Sorghum is a globally significant grain crop, known for its adaptability to various climates and soil conditions. This versatile plant thrives in environments with limited water, making it a valuable food source in many agricultural systems worldwide.
Livestock Consumption
Sorghum is a primary feed source for various farm animals due to its energy and protein content. For cattle, both grain and forage sorghum are important feedstuffs, often replacing corn in rations. It is commonly used in silage, providing a digestible energy source for beef and dairy producers, with processing methods like steam-flaking enhancing digestibility.
The grain is also a component in poultry diets, substituting corn for broilers, turkeys, and laying hens. Modern tannin-free sorghum varieties improve nutrient digestibility for poultry, allowing inclusion rates of up to 70% in broiler and layer rations.
In swine nutrition, sorghum is a main grain source across all diet stages, from nursery pigs to finishing hogs. Its energy profile is comparable to corn, and it can contribute to firmer carcass fat, advantageous for processors.
Sorghum forage is also fed to sheep and goats, with its leaves and stems offering digestible fiber and protein. Some high-tannin varieties are explored for sheep and goats as potential natural dewormers.
Wildlife Foraging
Beyond domesticated animals, sorghum fields attract various wild species, providing sustenance and cover. Many bird species, including upland game birds like quail, pheasants, and turkeys, along with migratory birds such as doves and geese, consume sorghum seeds. Songbirds, including mourning doves, also feed on the seeds, particularly ground-feeding species.
Deer consume the seed heads of grain sorghum as they mature, providing a valuable carbohydrate source during fall and winter. While deer generally do not browse on the plant’s leaves early on, they utilize the seed heads once formed. Small mammals like rabbits, squirrels, and rodents also feed on accessible seeds in sorghum fields.
Common Pests
Despite its benefits, sorghum is susceptible to pests, causing crop damage. Insect species threatening sorghum include sap-feeding aphids (sugarcane aphid, corn leaf aphid, greenbug), armyworms (fall armyworm), and headworms (corn earworm, sorghum webworm) that feed on ripening kernels. Stem borers, sorghum midge, chinch bugs, and stink bugs also contribute to yield losses by attacking different plant parts.
Rodents like mice and rats damage seeds and young plants, impacting crop establishment and yield. Certain bird species are also pests, especially during grain development. Blackbirds, sparrows, and starlings consume ripening grain; some sorghum varieties are developed with a bitter taste to deter them. Other problematic birds include Quelea quelea, parrots, and pigeons, which can inflict substantial losses.
Factors Influencing Consumption
Several factors influence sorghum consumption, from its composition to its availability. Sorghum’s high nutritional content, offering energy from starch, protein, and essential minerals like phosphorus and potassium, makes it an attractive feed source.
However, some varieties contain anti-nutritional factors, notably tannins, which can reduce palatability and digestibility for certain animals, particularly non-ruminants like poultry and swine. Tannins can bind to proteins, reducing availability, though modern varieties often have low or no tannin content.
Another concern is the potential for prussic acid (cyanide) formation under stress conditions like frost or drought, posing a toxicity risk to grazing livestock, especially ruminants. The form of sorghum (whole grain, ground, ensiled, or steam-flaked) significantly impacts digestibility and intake. Its availability, whether cultivated or processed, also dictates consumption.