Possibilities for forecasting the exchange energy of feed and concentrate mixtures through the level of gas production

Abstract

The study aims to establish the value of the exchangeable energy of grain, protein, and roughage feeds, as well as concentrate mixtures, through the level of their gas production. The experiment was conducted at the Experimental Base of the Agricultural Institute, Stara Zagora. During the experiment, three types of rations were tested: control, high-energy (based on corn grain), and high-protein (based on soybean meal). The Latin square method was applied, with the preparatory period of each animal when switching from one ration to another being 7 days, and the experimental period being 5 days. During the experiment, the tested rations were analyzed using the Gas Production System ANCOM RF /Ankom®, Tech. Co., Fairport, NY, USA, for which the rumen contents of the animals were taken in the morning (09:00).

In the study conducted using the gas production method at the 24^th hour of incubation, the following values of exchange energy were obtained for the individual feed and concentrate mixtures:

When feeding the experimental animals with a control mixture, the exchange energy of alfalfa hay was established at a value of 9.19 MJ/kg CB at the 24^th hour of incubation. When receiving a high-energy mixture, the OE level was 11.54 MJ/kg CB, and for the high-protein mixture, it was 11.12 MJ/kg CB. For wheat, the OE was established at 9.75 MJ/kg CB, for barley – 8.02 MJ/kg CB, and for corn – 8.85 MJ/kg CB, when feeding the experimental animals with a control mixture. The highest amount of OE is in wheat – 11.87 MJ/kg BW and barley – 12.09 MJ/kg BW when giving a high-energy mixture to the experimental animals. In corn, the value of metabolic energy is 9.81 MJ/kg BW. When feeding a high-protein mixture, a metabolic energy of 11.92 MJ/kg BW was established in barley. When receiving a control mixture from the experimental animals, a value of OE at the 24^th hour was established for sunflower meal of 9.03 MJ/kg BW, and for soybean meal, 12.34 MJ/kg BW. In the high-energy mixture, the values are 10.18 MJ/kg BW and 16.65 MJ/kg BW for both types of meal. In the high-protein mixture, ME is 12.0 MJ/kg BW for sunflower meal and 14.22 MJ/kg BW for soybean meal. The exchangeable energy according to the gas released at the 24^th hour of incubation is 8.85 MJ/kg BW for the control mixture, 9.01 MJ/kg BW for the high-energy mixture, and 9.41 MJ/kg BW for the high-protein mixture when feeding the rams with the control mixture. When feeding a high-energy mixture, these values are – 11.21 MJ/kg BW for the control, 10.49 MJ/kg BW for the high-energy, and 10.02 MJ/kg BW for the high-protein mixture. When feeding the animals with a high-protein mixture, 10.38 MJ/kg CB was obtained for the control mixture, 10.75 MJ/kg CB for the high-energy mixture, and 9.82 MJ/kg CB for the high-protein mixture.