44 Pre-transit vitamin C injection improves post-transit performance of beef steers

Abstract

Abstract This study sought to determine the effects of injectable vitamin C (VC), pre- or post-transit, on blood parameters and feedlot performance of beef steers. Seventy-two, Angus-cross steers were blocked by weight (356 ± 18 kg) and randomly assigned to intramuscular injection treatments (20 mL/steer): saline pre- and post-transit (CON), VC (Vet One; 250 mg sodium ascorbate/mL) pre-transit and saline post-transit (PRE), or saline pre-transit and VC post-transit (POST). Following pre-transit injections (d 0), steers were transported for ~18 h (1,675 km). Upon return (d 1), steers received post-transit injections and were sorted into pens (6 steers/pen) equipped with GrowSafe bunks. Steers were weighed on d 0, 1, 7, 30, 31, 56, and 57. Blood was collected on d 0, 1, 2, and 7. Data were analyzed as a randomized complete block design using ProcMixed of SAS (experimental unit = steer; 24 steers/treatment); treatment and block were fixed effects. Blood variables were analyzed as repeated measures. Injectable VC did not affect BW shrink due to transit (P = 0.28). Compared to CON-steers, PRE or POST-steers exhibited greater dry matter intake from d 31-57 and overall (d 1-57; P ≤ 0.02). Average daily gain was greatest for PRE-steers from d 7-31 and overall (P ≤ 0.05), resulting in PRE-steers being heaviest on d 30/31 (P = 0.03) and tending to be heaviest on d 56/57 (P = 0.07). Plasma ascorbate concentrations were decreased immediately post-transit for CON and POST-steers but increased for PRE-steers (treatment × day; P < 0.01). Plasma ferric reducing antioxidant potential and malondialdehyde were decreased post-transit while serum non-esterified fatty acid and haptoglobin were increased; all blood parameters returned to baseline by d 7 (day; P < 0.01). Timing of injectable VC administration appears to influence how cattle respond to transit as pre-transit administration improved subsequent performance of steers.