The effect of diet of the donor cows on in vitro measurements of methane production from wheat and corn incubated in various forage‐to‐grain ratios

Abstract

BACKGROUND Supplementation of ruminant diets with wheat and corn grains influences ruminal fermentation. In vitro fermentation is a methodology that can be used to screen feeds for their potential to produce enteric methane. However, there is evidence that the diet of the donor cows could impact the results of in vitro analysis. This research investigated the in vitro fermentation of wheat and corn grain when incubated in ruminal fluid from cows fed different grain types and different forage‐to‐grain ratios. RESULTS The type of grain fed to the donor cows, as well as forage‐to‐grain ratio, affected the outcome of fermentation of wheat and corn grain. Differences in methane production (MP) between grains were only observed when incubated with ruminal fluid adapted to each specific grain type. Increasing proportions of wheat but not of corn decreased in vitro MP in a linear manner compared with MP produced from forage only. CONCLUSIONS Wheat grain has a greater in vitro antimethanogenic effect than corn. However, to detect the different fermentations between wheat and corn, grains should be incubated in ruminal fluid from cows adapted to that specific grain type. © 2019 Society of Chemical Industry

Effects of Feeding either Red or White Grape Marc on Milk Production and Methane Emissions from Early-Lactation Dairy Cows

“…Condensed tannins from grape seeds have been shown to have a direct inhibitory effect on methanogenesis in vitro [ 44 ]. However, findings from experiments conducted in vitro do not always relate to what happens in vivo [ 34 , 45 ]. In the current experiment, the apparent lack of a major effect of grape tannins on methanogenesis is not surprising as there is great diversity in the total concentration and the different types of tannins present in different types and sources of grape marc [ 15 , 16 , 17 ].…”

Dietary wheat and reduced methane yield are linked to rumen microbiome changes in dairy cows

“…Is it due to starch degradation rate for example, or some unidentified factor in one grain or another? Perhaps also the outcome of feeding different diets may depend on the pre-existing state of the ruminal microbial population [ 9 ]. Different forages and grains have been compared and exotic additives tested in an effort to manipulate the fermentation process occurring in the rumen [ 6 ].…”

Does Replacing Maize with Barley Affect the Animal Performance and Rumen Fermentation, including Methane Production, of Beef Cattle Fed High-Concentrate Diets On-Farm?

“…Not all grains are equally effective in reducing methane production in the rumen, and there are indications that the response of methane production to different proportions of grains may not be linear [14]. Moate et al [15] found that dairy cows produced less methane when fed wheat than when fed maize or barley, and Herrera-Saldana et al [16] observed in vitro that maize grain has a lower rate and extent of degradation than barley grain.…”

“…A few reasons may account for the discrepancy between papers on methane production from different grain sources: 1. When working in vitro, grains should be incubated in ruminal fluid from animals adapted to that specific grain type [14]; in the case of Fellner et al [19], the donor animal (a dairy cow) was fed a forage diet. 2.…”

“…4. Methane production obtained in vitro using pure substrates may not represent the in vivo facts with more complex diets [14], indicating the need for caution when interpreting the results from in vitro studies.…”