Effects on growing-finishing pigs fed with wet/dry feeders
By Kelsey Hammers, Jessica Jasper, Simon Kern, Lee Johnston, Jeff Knott and Mike Boerboom
Wet/dry feeders are a common feeder design used for growing and finishing pigs and have been increasingly incorporated into new swine barns in recent years. Considerable research has been conducted evaluating the effect of wet/dry feeders on pig performance. These feeders can reduce water wastage and simultaneously increase feed intake and daily gain of pigs.
However, studies evaluating feed efficiency and carcass characteristics of pigs fed from wet/dry feeders have not been consistent. Pigs fed from wet/dry feeders consistently gain faster compared to pigs fed from dry feeders but may have increased backfat depths and lower lean percentages at market.
An unanswered question related to wet/dry feeders is: Do pigs need an additional water source to optimize growth performance?
Water requirements can change depending on stocking rate, health status of pigs, season or the severity of heat stress. Water intake increases as pigs reach heavier weights, placing more pressure on the water source in a wet/dry feeder.
Therefore, our group conducted two studies to determine if the water source provided in a wet/dry feeder is sufficient to meet the water needs of pigs or if a supplemental water source would improve performance in growing and/or finishing pigs.
In the first study, pigs were assigned randomly to pens with only a wet/dry feeder (SDI, drop shelf wet/dry feeder, 15 pigs per 15” feeder opening) or to pens equipped with a wet/dry feeder and a fixed double water nipple (Figure 1).
The trial commenced at the beginning of the growing phase (initial body weight = 53.9 lb) and ended at the first marketing event as we assumed that the most pressure on the water sources occurred when all pigs were present in each pen. Overall growth performance was unaffected by the addition of an extra water source to pens (Table 1); however, water disappearance increased by 0.6 gallons/head/day.
Supplemental Water1
No Yes
Trial 1. Growing and finishing periods2
Table 1. Effect of a supplemental water source on overall performance of growing-finishing pigs
1All pens contained a wet/dry feeder. Selected pens were equipped with an additional fixed double nipple waterer starting on d 0 up to marketing in Trial 1 and on d 56 throughout marketing in Trial 2. 2Pigs (n = 2,332; average initial BW = 53.9 lb) were used in a growth performance study with 27 to 30 pigs per pen and 40 replicates per treatment. 3Calcuated as total gallons used divided by number of total pig days. Represents daily measurements of water disappearance across all pens in each treatment for each trial, thus statistical analysis was not conducted. 4Pigs (n = 2,388; average initial BW = 163.0 lb) were used in a growth performance study with 27 to 30 pigs per pen and 40 replicates per treatment.
From the results of this initial study, we concluded the wet/dry feeder provides adequate water to meet the needs of growing-finishing pigs. However, results may differ if the trial was conducted in summer and if the additional water source was first available at the beginning of the finishing stage during peak water needs.
Thus, in the second study, pigs were assigned randomly to pens with a wet/dry feeder or to pens with a wet/dry feeder in combination with the fixed double water nipple. The additional nipples supplied water from the beginning of the finishing phase (average initial body weight = 163.0 lb) until all the pigs were marketed.
This second study was the combination of two trials that were conducted from December to April and June to September 2021 in southwestern Minnesota.
In contrast to our first study, pigs with access to the additional water source experienced reduced daily gain and feed intake compared to pigs only drinking water from the wet/dry feeder. Pigs with access to a secondary water source exhibited reduced market weight due to depressed feed intake and growth.
Water disappearance also increased by 0.7 gallons/head/day when pigs were offered the additional water source. Pig behavior was not monitored, but we theorize that pigs preferred drinking water from the water nipple and spent less time at the feeder and consequently less time eating.
From these studies, we concluded that offering an additional water source to pigs in a finishing barn equipped with wet/dry feeders has minimal benefits to pig growth performance, increases water usage and likely increases water wastage.
Hammers and Johnston are with the University of Minnesota, West Central Research and Outreach Center; Jasper, Kern and Knott are with Ideal Animal Nutrition; and Boerboom is with Boerboom Ag Resources.