In vitro methods for laboratory estimations of feed degradation are important tools for studying ruminant nutrition. These methods measure either substrate disappearance or fermentation products, the exact nature of which depends on the nature of the feed and the system being used to determine the digestibility. Consequently, there is a need for comparisons of in vitro and in vivo results, especially when new feeds are being assessed. The following study compared the gas production procedure to whole tract digestibility measurements for a range of alternative crop silages.

Round bale silages were prepared from five different alternative crops, red clover, lucerne clover, lotus, kale and a barley/pea bicrop, harvested at difference growth stages (Table 1). Freshly cultured Lactobacillus plantarum was used as an inoculant on half the material from each kale and barley/pea bi-crop harvest, and applied at a rate of 106 colony forming units per gram fresh forage.