Influence of starch or fiber on realimentation of transit -stressed ruminants

Two studies were conducted to determine the use of soybean hulls as a replacement for corn in receiving/realimentation diets. The first study was designed to determine the effects of a starch-based (HS; corn) compared to a fiber-based (HF; soybean hulls) diet (15% CP) on 14 d realimentation performance of transit stressed lambs. All lambs were subjected to 48 h of feed deprivation. Lambs consuming the HS diet and a group of lambs consuming the HF diet were subjected to 10 h of transit (S), while a second group of HF lambs were not transported (NS). Gain performance was not different (P > 0.15) between treatments. Nitrogen digestibility was higher (P 0.10) between HF treatments. Cumulative nitrogen retention was greater (P 0.10) between HF treatments. Glucose concentrations tended (P < 0.15) to be higher for SHS compared to SHF during d 7 and 14 of realimentation, while NEFA concentrations were higher (P < 0.05) for SHF during d 2 and 3 of realimentation. The second study was designed to determine the influence of soybean hulls compared to rolled corn on gain performance and blood metabolites in newly received feedlot steers. Newly arrived Angus steers (n = 174) were randomly assigned to one of three receiving diets for 59 d. Oat silage-based diets (11.75% CP) consisted of: (1) rolled corn (RC) and soybean meal (HS), (2) soybean hulls (SBH) and soybean meal (HF-SB), and (3) soybean hulls and dried corn gluten feed (HF-Z). Steers consuming the HF diets had greater (P < 0.05) DM and estimated ME intake during the first 28 d, but ADG and gain:feed ratio was not different (P > 0.10). Cumulatively, no differences were detected for MEI, ADG or gain:feed ratio over the 59 d feeding period. Estimated net energy values, calculated from performance and intake were similar between SBH and RC (P > 0.10). Blood chemistry showed that HF-Z increased glucose levels (P 0.10) from HS. The HS steers had higher (P 0.10) from HF-Z. Steers consuming the HF-SB diet had higher PUN levels compared to HS on d 7, but were similar at all other times. Based on gain performance, soybean hulls are a viable replacement for corn in receiving/realimentation diets. Soybeans should be used with caution on ruminants with marginal or inadequate nitrogen or glucose status.