While energy is the main driver of growth in animals, protein is an essential inclusion in animal feed, particularly for calves, weanlings and in-lamb ewes, with protein being the building block for growth and development of the animal or foetus.
Protein percentages of feeds targeted at younger cattle and in-lamb ewes will vary between 16% and 21%, and the percentage protein requirement will depend on the fodder or forage provided to the animal.
High-quality ryegrass or red clover silage will have a protein content of 16.5% to 18%, meaning a lower protein feed can be used, while poorer-quality silage, haylage or hay will generally have a protein content below 15%, meaning supplementation will be required.
It is important that excess protein is not being fed to animals, as energy is utilised to burn off this excess, causing a reduction in thrive and weight gain.
Soybean meal is the gold standard when it comes to a protein source, and is especially recommended in feed for pregnant ewes.
However, the ethics around the use of soybean meal being used in Irish feed is questionable at best, with soybean being linked to deforestation in southern America, not forgetting the carbon footprint of the feed when transportation is included.
Alternative protein sources are available, though their quality can be extremely variable.
Distillers grains is a byproduct from the distillery industry. Corn (or maize) distillers grains, imported from the US, is commonly used in the country. But other sources include barley and wheat distillers grains from the UK and Europe.
It is high in protein (26% CP) and energy. However, due to high concentrations of copper levels, its inclusion in a ration should not exceed 30%.
Maize gluten feed is a byproduct of the manufacture of maize starch. It is a moderate protein source (20% CP) but its protein quality can be variable.
Due to high concentrations of copper, a maximum inclusion rate of 30% is advisable.
Rapeseed meal is a byproduct of oil manufacture. It is a medium energy, high protein (34% CP) feed. Its inclusion should be limited to 20% of the ration due to palatability issues.
Sunflower meal is a byproduct of oil manufacture. It is a very poor energy source and while its crude protein is 25%, the quality of the protein is poor.
Its inclusion should be severely limited, particularly if other low energy feeds are being used in the ration.
Peas are a good source of energy and moderate source of protein (21% CP). Inclusion rate should be limited to 20% to 25% due to anti-nutritional factors.
Beans are a good source of energy and protein (25% CP). Beans are commonly used to replace distillers grains in rations. The inclusion rate should be limited to between 20% and 25% due to anti-nutritional factors.
While we primarily focus on concentrates when it comes to protein sources, livestock farmers can produce protein on their own farm in the form of red clover silage and combi crops, both of which have been subsidised in previous years, including 2024.
Red clover silage can be cut three to four times a year and yield circa 20 bales/acre of high protein feed in this multi-cut system without the need for chemical nitrogen, provided P and K offtakes are replaced with organic fertilisers such as farmyard manure and slurry.
Typical protein content of red clover silage varies between 16% and 20% depending on clover percentage in the sward.
While red clover will eventually die out of the sward after three to five years, the high-quality perennial ryegrasses that were sown alongside it should persist and the field can return to grazing/single or double-cut silage system.
Combi crops generally comprise a 50:50 mix between the legume and cereal crop. A combi crop of peas, oats and barley was sown on Tullamore Farm this year, with the crop yielding 11 bales/acre. The combi crop will be targeted at weanling bulls and heifers on the farm in an effort to reduce the importation of protein.
Feed analysis will be completed on the combi crop in the coming weeks with details to be printed in the Irish Farmers Journal.