Organic flocks can return respectable results on diets free of synthetic amino acids…but only if the feed is properly formulated and closely monitored. That is the picture emerging in the first few months after the EU ban on the use of SAAs for the organic sector.
Some flocks fed on the new diets are thriving and have hit a peak production levels as high as 92%. Other reports speak of poor performance and outbreaks of aggression.
Consultant and vet David Spackman has reported bleak results for some producers. “The first few flocks on SAA-free diets are showing signs of deficiency,” he says. “Where normal diets would aim for, and achieve, levels of Methionine of 0.4 - 0.45% the SAA-free diets are consistently below 0.4% and, on analysis, have been shown to be as low as 0.25%.
“The birds are exhibiting peaks below 80 per cent, breakdown in evenness of bodyweight and, worse still, an aggressiveness which even progresses to cannibalism.
“Whilst it is acceptable to have an ideological view of what an organic ration should or should not contain it is totally unacceptable if bird health and welfare are compromised as a result.”
But David Stephens of leading organic supplier CMC Vitrition says that none of the flocks being fed by his company have faced any such difficulties. He told the Ranger: “Our experience is that flocks are reaching peaks of between 90-92% with pullet bodyweight up to standards. We have not seen any evidence of increased aggressive behaviour.
“If the feed supplier has adequate sources of raw materials there is no reason why a methionine level around 0.37% cannot be readily maintained and even though this is below what is considered the norm in conventional diets it is producing very acceptable results.”
One of the first flocks switched to the new diet in the south west is now at week 29 and has peaked at over 90%. “This is certainly lower than previous flocks fed organic diets with SAAs,” said the producer, “but they were a particularly uneven batch of pullets and it is impossible to tell which factors are having most affect. In any case we have a long way to go to see how well the performance is sustained. Mortality levels are the best we have ever had.”
If these kinds of results are maintained they are bound to prompt the question of whether high methionine levels are necessary in conventional diets. Meanwhile a new debate is already under way on whether SAAs should be fed during the rearing period and if so at what level. One view is that feeding a conventional diet to growing pullets may lead to a marked reaction when the SAAs are withdrawn at 16 weeks. The opposing argument is that removing SAAs in the growing bird is bound to impact on performance.
What is your SAA-free experience? Whether you are a producer or feed supplier BFREPA would like to hear your views. Please get in touch with Ranger editor John Widdowson (go to contacts).
