"How much distillers’ dried grains with solubles can I add to my finishing-pig diets?” That’s a question many producers are asking, but providing a general recommendation for inclusion levels is more challenging. 

According to Joel DeRouchey, animal scientist at Kansas State University, “Quality is the deciding factor on DDGS feeding recommendations. If you’re looking at it from a growth standpoint, you have to find out if it’s best to feed anything from zero percent to 30 percent.”

Kansas State animal scientists have completed a series of projects to evaluate the effects of DDGS levels on growth performance and carcass characteristics on market hogs.

  • The first project included 1,050 pigs, starting with an average weight of 104.9 pounds each. Researchers conducted the 28-day study with seven replications per treatment. They fed pigs a diet that included zero percent or 15 percent DDGS, with zero percent, 3 percent or 6 percent choice white grease. All diets had an equal lysine-to-calorie ratio.
  • The second project consisted of 1,038 pigs with an average starting weight of 102.1 pounds each. This 56-day study had 10 replications, feeding zero percent, 10 percent, 20 percent or 30 percent DDGS. Once again, the diets contained equal lysine-calorie ratios.
  • The third project involved 1,112 pigs averaging 110.4 pounds initially. The 78-day study had nine replications per treatment, feeding zero percent, 5 percent, 10 percent, 15 percent or 20 percent DDGS. Like the others, each diet had an equal lysine-to-calorie ratio. (See chart below for a breakdown of average daily gain for different DDGS levels in the finishing-pig diet).

The studies were all conducted at the same commercial research site with all of the DDGS sourced from the same plant. DeRouchey says the results indicate that pigs could be fed a finishing diet of 10 percent to 15 percent DDGS before growth performance was reduced.

Other studies show varying results of DDGS inclusion in finishing-pig diets.

For example, according to a University of Minnesota study, feeding no more then 10 percent DDGS to grow/finish pigs is the ideal level from a growth standpoint. On the other hand, a study from Akey Co. and Dakota Gold Research shows that up to a 30 percent inclusion rate works well in terms of pig growth.

Of course, most ethanol plants don’t have data on how their DDGS products perform in swine diets or the impact on hog growth performance. DDGS suppliers have only limited nutrient-analysis data. That’s why you have to investigate the suppliers’ product quality, nutrient levels and product consistency for yourself.        

So far, there are no standard guidelines for measuring those factors. “This takes producer research,” DeRouchey says. “If you’re confident in a DDGS source, make sure you monitor your packer closeout data to see if there are any trends in decreased performance, either on pig growth or carcass.”

While the DDGS swine-growth-performance data is fairly positive, the same cannot be said for carcass characteristics. From a carcass standpoint, including DDGS in finishing-pig diets tends to increase the iodine levels, which in turn causes softer carcass fat. The degree of softness depends largely on the DDGS levels and on what other ingredients you include in the finishing diet. The overall issue is the amount of unsaturated fat that ends up in the diet with DDGS and other ingredients, especially when you add fat.

This is important because softer fat makes the carcass more difficult to process and can potentially shorten the meat’s shelf life.

DeRouchey points out that some packers have set maximum carcass-iodine levels, so it’s wise for you to have a conversation with your packer about incorporating various sources of unsaturated fat into your finishing diet.   Initial data indicates that feeding 10 percent DDGS will not alone increase the carcass-iodine values to a point where a packer will discount or refuse the carcass.  

“The biggest concern on the carcass side is the drop in percent yield,” DeRouchey says. “On average in published trials, for every 10 percent DDGS fed, you lose approximately 0.5 percent in yield. On a 265-pound hog that equals to 1.3 pounds of carcass.” (See chart below)

Understanding that you could take a hit on carcass yield, you will need to balance that with the cost of DDGS to create a diet that’s cost-effective enough to overcome the lost revenue, he notes. Unfortunately, you probably won’t get a good handle on DDGS’ impact on your herd’s carcass yield until you have some closeout sheets in hand to compare. Still, “the research data is clear that there is a real effect that you must  account for when figuring the economics of DDGS use,” DeRouchey says.

Ultimately, feeding DDGS to finishing pigs is an option worth considering. However, it’s an individual option that requires personal considerations such as potential DDGS suppliers’ product quality and consistency; packer demands; and an overall economic evaluation, including both growth performance and carcass characteristics for your herd.


ANOTHER LOOK AT GROW/FINISH PIGS

University of Minnesota researchers ran a test on 240 crossbred hogs, averaging 62-pound starting weight. The pigs were randomly assigned, based on sex and weight, into one of four dietary treatment groups.  Each group was fed a diet formulated at different distiller's dried grains with soluables concentrations (zero percent, 10 percent, 20 percent and 30 percent).  All diets were calculated to meet amino acid, metabolizable energy and mineral requirements throughout the feeding period.  Pigs were marketed at a 250-pound average weight.

In the study, the pigs receiving diets with 20 percent and 30 percent DDGS levels had reduced average daily gain in the growing and finishing stages. The DDGS levels did not affect average daily feed intake. The pigs receiving 30 percent DDGS did have a drop in feed efficiency, compared to the other three groups.

Carcass characteristics showed that loin depth declined in pigs fed 30 percent DDGS versus the other groups. Backfat and percent lean revealed no difference between the pig groups. Pork quality evaluations-- color, marbling, ultimate pH-- of the loin muscle did not differ between groups. As for loin tenderness, DDGS levels did not influence those scores.

While DDGS will no doubt find a role in finishing-pig diets, determining the right levels for your herd and your packer will be important.


MAINTAIN GROWTH WITH DDGS

Increasing the amount of distillers’ dried grains with solubles in finishing-pig diets doesn’t tend to have a big impact on average daily gain. The key is to work with your supplier to continually monitor the quality and consistency of the DDGS. This chart shows that average daily gain only slightly declines with increased DDGS levels.


CARCASS QUALITY LOSES OUT

More isn’t always better, especially when it comes to carcass quality traits. This chart outlines how carcass-yield-percentage declines as you increase the levels of distillers’ dried grains with solubles in finishing-pig diets. There also are questions and concerns about soft carcass-fat levels at some DDGS inclusion rates.