Most liver disease is the result of infections; viral, bacterial or fungal and poisons e.g. pyrethroids, organophosphate pesticides, plant toxins; ragwort (Senecio), lead, phosphorous, arsenic and copper.

Liver diseases are often associated with malnutrition, though it is more likely that poor nutrition is the result of chronic liver disease, and not the cause. One of the most common of these is cirrhosis. Cirrhosis is the replacement of damaged liver cells by fibrous scar tissue that disrupts liver functions. Cirrhosis occurs as a result of common viral hepatitis, obstruction of the bile ducts and exposure to certain drugs or toxic substances.

The scarring of cirrhosis leads to interference with the flow of blood from the stomach and intestines to the liver. This may result in reduced ability to synthesize urea leading to ammonia and toxins accumulation in the blood. Elevated plasma levels of ammonia are highly neurotoxic and when it reaches the brain, it causes a condition called hepatic encephalopathy (liver caused mental impairment/confusion), also known as “brain fog”. Affected horses may develop behavioural changes, irritability, lethargy, ataxia, neurological dysfunction, seizures, coma, cerebral oedema, and ultimately circulatory collapse.

Another feature of cirrhosis is impaired fat metabolism with dietary fats being incompletely metabolised by the liver. Therefore overfeeding regardless of energy source should be avoided, because excess calories can contribute to fat synthesis and accumulation in the liver. Cirrhosis is also characterized by excess sodium and fluid retention with increased urinary potassium losses.

If gallstones are present and the ducts are blocked, bile may be forced back into the liver and enter into the bloodstream. The mucous membranes may take on a jaundiced colour. Ultimately, the bile is excreted through the urinary tract. The urine is often dark red or amber coloured and is very concentrated.

may include

* flatulence
* burping/belching
* skin problems (dandruff, itching)
* jaundice
* constipation
* diarrhoea
* inappetance
* anorexia /weight loss
* weak ligaments, tendons and muscles
* emotional instability
* laminitis
* seizures
* oedema of chest, abdomen and legs
* strong smell of ammonia in stable
* aimless walking
* head banging

* Blood tests for raised liver enzyme
* Liver biopsy
* Function test: dye injected and rate of disappearance from the blood is measured.

Liver dysfunction can be a difficult problem to manage, particularly for the performance horse. The oft repeated rule of feeding “Little and often” takes on increased importance.

Nutritional support becomes an essential part of treatment. A high fibre diet is important as fibre plays a role in the excretion of nitrogenous compounds.

A horse with liver disease requires energy and protein in a form that does not rely heavily on liver metabolism in order to reduce the work of the liver. Too much protein will result in an increased amount of ammonia in the blood, while too little protein can reduce healing of the liver. Rations for horses with liver disease should include high levels of soluble carbohydrates and low levels of high biological protein. Alfalfa, clover, soya and oats should be avoided as the main sources of energy and protein. Adequate intake of energy molecules, both carbohydrate and fats, is said to “spare protein”, permitting a small protein intake to maintain positive nitrogen balance. The body recycles amino acids and becomes every efficient when protein intake is low. When a precisely calculated amino acid set is available, the total daily requirement is 30% to 50% lower than the RDA values for food protein intake.

Amino Acids: Supplementing amino acids may be more beneficial than increasing the protein portion of the ration. In their pure form amino acids tend to be completely absorbed and utilized. The short branch-chain amino acids: valine, isoleucine, and leucine, are utilised as a source of energy and protein. Argenine and proline help to maintain a proper nitrogen balance by acting as a carrier for transportation and storage, and aiding in the excretion of excess nitrogen. A variety of functions, including insulin production, glucose tolerance, and liver lipid metabolism, are impaired when the body is deficient in argenine. Argenine rich foods include, coconut, oats, soybeans, wheat and wheat germ. L-carnitine is essential in fat metabolism. Carnitine is synthesised from the amino acids lysine and methionine, in the presence of different enzymes in the liver and kidneys. Carnitine performs two important functions in fat metabolism:

1. As a carrier molecule that transports long chain fatty acids into cellular mitochondria
2. It shuttles the 'acyl' groups outside the cell (chemicals that are toxic to the cell), where they can be safely excreted in the urine.

L-Citrulline boosts the immune system, protects the liver against ammonia and is an energy booster. Citrulline malate stimulates hepatic ureogenesis and favours renal re-absorption of bicarbonates. These metabolic actions have a protective effect against acidosis and ammonia poisoning. Sources of Citrulline are grapefruit and lemon juice.

For the performance horse, replacement of some of the dietary fat with medium chain triglycerides (found in coconut oil) may be useful.

Vitamin and mineralsDeficiencies of fat-soluble vitamins A, D, E, and K, have been found in all types of liver failure and should be supplemented. Supplementation of the antioxidants vitamins C and the B group are essential due to their roles in oxygen reduction reactions and co-enzyme activity during cellular respiration. Carrots, beetroot, spinach, celery, wheat grass and parsley are natural sources of the vitamins and can all be used in liver cleansing diets.

