Milena Mihaylova1, Gancho Ganchev2 and Dimo Penkov3
1 Agricultural Academy, Agricultural Institute – 6000 Stara Zagora, Bulgaria
2 Department of Fundamental Sciences in Animal husbandry, Faculty of Agriculture, Trakia University – 6000 Stara Zagora, Bulgaria
3 Agricultural University – 4000 Plovdiv, Bulgaria, 12 D. Mendeleev Str.
Mihaylova, M., Ganchev, G. & Penkov, D. (2025). Assessment of net energy and protein utilization in fattened calves using the indexes “Clarc of energy distribution/protein transformation“. Bulg. J. Agric. Sci., 31(6), 1198–1202
The purpose of the study is to present an adapted methodology for calculating the net utilization of energy and protein along the chain “forage – edible meat” in the fattening of calves by using the newly introduced indices “Clarc of energy distribution (CED)” and “Clarc of protein transformation (CPT)”. Using data from scientific trials with calves of the Bulgarian Brown Cattle and Bulgarian Black-and-White Cattle breeds, the formulas for the calculations in detail are described, and real data for numerical values are presented.
Based on the results of scientific experiments of 207 days with fattened calves after sucking period (initial live weight 233.50±5.60 and final live weight 454.60±15.90 kg), the following values were established: CED (net energy fodder – gross energy meat) – 0.0569 (5.69%); CPT (protein digestible in the intestine from fodder – crude protein meat) – 0.1380 (13.80%).
The authors recommend introducing the indices as objective criteria in the following aspects: selection, technological, and ecological.