Date Full Report Received


Date Abstract Report Received



Primary Investigator:
Co-Investigators: Michael Tokach, S.S. Dritz, R.D. Goodband, Jim Nelssen, Devin Goehring, Brad James

The objectives of this research were to expand on current limited knowledge of feeding soybean hulls in diets for nursery and finishing pigs. A series of four experiments were conducted in commercial and university facilities feeding increasing levels of soybean hulls in combination with DDGS or in reduced particle size form on growth performance, caloric efficiency, and carcass characteristics.

In both nursery and finishing diets under both commercial and university settings, feeding up to 15% soybean hulls did not influence ADG or ADFI. However, the data showed some inconsistency in results for F/G between trials. Since the estimated dietary energy of soybean hull is lower than that of corn, feed efficiency would be expected to decline with increasing dietary levels. However, in the nursery, one study it was unchanged up to 10% of the diet, in another it began to worsen at as little as 3%, and in the third it was worse for 20% compared with 10 % soybean hulls. In finishing, F/G worsened as the level of soybean hulls increased in the diet, which was expected. One consistent response in both nursery and finishing diets was for improved caloric efficiency on both a ME and NE basis as the level of soybean hulls increased in the diet. This means that the book energy values associated with soybean hulls is too low, thus an underestimation of the economic value in swine rations could occur.

In nursery diets when the highest levels of soybean hulls and DDGS are fed together (12-15% soybean hulls with 30% DDGS) ADG was reduced. While not fully understood, this could be due to lower diet bulk density, reduced diet energy, and higher dietary fiber content leading to reduced nutrient digestibility or combinations of the above.
Reducing particle size of soybean hulls negatively impacted growth performance in both nursery and finishing pigs, This was not anticipated but an important discovery. The data showed that nursery ADG and ADFI and finishing F/G was poorer when pigs were fed ground soybean hulls compared to unground. In finishing, this led to worse caloric efficiency, which indicated that the energy value of ground soybean hulls is lower than that of unground. These data suggest that soybean hulls do not respond similarly to cereal grains when fed at a reduced particle size in nursery and finishing pig diets.
Carcass yield was reduced as the level of soybean hulls increased in fishing diets. This data is similar to other research where increasing levels of dietary fiber leads to greater gut fill and an increase in digestive tract tissue weights, thus causing a reduction in carcass yield and HCW.
Producer bottom line:
• Soybean hulls can be used up to 15% of the diet without affecting ADG but F/G will be poorer due to a lower diet energy concentration.
• Data reveals that current book values of soybean hulls underestimate the actual energy concentration. Thus, more research to accurately determine the ME and NE of soybean hulls is needed to value them correctly in swine diets.
• Soybean hulls should not be reground from the original particle size as growth performance was negatively impacted in both nursery and finishing pigs.
• Finishing pigs fed soybean hulls will have reduced carcass yield and thus lower hot carcass weight. Therefore, removing or reducing the level prior to marketing should be practiced, similar to feeding practices with other fibrous ingredients such as DDGS or wheat middlings.
Dr. Joel DeRouchey
Kansas State University
Department of Animal Sciences and Industry
222 Weber Hall
Manhattan, KS 66506