Level of Fat from Canola Seed Supplementation in Pregnant Beef Cow Diets - Effects on Cow and Calf Performance

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Researchers from the University of Saskatchewan found that canola-fat based pellet supplementation in the diet of beef cows during late pregnancy led to greater growth of their calves from birth to slaughter, translating into 22 kg more carcass. The difference between the control diet and the fat-supplemented diet was the source, not the amount, of dietary energy. In the control diet energy came from hay, barley straw, and barley grain, while in the pellet-supplemented diet energy came largely from barley grain with a slight amount of the energy supplied by the hay and barley straw replaced by the fat-pellet.Expression of a gene that controls growth and muscle development was also affected by prenatal diet. This gene is also under the control of DNA methylation, a modification of DNA that can be altered by general nutrition, and sometimes permanently by prenatal nutrition. The difference in gene expression could indicate that fat supplementation during pregnancy has permanently altered the way genes are expressed in the calves of these cows, and this difference may be contributing to the growth difference in the calves.The proposed research will test the repeatability of these results, and find an optimal level of inclusion of canola-fat in the prenatal diet. Blood will be collected at birth, weaning, and slaughter from steer calves exposed to the prenatal diets to identify differences in epigenetic and metabolite profiles. Tissues fundamentally driving metabolism and growth will be collected at slaughter to determine if prenatal fat supplementation affects DNA methylation and gene expression within the tissues themselves. Blood DNA methylation and metabolite profiles measured at birth and weaning will be examined for use as predictors of postnatal growth, and patterns of DNA methylation and gene expression in metabolically important tissues. Understanding biologic and epigenetic pathways that underlie connections between prenatal nutrition and postnatal growth and development can lead to increased predictability of calf performance and novel strategies to improve postnatal growth.