161 Evaluation of cull sweet potato storage roots as a winter supplement to grazing for cow-calf pairs

Abstract

Abstract Cull sweet potato storage roots that would otherwise be left unharvested in production fields or dumped as waste from excess supplies in storage may be available for use as livestock feed at competitive pricing relative to other feedstuffs. Given this potential economical source of nutrients for consumption by beef cattle, the objective of this study was to assess cow-calf performance using unprocessed sweetpotato storage roots as a winter supplement to grazing cow-calf pairs as compared to whole cottonseed or no supplement. Fall-calving multiparous Bos taurus crossbred cows in Prairie, MS, were allotted ad libitum access to mixed-grass pasture with tall fescue as the predominant forage species and randomly allocated to one of three as-fed basis supplement groups: 6.8 kg/cow/d of sweetpotato storage roots (SWP); 2.3 kg/ cow/d of whole cottonseed (WCS); or no supplement (NONE). Supplements were offered to cows on a group basis on every Monday, Wednesday, and Friday for 93 d each winter initiating December 5, 2016 (n = 81) and December 11, 2017 (n = 105). Cow BCS on a scale of 1 to 9 (1 = emaciated; 9 = obese) at supplementation initiation was 6.1 ± 0.1. From supplementation initiation until calf weaning in March, change in cow BCS (P < 0.01) was greatest for NONE (-1.1 ± 0.1), intermediate for SWP (-0.7 ± 0.1), and least for WCS (-0.4 ± 0.1). Adjusted 205-d calf BW was 16.9 ± 3.8 kg heavier (P < 0.01) in steers than heifers but did not differ (P = 0.41) among supplementation groups. Although nursing calf performance was not impacted by supplementation regime, results suggest that cull sweetpotato storage roots may be an effective feedstuff for winter supplementation intended to reduce BCS loss in lactating beef cows. Additional research to determine optimal frequency and quantity of SWP supplementation is warranted