Publication Date
1993
Description
In healthy ruminants, blood urea nitrogen (BUN) concentrations are positively correlated with ruminal ammonia nitrogen concentrations and are indicative of the protein to energy ratio in the diet. Our objective was to determine whether BUN could predict the biological response (average daily gain, ADG) to protein or energy supplementation in freegrazing steers and heifers on tropical grass pastures, Change in ADO (-0.0S to 0.30 kg) due to protein supplementation was linearly related to BUN concentration (6,2-15,5 mg/di) in control cattle (P<0.05, slope= 0.023, r = 0.69, s = 0.07 kg). BUN concentrations of 9-12 mg/di were a transition range ttow which ADG response to protein supplementation was greater (P«J.05) and above which ADG response was lesser (P<0, l 0) than the response within thls range. Change in ADO due to energy supplementation was not related to BUN in control cattle, but the range of BUN in our trials was limited to concentrations above 9 mg/di. Concentration of BUN may be a useful tool for predicting biological response to protein supplementation of grazing beef cattle.
Citation
Hammond, A C.; Kunkle, W E.; Bates, D B.; and Sollenberger, L E., "Use of Blood Urea Nitrogen Concentration to Predict Response to Protein or Energy Supplementation in Grazing Cattle" (2025). IGC Proceedings (1993-2023). 8.
https://uknowledge.uky.edu/igc/1993/session55/8
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Use of Blood Urea Nitrogen Concentration to Predict Response to Protein or Energy Supplementation in Grazing Cattle
In healthy ruminants, blood urea nitrogen (BUN) concentrations are positively correlated with ruminal ammonia nitrogen concentrations and are indicative of the protein to energy ratio in the diet. Our objective was to determine whether BUN could predict the biological response (average daily gain, ADG) to protein or energy supplementation in freegrazing steers and heifers on tropical grass pastures, Change in ADO (-0.0S to 0.30 kg) due to protein supplementation was linearly related to BUN concentration (6,2-15,5 mg/di) in control cattle (P<0.05, slope= 0.023, r = 0.69, s = 0.07 kg). BUN concentrations of 9-12 mg/di were a transition range ttow which ADG response to protein supplementation was greater (P«J.05) and above which ADG response was lesser (P<0, l 0) than the response within thls range. Change in ADO due to energy supplementation was not related to BUN in control cattle, but the range of BUN in our trials was limited to concentrations above 9 mg/di. Concentration of BUN may be a useful tool for predicting biological response to protein supplementation of grazing beef cattle.