Some farmers are already starting to feed less soya in dairy cow diets because of its environmental impact – a move being encouraged by a small number of retailers with concerns about deforestation in soya-producing countries. Currently, however, the main driver is the price of soya which in the past eight months has risen from around £300 to £450 per tonne.
Soya alternatives in cow diets
Soya is one of the best sources of vegetable protein in terms of quantity and quality of amino acid and nitrogen (N) provision and is currently a key component of rations for UK dairy herds. But when market drivers steer dairy farmers away from soya, there are three main alternatives:
- Vegetable proteins such as rapeseed meal, pulses, dried distillers’ grains (DDGS) and sunflower meal
- Slow-release urea, which releases N at a similar speed to soya
- Balancing amino acids such as protected lysine and methionine
Limitations of alternative soya proteins
A key issue is that availability and price of alternative materials are variable, often making their inclusion in place of soya difficult to justify. With protected amino acids, it can also be challenging to ensure accurate mixing into dairy rations.
Benefits of alternative proteins
Irrespective of current cost savings, in the longer-term herd performance could benefit from the increased use of balancing amino acids – currently fed to <2% of UK dairy cows.
Protected amino acids already form an intrinsic part of monogastric diet formulations and using less soya in dairy rations should mean total protein usage and wastage are reduced, so nitrogen efficiency is increased.
Short term effects on dairy cow performance are difficult to measure, but sustained use of balancing amino acids can help to improve milk yields, composition, and health, as well as reducing carbon footprints.
Reducing soya in dairy diets needs to be done carefully, keeping focused on maintaining good rumen function. Using technology like slow-release urea and synthetic amino acids is a key part of this.