Effects of silage additives on intake, live-weight gain and carcass traits of growing and finishing dairy bulls fed pre-wilted grass silage and barley grain-based ration

SUMMARYThe effects of silage additives on performance of dairy bulls were determined in a feeding trial using 45 Nordic Red and 45 Holstein bulls. Both breeds were allotted randomly to three treatments: (1) timothy silage (TS) without additives + barley (CON); (2) TS with sodium benzoate, potassium sorbate and sodium nitrate-based additive + barley (SALT); and (3) TS with a mixture of mostly formic acid and propionic acid-based additive + barley (ACID). The bulls were fed total mixed rationsad libitum. During the experimental period of 259 days, the average dry matter intake was 10·1 kg/d and there was no difference among the treatments. The average live-weight gain (LWG) and carcass gain was 1363 and 741 g/d, respectively. There were no treatment differences in the carcass gain but LWG of the CON bulls was 5% higher compared with the SALT and ACID bulls. Carcass conformation score of the SALT and ACID bulls was 6% higher compared with the CON bulls. The experiment demonstrated that there was only a slight benefit from silage additives in animal performance when silage dry matter was 350–400 g/kg and silage was ensiled in round bales.