Can Associative Effects Affect In Vitro Digestibility Estimates Using Artificial Fermenters?

Abstract

We aimed to test the associative effects among forages, and between forage and concentrates on the in vitro digestibility of dry matter and neutral detergent fibre using an artificial ruminal fermentation system. The study consisted of two assays, in which associative effects were evaluated among three forages, sugarcane, maize silage, and Tifton 85 hay under two incubation conditions (single feed or all feeds together in a jar), and the associative effects between sugarcane and soybean meal and/or ground maize. For the first assay, sugarcane digestibility increased (p < 0.02), whereas the maize silage digestibility decreased (p < 0.01) when forages were incubated together in the same jar. Tifton hay digestibility was not altered (p ≥ 0.57) by the incubation condition. In the second assay, the sugarcane digestibility was depressed (p < 0.05) when the forage was incubated along with maize grain. For both assays, the pattern of repeatability for digestibility estimates presented an influence of the incubation condition. We concluded that the incubation of different feeds together in the same jar using artificial fermenters causes associative effects among them. These effects can influence the estimates of in vitro dry matter and fibre digestibility and alter their repeatability.

Rumen Content from Slaughterhouse as an Alternative Inoculum Source for In Vitro Analysis of Feeds: A Multivariate Approach

“…Cannulated cattle are generally used to obtain the ruminal inoculum, and even with this method, it is recommended that the animals be adapted to specific diets. According to Camacho et al [35], the rumen microbiology of animals not adapted to diets containing concentrate and forage can be a source of variation for the in vitro analysis of feed digestibility. To avoid sources of variation that affect the ruminal inoculum, sampling should be similar in time and collection method as described by Fortina et al [21].…”