| Abstract: | Three silages were prepared from perennial ryegrass; unwilted without additive (UW), unwilted treated with 3·5 litres commercial (85%) formic acid (UWA) and prewilted without additive (WN) with dry matter (DM) concentrations of 189, 209 and 328 g kg?1 respectively. The three silages were offered ad libitum in a 348-d feeding experiment to three groups of eight Belgian white-blue bulls with an initial live weight (LW) of 277 kg. The concentrate (47 g digestible crude protein (CP) kg?1) supplementation was 7·5 g (kg LW)?1. Acid treatment (UWA) slightly improved digestibility of all silage nutrients except CP, whereas wilting generally slightly decreased digestibility of the nutrients except DM and ether extract. The daily LW gain averaged 912 g and was not significantly different on the three different treatments. DM intake per (kg LW)0.75 was higher with the UWA silage, 69·3 g, and with the WN silage, 71·6 g, than with the UW silage, 65·8 g. However, this difference in DM intake was not reflected in either daily LW or carcase gain. The DM of UW silage was more efficiently utilized than DM of UWA or WN silage. |
