Effect of dietary protein source on net utilization of energy and protein in the carcass of fattening steers
Gancho Ganchev, Milena Mihaylova, Dimo Penkov
Abstract: A comparative study of the net energy and protein utilization of 2 groups of fattening calves from 200 to 407 days of age, which received nitrogen from different sources - urea and sunflower meal, was conducted. Newly introduced indices "Clarc of energy distribution (CED)" and "Clarc of protein transformation (CPT)" expressing the transformation along the chain "net energy/intestinally digestible protein in feed - gross energy/crude protein in boneless meat", were used.
The authors found a lower utilization of net energy for growth (CED = 5.78 against 7.22%), but a higher utilization of protein (CPT = 17.10 against 15.73%) in calves receiving forage protein via urea compared to those receiving it via sunflower meal.
Keywords: bulls fattening; Clarc of energy distribution/protein transformation; sunflower meal; urea
Citation: Ganchev, G., Mihaylova, M. & Penkov, D. (2026). Effect of dietary protein source on net utilization of energy and protein in the carcass of fattening steers. Bulg. J. Agric. Sci., 32(2), 435–439
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| Date published: 2026-04-29
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