What is Buffel Grass Poisoning?
Buffel grass is a quick growing bunchgrass normally found in tropical areas in fields, deserts, woodlands, waste areas, roadsides, and other poor draining areas. Although it is native to Africa and Asia, it is now found worldwide used for control of erosion and fodder. However, it is considered an invasive weed in Hawaii, Mexico, southwestern United States, and Australia. It has long gray or bluish green leaves and a hairy seed head that looks similar to foxtail and grows up to four feet tall. The insoluble calcium oxalates in the plant will eventually cause a lack of calcium in the body and create life-threatening emergency situations such as broken bones and collapse. This is especially concerning in foals, yearlings, and lactating mares.
The insoluble calcium oxalates in buffel grass (Cenchrus ciliaris) are toxic to horses and may even be fatal in some cases, depending on how much is consumed. Insoluble calcium oxalates are acids that are found in many different kinds of plants and cause chronic or acute poisoning in horses. In the case of buffel grass, the oxalates are insoluble so the calcium cannot be absorbed and they interfere with the body’s ability to absorb calcium. This creates an abnormal calcium and phosphorus ratio (Ca:P), which can have devastating consequences.
If your horse consumes a large amount of buffel grass in a short amount of time, acute insoluble calcium oxalate poisoning occurs, triggering a severe decrease in calcium levels in the blood and forming calcium oxalate crystals in the horse’s kidneys. Chronic poisoning is called Nutritional Secondary Hyperparathyroidism or Big Head syndrome. This is from eating small amounts over a longer period such as two or three months. This creates a calcium deficiency bad enough to cause demineralization and brittle bones that are susceptible to fractures.
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Symptoms of Buffel Grass Poisoning in Horses
Some of the most often reported signs of buffel grass poisoning are:
- Gastroenteritis, including abdominal pain and diarrhea
- Irregular breathing
- Slow heart rate
- Muscle tremors
- Inability to get up
- Abnormally large head (chronic poisoning)
- Rounded back (chronic poisoning)
- Broken bones (chronic poisoning)
Buffel grass (Cenchrus ciliaris) is part of the Poaceae (grass) family. It is commonly known as:
- African Foxtail
- Pennisetum ciliare
- Pennisetum cenchroides
Causes of Buffel Grass Poisoning in Horses
There are insoluble calcium oxalates in the buffel grass that create a calcium deficiency known to cause conditions such as minor colic and diarrhea to collapse and death. Those most at risk for buffel grass poisoning include horses with lower than normal calcium levels such as:
- Horses under three years old
- Lactating mares
- Older horses
- Performing horses
- Horses with immune disorders
Diagnosis of Buffel Grass Poisoning in Horses
It is helpful if you can bring a sample of the plant your horse was eating with you to show the veterinarian. This will help in diagnosing and treating the condition. The veterinarian also needs your horse’s medical history including any medications or supplements you have given your pet for this or any other condition. A comprehensive physical assessment is done first to determine body condition, vital signs, lameness evaluation, and an overall health examination. In cases of suspected poisoning, the veterinarian may want to continue the examination after performing an evacuation on your horse to prevent any more toxins from entering the system.
In addition, blood tests are done to check for decreased levels of calcium and other abnormalities. A urinalysis will usually show calcium oxalate crystals in the urine if enough buffel grass is eaten. An electrocardiograph (EKG) may be necessary to check the heart’s electrical functioning because calcium deficiency can cause a slowed heart rate. Also, radiographs (x-rays) will be done to check for fractures. With an animal this large, some veterinarians prefer to use a bone scan if it is available to them. This can check the entire horse at one time.
Treatment of Buffel Grass Poisoning in Horses
Treating buffel grass poisoning includes evacuation, fluids, calcium supplements, and supportive treatments. In serious cases, the veterinarian will likely suggest a hospital stay for observation. This is recommended so there are veterinary professionals available immediately if needed while monitoring.
The veterinarian will use a tube inserted into the stomach to cleanse the digestive tract with warm saline. This washes away any plant particles and toxic substances that may still be in the stomach.
After clearing the stomach, fluids will be given intravenously (IV) to increase circulation. This helps flush the kidneys and replenish fluids.
Since buffel grass decreases calcium, the veterinarian will administer calcium intravenously (IV) along with the fluids. Other vitamins and nutrients as well as other medications may be added at this time, as needed.
Supportive treatments such as oxygen administration, feeding tube, and other medications can be given while your horse is being observed in the hospital. The length of stay depends on how well your horse responds to treatment.
Recovery of Buffel Grass Poisoning in Horses
You may be given prescriptions for calcium supplements and other medications when you go home. Be sure to get them filled right away and give as directed. Keep your horse and other animals out of the pasture with the buffel grass until it can be safely eradicated.