Feeding extruded linseeds reduced methane production but not milk yield
Take Home Message: Methane output from dairy cows can be decreased by up to 40% by including 150 g/kg DM extruded linseeds in the diet without affecting intake or milk yield.
It is possible to feed cattle using extruded linseeds to reduce methane production without altering milk yield. That was the finding of two studies, carried out by Michel Doreau and his team at INRA in France, the results of which were presented to delegates at this year’s British Society of Animal Science annual conference.
“The extent of the decrease depends on the dietary linseed content,” said Dr Doreau, adding that the feeding regime was one of the most efficient yet to be studied to mitigate methane emissions, but it needs to be confirmed with a larger number of animals and by long-term experiments.
He explained that because ruminants make a significant contribution to greenhouse gas emissions, attempts were being made, through dietary manipulation, to mitigate methane emissions without altering animal performance.
“Dietary fat supply may be a promising solution and our first experiment has shown that increasing extruded linseed supply in a hay-based diet resulted in a decrease in methane production.
“Our second study looked at feeding a maize silage-based diet and the same linseed supply.”
In each experiment, four lactating Holstein dairy cows were randomly assigned to four dietary treatments. The rations comprised control diets – 50% natural grassland hay and 50% concentrates for the first study and 60% maize silage and 40% concentrates for the second trail – and these same diets supplemented with 5%, 10%, or 15% of extruded linseeds, corresponding to an expected oil supplementation of 2%, 4%, and 6% of dietary dry matter (DM), respectively.
Each experimental period lasted for four weeks, with measurements occurring during the last week of each period.
Milk yield was determined on five days, organic matter digestibility was measured by total faeces collection on six days and individual CH4 productions on four days using the sulphur hexafluoride (SF6) tracer technique.
“For each experiment, no significant difference among diets was shown for DM intake or milk yield. But linseed supply significantly decreased methane emission in both
Experiments,” said Dr Doreau.
“The decrease was significant for the rations including 10% and 15% extruded linseed with the hay diet, and also for the maize silage diet containing 15% extruded linseed.
“The extent of the decrease was 15%, 19% and 40% in the first study, and 6%, 13% and 42% in for the second study for a supply of 5%, 10% and 15% of extruded linseeds, respectively.
“And these variations cannot be explained by changes in organic matter digestibility, which did not vary among diets,” added Dr Doreau.
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