Soy hulls are a by-product of soybean processing for oil and soybean meal. According to the 1984 NRC publication, Nutrient Requirements of Beef Cattle, crude protein and TDN values are 12% and 64%, respectively. However, most of the soy hulls in this area check higher than this in protein. The energy value is also underestimated, especially relative to other feeds such as corn. Soy hulls contain highly digestible fiber which makes them an excellent supplement for high forage diets.
A previous study at this location showed soy hulls to have a feed value comparable to corn and soybean oil meal for growing beef calves in hay-based diets. This project was designed to further evaluate the feeding value and economics of soy hulls (SH) rela tive to corn (C) and soybean oil meal (SBOM) in hay and corn silage-based stocker rations.
A value was determined for the calves on this date that included the pre-conditioning and pasture cost from the date of purchase to November 30th. On November 30th, 80 head of uniform steers were selected for this trial and randomly assigned by breed and weight to one of 8 pens, 10 head per pen, 2 pens per treatment. Weights were taken on two consecutive mornings before feeding at the initiation and termina tion of the trial to determine weight gains.
The calves were fed rations balanced to provide 12.5% crude protein (CP) and 67.5% TDN. Ingredient prices of 26, 80, 140, 241 and 100$/ton, were used for corn silage, hay, ground corn, soybean meal, and soyhulls, respectively. The soyhulls contained 16.6% crude protein. All diets were formulated to provide at least 200 mg lasalocid/head/day.
Four pens received free choice hay supplemented with 6.5 pounds of grain mixture. Two of these pens received a ground corn plus soybean oil meal mixture (82% corn and 17% SBOM) and two a soy hull mixture (99% SH). Four pens received a free choice ration that consisted of 75% corn silage plus 25% grain supplement (dry basis). The grain supplement for two of these pens was 51% corn and 48% SBOM and the grain supplement for the other two was 17% SBOM and 82% SH. All 8 pens received trace mineralized salt blocks free choice.
A value of $93.97/cwt. was established for the cattle at the beginning of the trial, and final value was assumed to be $82.00/cwt. for the cattle in the four hay treatment groups and $80.00/cwt. for the cattle in the four corn silage treatment groups. The reason for this difference in value was the corn silage cattle weighed approximately 60 pounds more than the hay cattle at the conclusion of the trial. The total feed costs for the diets containing soy hulls averaged $17.32/hd. (hay ration) and $8.63/hd. (corn silage ration) lower than for the diets containing C+SBOM. Likewise, average feed cost/cwt. of gain was $7.00 lower for SH in the hay ration and $4.04 lower in the corn silage ration. The average return over feed costs and average net return, reduced by $25 per head fixed costs, were $12.56 per head higher for the SH diet than for the C+SBOM diet for the cattle receiving hay rations and $13.18 per head higher for the SH diet than the C+SBOM diet for the cattle receiving corn silage rations. Based on the crude protein and energy values the soy hulls should have been worth $144. 29/ton. However, based on the net returns, the realized value of soy hulls was $139.54/ton in the hay ration and $186.14/ton in the corn silage ration.