Genetic variation of maize silage ingestibility in dairy cattle

During a three-year experiment, twelve registered or experimental maize hybrids were investigated for their ingestibility in dairy cows. Their digestibility values in sheep were also available from simultaneous experiments. Significant intake differences were observed between maize hybrids, ranging from 14.4 to 17.9 kg . cow(-1) . day(-1). The highest intake was observed for the bm3 hybrid. Among normal hybrids, DK265 had a higher ingestibility than other hybrids. However, two recently registered hybrids and an experimental hybrid had only little lower values of intake than DK265. In vivo NDF digestibility explained about 50% of the intake variation ( bm3 hybrid excluded), but in vitro cell wall digestibility (DINAGZ) explained only 25% of the intake in similar conditions. Ingestibility variation were probably related to both rate of cell wall degradation and friability traits, that are not relevantly measured through usual digestibility or lignin content estimates.