Effects of feeder design (conventional dry vs. wet-dry) on growth Effects of feeder design (conventional dry vs. wet-dry) on growth performance of 45-to 246-lb pigs performance of 45-to 246-lb pigs

Summary A total of 1,253 pigs (PIC 1050 × 337; initially 45 lb) were used in a 104-d study to evaluate the effects of using a wet-dry (WD) or conventional dry (CD) feeder on growth performance of growing-finishing pigs. At the start of the trial, pens of pigs were weighed and randomly allotted to 1 of the 2 feeder types. The CD feeder was a single-sided, 56-in.-wide, stainless steel feeder (Thorp Equipment, Inc., Thorp, WI) with 4 14-in. feeding spaces and a 4.25-in.-deep trough. A cup waterer in pens using CD feeders ensured ad libitum access to water as well as feed. The WD feeder was double-sided (15-in.-wide feeder opening on each side) with a single nipple waterer (Crystal Springs, GroMaster, Inc., Omaha, NE), and the feeder was the only source of water. All pigs were fed the same corn-soybean meal diets containing 30% bakery by-product and 10 to 45% dried distillers grains with solubles (DDGS) during 5 dietary phases. For the overall period, pigs fed with the WD feeder had greater ADG ( P < 0.01) and ADFI ( P = 0.01) with no differences in F/G ( P = 0.50) compared with pigs fed using the CD feeder. This study confirms previous results where pigs fed using a WD feeder have greater ADG and ADFI than those fed with a CD feeder.

Effects of Feeder Design (Conventional Dry vs. Wet-Dry) on Growth Performance of 45-to 246-lb pigs 1

Introduction
Recent studies have demonstrated that finishing pigs fed using WD feeders had improved weight gain, feed intake, and final BW; however, F/G responses were inconsistent among trials.Last year, Nitikanchana et al. (2011 3 ) observed improved ADG and F/G in pigs fed using a WD feeder.This result was in contrast to studies in the same facility where poorer or no difference was observed in F/G for pigs fed with a WD compared to a CD feeder 4,5 ; therefore, this trial was conducted to validate the response of WD feeder on growth performance and to obtain further data to use in a meta-analysis comparing growth performance and carcass characteristics of pigs fed with CD and WD feeders.

Procedures
The Kansas State University Institutional Animal Care and Use Committee approved the protocol used in this experiment.The study was conducted at a commercial research-finishing barn in southwestern Minnesota.The barns were naturally ventilated and double-curtain-sided. Pens had completely slatted flooring and deep pits for manure storage.Twenty-four pens were equipped with a single-sided, 56-in.-wide,conventional dry stainless steel feeders (Thorp Equipment, Inc., Thorp, WI; Figure 1) with 4 14-in feeding spaces and a 4.25-in.-deeptrough.A cup waterer in pen using CD feeder ensured ad libitum access to water as well as feed.The remaining 24 pens were equipped with double-sided, stainless steel WD feeders (Crystal Springs, GroMaster, Inc., Omaha, NE; Figure 2) with a 15-in.-widefeeder opening on both sides and a single nipple waterer to provide water.Feeder opening was adjusted throughout the study to accommodate the flowability of feed and to provide unrestricted access to feed with little wastage for both feeder types.Daily feed additions to each pen were accomplished through a robotic feeding system (FeedPro; Feedlogic Corp., Willmar, MN) capable of providing and measuring feed amounts for individual pens.
A total of 1,253 pigs (PIC 1050 × 337) with an initial BW of 45 lb were used in a 104-d study.Pens contained 25 to 27 pigs with equal number of barrows and gilts.At the start of the trial, pens of pigs were weighed and randomly allotted to 1 of the 2 feeder types.All pigs were fed the same corn-soybean meal diets containing 30% bakery by-product and 10 to 45% DDGS during 5 dietary phases from 45 to 70 lb , 70 to 123 lb, 123 to 180 lb, 180 to 205 lb, and 205 to 246 lb (Table 1).Pens of pigs were weighed and feed disappearance was recorded at d 15, 43, 71, 83, and 104 to determine ADG, ADFI, and F/G.The experimental data were analyzed using the MIXED procedure of SAS (SAS Institute, Inc., Cary, NC).Pen was the experimental unit for all data and significance and tendencies were set at P < 0.05 and P < 0.10, respectively.

Results and discussion
For the overall period, pigs fed with the WD feeders had 3% greater ADG (P < 0.01; Table 2) and 4% greater ADFI (P = 0.01) than pigs fed with the CD feeders.No differences were observed in F/G (P = 0.50) among pigs fed with the WD vs. CD feeder.The improvement in ADG confirms previous results, where pigs fed with a WD feeder had greater ADG than those fed with a CD feeder (Bergstrom, 2011 4 ); however, in many of the previous studies, F/G responses varied widely among pigs fed with different feeder types.Many results show that pigs fed with WD feeders have poorer F/G than those fed with CD feeders (Bergstrom et al., 2011 4 ).Recent results of a study conducted at the same facility (Nitikanchana et al., 2011 6 ) found improved F/G in pigs fed with WD feeders.The variation in response to F/G among trials demonstrates the need for careful feeder management to ensure benefits in ADG are not offset by poorer F/G.