Analysis of a casualty animal recently submitted to one of the Scotland’s Rural College veterinary investigation centres is confirming earlier fears some silages being fed to livestock this winter are low in protein and could, if unnoticed, lead to slow starvation and death.
The dead cow, examined by vets from SAC Consulting, part of SRUC, was diagnosed with a condition called rumen impaction.
A cow’s first stomach, the rumen, is effectively a large bag hosting millions of microbes which help ruminant animals begin to digest the fibrous plant material they eat.
Rumen impaction occurs when an animal’s feed contains insufficient protein to supply these microbes, affecting their activity.
This reduces the rate of fermentation or digestion and leads to blockages which slow the progress of food into the next part of the digestive system. It also means there is less space in the rumen for any new food the animal eats.
Veterinary investigation officer Heather Stevenson says: “In November, SRUC warned its analytical labs had identified there were more low protein silages than usual this winter.
“Animals not receiving enough protein from feed often look healthy and full, which means their condition is sometimes not discovered until too late. The case investigated was one of two cows to die in a group.”
SRUC is recommending any farmer who has not recently analysed their silage to get it done as soon as possible. While bulk and energy levels are often good, low protein content can be difficult to spot.
“Sometimes there are signs in dung, which is far firmer and drier than normal for the time of year,” says Ms Stevenson.
“Blood samples can be used to confirm low protein status and the farmer’s vet would notice other signs.”
Problems can arise in other ruminants, such as sheep fed on similar silages, and SRUC recommends farmers seek advice on the best way to provide protein supplements.
It is important to assess body condition so animals can be grouped and fed accordingly, as many conventional protein supplements are also high energy.