Solutions > Agriculture > Livestock
Feed management
Proper grassland and pasture management are not the only ways to reduce methane emissions from livestock. Further options for improving animal nutrition and feed efficiency will also cut greenhouse gas emissions. Many of these suggestions relate specifically to enteric fermentation by cattle.
However, employing good feed management may also reduce greenhouse gas emissions produced from all types of livestock manure.
Production efficiencies (all livestock)
Any practice that reduces the number of livestock needed to meet demand will reduce overall emissions. Such steps include accelerated growth, improved reproduction, selective breeding, and improved herd health. (1) Emissions per pound of liveweight gain are reduced as production efficiencies increase. (2)
Feed efficiency (cattle and hogs)
Feeding excessive nutrients results in more nutrients excreted in manure. For cattle it also increases rumen methane emissions and wastes money on additional feed. (3)
Animal nutritionists can analyze the nutrient content of feed and formulate diets with the ideal mix of proteins, minerals and other essential nutrients. (4)
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Vegetable oil (cattle and hogs)
Adding a low level of vegetable oil to the diet will have positive results. The added oils—such as canola oil—reduce methane emissions by gathering hydrogen in the rumen that might otherwise be converted to methane. They also add energy to the diet. (5)
Vegetable oils should be added at a rate of no more than 5–6 percent of ration, as any higher rates will depress fibre digestion. (6)
A recent trial in Manitoba found cattle fed small amounts of whole sunflower seeds emitted 25–30 percent less methane than without the added vegetable oil. (7) However, so far this approach hasn’t been economically attractive for cattle producers.
There is some evidence that methane released from hogs by enteric fermentation can also be reduced by adding edible oils to their diet. (8) Raw canola oil is already routinely used in swine diets as an energy source. Edible oils are also beneficial for dust control.
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Higher quality feeds (cattle)
Low quality feeds produce elevated levels of methane. Limiting straw intake and incrementally increasing higher quality feeds will reduce methane emissions.
For instance, straw intake could be cut from 24 lbs to 18 lbs, with an additional 1 lb of barley added to an 8 lb/day barley ration. That small addition of higher quality feed is all that is needed to replace the lost straw. The cow would then be fed 18 lbs straw and 9 lbs barley daily. This reduces methane emissions without compromising nutrition. (9) And while there could be some increase in feed costs, the added benefit of energy and better utilization could outweigh the added cost of grain.
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Balanced diet to wintering cattle
Many producers do not test their winter rations for nutrients, instead feeding whatever is available. A balanced winter diet of energy, protein, minerals and vitamins, however, could cut greenhouse gas emissions by 15 percent. (10)
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Dietary protein (hogs)
Reducing protein levels and including a proper balance of amino acids in the diet is a cost-effective means to reduce greenhouse gas emissions from hogs. This could be done without impacting performance and at little or no cost to the producer. (11)
In one study, low protein diets, with supplementary synthetic amino acids, cut greenhouse gas emissions from growing pigs by 25–30 percent and from sows by 10–15 percent. (12) This change could lead to significant cuts in nitrous oxide and methane emissions when slurry is later applied to fields. (13)
This is particularly important in barley-based diets, which result in greater methane emissions than corn-based diets. (14)
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Digestion (hogs)
Pigs struggle to digest phytate in cereal grains. Adding phytase to the feed helps break down the phytate. The main benefit of this strategy is reduced phosphorus excretion, but it also increases feed use efficiency, which could lead to a decrease in nitrogen output in the manure. (15)
Another option is to give pigs a more easily digestible food supply. A University of Manitoba study showed that feeding a diet including raw or micronized peas cut manure production by 25–33 percent, with similar reductions in total nitrogen excretion. (16) This tactic is not widely adopted yet because of the cost.
