With increasing cattle feed prices and limited supplies, there is a need to consider other alternative cattle feed. A good option is potatoes especially because during glut there is a lot of potatoes that go to waste. However a few practical points should be considered when feeding potatoes to cattle.
- Nutritional value
Potatoes are high in moisture (20% dry matter), are highly digestible and good source of Metabolizable Energy (ME) 13 MJ/kg Dry Matter (DM).They are rich in starch (57% DM basis) but low in protein and fiber (11 and 2.6% DM basis respectively). The protein in fresh potatoes is readily soluble in the rumen. Potato starch is in a granular/crystal form. Due to this structure, the rumen degradability of the starch tends to be slower than wheat or barley and somewhat similar to maize grain. The rumen by-pass starch provides a good source of glycogenic energy but care is needed in ration formulation to avoid excessive Starch entering the small intestine resulting in digestive upset. This is a key consideration in upper feeding limit recommendations for potatoes.
Potatoes can be a replacement for some cereals and forages. On an energy basis, 1kg potato dry matter can replace between 970-990g of barley or around 910- 925g maize (DM basis). Similarly, solely on the basis of Metabolizable energy, 1kg of potato dry matter can replace around 1.2kg of grass silage or 1.1kg of maize silage (DM basis), dependent on their energy value. In times where fodder is in short supply this can be a useful option. However, such a replacement will not supply the forage fiber contribution which must therefore be balanced to avoid inducing acidosis. This is particularly important when wet and/or high acid loading silages are being fed as part of the ration.
- Feeding rate
On a fresh basis, up to 9-10kg/head/day can be fed to lactating cows. At 20% dry matter, this can replace around 2.3kg of cereals (fresh basis)
When feeding potatoes, ensure that the total ration is balanced for all nutrients beyond ME, particularly metabolizable protein, NDF, minerals and vitamins, starch and rumen health.
- Production parameters
Milk production and milk quality is not significantly affected when potatoes replace a moderate level of cereal in the diet. However there have been some reports where feed intake was depressed which may have been due to soil contamination.
- Potatoes pose a risk of choking and should not be fed whole. Chopping or crushing will reduce this risk. Small or frozen potatoes pose the biggest threat to choking and must be carefully processed before feeding.
- Excess soil can be a problem which can decrease the intake significantly and affect rumen function. Beware of stones when feeding
- Avoid feeding green and sprouted potatoes as these are high in glycoalkaloids, which can be toxic to cattle.
- Rotten potatoes should also be
- Store potatoes for stock feed to minimize sprouting or rotting. This is not easy and as such rapid consumption of the delivery is often the only practical solution
- Introduce potatoes slowly to allow rumen microbes to adapt to the starch
- Potatoes are low in minerals and vitamins and as such the balance in the total diet must be
- Feed values may differ slightly for different varieties (there are over 70 registered varieties in Kenya). The composition table below provides a useful