Case study: Beef finishers John and Jim Brown, Gaindykehead, near Airdrie
Father and son Jim and John Brown use potato rejects and waste mashed potato to finish 2,300 to 2,500-head of cattle a year at their farm, near Airdrie in Lanarkshire.
The potato-based products would be packed for supermarkets. A lot of the potatoes and mash are rejected for minor blemishes because retailers demand product uniformity. But they are still fresh and good enough to eat in nutritional terms, says Jim.
To ensure freshness is maintained, the Browns haul potatoes five days a week from the processing factory two miles away. Frequent pickups overcome the need for large storage areas on the farm, reducing spoilage.
The potatoes are mixed with silage for feed once a day – in the morning, then pushed up in the afternoon. Potatoes are fed whole so there is a risk of choking, warns Jim. However, this has proved to be a small risk and the farm has successfully used the system with few incidents since 1972.
The alternative is to crack or crush the potatoes, but this causes the starch content to break down, turning them black. “We would have to feed potatoes twice a day to keep them fresh and palatable if we cracked them first,” he explains.
John manages the farm and says potatoes need to be introduced to the ration gradually. Cattle are bought in at about 500kg, but they have never eaten potatoes before, so they tend to avoid them initially.
The potatoes represent the energy content, so the starter ration includes 2kg of barley, which is fed for the first 50 days on the farm.
Starter ration includes:
- 10-15kg silage
- 2kg barley
- 100g urea
- 5kg (rising to 40kg) potato – either whole or mashed.
Cattle then move to a finisher ration for the remaining 50-60 days.
Finisher ration includes:
- 5-6kg silage
- 1kg brewers barley
- 100g urea
- 40-45kg whole potato
- 5kg mashed potato.
The waste potatoes are regularly analysed so the ration can be adjusted if quality changes. About 5kg of mashed potato is equivalent to feeding 1kg of grain, says John.
But low-protein and low-fibre levels mean the ration is anchored by high-quality silage at about 13-14% protein and 30% DM.
Growth rates vary according to breed and conformation, but cattle can achieve daily liveweight gains (DLWG) of up to 2kg/day.
The average DLWG is 1.3kg across 110 days on the farm, taking them from 500kg to 700kg.