Prevent scours to optimise performance

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Scours is the most common disease in young calves, and the greatest single cause of death. Managing the risk of disease is crucial to reduce both long-term performance and economic losses.

About half of all calf deaths are caused by scours. But, the consequential economic loss from these deaths represents only a small proportion of the total cost of the disease.

“Rotavirus and coronavirus are two of the most common causes of infectious scours in calves,” says Nia Williams, Nettex technical manager.

“Treating a single calf for scours, costs on average, £120. But this does not take into account the additional time and labour costs needed to rear sick calves initially, and the effect of an extended rearing period on future production and productivity.”

Reducing the risk of disease to young stock is therefore crucial to optimise heifer performance and longevity.

Causes and implications

Calf scours can be caused by either infectious agents or nutritional sources.

Infectious scours caused by rotavirus and coronavirus cause damage to the lining of the small intestine leading to diarrhoea and dehydration. The virus is most common in calves from one week of age, but can affect calves from as young as one to two days old.

“Damage to the gut lining means calves can’t absorb nutrients effectively, resulting in the clinical symptoms of the disease, such as diarrhoea.

“This can predispose calves to secondary infection with E. coli or Cryptosporidium due to the fact it’s easier for these pathogens to adhere within the gut, and cause infection,” says Nia.

“If calves suffer from a bad, or repeated, case of scours during rearing, the damage caused has the potential to set back affected animals, causing long term implications for health and performance.”

The period between birth and weaning is the time when calves are most efficient at converting feed into weight. “Any challenges experienced during this stage can mean calves are playing catch up and can delay their time to first service,” says Nia.

Research has shown that calving heifers at 24 months can play a significant role in long term milk productivity and reduce the likelihood of calving difficulties. “The effect of scours on heifer performance can extend the time to first calving.

“Ultimately this means rearing costs are not paid back as quickly, effecting farm finances,” she adds.

Management of scours

A calf is born with no circulating antibodies and is therefore reliant on a quality source of colostrum to protect against disease challenges. Good colostrum management should be a key focus for dairy farmers, explains Nia.

“Ensuring calves receive at least three litres of a quality source of colostrum in the first six hours of birth, followed by a further three litres by 12 hours of age, will mean they absorb the largest quantity of antibodies available in the colostrum.

“However, the immune status of the cow determines the antibodies she produces and passes onto the calf via colostrum. But she may not have the necessary antibodies to protect her calf against rotavirus and coronavirus.”

Therefore, providing the calf with an additional boost of energy and active proteins at birth, can help enhance natural defence against disease challenges, such as calf scours.

The Roto Corona Plus Syringe, from Nettex, is formulated to provide calves with a source of concentrated bovine colostrum, and specific active egg proteins to help support natural defences.

“Roto Corona Plus does not replace colostrum but is administered to help support the dam’s colostrum in the first hours of life,” she adds.

“The additional intake of active proteins helps ensure calves receive the tools they need to help fight immune challenges,” says Nia.

An alternative practice for famers is to vaccinate cows for rotavirus and coronavirus four to six weeks prior to calving. The aim of this is to allow the cow to generate an antibody response which she is able to concentrate in her colostrum ready for the calf to ingest.

Nia warns that a common mistake by farmers using the vaccine is to think that the job is then done. “However, to get the most out of the vaccine, the colostrum management programme must be spot on.

“Roto Corona Plus is therefore a good support to the vaccine and colostrum management plan, or where vaccination is not routinely used, it is an excellent addition to the heifer rearing programme. One 30 gram syringe will help provide the complementary resource for calves to thrive,” she says.

Nia also advises that good hygiene and calf rearing management practices will also help limit the risk of disease. “Ensuring calf feeding buckets are kept clean, used only for one calf, and thoroughly washed and sanitised before being used for another calf, will help reduce disease challenges.

“In addition to this, washing down, disinfecting and resting calf rearing buildings, if possible, and ensuring adequate ventilation, are methods that can help to minimise the impact of calf scours.

“If a calf is showing signs of scours they should be isolated from the main group and treated to reduce the impact of disease.”

Whether or not a calf develops scours is dependent on the interaction between the calf, its environment and its management. Reducing the risk of exposure to disease will help enhance long term performance and optimise returns. “The value of dairy calves is often overlooked, but putting in the effort in the early stages of life will reap long term benefits,” adds Nia.