The influence of partial replacement of barley with dietary fat sources on growth and feed conversion efficiency of growing bulls

This paper presents animal performance and carcass quality in an experiment conducted to observe the effect of replacing some of the barley in a concentrate mixture with different fat sources and wheat bran. The treatments were: concentrate mixture with no added fat (control); in the test feeds, some of the barley was replaced with 5 % of a fat source plus 10 % wheat bran, 1 % wheat molasses and 1 % Ca-lignosulphonate. The fat sources were rapeseed oil (RSO), calcium salt palm fatty acids (CaSFA), or tallow (TS). These four concentrate mixtures were fed to growing bulls with hay (45:55) at a rate of 85 g dry matter kg-1 metabolic body weight (W0.75). Partial replacement of barley with different fat sources slightly decreased dry matter intake and thereby reduced the daily intake of estimated metabolizable energy in all fat containing diets. Average daily weight gain was 1.20; 1.05; 1.05 and 1.08 kg for the control as to RSO; CaSFA and TS, respectively. Carcass weight was similar for all fat sources but slightly higher for the control diet, while dressing percentage was slightly lower for the control diet. Feeding RSO, TS or CaSFA had no effect on feed conversion efficiency in comparison to the control. No apparent difference was observed between treatments on carcass quality and palatability scores of the meat. Oleic and stearic acids were increased for RSO and TS containing diets as compared to the control and CaSFA containing diets