392 Vitamin C and transit stress in beef cattle

Abstract

Abstract Transportation of cattle by road is unavoidable in beef production due to segmentation of the industry. Psychological and physical stress associated with transit can negatively impact cattle health and performance upon arrival at their destination. Thus, investigation of resiliency or recovery-based nutritional strategies to mitigate transit stress are warranted. Because oxidative stress is likely linked to transportation stress, one such strategy is antioxidants such as vitamin C (VC). Seventy-two Angus-cross steers (356 ± 18 kg) were used to determine the effects of a pre- versus post-transit VC injection on 56 d feedlot performance. Steers were randomly assigned to intramuscular injection treatments (24 steers/treatment): saline pre- and post-transit (CON), VC (Vet One; 250 mg sodium ascorbate/mL; 5 g sodium ascorbate/steer) pre-transit and saline post-transit (PRE), or saline pre-transit and VC post-transit (POST). Steers were transported for ~18 h (1,675 km) prior to sorting into pens equipped with GrowSafe bunks (6 steers/pen). Blood was collected from 12 steers/treatment on d 0, 1, 2, and 7 for analysis of plasma ascorbate concentrations. Plasma ascorbate concentrations were decreased by ~10% immediately post-transit for CON and POST-steers but increased for PRE-steers; regardless of treatment, concentrations were similar to pre-transit values by d 7 (treatment × day; P < 0.01). Steers that received VC at either timepoint (pre- or post-transit) exhibited greater dry matter intake from d 31–57 and d 1–57 compared to CON-steers (P ≤ 0.02). However, PRE-steers exhibited the greatest average daily gain from d 7–31 and d 1–57 (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). Based on these data, timing of nutritional intervention is vital for optimal effectiveness. Furthermore, nutritional strategies that improve antioxidant status prior to long-distance transit events may positively influence post-transit performance.