STUDIES ON IMPROVING BEEF TESTING SYSTEMS ON STATION .2. AUTOMATION OF FEEDING OF STANDARDIZED TEST DIET

The aim of this study was to prove an automation of beef testing proce dures on station by feeding a 2 component diet of a fixed amount of co ncentrates and treated straw cobs ad libitum through an adapted transp onder-feeding system for dairy cows. Besides studying the general feas ibility of transponder feeding systems for beef testing procedures it should be evaluated whether group feeding at one transponder station w ould affect feed intake and growth performance and furthermore to what extent the housing system (slatted floor, straw bedding) would influe nce the testing results. In total the experiment consisted of 4 groups of 9 bulls each with one transponder station, 2 groups on slatted poo r and 2 groups on plane floor with straw bedding. There was no greater technical problem in adapting a dairy transponder feeding system to t he needs of growing young bulls. The development of a feed back mechan ism of the straw cob supply with the uneaten feed rest through an infr ared feeler fixed in the bottom of the feeding bowl could prevent a sa livation of the cobs and improve the accuracy of the feed intake measu rements. The planned fattening strategy with a semi intensive prefatte ning phase of 200 days could be verified in case of keeping the bulls on straw bedding. In case of slatted floor housing, however, a signifi cantly increased intake of treated straw cobs was observed leading to an unwanted increase of early growth and subsequently to an unwanted d egree of fatness at the later slaughter stage. Thus the testing diet h as to be adapted to the housing system by adjusting the fixed amount o f concentrates. With regard to animal behaviour aspects a housing syst em with bedding should be preferred however, the bedding material shou ld be of very law digestibility to minimize uncontrolled roughage inta ke. Group feeding at one transponder station doesn't have a greater im pact on either feed intake or growth performance. All relevant rank co rrelations were low and statistically insignificant. The observed vari ability in roughage feed intake was at 8.3% slightly higher as observe d in other feed intake studies based on a comparable source of roughag e diet. The use of the described feeding system in beef testing on sta tion has to be evaluated positively without restriction. By this it wo uld be possible to record the animals individual voluntary roughage in take capacity in a feeding system that simulates a roughage based fatt ening system similar to commercial farm conditions. Simultaneously an automation of the feeding processes would allow an accurate recording of feed intake throughout the testing period. The examined testing sys tem may also be applied for performance testing on station.