Equine Cushing’s or PPID (Pituitary Pars Intermedia Dysfunction) is the most common equine hormonal disorder. It is generally caused by an enlargement of the pituitary gland or a tumour affecting the pituitary gland. If your horse or pony has PPID, nutrition can be pivotal to helping manage the condition throughout the year. This is especially important during the autumn and winter, when they may be in less work, the changing nutrition in grass and a drop in temperature. Lisa Elliott MSc – Equine Nutrition Solutions explains more.  

Signs and Symptoms of PPID

Equine Cushing’s commonly affects horses and ponies over the age of 15 but has been known to affect horses as young as 7. The signs of this condition can be quite varied, but if your horse has been diagnosed with Cushing’s they will probably have shown any or a combination of the below symptoms at some point.

• Longer, thicker coat that fails to shed in the spring
• A pot-bellied appearance
• Excessive urination and drinking
• Lethargy
• Loss of muscle tone
• Increased susceptibility to laminitis
• Recurrent Infections (due to decreased immunity)

Nutritional Support for Cushing’s

From a nutritional standpoint, horses diagnosed with the condition should be fed a diet that supports muscle mass, weight maintenance, and all body functions, alongside good immunity.

Provide suitable forage

Research studies have shown that laminitis is a common occurrence in horses and ponies with PPID with prevalence between 50 per cent and 80 percent in some reports (Schott et al. 2001; Donaldson et al. 2004, McGowen 2010). Due to this high prevalence, horses and ponies with PPID should be managed in a similar way to those prone to laminitis. 

They will often have reduced insulin sensitivity leading to insulin dysregulation and an increased risk of laminitis, so a diet that is low in starch and sugar all year round is required.  Grass intake may need to be restricted even through winter to minimise sugar levels, but they will need to be fed an alternative form of forage such as hay or haylage to keep the digestive system functioning well. Ideally, hay or haylage should be offered on an ad-lib basis as its digestion creates internal heat, helping to keep horses and ponies warm from within. This is particularly important through the autumn and winter. 

Forage should be low in sugar and starch so it’s always advisable to have it analysed, so you can keep track of sugar and starch levels within the diet.  A typical analysis will show WSC (water soluble carbohydrates or simple sugars plus fructan), ESC (ethanol soluble carbohydrates or simple sugars minus fructan) and starch.

ESC is important for PPID horses and ponies with insulin dysregulation as it’s these simple sugars plus starch which need to be kept to a minimum. Ideally, ESC + starch should be less than 10%. Some very sensitive horses can also benefit from having lower WSC levels in the diet, and for these, it is often best to avoid turning them out onto frosty grass, waiting until the temperature rises above 5°C before letting them graze.  It’s generally recommended that horses with PPID are fed forages with no more than 12% NSC (Non-Structural Carbohydrates) which encompasses simple sugars and fructan, plus starch.

If the NSC of the forage is above 12%, soaking is often recommended to reduce WSC (water soluble carbohydrates), but some research has shown that it can be ineffective in reducing it to a safe level.  Steaming hay has some great benefits, particularly in the winter to avoid carrying heavy buckets of cold water and has shown some reduction in WSC which could make it useful for a hay whose NSC is only just over the safe level.  Alternatively, feeding specifically produced low NSC (<12%) forage or replacing up to 25 per cent of the forage with oat straw or a low starch and sugar straw-based fibre chop can be useful.

Manage body condition

Horses with PPID can often lose body condition so it’s important to manage this by adding extra dietary energy or calories when needed to help with weight gain. Cereals should be avoided as they are high in starch.

Coligone High Fibre Cubes and Fibre Bio Cubes are both very low in starch and sugar and are therefore ideal for horses with PPID who need additional calories without exacerbating insulin resistance and increasing the potential for laminitis.

As PPID tends to affect older horses, poor dentition may be a problem, fibre-based feeds that can be soaked like Coligone High Fibre Cubes and Fibre Bio Cubes are even more ideal and can be made into a nutritious, easily digestible mash.  Additionally, for horses and ponies with a significant loss in body weight and condition, Ex Selenium Oil can help provide increased calories to help regain and maintain lost condition.

