• Research Results & Reports
• Animal welfare campaign
• Current Housing Systems
• Energy content and feed evaluation systems
• Guidelines for A.I. stations
• Nutrients Standards

Print version

Report no. 385

Abstract
Coarsely ground, pelleted feed for growing-finishing pigs was in two herds compared to finely ground, pelleted feed.

At the same time, half of the pigs within each type of feed were given straw via straw dispensers. In one of the herds, pelleted feed was also compared to meal feed (not heat-treated), both coarsely and finely ground. The feed was given to pigs in the weight interval 29 to 99 kg. Dry feeding was used ad libitum in both herds. The test comprised 38 blocks in total and 2,244 pigs.

In herd A, where only pelleted feed was used, and where fine grinding (particle distribution 56/37/7 (distribution in percent in the categories < 1 mm/1-2 mm/ > 2 mm)) versus very coarse grinding (particle distribution 38/34/28) was compared, there was no difference in the production value. However, coarse grinding caused a significant decrease in the number of pigs with ulcers, and starch in manure was doubled. The herd had no Salmonella problems. In herd B both pelleted feed and meal feed were used. Fine grinding (particle distribution 79/18/3) was compared to a coarser grinding (particle distribution 52/35/13). In this herd, the following discoveries were made:

1. Pelleted feed resulted in a significantly better production economy compared to meal feed primarily due to a better feed conversion.
2. The content of starch in manure was affected by both grinding and the production process. Thus, there was approx. 25 times more starch in the manure when using coarsely ground meal than when using finely ground pelleted feed.
3. Pelleted feed resulted in a significantly poorer stomach health than meal feed.
4. Coarse grinding improved stomach health but the improvement was only significant for meal feed. The stomach health was considerably better for coarsely ground feed compared to the other groups.
5. Meal feed resulted in a significantly lower Salmonella level than heat-treated, pelleted feed.
6. There were fewer Salmonella positive pigs when using coarse grinding but the effect of grinding was not significant.

The weight gain of the individual growing-finishing pig is affected negatively when experiencing increased stomach changes and particularly at the score 8 or above (wound/scar >5cm² or contracted oesophagus). This has meant a loss in weight gain in the entire test of approx. 15 g per pig per day corresponding to 2% of the gross margin per pen place per year.

It can be concluded that the best production economy is achieved by using very finely ground feed that is heat-treated and pelleted. However, pelleted feed results in a higher frequency of ulcers and an increased risk of Salmonella. Very finely ground feed results in an unacceptably high level of stomach changes. Future work should be directed towards developing methods for using the improved feed conversion achieved at fine grinding without causing an unacceptably high level of stomach changes.

The decreased feed conversion when using meal feed may partly be due to wastage of feed, however reduced digestibility may also have played a part especially for the pigs fed coarsely ground meal feed where 5.1% starch was found in the manure dry stuff.

There were no significant effects on the measured qualities of straw supplied via straw dispensers.

To the top