Maternal and Lactocrine Programming of the Neonatal Gut

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There are over 15 million ruminants in Canada producing milk and meat, which contributes over 40 billion dollars to Canada's economy. The ruminants raised on approximately 50,000 farms throughout Canada follow the highest standards of animal welfare, however gastrointestinal (GIT) diseases and metabolic disorders in young stock are still serious threats to animal welfare and the profitability of agriculture. The first phase of my DG focused on characterizing the GIT and metabolic adaptations in food-producing ruminants postnatally, with an emphasis on colostrum, milk feeding and weaning regimens. Although this research has generated impact in the industry, it did not consider how maternal signals could influence offspring prenatally and via colostrum bioactivity. There is currently a paucity of research characterizing prepartum factors, including prepartum dietary management, that impact colostrogenesis in ruminants and consequently, the development of the offspring. Further, it is necessary to distinguish between prenatal programming - the effects of excess nutrient provision in the gestating animal and their subsequent effects on the developing fetus - and lactocrine programming - the transmission of bioactive factors from the dam to offspring via consumption of colostrum or milk that may be altered as a consequence of increased prepartum nutrient intake. The first hypothesis of this research is that colostrum bioactives can regulate GIT function and metabolism of the young ruminant. Extending my research program to also include prepartum programming, an additional hypothesis is that late gestation nutritional interventions can alter colostral bioactivity, which in turn alter GIT function and metabolism of the offspring (Objectives 2&3). Twin-bearing ewes are the suitable experimental model for both research objectives due to their reduced-management intensity and the ability to allocate genetically similar twin lambs into different postnatal treatments. This research will provide a comprehensive understanding of the integrated responses to signals the offspring receive prenatally or through lactation that may imprint metabolic and GIT thriftiness. The basic research from the DG proposal will be fundamental to designing more applied, NSERC Alliance driven research with cattle. Collectively, these research foci will enable us to meet our goal of developing nutrition regimens for ruminants during the prepartum period to produce high-quality colostrum and utilize colostrum and milk to improve ruminant development and prevent disease. This will benefit ruminant producers economically through improved growth and health, as well as create alternatives that reduce antimicrobials, effectively addressing the many current socio-economic and environmental concerns.