By Wendy Short North-east correspondent
BASED on a £55/t grain price, it could cost as little as 66p/lamb/ month to supplement forage diets with cereals. But care is needed to avoid health problems.
ADAS sheep specialist Kate Phillips says low grain prices have encouraged some producers to look more closely at cereals as an option for lamb finishing diets this autumn.
"Cereals could add an extra 3kg to finished liveweights in a month. But watch out for acidosis, which is the number one risk. Some producers like to process cereals before feeding, but that is not always a good idea. When cereals are finely ground, starch is quickly attacked by rumen bugs, leading to acidosis. It is much better to leave grains whole."
There are varying degrees of risk from acidosis, depending on which grain is chosen, says Mrs Phillips. Wheat, barley and oats all have different effects on the rumen.
"All three grains are fairly safe when fed whole in the right amounts. Wheat can be the most dangerous because it has the highest starch content. It also has a slightly higher protein content than barley. For that reason, many producers have preferred wheat in recent years.
"Oats are the safest because they have the lowest starch content and lots of fibre. However, they also have the lowest energy at 12MJ of ME/kg DM."
Although whole-grain cereals are generally recommended, there are instances where rolled grain works better, says Mrs Phillips. "Rolling may be appropriate when cereal is being mixed with other ingredients. Otherwise, the grain tends to separate out from the ration. And there is evidence that rolling is better where high quality forage is fed. In this case, whole grains are likely to pass through the lamb without being digested."
The main disadvantage with cereals is their low protein content compared with other feeds. While they are useful for lambs close to finishing, she stresses that an additional protein source is necessary for lambs needing to grow frame.
"This can be in the form of soya, maize gluten or rapeseed meal, depending on price. For smaller lambs, aim to have an overall mix containing 14-16% protein."
Housed lambs must be offered ad-lib forage to keep the rumen healthy, she advises. Where good quality silage is fed, adding cereals alone may be enough to finish lambs successfully. But this only works where the marketing strategy is flexible, allowing lambs to finish at different times.
To achieve more specific finishing times, 0.25kg/lamb/day of a soya and barley mix is usually needed, says Mrs Phillips.
Cereal-based rations should be introduced gradually, she adds. "Start with about 0.12kg/ lamb/day for animals of 30-35kg and build up to 0.5kg/day over seven to 10 days to get the rumen used to the new feed."
For producers who are not keen on cereals as an option, well-managed grazing can produce a good quality lamb with no need for extra supplementation.
Fodder root crops are also ideal for finishing lambs, but she believes some form of dry supplement is beneficial in poor weather or under difficult grazing conditions. "A 14% protein mix of cereals and soya is suitable." *
Cereals could prove economic for lamb finishing this autumn, says Kate Phillips.
• Low cereal costs.
• Introduce gradually.
• Accelerates liveweight gain.