Coccidia and Coccidiosis – what are they?

Coccidia are parasites of the intestine. Healthy animals protected from coccidial disease by immunity, unfortunately still carry these parasites. In consequence, their eggs are shed in dung so susceptible calves pick up coccidial eggs from pastures or buildings, where previously calves have been kept and also from each other.

Diarrhoea, dehydration, anorexia and the loss of blood are all signs of a coccidia infection. The trouble is that these signs are not always apparent; blood may or may not appear in the faeces but there will be an observable downturn in overall health, a loss of appetite and eventually there will be loss of condition – the animals being classed as ‘poor doers’.

Coccidiosis is said to be one of the most critical intestinal diseases to affect the cattle industry, due to its deleterious affect on farm incomes. In most cases, before any symptoms are visible, damage from the disease has already occurred. It is easy to calculate the cost of animals lost through coccidiosis or secondary infections but the main cost to the national and individual herd from this infection is from the poor rate gains achieved by sub-clinically infected animals.

An infection of sub-clinical coccidiosis, when the symptoms are so slight as to not raise attention, can be costly. Animals will achieve lower than expected weight gains and their overall performance will not be as expected; damaging overall herd profitability. There has been little research into the financial effects of sub-clinical coccidiosis but this could be considerable with the reduced weight gains and poor condition.

The weight loss experienced with animals infected with coccidiosis is not regained during their normal growing period. Research with young stock infected at 2 months old has shown that, on average, they weighed 43.2kg less than uninfected controls at 13 months old. They subsequently required four to eight weeks to make up the additional weight loss. After they recovered their weight gain was about the same but they needed to be fed and houses for an extra 40 days compared to the control group.

It costs more to treat an animal that is infected than it does to prevent the disease in the first place. The cost of veterinary visits and treatments for secondary infections such as pneumonia can be considerable. Additionally, later treatment may not be as effective as the available coccidiostats are not as effective on the latter stages of the coccidia as they are on the younger forms. Therefore, the maxim of ‘prevention being better than a cure’ holds well with coccidiosis.

Can management help?

A strategic plan of preventive treatment based on previous history of the disease in a particular environment, and other management considerations, could offer the best way to reduce losses due to cattle coccidiosis.
However, coccidiosis can occur in any management system. Contamination of feed or water and failing to thoroughly clean calf pens and other housing along with the repeated use of the same pasture for turning out calves are all likely to be associated with incidents of coccidiosis. Animals do appear to build up a resistance to coccidiosis but can remain carriers. It is therefore vital that any infections are dealt with swiftly and effectively.
With the economic pressures for feed efficiency in production animals, producers can no longer afford to let clinical and sub clinical coccidiosis go uncontrolled.

How can it be prevented?

One of the most recognised methods is treatment with Deccox. This is a highly effective anticoccidial and can be offered to disease prevention and treatment. Calves should also have access to colostrum, which will help to build up immunity.
The pens that calves are put into should be thoroughly cleaned between calves and the building disinfected.

Ideally calves should be grazed on pasture that has been free of stock for two seasons as coccidial oocysts are capable of surviving on pasture for at least 18 months. However, if these options are not available a supply of Deccox should be continually on offer to calves to ensure that they remain coccidiosis free.

The introduction of Deccox combined with good hygiene and husbandry, use of clean grazing through rotation of lambing paddocks and movement of concentrate feeding troughs at regular interval, to reduce contact with contaminated areas, will also help to prevent coccidiosis becoming a problem.