Scours linked to wheat diet
RYE genes bred into some modern wheat varieties could be the reason why pigs fed wheat-based diets are more likely to suffer scours, according to Dalgety.
Company pig nutritionist Mick Hazzledine told the Kegworth meeting that the rye gene was introduced into wheat varieties by plant breeders in the mid-80s to improve yields and yellow rust resistance.
"Under heat treatment the rye gene makes the feed more viscous, which reduces absorption and encourages colitis," he explained.
Younger pigs are particularly vulnerable because they have a shorter gut retention time for feedstuffs and so are less able to digest the stickier modern wheats.
"Stickiness also increases when wheats are subjected to higher processing temperatures for pelleting and the higher temperatures now being used to ensure bacteria are eradicated."
However, UK trials showed that in varieties such as Soissons and Riband, stickiness did not increase as markedly as the more viscous wheats such as Lynx which was 10 times stickier than Soissons after heating.
Mr Hazzledine predicted, therefore, that premiums would be paid for older varieties, such as Riband and Buster, that are bred without the rye gene. Pig feed compounders would avoid varieties such as Brigadier and Lynx and include enzymes to improve feed digestion, particularly in young pig diets.n