This experiment was completed in Wenger Feeds Swine Research Barn.
Background: Distiller’s Dried Grains with Solubles (DDGS) are a byproduct of ethanol production. The increased demand for ethanol in the U.S. has dramatically increased the availability of DDGS to the feed industry. The large volume of DDGS available to industry has made DDGS an attractive byproduct from a cost standpoint. Nutritionally, DDGS has been shown by several researchers to work well in swine grow-finish diets at levels up to 20% of the diet.
DDGS has a high oil content (~ 10%), which is primarily made up of unsaturated fatty acids. Feeding high levels of unsaturated fatty acids to grow-finish pigs can result in softer fat, which may negatively influence meat quality. A recently completed study at the Jim Charles Research Farm indicated that the inclusion of 15% DDGS in finishing diets resulted in a 5 unit increase in the iodine value of bellies (85 to 90) and increased the incidence of soft bellies.
Although the use of DDGS in finisher diets may result in substantial cost savings, these savings on the live production side must be balanced with the potential negative effects of reduced belly quality. In addition, several researchers have reported reduced carcass yield when DDGS are included in finisher diets; although, a reduction in carcass yield was not evident in the previously described experiment.
Although the use of DDGS in finisher diets may result in substantial cost savings, these savings on the live production side must be balanced with the potential negative effects of reduced belly quality.
Based on this background information, two experiments were conducted to evaluate the effect of feeding diets with or without DDGS on the performance and carcass characteristics of Newsham grow-finish pigs. The level of DDGS was reduced from 30% in the grower diets to 5% in the finisher diets to evaluate whether a reduction in dietary DDGS level can overcome the increased incidences of soft bellies.
PROCEDURES: Two experiments were conducted at the Jim Charles Research Barn. The research barn is a tunnel-ventilated commercial swine building with fully-slatted floors. Experiment 1 was conducted from March to August, 2008 (summer harvest) and Experiment 2 was conducted from August to December, 2008 (fall/winter harvest).
A total of 1,120 pigs were used in Experiment 1, and 1,140 pigs were used in Experiment 2. Pigs were Newsham pigs (XM x Supermom) with an average initial weight of 51.0 and 60.9 lb in Experiment 1 and 2, respectively. Pigs were housed at 280 pigs per pen in Experiment 1 and 285 pigs per pen in Experiment 2.
|Table 1. The Effect of DDGS on the Live Performance of Pigs.|
|Experiment 1||Experiment 2|
|Initial Wt, lb||51.9||51.9||60.6||60.6|
|Final Wt, lb||266.0||262.2||276.6||287.4|
|Days on Feed||121||122||112||111|
|Daily Gain, lb||1.77||1.72||1.95||1.92|
|Daily Feed, lb||4.66||4.67||5.03||5.17|
|Feed Cost/lb Gain, $/lb||.419||.418||.345||.353|
|a,b Means within an experiment with different superscripts are different (P < 0.05).|
|Table 2. The Effect of DDGS on Carcass Characteristics of Pigs.|
|Experiment 1||Experiment 2|
|Carcass Wt, lb||203.7||202.5||208.8||208.9|
|Carcass Yield, %||77.0||76.8||75.0a||75.5b|
|Fat Melting Point, degrees F||80.30a||73.85b||76.35c||74.70d|
|a,b Means within an experiment with different superscripts are different (P < 0.05).
c,d Means within an experiment with different superscripts are different (P < 0.13).
Pigs were allotted to one of two dietary treatments. Treatment 1 was a standard, 5-phase grow-finish feeding program. Treatment 2 was as Treatment 1 with DDGS replacing corn and soybean meal at 10, 15, 15, 10 and 5% in Phases 1 to 5, respectively. Pigs were fed 50, 75, 100, 125 lb/pig of the Phase 1 to 4 diets, respectively. The Phase 5 diets were fed to week 15. Paylean (4.5 g/ton) was added to both treatment diets from Week 15 to market. The Treatment 2 diet with Paylean contained 5% DDGS.
All diets were corn-soybean meal based and contained wheat middlings and bakery byproduct meal. The level of byproducts added to diets was consistent between treatments. All diets were high energy diets containing 5.4 to 6.0% added fat.
At marketing, pigs were kept separate on the truck, by pen, to maintain treatment identity upon arrival at the plant. Pigs were loaded on a split load trailer with each pen of pigs (4 pens) identified on the trailer. An equal number of pigs from each treatment were marketed at one time. In Experiment 1, the first pigs were marketed on June 30, 2008 (day 105 of experiment) with final marketing on August 5, 2008 (day 141). In Experiment 2, the first pigs were marketed on November 17, 2008 (day 91) with final marketing on December 16, 2008 (day 120).
Animals were evaluated through the unloading process. Pigs were separated into separate lots at the plant and lots were harvested on the same day. Carcass tattoo and sequence was identified, and Autofom data was collected and recorded. Autofom data included backfat, percent primal, ham weight, loin weight, shoulder weight, and bacon weight. Fat melting point and iodine value was determined on belly fat collected from carcasses. Iodine value is a measure of the degree of unsaturated fatty acids in fat. A more unsaturated fat has a higher iodine value, which has been shown to be associated with soft bellies.
RESULTS AND DISCUSSION: The live performance of pigs is presented in Table 1. The inclusion of DDGS in diets had no influence (P > 0.10) on the growth rate or the efficiency of feed utilization of pigs. In Experiment 2, feed efficiency was nearly 5% poorer when DDGS was included in diets, and this appeared to be associated with an increase in feed disappearance. No difference (P > 0.10) in mortality or culls was apparent between treatments.
The effect of dietary inclusion of DDGS on carcass characteristics is presented in Table 2. Carcass yield was improved (P < 0.05) by the inclusion of DDGS in diets in Experiment 2, but no difference was seen between treatments in Experiment 1. Other researchers have reported a reduction in carcass yield when DDGS are included at greater than 10% of the diet. The reasons for improved carcass yield when DDGS was added to the diets in Experiment 2 are not clear and are not consistent with other research. The overall percent of primal cuts and the weight of the individual primal cuts were not different between treatments (P > 0.10) in either experiment.
Belly fat melting point tended to be lower and belly fat iodine value tended to be increased when DDGS was included in diets. These differences resulted in a greater incidence of soft bellies. However, the difference in iodine value in the second experiment (2 unit increase) was not as great as the difference observed in the first experiment (5 unit increase in iodine value). Possibly, this is a seasonal effect, which would be consistent with anecdotal data suggesting problems associated with soft bellies are greater in the summer.
SUMMARY: The results of these experiments suggest that the addition of DDGS at levels up to 30% of grower diets and then gradually reduced to 5% in finisher diets has little to no influence on live pig performance. However, the program for reducing DDGS in late finisher diets was not effective in preventing the negative effects of increasing the incidence of soft bellies, increasing iodine value of belly fat, and reducing fat melting point; although, this negative effect appeared to be less when pigs were harvested in the fall/winter compared with summer.
The potential cost savings associated with the use of DDGS in grow-finish diets with the current fat source needs to be weighed against the increased potential for soft bellies at the processing plant.
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