Sodium (salt) encourages the body to retain water and higher levels of potassium are excreted in urine, so substituting potassium chloride for sodium chloride in the ration would be appropriate.

Liver dysfunction can be a difficult problem to manage, particularly for the performance horse. The oft repeated rule of feeding “Little and often” takes on increased importance.

Nutritional support becomes an essential part of treatment. A high fibre diet is important as fibre plays a role in the excretion of nitrogenous compounds.

A horse with liver disease requires energy and protein in a form that does not rely heavily on liver metabolism in order to reduce the work of the liver. Too much protein will result in an increased amount of ammonia in the blood, while too little protein can reduce healing of the liver. Rations for horses with liver disease should include high levels of soluble carbohydrates and low levels of high biological protein. Alfalfa, clover, soya and oats should be avoided as the main sources of energy and protein. Adequate intake of energy molecules, both carbohydrate and fats, is said to “spare protein”, permitting a small protein intake to maintain positive nitrogen balance. The body recycles amino acids and becomes every efficient when protein intake is low. When a precisely calculated amino acid set is available, the total daily requirement is 30% to 50% lower than the RDA values for food protein intake.

Amino Acids: Supplementing amino acids may be more beneficial than increasing the protein portion of the ration. In their pure form amino acids tend to be completely absorbed and utilized. The short branch-chain amino acids: valine, isoleucine, and leucine, are utilised as a source of energy and protein. Argenine and proline help to maintain a proper nitrogen balance by acting as a carrier for transportation and storage, and aiding in the excretion of excess nitrogen. A variety of functions, including insulin production, glucose tolerance, and liver lipid metabolism, are impaired when the body is deficient in argenine. Argenine rich foods include, coconut, oats, soybeans, wheat and wheat germ. L-carnitine is essential in fat metabolism. Carnitine is synthesised from the amino acids lysine and methionine, in the presence of different enzymes in the liver and kidneys. Carnitine performs two important functions in fat metabolism:

1. As a carrier molecule that transports long chain fatty acids into cellular mitochondria
2. It shuttles the 'acyl' groups outside the cell (chemicals that are toxic to the cell), where they can be safely excreted in the urine.

L-Citrulline boosts the immune system, protects the liver against ammonia and is an energy booster. Citrulline malate stimulates hepatic ureogenesis and favours renal re-absorption of bicarbonates. These metabolic actions have a protective effect against acidosis and ammonia poisoning. Sources of Citrulline are grapefruit and lemon juice.

For the performance horse, replacement of some of the dietary fat with medium chain triglycerides (found in coconut oil) may be useful.

Vitamin and mineralsDeficiencies of fat-soluble vitamins A, D, E, and K, have been found in all types of liver failure and should be supplemented. Supplementation of the antioxidants vitamins C and the B group are essential due to their roles in oxygen reduction reactions and co-enzyme activity during cellular respiration. Carrots, beetroot, spinach, celery, wheat grass and parsley are natural sources of the vitamins and can all be used in liver cleansing diets.

Sodium (salt) encourages the body to retain water and higher levels of potassium are excreted in urine, so substituting potassium chloride for sodium chloride in the ration would be appropriate.

Methods of reducing blood and urinary pH have been to either manipulate the dietary electrolyte balance, or add organic salts and acids to the diet.

Lactulose and neomycin may be used by veterinarians to control blood ammonia levels.

Citric acid, ascorbic acid (lemon) is good for the liver, as it contains diluted hydrochloric acid needed for protein digestion and can also affect blood and urinary pH. Acetic acid (vinegar) may also be beneficially added to the diet.

Yucca schidigera extract is a natural feed additive that represents a means of reducing ammonia levels via the diet.

Herbal supplements that are valuable for liver detoxification include liquorice, nettles, dandelion root and turmeric.

Milk thistle (Silymarin) has been proven to protect the liver from damage. The detrimental effects of environmental toxins, drugs and chemotherapy may be countered with this herb. The active chemical component in the herb is silybin, which functions as an antioxidant and is one of the most potent liver protective agents known. Clinical trials have shown silybin to be effective in treating chronic liver diseases and in protecting the liver from toxic chemicals.

MSM has been shown to be effective in lowering death rates and liver damage and providing a longer life expectancy in animals with liver dysfunction.

DMG- Dimethylglycine, is thought to benefits liver metabolism and detoxification. It may help eliminate hypoxia in the tissues and toxins from the blood stream by improving oxygen utilization.

The following herbs have been found to be deleterious to the liver: Crotalaria, Symphytum, Comfrey, Heliotropium, Pennyroyal oil, Chaparral-Larrea, Creosote bush, Germander-teucrium, Senna, Jin Bu Huan, Atractylis gummifera, "Chinese herbals", Skullcap, Valerian, Mistletoe, Sassafras and Nutmeg.