What is Big Head Disease? - McDowell's Herbal Treatments


Big Head Disease is also known as Bran Disease or NSH which stands for Nutritional Secondary Hyperparathyrodism. It is caused by a lack of calcium and magnesium in the diet, 
This disease still occurs today, despite the fact that it has been known about since 1860. It is generally a lack of calcium and magnesium in the diet and, if left untreated, can create permanent damage.


tropical and subtropical grasses, including buffel, setaria, green panic, and purple pigeon grasses
Diets low in calcium and high in phosphorus, such as found in bran and grain, which contain phytates that bind to calcium like oxalates

Big Head Disease can happen when a diet low in calcium and high in phosphorus is given, as the high level of phosphorus impairs the utilization of calcium in some bones, connective tissue invades the affected bone which actually increases in size hence the common name Big Head. Feeding high levels of wheat bran, which has a high phosphorus ratio to calcium can cause the disease by removing more calcium from the body then is deposited.

CausesThe symptoms  are due to the demineralization of the bones, and often affects the head and limbs, causing swelling and lameness. While often horses will adapt to the gradual changes, eventually obstruction in the airway and jaw and tooth problems can cause weight loss and difficulty breathing. Symptoms generally appear within 2 to 8 months after initial grazing of grasses high in oxalates. An acute poisoning can occur with the ingestion of grasses containing high amounts of soluble oxalates, which produces muscle tremors and interferes with kidney function.

Symptoms of Big Head

Signs that a horse is developing (or has developed big head) can appear two to eight months after initial turn-out on high oxalate pasture. The signs are due to the meminerisation of the bone. Acute poisoning can also occur, which appears as muscle tremors, pica (eating dirt or wood), lameness and pain in joints. Symptoms include:

  • Swollen face and jaw
  • Loose teeth and possible infections
  • Pain during eating and difficulty chewing
  • Loss of appetite and weight loss
  • Nasal collapse
  • Breathing obstruction and difficulty breathing
  • Poor condition, lethargy and excessive lying down

It is imperative that these are caught early. 

Diet recommendations



McDowells product recommendations

We recommend a combined treatment of Chamomile and Rosehip Tea, Kelp, Dolomite, Lucerne chaff or hay and our Tendon and Bone Mix. Dolomite contains calcium and magnesium, Lucerne chaff is also a good source of Calcium. The Kelp granules are for trace minerals. Rosehip tea is high in Iron and Vit C and the Chamomile is a good help to the thyroid which can become affected by high phosphorus levels causing what is know as Nutritional Secondary Hyperparathyroidism in turn causing the big head.

The Tendon and Bone mix is made up fresh (for each new horse), as a bucket of ground herbs and seeds extracted into vinegar. The dried herb version can not be shipped to WA for quarantine reasons. (If you are from Western Australia ask our Herbalist about the extract version of this mix).

Make a tea using 2 Desert spoons of Rosehips granules and 4 Desert spoons of Chamomile flowers in 1 litre of boiling water. Divide in half and use for morning and afternoon feed. Add to each feed 2 teaspoons of Kelp, 1/3 a cup of Dolomite and 1 cup of Tendon Bone Mix. Mix this with some Coconut Meal to make a mash.
The horse needs at least 2 - 3 biscuits  of good quality hay TWICE a day. As well as a mineral lick in the paddock placed near the water trough.

Have a question? Contact McDowell's Herbal Treatments

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02 6331 3937
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McDowell's staff Herbalists can not diagnose your disease or illness. What they can do is offer a herbal program to assist with healing, after you have had advice from your doctor or specialist. If you have unexplained pain or symptoms, seek medical advice.

EMAIL info@mcdowellsherbal.com  |  PHONE 02 6331 3937  |  INTERNATIONAL +61 2 6331 3937