Angular Limb Deformities

Angular limb deformities are very common in all breeds of foals. These can include both an inward deviation of the joints (varus) or outward deviation of the joints (valgus). Most commonly these deviations are seen in the knee, hock and fetlock joints. The foal can have one or more joints affected, and can also vary quite widely in the severity of the condition. The causes of this condition vary, with some the manager can address, while others are due to random chance. Both premature and dismature foals very commonly have angular limb deformities due to the lack of strength in supporting structures, or the failure of complete ossification of the cuboidal bones (small bones of the knee and hock). The causative factors of these conditions may be an infection or inflammation of the placenta or uterus, twinning, and severe stress in the mare. Development of angular limb deformities post foaling is due to a difference in the growth rate across the inside and outside of the growth plate. In essence, the difference in speed in bone development causes the bone to veer to one side or the other. This can be due to a variety of factors including dietary imbalances, environmental factors, as well as genetics.

If your foal does have angular limb deformities, there are actually many therapeutic management techniques used to help straighten the limb. They range from quite simple to the complex and expensive, usually depending on the severity of the deviation. Conservative techniques involve stall rest in order to prevent uneven loading of the foal’s developing legs. The foal may be bandaged or splinted, or the hoof can be trimmed or glue on extensions can be used to help straighten the limb. For example if the foal has a valgus deformity in in its knee (the lower leg will sweep outwards), the outside hoof wall is lowered, or a glue on extension is placed on the inside of the hoof. Often dramatic improvements are seen with these simple techniques. If the limb deviation is more severe, and budgets allow, corrective surgery may be required. These include periosteal stripping, or placing screws, staples or wires across the growth plate. The goal of periosteal stripping (removing a section of the periosteum, or membrane covering the bone) is to accelerate growth of the side of the bone growing too slowly. Typically this procedure is done in young foals. Alternatively, transphyseal bridging is used to slow down the rate of growth on the side of the bone with too fast a growth rate. However, consult with your veterinarian to decide which management technique is the correct one for your foal. Mismanagement can acerbate the problem, and it is also possible to overcorrect the foal, and end up with a deviation in the opposite direction!

Want to know the difference between premature and dismature?

Premature foals are those born before 320 days of age, while dismature foals may be of a normal gestational age but are weak, small and appear unready to have been born. These foals are typically thin, are slow to stand, have poor suckle reflex, can chill rapidly and are marked by fine silky hair coats and soft ears and lips. These foals will require a high level of assistance in their care, but with proper supportive care and a lot of time and effort, can continue on to lead normal lives.

Kris Hiney, PhD

Equine Extension Specialist

Oklahoma State University

Bermudagrass for Forage

Agricultural producers in central Oklahoma should be finalizing plans now if they want to establish bermudagrass for forage production.

Bermudagrass used as forage may be a viable option for central Oklahoma cattle producers and horse owners. A good bermudagrass field has the potential to produce several tons of good-to-fair-quality hay and several months of grazing for beef cattle and horses. However, Lee explains it is important producers recognize the establishment of bermudagrass pasture is an expensive operation and several steps should be considered if they are to receive a return on their investment.

A producer’s first consideration should be where to try to establish the bermudagrass pasture. “The more fertile the ground, the better production a producer will obtain from bermudagrass,” Lee said. “Clayey, upland soils with low fertility are probably better suited to native grass species.” A well-prepared firm seedbed is essential to getting a good stand of bermudagrass. It is best if the soil is fully prepared and sprigs or seed are planted soon after a rain without disturbing the soil. “Many failures have been caused by loose soil drying out beneath newly planted sprigs or seed,” Lee said. “On very sandy wind-blown soils, bermudagrass can be sprigged directly into small grain stubble.”

Bermudagrass is a permanent pasture that requires a large amount of nutrients. Immobile nutrients such as phosphorus and potassium should be added and incorporated into the soil. Any issues with soil acidity and alkalinity also should be corrected before the crop is planted.

“Any field with a pH below 5.7 should be limed according to a soil test,” Lee said. “Nitrogen is a mobile nutrient and can be added from the top.”

Hybird types of bermudagrass can be sprigged, while non-hybrid types can be seeded. Under high fertility, an adapted hybrid type typically will out produce a seeded type. The most widely sprigged types in central Oklahoma are Midland, Midland 99, Tifton 44 and Hardie. Further south, varieties such as Coastal produce excellent yields, but are not winter hardy enough for locations such as McClain County.

“Producers who are unsure what varieties are most suited to their specific locale can receive useful insights by contacting their OSU Cooperative Extension county office,” Lee said. “We’re listed under ‘County Government’ in most local directories.”

In general, common-seeded bermudagrass varieties produce 70 percent to 95 percent of the production of a hybrid type under high fertility. Also, common-seeded bermudagrass varieties tend not to be very winter hardy. Two notable exceptions are Guymon and Wrangler. “Even though Guymon and Wrangler have lower yields compared to hybrids, they may be the best choice under certain circumstances,” Lee said. “The cost of establishment is generally cheaper than sprigging. On small acreages, seeding may be the most cost-effective choice in situations where sprigging would be difficult or where maximum forage production is not important.”

On larger fields, hay fields and where high forage rates are needed, Lee favors the use of sprigs, all other considerations being equal. “For McClain County and areas similar to ours, the best time to plant sprigs would be between March 1 and May 1,” Lee said. “Twenty bushels of sprigs per acre planted, 1.5 to 2 inches deep should be sufficient. More sprigs will encourage lapping or coverage faster.”

Seeds should be planted between April 15 and June 1 at a rate of 3 to 5 pounds of pure live seed – often referred to as PLS – per acre.

“Grazing and haying should be delayed until runners lap or until dormancy the first year,” Lee said. “Once established, it takes approximately 50 pounds of nitrogen for every ton of forage produced.”

Additional information about bermudagrass forage production is available online from OSU’s Division of Agricultural Sciences and Natural Resources at http://osufacts.okstate.edu through OSU Extension fact sheet PSS-2583, “Choosing, Establishing and Managing Bermudagrass Varieties in Oklahoma.”