PSIII-10 - Flaxseed oil-based supplement alters water consumption and plasma fatty acid profile of beef heifers

Abstract: The objective of this study was to determine the effects of a flaxseed oil-based supplement (FlaxLic®, New Generations, SD) on reproductive parameters, feeding behavior, and lipid profile in beef heifers. Sixty crossbred Angus heifers (BW=397kg±5.2kg) were blocked by BW and antral follicle count and randomly assigned to two supplementation treatments: free-choice commercial lose mineral supplement (CON; n = 30) or free-choice flaxseed oil-based supplement (FLAX; n = 30) for 7 weeks (w). Heifers were individually fed via the Insentec feeding system (Insentec RIC, Hokofarm, Marknesse, Netherlands), where basal diet (TMR) and supplements were provided in separate feeders to measure supplement intake and feeding behavior. Further, water intake and behavior were measured via Insentec water system. Individual intake was compiled over 24h for each animal. Body weight, transrectal ultrasonography, and blood samples (BS) were collected weekly. On w5, heifers were enrolled in a fixed-time artificial insemination (FTAI) commercial protocol. Largest follicle diameter (LF) and corpus luteum (CL) presence were recorded weekly and on days of the FTAI protocol (d0, d7, and d9). Pregnancy diagnosis was performed 30d and 60d following AI. BS were analyzed for progesterone (P4) by radioimmunoassay (RIA) to determine puberty attainment before w5, and fatty acid profile was determined via gas chromatography-flame ionization detection. Heifers with a CL or P4 ≤ 1.0 ng/mL were considered pubertal. Data were analyzed using SAS 9.4. ADG was similar between groups (p = 0.90) but was affected by w (p < 0.01). TMR intake was similar in duration and quantity (p > 0.18) between groups. Supplement intake was greater (p < 0.01) for FLAX (0.73±0.03 kg/d) compared to CON (0.18±0.02 kg/d) and from w2 to w8 (p=0.01). Time spent consuming the supplements was greater for FLAX compared to CON heifers (62.65±2.11 vs 0.10±0.11 min/d, respectively) over the entire trial (p < 0.01). Further, FLAX heifers consumed less water than CON heifers (32.2±0.39 vs 33.93±0.35 kg/d, respectively; p=0.03) and from w2 to w7 (p=0.03). LF was not different between groups on any of the days of the protocol (d0, d7, d9; p >0.20). Additionally, P4 (p≤0.20), puberty attainment by w5 (p = 0.24), and pregnancy rates (p >0.48) were similar between groups. Concentrations of arachidonic acid (3.00±0.24 vs 2.32±0.19 mg/ml; p = 0.04), linoleic (60.11 ± 4.34 vs 40.35±4.04 mg/ml; p = 0.002), αLinolenic (16.73±0.26 vs 15.86±0.23 mg/ml; p=0.02), and total PUFA (130.52±5.97 vs 111.19±5.56 mg/ml; p=0.02) were greater on w8 for FLAX compared to CON heifers. Collectively, these findings did not show evidence that the flaxseed oil-based supplement affects variables that impact reproductive performance. However, it altered the plasma lipid profile, increasing omega-3, arachidonic, and linoleic fatty acids, as well as total PUFA.