Effect of hammer mill screen size and addition of fibre or S-methylmethionine-sulphonium chloride to the diet on the occurrence of oesophagogastric lesions in fattening pigs.

Four groups of about 86 pigs from a common source were fed a grower diet from 25 kg to 45 kg liveweight, and then from 45 to 107 kg liveweight they were offered one of four diets ad libitum: A) normal commercial feed, ground through a 3 mm screen (the control diet), B) the same diet ground through a 6 mm screen, C) the control diet to which lucerne meal was added before the diet was ground to increase its crude fibre content, and D) the control diet to which was added 400 ppm S-methylmethionine-sulphonium chloride (MMSC). All the diets were pelleted. Approximately 21 per cent of the animals fed the control diet had severe oesophagogastric erosions and/or ulcers after slaughter. The addition of 400 ppm MMSC decreased (P = 0.066) the proportion of severe oesophagogastric erosions and/or ulcers by about 50 per cent compared with the control diet. The diet with the higher crude fibre content (but finely ground) did not have a significant effect on the proportion of severe oesophagogastric erosions and/or ulcers. There was a tendency for the pigs fed the diet ground through a 6 mm screen instead of a 3 mm screen, to have fewer severe oesophagogastric erosions and/or ulcers. However, there were only small differences between the particle size distribution obtained from the wet sieve analysis of the two diets. As a result, the observed tendency for a decrease in the proportion of severe oesophagogastric erosions and/or ulcers in pigs fed the diet milled through the larger screen size was of questionable significance.(ABSTRACT TRUNCATED AT 250 WORDS)