DDGS decreased feed-to-water ratio
Critical to consider water usage alongside feed formulation strategies in swine production
By Daniel Rosales, Eric Weaver and Ryan Samuel
In recent years, the utilization of distillers’ dried grains with solubles (DDGS) in swine diets has increased. The use of DDGS, a co-product of the ethanol production process, has emerged as a valuable feed formulation strategy replacing portions of more expensive corn and soybean meal in swine diets.
However, in the face of increasing pressure to optimize production efficiency while maintaining sustainability of the swine industry, all the inputs associated with swine production, including water usage, should be considered.
In previous trials, pigs showed no differences in average daily gain, average daily feed intake, or feed efficiency between different diets. However, water usage was doubled for those pens fed a diet containing phytase.
At the South Dakota State University commercial wean-to-finish research barn, grower pigs were distributed into 44 pens. Each pen was balanced evenly by sex, averaging 25 pigs per pen, and the initial body weight was 60.2 ± 6 lbs. Experimental diets were fed as four distinct treatments over two phases. In particular, treatments included a corn and soybean meal diet with or without 30% DDGS.
Pens of pigs were weighed as they entered the barn and at the end of each diet phase. The weight gained, the feed delivered and remaining, and the water usage between each phase of the trial was used to calculate average daily gain, average daily feed intake, and average daily water intake for each treatment. The trial occurred over a month and a half where attention was paid to dietary composition and its potential impact on feed intake and water consumption patterns.
This specific farm is equipped with water meters per pen, with each pen having access to four different water sources. By leaving only one of the four open per pen and assigned to be the same with the pens from the same treatment, the water consumed for that specific treatment can be measured. There are water meters for the main line of each of those water lines, meaning that water usage is measure per pen and per treatment.
Determining feed intake made use of a feed density equation. The measured distance from the feed to the top of the feeder was used in the equation to determine the amount of feed that remained in a feeder on weigh days. That value, subtracted from the amount of feed that was dropped by the Feedlogic feeding system, calculated that amount of feed that disappeared from that pen.
Although detailed results for the growth performance of pigs during the trial are pending, the current analysis indicated that treatment did not affect average daily feed intake.
However, at the same time, water usage increased when pigs were fed corn and soybean meal diets with DDGS, and it approached 1 gallon of water for every 2.5 pounds of feed. Therefore, the feed-to-water ratio decreased below previously observed estimates for pigs consuming 1 gallon of water for each 3 or 4 pounds of feed consumed taken from Brumm’s reported values of 1/4 to 1/3 gallon of water per pound of dry feed.
Water intake may increase due to the high fiber content of DDGS. Fiber can absorb water in the digestive tract and increase the bulk of digesta in the pig and stimulate thirst in pigs, leading to higher water intake. Furthermore, the presence of fiber in DDGS can also influence the rate of passage of digesta through the gastrointestinal tract. High-fiber diets tend to slow down digestive transit time, allowing for more efficient fermentation of nutrients in the hindgut. This prolonged retention of digesta in the gut may stimulate pigs to drink more water to aid in the digestion and processing of feed.
The utilization of DDGS in swine diets showcased a significant impact on water consumption, leading to a decrease in the feed-to-water ratio. However, it’s essential to note that while these initial findings shed light on the potential influence of DDGS on water intake in pigs, detailed results regarding growth performance from the trial are pending.
Nevertheless, the observed increase in water intake with DDGS inclusion underscores the necessity of considering water usage alongside feed formulation strategies in swine production. It becomes increasingly clear that an approach, integrating both nutritional and environmental considerations, will be crucial in optimizing feed and water management practices to enhance the efficiency and sustainability of swine production systems.
Rosales is a graduate research assistant, Weaver is an assistant professor and Samuel is an assistant professor and Extension swine specialist, all with South Dakota State University. Photos courtesy of SDSU.
