Early-life experiences, including the intrauterine thermal environment, can profoundly influence fetal growth and development and exert long-term effects on postnatal disease and productivity. In utero heat stress, for instance, adversely alters dairy cattle growth, immune response, and lactation even years after the initial event occurred. These heifers are less likely to survive to lactation and produce less milk across their first, second, and third lactations relative to in utero thermoneutral counterparts. Producers who raise in utero heat-stressed heifers are investing large sums of money (rearing costs). Moreover, these animals have a chance in being culled earlier, thus hampering economic and environmental sustainability of the dairy sector. However, for now, the only way to know if a heifer has been impacted by in utero heat stress is to wait until the end of the animal’s first lactation, which occurs when the animal is around 3 years old. An epigenetic analysis at birth could identify heifers that were in utero heat stressed without having to wait three years.
Ultimately, the project would generate new markers to help all Quebec dairy producers selecting animals to raise to optimize their durability as we face climate change.
Genome Centre: Génome Québec
Dairy Farmers of Canada