140 Effects of ɷ-3 PUFA supplementation during late gestation to first-calf beef heifers on physiological and performance responses of offspring

Abstract The objectives of this experiment were to evaluate the effects of ɷ-3 PUFA supplementation to late gestation first-calf beef heifers on milk and immunoglobulin production and performance and physiological responses of the offspring. Non-lactating, pregnant Angus heifers (n = 44) were ranked by age, body weight (BW), and body condition score (BCS) and allocated to receive DDG + 1 of the 2 treatments: 1) 234 g/heifer per feeding of Ca salts of PUFA based on eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids (OMG, Strata; Virtus Nutrition LLC, Corcoran, CA; n = 22), 2) 234 g/heifer per feeding of Ca salts of saturated and monosaturated fatty acids based on palmitic and oleic acids (CON; EnerGII, Virtus Nutrition, LLC; n = 22; Table 1). The animals were gathered each week on Mondays, Wednesdays, and Fridays and individually fed DDG + treatments. Immediately after calving, heifer-calf pairs were removed from their respective treatments and assigned to the general management of the research herd until weaning, which did not include fatty acid supplementation. Calves were transported to a feedyard for a 90-d preconditioning and feedlot receiving period. Initial cow BW and BCS were similar (P ≥ 0.49) among treatments. No differences were also detected (P ≥ 0.33) for BW or BCS change, and at calving BW or BCS (Table 3). No differences were observed between groups for average colostrum composition (P 0.37). However, there was an increase in colostrum fat percentage (P = 0.03) and a tendency of greater concentration of colostrum IgG (P = 0.08) in OMG heifers compared with the control group. No significant differences were observed among treatments at calving results (P 0.83; Table 3). However, a tendency was observed for crown to rump measure (P = 0.07). During the preconditioning period, there was a difference among groups for final BW (P = 0.04) and average daily gain (ADG; P = 0.05), remaining throughout the receiving phase among treatments for initial BW (P = 0.04), final BW (P = 0.04) and ADG (P = 0.05). A tendency (P = 0.09) for greater NEFA concentration and greater cortisol concentrations (P = 0.05) was observed in OMG vs. CON cohorts (Table 4, Table 5). Supplementation during late gestating first-calf beef heifers yielded similar outcomes on cow and offspring performance from birth to weaning; however, OMG calves were 6 kg heavier when compared with CON after being fed a high-energy feedlot diet, meaning that ɷ-3 PUFAs supplemented during late gestation might be an alternative to optimize feedlot responses of the offspring.