By Garth Ruff and Jason Hartschuh et.al.
The combination of poor quality hay made in 2018, historic alfalfa winter kill, and excessive rainfall across most of Ohio in the spring of 2019 created a large need for high quality alternative forage sources this past year. Record amounts of prevented plant acreage across the state created an opportunity to grow forages on traditionally row cropped acres. As crop and livestock producers planted a variety of forage and cover crop species to supplement feed stocks, it was recognized that there was also a need to gather forage analysis results from these fields in order for growers to properly value and feed the forage grown. The following data are from cover crop forage samples that were submitted by farmers and from OARDC research stations where annual forages were grown as part of the 2019 Ohio State eFields program available at your local extension office or digitalag.osu.edu/efields.
A total of 208 forage samples were collected by farmers and county Extension Educators and sent to a lab for wet chemistry feed analysis. With the variety and mixes of species grown, wet chemistry analysis was chosen for increased accuracy of nutrient composition. Near Infra-Red (NIR) analysis often cost less per sample, it is best utilized when evaluating alfalfa or frequently grown monoculture grass hay. Full trial results by location, more quality factors, and samples with less than 3 locations can be found at go.osu.edu/forages19 .
The following results in Table 1 show the differences in Yield, Crude Protein (%CP), TDN, NDF and Forage Value for species/mixes where there were multiple samples from at minimum, three locations across the state.
Table 1. Forage analysis of July planted Ohio cover crop and annual forages. Averages include ± Standard Deviation. Quality factors are statistically different across species when letters are different, a≠b.
Crude Protein levels vary and are greatly influenced by the amount of nitrogen applied to each field and rainfall after application. For example, plots at the NW Agricultural Research Station in Wood County received 4.2 inches of rainfall in 10 days after nitrogen application. Leaching of nitrogen from the plots were reflected in low forage Crude Protein levels. Ash values varied significantly across the sample species ranging from 5.67% – 18.67% across the tested samples.
Even when planted in July, corn was the highest yielding ‘cover crop’
Maturity at harvest also has significant impact on CP, TDN, and NDF values. As forages, especially grasses enter the reproductive stage TDN and CP tends to decrease, while NDF tends to increase. As NDF increases, intake can become limited.
When evaluating forages knowing the nutritional requirement of the livestock you are feeding is key. Nutrition factors to consider are Dry Matter Intake (DMI), %CP, TDN. On average, a lactating ewe requires the following: DMI-4%, TDN-64.52%, CP-14.84%. The needs of a 1,400 pound beef cow are vastly different depending on stage of production. The following are requirements for Maintenance: DMI-1.7%, TDN-50%, CP-7.1%, and Lactation: DMI-2.6%, TDN-59%, CP-10.6%.
To supplement low CP, TDN and high NDF forages, whole shelled corn, or corn gluten feed maybe a potential supplemental source of energy. Forages that are typically grown as winter annuals were found to either not grow or have extremely low yields when planted in the heat of summer, i.e. winter rye, winter wheat, and winter barley.
Considering economics, corn silage planted in July yields the best dollar per acre value, due to being significant higher yielding than other annual forages. After August 1st one may consider planting oats to fill a forage need. As previous Ohio State research has shown, it is recommended that oats intended for forage be planted in early August to prevent seed production.
Source : osu.edu