Wet-dry feeders improved finishing pigs' feed intake by close to 9% and growth rate by 6-7% compared to conventional dry feeders in two recent Kansas State University research trials. And, pigs fed on wet-dry feeders were 4.5% heavier at marketing, but their carcasses were fatter and they yielded less than the pigs fed with conventional feeders.

Both experiments investigated the effects of conventional dry feeders with cup waterers (see Figure 1), compared to wet-dry feeders with a nipple in the feed pan, their sole source of water. Although pens with a wet-dry feeder also contained a cup waterer, they were shut off during the experiments.

Water was delivered to all of the pens of each feeder type, independently, and daily water consumption was measured using water meters.

The first experiment included 1,186 pigs, averaging 70.8 lb., on test. Groups were divided into 26-28 pigs/pen and allocated to one of two feeder types (22 pens/feeder type).

All pigs received the same diet sequence in four phases — Day 0-10, Day 10-28, Day 28-50 and Day 50-69.

Overall, pigs using the wet-dry feeder had greater average daily gain (ADG), average daily feed intake (ADFI) and final weight compared with pigs using the conventional dry feeder (Table 1). Feed-to-gain ratio (F:G) was essentially the same with both feeder types.

Average daily water usage for pigs on the wet-dry feeder was 1.44 gal./day. Pigs on the conventional dry feeders averaged 1.38 gal./day.

The second experiment was conducted with 1,236 pigs allotted to pens with one of the two feeder types. There were 23 pens per feeder type with 25-28 pigs/pen. Pig weights averaged 63.2 lb. at the beginning of the 104-day research trial. All pigs were fed the same feed budget.

The three largest pigs per pen were marketed on Day 84. The remaining pigs were fed a fifth dietary phase containing Paylean until they were slaughtered on Day 104. Table 3 shows the effects of feeder design on the carcass characteristics and the resulting economic return.

Overall, pigs using the wet-dry feeder had greater ADG, ADFI and final weight compared with those using the conventional dry feeder. However, pigs using the wet-dry feeder consumed more feed, had poorer feed/gain and higher feed cost/pig than pigs using the conventional feeder (Table 2).

Carcass yield, fat-free-lean index, premium per pig and live value per cwt. were higher and average backfat depth was lower for pigs using the conventional dry feeder. All of these effects combined resulted in a lower net income per pig for pigs fed with the wet-dry feeder (Table 3).

The KSU researchers felt the experiments demonstrated that growth performance is improved when pigs are offered feed and water, ad libitum, via a wet-dry feeder when compared to a conventional dry feeder and drinker bowl.

Still, the research results brought up some interesting questions for further study, such as: “Can we manage within-group variation better by feeding the lightest pigs placed in a finisher, or even gilts, with a wet-dry feeder?” asks Jon Bergstrom, KSU swine laboratory research coordinator.

He predicts that with the growing emphasis on understanding behavior, maximizing welfare and related productivity, research in this area will continue. And he wonders if feeder design and feed presentation can overcome the reduced feed intake associated with feeding some by-products.

Because carcasses of pigs fed with a wet-dry feeder yielded less and were fatter, the use of wet-dry feeders may not be justified with some carcass incentive programs, note researchers.

Researchers: Jon Bergstrom; Mike Tokach; Steve Dritz; Jim Nelssen, DVM; Joel DeRouchey and Robert Goodband, Kansas State University. Contact Bergstrom at 785-532-1277 or e-mail jberstr@ksu.edu.