Feeding and Ensiling Potatoes for Cattle
30 March 2026Stockfeed potatoes are a viable energy feed for cattle and a useful additive to ensiled forage when managed correctly. They offer an economical alternative to cereals but require:
- Gradual introduction into diets
- Balanced nutrition with adequate protein and fibre
- Safe handling to reduce disease and toxin risks
- Appropriate ensiling techniques to preserve feed quality
Potatoes can be a cost-effective feed for livestock. Acting as an energy supplement to silage when prices are favourable compared with cereals. They can be particularly useful for bulking up feed stocks in years when forage and cereal yields fall short. However, careful management is essential to maintain animal health and ensure rations are effective.
Nutritional Profile and Feeding Value
Rations should always be balanced for energy, protein and long fibre. Potatoes are nutritionally similar to barley, though there are some differences:
- Dry matter: 20–25% (vs. 86% in barley)
- Energy: Contains good energy and a high starch content, comparable to feed grains on a dry-matter basis
- Protein: ~9%, requiring supplementation with other protein sources
- Feeding equivalence: 4–4.5 kg potatoes = 1 kg dried barley
Introducing Potatoes as an Alternative to Barley
Potatoes must be introduced gradually to allow rumen microbes to adapt and avoid digestive upsets, even if cattle have been on an intensive ration for an extended period. Replace 1kg of barley with the equivalent potatoes every 3-4 days, rather than all at once. The way the ration is presented affects intake levels: in a total mixed ration (TMR) potatoes can be incorporated easily, while in ad-lib cereal rations, feeding once or twice a day is more appropriate. Potatoes should always be fed at ground level or chopped before feeding to reduce choking risks. Potatoes should be cleaned prior to being fed out to cattle, the inclusion of soil in the diet can cause clostridial diseases and impact intakes.
Ensiling Potatoes with grass silage
Ensiling potatoes with grass is a well-established method to preserve them and increase silage energy. The potatoes should be cleaned of soil as far as possible (as this causes bad patches in the silage) and either mixed in or put in alternate layers: about 0.6m of grass followed by 0.15m of potatoes. The usual recommended ratio of grass to potatoes is 5:1 but some authorities have suggested that a ratio as low as 3:1 is acceptable. There should always be a layer of grass on the bottom of the pit prior to putting potatoes in and too many potatoes in one layer can lead to air pockets and spoilage which can be harmful to stock.
Toxin Risks: Glycoalkaloids
Green and sprouted potatoes contain glycoalkaloids (GA), toxic compounds similar to those in Woody and Black Nightshade. Even non-green potatoes contain small amounts of GA’s. Exposure to light and sprouting increases toxin concentrations, with sprouts containing up to 30 times more toxins than green tubers. White sprouts contain ~30-40% less GA’s than green sprouts, so it is important to note that sprouts do not have to be green to be toxic. Cattle and sheep are more resistant to toxicity as it appears some of the GA’s are destroyed in the rumen. However, sprouts should be removed wherever possible, and badly greened potatoes should not be fed.
Practical Considerations
Handling and Logistics
Consider the logistics required to pit potatoes; the haulage required for hundreds of tonnes may not be achievable in a short time scale. Adding potatoes in the correct way will enhance the nutritional value of the silage pit however, it may not be suitable for all farms, for instance if the pit is destined for dry suckler cows that do not need additional energy.
Diet Balance
- Balanced rations require sufficient forage and supplementation. Potatoes are low in fibre and minerals so bear this in mind.
- Seek nutritionist advice when making significant changes to your livestock’s diet
Field and Land Risks
Feeding potatoes at grass in fields rotated with potato crops risks contamination with powdery scab (takes 14+ years to eradicate) and potato cyst nematode (PCN) (7+ years to eradicate). This also applies when spreading dung from potato-fed cattle on potato fields.
If you’d like to learn more, visit the FAS Livestock section, or contact the free Advice line at 0300 323 0161 or advice@fas.scot.
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