Research communication: comparison of calf faeces and rumen digesta as inoculum to measure in vitro digestibility using the gas production technique

< 0.53), although modelling indicated that incubations using faecal and rumen inocula from pre-weaned calves had similar lag times and rates of degradation. In weaned calves, aged 13 weeks, faecal incubations produced less gas, lag times were longer, and the rate of degradation of the slowly degradable fraction of calf starter was slower, compared to rumen incubations. Weak relationships, and kinetic differences, between rumen and faecal inocula would likely hinder the use of faeces to model calf rumen fermentation.