Joint research on the precise determination of the energy and protein requirements of fattening pigs. 10. Comparative evaluation of the research for the precise determination of the energy and protein requirements of fattening pigs

Institutes from 5 CMEA countries took part in complementary joint investigations in order to ascertain the variance in energy and protein requirement and parameters of nutrient and energy metabolism with such fattening pigs as test animals as characterise the prospective breeding development in each of the countries and in order to establish the bases for the critical revision of the norms of energy and protein requirement for fattening pigs and, if necessary, their more precise determination. The most important conclusion drawn from the comparative assessment of the results presented in 9 articles is that due to wide variations in the energy and protein requirement values between the individual investigators as well as within the institutions themselves, norms of energy and protein requirement for fattening can only be adopted between countries when adequate investigations under the specific conditions of the individual countries justify this.     

Joint research on the precise determination of the energy and protein requirements of fattening pigs. 5. The effect of the crude protein concentration in the isocaloric diet on the fattening performance of swine of the Bulgarian Landrace

Live weight development and feed expenditure on 3 levels of crude protein supply and with isocaloric rations were investigated in scientific feeding experiments with 7 castrated male pigs each of the Bulgarian land race in the live weight range between 30 and 100 kg with a subdivision at 60 kg. The crude protein concentrations in the rations for the 3 groups were 17%, 15% and 13% in the first fattening period and 15% 13% and 11% in the second fattening period. In the two fattening periods the digestibility of the feed mixtures used was ascertained in experiments. The daily live weight gain in the three groups over the whole fattening period reached a high level of performance (836 g, 778 g and 757 g). The feed expenditure values were 3.3, 3.7 and 3.7 kg mixed feed (88% dry matter) per kg live weight gain. The highest protein supply resulted in the best weight gain performance and the lowest feed expenditure.