INFLUENCE OF DIFFERENT CRUDE PROTEIN AND ENERGY-LEVELS ON GROWTH AND CARCASS TRAITS OF SIMMENTAL BULLS .2. CARCASS AND MEAT QUALITY AND EFFECTS ON REQUIREMENT OF CRUDE PROTEIN

A total of 144 Simmental bulls were fed rations of maize silage and co ncentrate, differing in four levels of crude protein (CP) supply (mean daily CP intake (DCPI) during the total fattening period of 750 g (I) , 950 g (11), 1120 g (III) and 1320 g (IV)) and differing in three lev els of energy supply (feeding maize silage restrictively and 1.8 kg co ncentrate (A), maize silage ad libitum and 2.3 kg concentrate (B) and maize silage completed with ground corn ad libitum and 3.5 kg concentr ate (C)). All bulls were slaughtered with nearly the same live weight (LW) after the fattening period from 212 kg to 623 kg. The mean carcas s weight was 355 kg. The increasing energy supply significantly rised the fatty status from level A to B and C, but only slightly from level B to C. The different CP supply distinctly increased the fat depositi on from level I to III, too, whereas it was slightly reduced in level IV. These influences on the carcass quality are closely connected to t he growth rate of the bulls. The criteria of the meat quality were not altered due to the different CP and energy supply. The average daily gain (ADG) in dependence on DCPI were evaluated by regression of Readi ng and Broken-line model. In the fattening period 1 (212-357 kg LW) ma ximum ADG of 1520 g was calculated with a DCPI of 960 g (15.5 % CPi.DM of the ration or 13.5 g CP per MJME), in the fattening period 2 (358- 470 kg LW) the maximum ADG of 1560 g needed a DCPI of 1050 (13.0% CPi. DM of the ration or 11.5 g CP per MJME) and in the fattening period 3 (471-623 kg LW) the maximum AD G of 1145 g was calculated with a DCPI of 1000 g (11.9 % DPi.DM of the ration or 10.7 g CP per MJME). The CP supply was calculated for lower ADG on the basis of the CP-ME relation .