AN INTERVENTION STUDY OF THE EFFECT OF INTRODUCING SALMONELLA CONTROLLING FEED STRATEGIES IN SALMONELLA HIGH PREVALENCE HERDS

摘要

Epidemiological studies (1) and clinical trials (2,3) have shown that pigs fed home-mixed feed had a lower salmonella-level than pigs fed purchased feed. Home-mixed feed is in Denmark characterized by certain physical characteristics. The cereal partof the feed is never heat-treated, and the feed is served as meal, whereas purchased feed is heat-treated, and normally pelleted. Purchased feed in Denmark is salmonella-controlled, and the number of Salmonella in feed is low. The most prevalent serotypein Danish pig herds and in Danish pork, Salmonella Typhimurium, is never isolated from feedstuff in Denmark (4). It seems appropriate to assume, that the salmonella-level in Danish herds is not as much related to Salmonella in feed, as to other characteristics of the feed. Although the protective effect of home-mixed feed is well documented, many herds find it difficult to use this type of feed in salmonella-reduction plans for high-prevalence herds. Establishing home-mixing is expensive, and especially for smaller herds, it is difficult to establish home-mixing. Casuistic stories from pig herds indicated, that pellets mixed with non-heat treated barley or wheat could have an effect similar to the effect of home-mixed feed.