Whilst most horses and ponies with PPID lose weight, some can be overweight which will increase the risk of insulin dysregulation and potentially laminitis. Monitoring weight and fat pads regularly is, therefore, essential using a body condition scoring chart (BCS).  Overweight horses and ponies can be managed with a low calorie forage-based diet to help them lose weight, fed alongside a high specification balancer like Coligone Balancer to supply a full range of essential micronutrients but without excess calories.

Provide Quality Protein

Good quality protein is an important consideration for horses and ponies with PPID as they can often lose muscle mass. Most with this condition are older individuals who have a lower rate of muscle protein production, meaning they need improved quality protein for muscle maintenance and repair.  Amino acids provide your horse with the building blocks for making good-quality protein, particularly the essential amino acids Lysine and methionine to help facilitate the production of muscle protein to help rebuild muscle mass and integrity. Both Coligone Balancer and MultiVit Pro provide essential amino acids to help ensure horses with PPID receive optimal support.

Deliver Antioxidant Support

Research has suggested that horses with PPID may have a higher level of oxidative stress in their body to which potent antioxidants like Vitamin E might offer support. Preserved forage such as hay, for example, can be quite low in vitamin E, and can lose nutrients if soaked to reduce starch and sugar content. So, it’s good to make sure you are delivering good levels by feeding a nutritious balancer like Coligone Balancer, a high specification supplement like Multivit Pro or a fully balanced feed suitable for horses with PPID like Coligone LAMIGONE which supplies an excellent specification of essential vitamins, minerals and antioxidants for optimum health and well-being.

Supply Essential Fatty Acids

Omega 3 fatty acids have been shown to improve insulin sensitivity and boost immunity making them a very useful addition to the diet for a horse with PPID. In spring and summer, grass is a good source of omega 3 fatty acids and helps provide them in the right ratio with Omega 6 fatty acids. However, in autumn and winter when grass loses its nutrition and horses are often fed mainly preserved forage like hay, they can be lacking in these essential fatty acids. Ex Selenium Oil will help provide correct levels of beneficial Omega 3, 6 and 9 fatty acids, to help support optimal immunity in horses with PPID.

Support Digestive health and immunity

Hindgut microbes are critical to the health of your horse, because they help keep the digestive tract healthy but are also involved in immunity. Immunity normally drops in horses with PPID, making them more vulnerable to certain health issues and disease, so it’s important to try and boost it through the promotion of a healthier Hindgut microbe population

Probiotics can support microbial health by introducing certain live microbes to improve and support the hindgut microbe population.  Yeasts (which are actually microscopic fungi) in the form of yeast cultures, such as Yea-sacc, have been shown to stimulate beneficial cellulolytic bacteria and increase fibre digestibility. 

Prebiotics provide a food source for beneficial bacteria and help to encourage their growth.  ScFOS prebiotics provide food for beneficial bacteria and help mitigate disruptions to the hindgut microbes and restore a healthy equilibrium. MOS prebiotics work in a slightly different way to ScFOS but are able to bind to invading pathogenic microbes and take them out of the hindgut, helping to boost immunity alongside the growth of beneficial microbes.

All three of these key pre and probiotics work together to promote a healthy, stable hindgut microbe community for optimum hindgut health and maximum immunity. These are included in generous levels within Coligone Powder and Liquid and throughout the entire Coligone Range, so a daily dose of Coligone provides excellent support for horses and ponies with PPID.

Maximise water and salt balance

Horses and ponies with long, thick coats will often sweat more than normal which combined with increased urination means that horses with PPID will often have higher requirements for electrolytes, like potassium, chloride, and sodium to combat these losses. Providing ab-lib forage to supply potassium, alongside a beneficial lick like Coligone Healthy Lick can make a significant difference to fluid and electrolyte balance by providing lost electrolytes and actively encouraging horses to drink more for optimal daily hydration.

Whilst there is no cure for PPID, by providing the right nutrition, care and support, alongside appropriate veterinary treatment, you can help minimise its effects and keep your horse sound, happy and healthy for many years to come.