Organic Swine Research

May 2023

By Yuzhi Li, Organic/Alternative Swine Production

Our organic pigs and hybrid rye project (titled: Integrating hybrid rye as a winter annual crop into organic pig production) has entered its second year of the grant period. One of the goals of this project is to evaluate whether growing organic winter hybrid rye for pig feed and bedding is economically viable. The economic viability depends on yield of organic winter hybrid rye and performance of pigs fed diets supplemented with hybrid rye.      

For optimizing hybrid rye yield, over the past year our team conducted a plot trial to test manure application rates on yield of organic winter hybrid rye. Three types of swine manure were tested: liquid, raw solid, and composted. Each type of manure was applied at five different rates: 0, 60, 120, 180, or 240 lb of available nitrogen per acre. Compared to solid and composted manure, liquid manure resulted in the highest yield of rye grain (about 100 bushels per acre for liquid manure versus about 80 bushels for solid and composted manure). In terms of manure application rates, the first year’s data demonstrated that applying liquid manure at 120 lb of available N can achieve the desired yield.

Besides the plot trial, we grew winter hybrid rye on 17 acres of organic land in 2021 and 2022 for pig feed and bedding. The organic land we used to grow winter hybrid rye had organic oats in the field before we planted rye. After chopping oat crops and mowing the field for weed control, we applied liquid manure to the field 3 days before planting rye. We planted winter hybrid rye on September 27, 2021. Then, the field was swathed the next year on July 19, and combined on July 22, 2022. Average hybrid rye yield was 104 bushels (with 13% moisture) per acre, and forage (straw) yield was 1.8 ton per acre.

We used hybrid rye grain and forage harvested in 2022 for feed and bedding, respectively, in a pig trial. The animal trial aimed at evaluating how integrating hybrid rye can impact the performance of pigs and costs of feed and bedding. In the study, we replaced 50% of organic corn with organic hybrid rye in diets fed to pigs from 50 lb to market weight (250-270 lb) in a hoop barn. The hoop barn housed two pens of pigs (50 pigs per pen), with one pen for pigs fed rye diets (treatment group), and another for pigs fed corn-soybean meal (SBM) based diets (control group) side-by-side. Pigs were managed from birth to market according to the standards of the National Organic Program. By now, we have collected data of growth performance and bedding usage from 200 pigs in two farrowing groups. Preliminary results indicate no difference in growth performance between pigs fed rye diets and pigs fed corn-SBM diets. On average, each pig in both treatment and control groups gained about 200 lb in 12 weeks. Over the 12 weeks of the growing-finishing period, a pig consumed about 555 lb of feed on average, resulting in a feed to gain ratio (feed efficiency) being 2.77 to 1 which means for each lb of weight gain, a pig needed 2.77 lb of feed. We estimated that replacing 50% of organic corn with organic hybrid rye in pig diets will save $23 per pig on feed costs, which is approximately 10% of total organic feed costs ($219/pig) during the growing-finishing period. Our straw usage for bedding in the hoop barn was 225 lb per pig on average, which was about $17 per pig. Using hybrid rye forage for bedding, we saved about $16 per pig or 93% of total organic bedding costs. These preliminary data suggest that integrating winter hybrid rye into organic pig production can save feed and bedding costs.

This project is still in progress. Currently, we have organic winter hybrid rye that was planted in September 2022 in the field at the WCROC. Meanwhile, we are repeating the plot trial for the second year. We expect to harvest hybrid rye in July 2023. Then we will use hybrid rye to repeat the animal trial for two more groups. Additionally, we plan on hosting an organic hybrid rye field day in conjunction with organic dairy and swine day on June 22, 2023. Please join us on June 22 to learn more about our organic swine and winter hybrid rye project.

This project is supported by the Organic Research and Extension Initiatives (OREI) of the USDA National Institute of Food and Agriculture (NIFA).