Bermuda grass (Cynodon dactylon) is a warm-season perennial grass widely utilized as a forage base across the Southern United States. Its deep-rooted, sod-forming nature allows it to withstand high temperatures and drought conditions, making it a reliable pasture and hay crop. For cattle operations, the suitability of Bermuda grass depends entirely on management practices, as its quality can fluctuate dramatically. Evaluating its nutritional profile, required management, and potential health concerns is necessary to determine its value for livestock production.
Nutritional Composition and Value
The nutritional contribution of Bermuda grass to a cattle diet is highly dependent on its maturity at harvest or grazing. When managed optimally, the forage can provide a good balance of energy and protein for many classes of cattle. Crude Protein (CP) levels in high-quality hay or pasture range between 10% and 15%, sufficient for a mature, non-lactating cow. This value decreases sharply as the plant matures, falling below 8% if the grass develops a seed head.
Total Digestible Nutrients (TDN), a measure of energy, also tracks closely with the plant’s age, often falling between 55% and 60% for hay cut at four-week intervals. Fiber content is measured by Neutral Detergent Fiber (NDF) and Acid Detergent Fiber (ADF), which indicate the bulkiness of the feed and its digestibility. High-quality Bermuda grass hay generally contains NDF levels around 70% and ADF levels near 35%, which is acceptable for ruminants. Early cutting ensures the fiber remains digestible, preventing the lignification that occurs with older forage.
Forage Management: Grazing and Hay Production
Proper management is necessary to maintain the forage quality of Bermuda grass pastures and hayfields. For grazing, cattle should be introduced when the grass reaches six to eight inches, and moved before it is grazed below three to four inches. This rotational grazing practice ensures the plant retains enough leaf area to recover quickly and prevents overgrazing, which depletes root reserves.
Hay production requires intensive fertilization, particularly with nitrogen, to maximize both yield and protein content. Applications of 50 pounds of nitrogen per acre are recommended after each cutting to support rapid regrowth. To secure high-quality hay, cut the grass at a four-week interval, before the seed head emerges. Harvesting on this schedule ensures the forage is in a vegetative state, offering the highest possible Crude Protein and TDN concentrations.
Potential Health Risks for Ruminants
While generally safe, Bermuda grass can present several health hazards under certain environmental or management conditions. One concern is nitrate poisoning, which occurs when plants accumulate excessive nitrogen, particularly after heavy fertilization followed by drought or cloudy weather. The nitrates convert to toxic nitrites in the rumen, impairing the blood’s ability to carry oxygen and potentially causing sudden death.
A neurological disorder known as “Bermuda grass tremors” (BGT) can affect cattle grazing on infected pastures. This condition is believed to be caused by a toxin produced by mold or fungi growing on the grass, and the toxic agent can persist in hay. Affected animals display muscle twitching, particularly of the head and flanks, with symptoms worsening when the animal is excited or forced to move quickly.
A third concern involves the formation of urinary calculi, or “water belly,” especially in male cattle. This condition, known as obstructive urolithiasis, is a blockage of the urinary tract by mineral stones. Poor-quality Bermuda grass hay with mineral imbalances can contribute to the formation of these stones in steers. Maintaining a proper calcium-to-phosphorus ratio in the total diet is necessary to mitigate this risk.
Key Cultivars for Livestock Forage
Common Bermuda grass is often low-yielding and inconsistent in quality, leading to the development of superior hybrid cultivars specifically for livestock. These hybrids are sterile and must be established vegetatively using sprigs, but they offer significant improvements in production and digestibility.
Coastal Bermuda Grass
Coastal Bermuda grass, released in 1943, is a hybrid known for its high yield, longevity, and excellent drought tolerance. It became the industry standard for decades, adapting well to a wide range of climatic conditions.
Tifton 85
Tifton 85 is a more recent and improved hybrid, resulting from a cross with a close tropical relative, stargrass. This variety produces approximately 25% more forage and is about 10% more digestible than Coastal, leading to better animal weight gains.
Jiggs
Jiggs is valued for its rapid establishment and ability to perform well on poorly drained or “tighter” soils where other hybrids might struggle. While its nutritive value is similar to Coastal, its regional adaptation offers a distinct advantage for producers in certain soil types.