteric methane emissions from beef cattle by selection for residual feed intake. A Finnish Hereford population was used to model selection for residual feed intake by incorporating residual feed intake into the current breeding objective of beef cattle. The breeding structure of the population was modelled using the computer program ZPLAN. The data used to estimate the reduction in methane emissions from beef cattle was based on the Finnish nutrient requirements and the growth experiment of beef cattle. In the traits included in the breeding objective the achieved annual genetic gain was the highest in weaning weight and yearling weight. The annual genetic gain in the residual feed intake of young cattle and mature cows, which were selected indirectly through the residual feed intake of a post-weaning test, was relatively low. The annual genetic gain was undesirable in mothering ability and birth weight. The estimated enteric methane production was 4.93 tons per year for a herd of 35 cows. The annual reduction in enteric methane emissions due to genetic improvement in residual feed intake was 10.24 kg per a herd of 35 cows. A single round of selection reduced the methane production per a herd of 35 cows by 192.96 kg over a 25-year period. A single round of selection had no significant effect on the enteric methane emissions from beef cattle over a 25-year period. However, with continuous selection for residual feed intake, the annual reduction in methane emissions from beef cattle is cumulative. Therefore, considering long term selection for residual feed intake, it might be possible to achieve significant reduction in methane emissions. In the future, selecting residual feed intake in beef cattle might have an even more important role in improving the environmental efficiency of Finnish beef production assuming that the beef production based on suckler cows will increase.