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ARS Home » Northeast Area » Ithaca, New York » Robert W. Holley Center for Agriculture & Health » Research » Publications at this Location » Publication #76920

Title: INFLUENCE OF MONENSIN ON HOLSTEIN STEERS FED HIGH-CONCENTRATE DIETS CONTAINING SOYBEAN MEAL OR UREA

Author
item LANA, ROGERIO
item FOX, DANNY
item Russell, James
item PERRY, TED

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Rumen fermentation losses decrease the availability of nitrogen and energy to ruminant animals. The feed additive, monensin, was originally marketed as a methane inhibitor, but in vitro experiments indicated that it could also decrease wasteful amino acid deamination. Our experiments indicated that animals fed soybean meal responded better to monensin than animals fed durea, a non-protein nitrogen source. Based on these results monensin has the capacity to improve the nitrogen utilization of ruminants, decrease feed costs, decrease nitrogen excretion, and lessen the impact of ruminants on the environment.

Technical Abstract: Two growth trials were conducted to evaluate the effects of monensin on amino acid-sparing & feed intake pattern of feedlot cattle. When Holstein steers were fed a 90% concentrate diet supplemented with soybean meal (13.5% CP), the DMI, ADG & efficiencies of feed & protein utilization were greater than with urea (P < .10). Monensin improved ADG with both nitrogen supplements (P < .05), but the positive effects of monensin on efficiencies of feed & protein utilization were greater for soybean meal than urea (P < .20). Increasing amounts of monensin (0, 11, 22 ppm) caused a linear increase in DMI with urea, but the soybean diet with 11 ppm monensin had greater DMI (P < .10). Animals fed urea had greater within day feed intake variation than animals fed soybean meal (P < .05). Monensin increased the within day variation with soybean meal, but 22 ppm monensin decreased the within day variation with urea (P < .05). Monensin did not decrease within steer feed intake variation (P > .05). Holstein steers fed soybean meal at 13.5% CP had lower DMI & greater efficiencies of feed & protein utilization than steers fed 16.7% CP (P < . 10). Crude protein had no effect on ADG (P > .10). Monensin always increased the efficiencies of feed & protein utilization (P < . 05), but these trends were greater for diets with 16.7 than those with 13.5% CP. Monensin decreased DMI (P < .05), but this effect was greater for 16.7% than 13.5% CP. Because the positive effects of monensin on diet NEg (P < .10) & efficiency of protein utilization (P = .18) were greater for soybean meal than urea, it appeared that monensin was sparing amino acids.