Determination of gas production in vitro and metabolizable energy content of ruminant feedstuff incubated with sheep excreta

An experiment was performed to determine the in vitro gas production at 3, 6, 9, 12, 24, 36 and 48 h of incubation with two types of inoculum collected from two Saint Croix sheep (T1: ruminal liquid, T2: excreta with yeast) in five diets for ruminants with different concentrate (C) and forage (F) ratios (100C:0F, 75C:25F, 50C:50F, 25C:75F y 0C:100F), with the aim to evaluate the feasibility of utilizing excreta instead of ruminal liquid as inoculum in the in vitro gas production (PGIV) technique, in order to determine the in vitro digestibility of organic matter (DIVMO) and metabolizable energy content (EM) in feedstuffs for ruminants. The PGIV registered with ruminal liquid was higher (P < 0.05), than with excreta + yeast as inoculum in each evaluated diet. However, utilizing simple linear regression, polynomial curves or correction factors developed in this research, similar results for PGIV, DIVMO and EM for ruminal liquid were estimated from gas production registered using excreta with yeast as an alternative inoculum.