Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2001
Publication Date: N/A
Interpretive Summary: For economic and efficient production of meat and dairy products producers need an inexpensive, readily available on farm source of high protein forage. Legume crops such as alfalfa have traditionally been used to provide this high protein forage. Soybeans are less expensive to establish and do not require insecticide to prevent damage from annual infestations of the potato leafhopper. In addition, soybean is a spring-seeded annual that can provide high protein forage when winter killing depletes alfalfa stands. The U.S. Department of Agriculture recently released three soybean cultivars bred for use as forage: Derry, Donegal, and Tyrone. These soybeans improve the concentration of "crude protein" in the silage mixture when grown with crops such as corn or sorghum. The tall growing soybeans will obtain more light and grow more vigorously than the traditional grain type soybeans. The ability of the new forage cultivars to produce high yields of high quality forage will enable dairy farmers and livestock producers to more efficiently provide products such as milk, cheese, meat, and wool for consumers at reasonable prices. The information in this report will provide guidance to research and extension scientists in making recommendations to farmers producing forage for livestock enterprises.
Technical Abstract: Seven tall growing soybean (Glycine max [L.] Merr.) lines, including the cultivars Derry, Donegal, and Tyrone plus the experimental lines OR 5-12-1T, OR 13-12-3, OR 19-12-2 and PA 5-2-1, were tested for nutritive quality to evaluate the potential of these lines as silage crops. A grain type soybean (Hutcheson) and sorghum (Sorghum bicolor [L.] Moench) (Pioneer 838 F) served as checks. Lines were replicated four times at sites near Fayetteville and Rohwer, Arkansas in 1995 and 1996, harvested at full seed (soybean growth stage R-6) and ensiled for 33 d. The three released cultivars Derry, Donegal, and Tyrone produced average DM yields for both years of 5,216, 7,118, and 6,900 kg/ha at Fayetteville and 6,738, 6,398, and 6,300 kg/ha at Rohwer, respectively. The tallest entries grown in Fayetteville were Tyrone and OR 13-12-3, while Derry was tallest at Rohwer. Mean concentrations of ADF, CP, and IVDMD in silage from Derry, Donegal, and Tyrone were 33.0, 33.6, and 33.2%; 12.6, 14.2, and 14.0%; and 70.4, 72.1, and 70.6% at Fayetteville and were 33.9, 37.0, and 31.3%, 13.8, 16.0, and 13.7%, and 63.0, 66.8, and 62.5% at Rohwer for both years. Silage for all lines was well preserved as indicated by the low final pH and a high lactic acid concentration. Soybeans improve concentration of CP of the silage mixture when grown with crops like corn or sorghum, and tall growing soybeans should compete for light better than the grain type soybeans.