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ARS Home » Southeast Area » Booneville, Arkansas » Dale Bumpers Small Farms Research Center » Research » Publications at this Location » Publication #414350
Research Project: Innovations for Small Farms Pasture and Silvopasture

Location: Dale Bumpers Small Farms Research Center

Title: Sorghum-sudangrass intercropped with cowpea for improved pasture for stocker cattle in the mid-south

Author
item THOMAS, IVAN - University Of Arkansas
item Nieman, Christine
item COFFEY, KENNETH - University Of Arkansas
item POPP, MICHAEL - University Of Arkansas

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2024
Publication Date: 12/3/2024
Citation: Thomas, I.R., Nieman, C.C., Coffey, K.P., Popp, M.P. 2024. Sorghum-sudangrass intercropped with cowpea for improved pasture for stocker cattle in the mid-south. Applied Animal Science. https://doi.org/10.15232/aas.2024-02568.
DOI: https://doi.org/10.15232/aas.2024-02568

Interpretive Summary: Low summer and early fall forage availability and nutritive value are issues for cattle producers grazing stocker cattle over summer months in the mid-southern US. Summer annuals, such as sorghum-sudangrass, in comparison to perennials, provide greater forage management options as they i) are generally of greater quality, thereby supporting moderate cattle gains (= 2.2 lb per day), and ii) are drought tolerant allowing great amounts of forage mass accumulation over the summer to fill gaps in forage availability in late summer and extend the grazing season into early fall. Additionally, inclusion of legumes in pastures mixtures provide greater forage crude protein and digestible nutrients compared to grass monocultures, and improve cattle productivity. Cowpea is a legume widely cultivated across west Africa, frequently intercropped with sorghum as a grain crop. This study evaluated forage mass production and cattle performance on three forage types, mixed bermudagrass pasture, sorghum-sudangrass alone, and sorghum-sudangrass mixed with cowpea in 2021 and 2022. Steer average daily gains were greater on sorghum-sudangrass and sorghum-sudangrass-cowpea pastures compared to mixed bermudagrass pastures in both years. When planting occurred around mid-June, warm season annual yield was greater in summer and fall than mixed bermudagrass, even under drought conditions. However, late planting (late-June) resulted in fewer grazing days and the increased average daily gain on warm season annual pastures could not compensate, resulting in similar gain per area for warm season annual mixtures and mixed bermudagrass pasture.

Technical Abstract: The objective of the study was to evaluate stocker cattle performance and forage production and nutritive value in bermudagrass, sorghum-sudangrass, and sorghum-sudangrass-cowpea pastures. In summers of 2021 and 2022, 144 steers (8 per experimental unit) were assigned to one of three grazing treatments (2.27 ha each), mixed bermudagrass (MB), mixed bermudagrass overseeded with sorghum-sudangrass (SS), and mixed bermudagrass overseed with sorghum-sudangrass and cowpea (SSCW), in a randomized complete block design with three replications each. Available forage mass differed between years and among treatments, with a later planting date and wet conditions creating lower production in 2021. Both warm-season annual pastures accumulated greater amounts of forage mass in late summer and early fall compared to MB. Forage nutritive value was slightly greater in SS and SSCW, but cowpea did not improve forage nutritive value compared to SS. Across years and months, cowpea dry matter proportion averaged only 12.4%. Average daily gain was greater in SS and SSCW in both years (1 kg d-1 for SS and SSCW, and 0.8 kg d-1 for MB), but gain per hectare differed by year, with no differences among treatments in 2021, due to the lower number of grazing days in SS and SSCW, but when grazing days were similar, SS and SSCW had the greater BW gain per ha than MB. When warm-season annuals were planted in mid-May, forage mass accumulation was greater in summer and fall, even under drought conditions. Animal performance was improved on warm-season annual species, however, when late planting resulted in fewer grazing days than MB, the increased average daily gain on warm-season annual species could not compensate and gain per hectare was similar across species.