232 Effects of bismuth subsalicylate and encapsulated calcium-ammonium nitrate on beef cattle performance and liver mineral concentration

Abstract

Abstract The effects of bismuth subsalicylate (BSS) and encapsulated calcium-ammonium nitrate (eCAN) on feedlot beef cattle performance and liver mineral concentration were evaluated. Two hundred Angus steers (BW = 385 ± 27 kg) were used in a randomize complete block design (block = BW) and allocated to 50 pens (4 steers/pen) where treatments were randomly assigned as follows: CTL (urea at 0.70%, 0.28% ruminally available sulfur [RAS]), NIT (eCAN at 2.0%, 0.28% RAS), UBS (urea at 0.70%, BSS at 0.33%, 0.28% RAS), NITBS (eCAN at 2.0%, BSS at 0.33%, 0.28% RAS), and LOW-S (urea at 0.70%, 0.14% RAS). Steers were fed for 171 d and weighed every 35 d. Dry matter intake (DMI) was recorded weekly. Liver biopsies were taken on d -5 and 124 from the same randomly selected animal per pen. The MIXED procedure of SAS was used with the fixed effect of BSS, eCAN, S, BSS × CAN, and the random effect of block. Cattle consuming urea as non-protein nitrogen source (NPNS) had greater final body weight (FBW; P = 0.045) than cattle consuming eCAN. There was a NPNS effect where eCAN reduced DMI (P < 0.001) and average daily gain (ADG; P = 0.041), but did not affect feed efficiency (G:F; P = 0.876). There was a tendency for BSS to reduce DMI (P = 0.095), but not affect ADG (P = 0.436) or G:F (P = 0.876). The effect of S was also observed (P = 0.042) where LOW-S cattle consumed less feed than CTL. A reduction of final liver Cu concentration was observed (P = 0.042) where BSS reduced the concentration of Cu by 58%. Bismuth subsalicylate did not affect cattle performance; however, it might be detrimental to cattle consuming low Cu diets.