Pelleting is the most common method of thermal processing used in the feed industry today. A summary of research conducted by university and industry researchers mainly in the 1980’s and 1990’s suggests feed efficiency is improved 3 to 10% during the grow-finish period when pigs are fed diets in a pelleted form compared with pigs fed meal diets. These improvements may be associated with less feed wastage and/or improved digestibility of nutrients when feeds are pelleted. Swine feed manufactured as pellets reduces the dustiness of feed, reduces ingredient segregation, increases the bulk density of feed, and improves the overall handling characteristics of feed. Few studies have been conducted in the past few years to evaluate the benefits associated with pelleting feeds when fed to modern genotypes.
These improvements may be associated with less feed wastage and/or improved digestibility of nutrients when feeds are pelleted.
Wenger Feeds has conducted a series of four experiments in conjunction with a commercial production company to evaluate the effect of pelleting on the performance of grow-finish pigs. The objective of these studies was to evaluate the effect of feeding pelleted feed on the performance of modern genotypes of pigs. The studies were conducted from December 2005 to June 2007.
Pigs were fed a standard five phase feeding program with feeds manufactured as either meal or pellets. The meal diets were formulated to contain 20 kcal more Metabolizable Energy (ME) per pound than the pelleted diets in each phase. This was a practical approach being used at the time of these studies to overcome some of the advantages (typically, a 2% improvement in feed efficiency would be expected with the 20 kcal ME/lb increase) expected from feeding pelleted feeds.
The first two experiments were conducted using corn-soybean meal based diets while the last two experiments were conducted with corn-soybean meal based diets with wheat middlings and bakery byproduct meal added to the diets. Wheat middlings were added at 7.5%, 8.8%, 10%, 10%, and 10% of the diet in Phases 1 to 5, respectively. Bakery Byproduct Meal was added at 7.5%, 10%, 12.5%, 10%, and 7.5% of the diet in Phases 1 to 5, respectively. Diets in all phases were high energy diets with an average of 5.7% added fat.
A total of 4,487 pigs were utilized in these experiments with an average starting weight of 57 pounds. The barn was divided into four large pens with, approximately, 280 pigs per pen. Pigs in the first two experiments were Newsham LG x SM pigs and the pigs in the last two experiments were XM x SM Newsham pigs. All studies were conducted in a tunnel-ventilated building with pigs housed on slatted concrete floors. The barn was operated using standard operating procedures for commercially produced pigs.
Table 1 summarizes the average change in performance parameters when pigs were fed pelleted feeds compared with pigs fed the meal feeds with extra energy. Overall, daily gain was similar for pigs fed pelleted or meal diets (1.76 vs. 1.75 lb/day). Daily feed disappearance was reduced an average of 3.9% (4.87 to 4.68 lb/pig/day) when pigs were fed pelleted feeds compared to meal feeds. The reduction in feed disappearance when pellets were fed was consistent across all experiments and ranged from 1.6% to 8.6%.
| Experiment Number | |||||
| Average | Exp. 501 | Exp. 601 | Exp. 602 | Exp. 701 | |
| Daily Gain | -0.6% | -3.8% | 0.0% | -1.1% | +2.3% |
| Daily Feed | -3.9% | -8.6% | -3.1% | -1.6% | -2.4% |
| Feed: Gain | -3.3% | -5.0% | -3.0% | -0.3% | -4.5% |
| Mortality | +.36% | -.37% | -1.07% | +2.60% | +0.19% |
| Culls | -.66% | -.73% | -.52% | -.35% | -1.06% |
| Mortality + Culls | -.69% | -1.1% | -.82% | +2.02% | -.86% |
| Carcass Yield | +1.9% | +1.1% | +0.9% | 0.0% | +0.3% |
| Backfat | +2.0% | +1.6% | +2.5% | +2.4% | +2.0% |
Feed efficiency (pounds of feed per pounds of pig gain) was improved an average of 3.3% (2.75 to 2.66) when pellets were fed. An improvement in feed efficiency was seen in three of the four experiments and ranged from 3.0% to 5% when pellets were fed.
Economically, the improvement in feed efficiency when pellets were fed saved approximately 20 lb of feed per pig (560 vs 580 lb/pig). The ingredient cost of the meal diets with extra energy averaged $2.54 per ton more than the pelleted diets due to the extra energy. When this cost was subtracted from the cost of pelleting ($6.50/ton), the net additional cost of pelleted diets was $3.96 per ton. At an average feed price of $250/ton for the high energy meal diets, the net savings of feeding pellets was $1.28 per pig.
One of the concerns in feeding pelleted diets to modern genotypes is the potential of increasing mortalities and culls. This potential is often associated with the fine grind of corn typically used in pelleted feeds, which may increase the incidence of gastric ulcers. In these four experiments, mortality was 3.0% for pigs fed the pelleted feeds and 2.6% for pigs fed meal feeds. This increase in death loss was mainly a result of one experiment in which death loss was increased from 1.1% for pigs fed meal feed to 3.8% for pigs fed pelleted feed.
Mortality plus culls was actually less for pigs fed pellets compared to pigs fed meal feeds. In three of the four experiments, mortality plus culls was lower when pellets were fed, but in one experiment mortality plus culls was 2% higher for pigs fed pellets than pigs fed meal feed. This was the same experiment with the high mortality discussed earlier. Based on the mortality plus culls, the percentage of full value pigs sold was similar for pigs fed pellets or meal.
Carcass yield was similar for pigs fed meal or pellets. Backfat was increased when pellets were fed, but this difference was less than 0.02 inches per pig. This increase may have been associated with more utilizable energy when pellets were fed. The percentage of primal cuts (ham, belly, loin, and shoulder) was not different between pigs fed either feed type.
In summary, pigs fed pelleted diets had a 3.3% better feed efficiency than pigs fed higher energy meal feeds. An additional 2% improved feed efficiency from the higher energy in the meal feeds plus the 3.3% improvement in feed efficiency in these studies would result in an estimated 5.3% improvement in feed efficiency from pellets alone. This improvement would be similar to those reported in the scientific literature. These results suggest that feeding pellets improves the feed efficiency of modern genotypes of pigs, and this improvement enhances the economics of swine production by lowering feed cost per pig.
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