Genomic imprinting is a term applied to an epigenetic phenomenon where alleles are fully or partially inactivated depending on their parental origin. The relevance of this kind of parent-of-origin effects (POEs) for agriculturally important traits is widely known. A model (imprinting model) with a transmitting ability (TA) as sire and a TA as dam has been proposed that provides an estimate of the imprinting variance, whether the allelic inactivation is maternal, paternal, full or partial. Although the model can be used in a reduced version, large data sets still prevent the imprinting variance from being estimated. To further reduce the size of the equation system, we developed a parsimonious imprinting model with genetic effects for male ancestors only, as the TA as dam is replaced by her father’s TA. This parsimonious model was applied to 1 366 160 Simmental fattening bulls with slaughter data available on killing out percentage, net BW gain, EUROP class and fat score in a linear and generalised linear version. The pedigrees contained up to 2 637 761 ancestors. Proportion of the total genetic variance attributed to POEs ranged between 8.6% and 17.0%. On average, the maternal gamete accounted for the greater proportion of the imprinting variance. An equivalent version of the parsimonious model facilitated the estimation of POEs with reliabilities ranging between zero and 0.97.

Cross-breeding with European beef breeds has become a standard approach for the intensification of smallholder cattle production in Indonesia. This study assessed the environmental impact of cross-breeding, in terms of Global Warming Potential (GWP) and land use. We sampled 90 local Ongole and 162 cross-bred (Simmental × Ongole) cattle farms in four study areas. Expressed per kilogram of live weight of young stock produced, GWP (26.9 kg CO2–equivalents) and land use (34.2 m2) of farms with Ongole breeding stock were not significantly different from the GWP (28.9 kg CO2–equivalents) and land use (37.4 m2) of cross-bred farms. Cross-bred young stock grew faster, but in general cross-bred cattle required more feed. In the current smallholder production system, the dominant cross-breeding practice of using Simmental semen on Ongole and F1 cross-bred cows does not result in lower greenhouse gas emissions or land use per kilogram of live weight produced compared with farms with Ongole cows. The advantage from the faster growth of cross-breds is counteracted by the higher emissions from feed production for cross-breds.