Volume 12: Livestock Farming
8. Cattle diseases and their control and management on farm
Some common cattle diseases
Metabolic disorders
Infectious diseases

Metabolic disorders

8.2 Metabolic disorders arise as a result of deficiency of a particular nutrient in the diet and can usually be treated by supplying the animal with the nutrient. Typical examples observed in the UK are:

• Anaemia - iron, folic acid, or vitamin B deficiency. Treatment depends on the cause of the affliction, but can include the provision of vitamin B12, liver extract, cobalt, copper or iron.
• Acetonaemia - can affect dairy cows in early lactation if demand for carbohydrates exceeds that available from feed, and is characterised by low blood glucose. Treatment consists of oral dosing with glycerine or propyleneglycol or sodium propionate as readily available energy sources.
• Hypocalcaemia or 'milk fever' - can affect dairy cows and is caused by a shortage of calcium in the blood. It is treated with an injection of calcium borogluconate solution, which may or may not contain magnesium. In the past, mortality rates were up to 90 per cent, but have been reduced to about 5 per cent with proper treatment.
• Hypomagnesaemia or 'grass staggers' - can occur in all types of cattle and is caused by too little magnesium in the blood system. A prompt injection of magnesium sulphate is the usual treatment, and can save the cattle inmost cases.

8.3 Animals affected with hypomagnesaemia are often unable to rise, and if lying down will paddle their legs when stimulated. If the animal is not recumbent, then shivering, a staggering gait, excitement, convulsions or paralysis may be present. Hypocalcaemia presents similar signs at first, though the cow will usuallyremain quiet after initial struggles to regain its feet. Partial or complete loss of consciousness and paralysis of the hindquarters follow. The signs of anaemia and acetonaemia are general appetite loss and various indications of general lethargyin the cow. ¹

Infectious diseases

8.4 Infectious diseases are caused by the presence in the body of micro-organisms or other infectious agents, and transmitted to other animals. Typical infectious cattle diseases that may affect UK cattle are:

• Mastitis - can occur in the udders of lactating cows and is treated with antibiotics introduced into the udder.
• Brucellosis - an infection leading to abortion in cattle, it can be passed to humans as undulant fever, in which the symptoms are similar to influenza, but incapacity lasts a long time.
• Bovine tuberculosis - can be transmitted in many ways, primarily through the respiratory system or digestive tract. The liver, lymph nodes and lungs are typically affected by lesions, which cause the characteristic coughing. The disease is usually chronic, and treatment is not attempted.
• Foot and mouth disease - is extremely virulent and characterised by the formation of sores in the mouth and feet; almost 100 per cent of animals exposed to infection will fall sick.
• Virus pneumonia in calves - is characterised by coughing, loss of appetite; scouring (diarrhoea) is also common.
• Johne's disease - is usually fatal, chronic infection of the small and large intestines, characterised by persistent diarrhoea, gradual emaciation and weakness. ²

8.5 Some infectious diseases, such as tetanus and listeriosis, cause damage to the nervous system. Tetanus is a rare disease in cattle, and when outbreaks do occur, they may be due to abrasive feed that allows entry of the infection through the gut. Early signs include a raising of the tail head and maybe bloat. The gait becomes stiff and there may be difficulty in feeding because of stiffness in the neck. ³

8.6 Listeriosis causes cows to exhibit nervous symptoms. A sick animal may keep its distance from the rest of the herd, and later on be unable to stand without support. If walked it will usually move in a circle, maybe with the head held back and to one side. Cows may also become violent near the terminal stage. ⁴

Parasitic diseases

8.7 Commonly occurring parasitic diseases in UK cattle include 'husk', or parasitic bronchitis, caused by lungworm; and general lack of strength and vigour and scouring caused by roundworm, tapeworm and liver fluke.

8.8 Warble fly is an example of a readily recognised parasitic disease in cattle, leading to loss in milk yield, reduced growth rates and damage to the cattle hides.It has been suggested to the Inquiry that organophosphates used for treating warble fly infestations under national eradication schemes contributed to the emergenceof BSE (see vol. 2: Science for an assessment of this theory). Policies oneradicating warble fly in the UK are discussed in Annex 1.