STUDIES ON ENERGY AND NITROGEN-METABOLISM OF PREGNANT AND LACTATING SOWS AS WELL AS SUCKLING PIGLETS .5. ENERGY AND NITROGEN-METABOLISM OF PREGNANT SOWS

The energy and nitrogen metabolism of pregnant sows was measured with the method of indirect calorimetry in dependence on the number of gestation (1, 2 and 4), on the energy supply (120, 100 and 80% of the requirement recommendation) and on the gestation stage. Values of maintenance requirement and of energy and nitrogen utilization for body deposition were calculated on the basis of results of energy and nitrogen metabolism. The energy maintenance requirement increased from 389 to 435 and 473 kJ metabolizable energy per kg LW(0.75).d with rising number of gestation. The heat production increased from 85(th) to 115(th) day of gestation by 6%. The efficiency of the partial energy utilization for the energy deposition amounted to 66% on the average. The efficiency of the partial utilization of digestible nitrogen for the nitrogen deposition was calculated to 75%. The nitrogen maintenance requirement values amounted to 0.5 and 0.4 g digestible nitrogen per kg LW(0.75).d in the 1(st) and 2(nd) half of gestation.