Scours is the leading cause of losses of suckler calves less than three weeks of age. However, the cost of this condition extends beyond mortality. Affected calves have reduced growth rates which can lead to lower weaning weights, delayed weaning and increased feed costs. The cost of treatment can also be significant if large numbers of calves require electrolytes and other medicines as well as the labour required for administering them.
Handling young suckler calves is an inconvenient and potentially risky business. A study into the cost of neonatal scours in Scottish sucker herds in the 1990s estimated an average loss of £33 for every calf at risk (i.e. £3300/year for the average 100 cow herd. This is likely to have increased significantly with rising input costs and may be much higher in herds with a high incidence of the disease.
Most cases of scours are caused by rotavirus, coronavirus or cryptosporidium. These bugs can be found on almost all farms whether scours is a problem or not. Prevention of scours depends on a combination of maximising the immunity of the calf while minimising the amount of bugs that it is exposed to early in life, with the critical period being the first 2 weeks. This involves reviewing the systems in place on your farm to identify what areas should be focused on to achieve the biggest improvements.
Research into calf scours has highlighted certain management practices which are risk factors for an increased incidence and should be avoided. These include the introduction of new animals into the herd during the calving season, cows and heifers calving together and feeding cows and heifers together prior to calving.
The first step is to understand the extent of the problem. Keeping good records of the number of cases of scours as well as the causes of any calf losses allows an assessment of the impact of the disease in your herd. Record analysis can also help to target any preventive measures. For example, highlighting a high incidence in calves born to heifers will identify the need to improve the management of this group of animals.
Below are some examples of focus areas for scour prevention. Please contact us if you would like to discuss which aspects to look at for the maximum benefit on your farm
Maximising the immunity of the calf
1. Minimise calving difficulties.
Difficult calvings are strongly associated with poor colostrum intake. Review calving records and the number of stillborn calves or losses <48h to assess your performance in this area. Estimated breeding values for calving ease should be used in sire selection
2. Provide optimal nutrition.
Good quality colostrum depends on adequate body condition as well as sufficient energy and protein intake in pregnant cows. However, there is a fine line to tread as overfeeding can lead to excessive body condition and an oversized calf leading to an increased risk of calving problems. Annual variations in forage quality may
mean that what worked well in previous years may not be successful every year. Forages should be analysed and the ration balanced accordingly. Appropriate levels of minerals are also essential for good colostrum quality and a healthy, vigorous calf with a strong immune system. Again, testing of forage is a good
way to identify any deficiencies and guide what supplements will provide the best value for money.
3. Ensure a good intake of colostrum.
Calves should be monitored carefully to check they have suckled well within a few hours of birth. Good protocols are required for supplementing colostrum intake when this is not the case.
4. Vaccinate for scours.
Bovigen scour is a highly effective vaccine against rotavirus and coronavirus. It is administered to the cow prior to calving and therefore relies on good colostrum intake to work to its full potential.
Minimising exposure to bugs
1. Aim for a tight calving pattern.
Calves born late in the season are at higher risk as the amount of bugs in the environment builds up over time. Older calves will shed large amounts of bugs even if they are not affected by scours themselves. A tight calving pattern requires close attention to fertility of both cows and bulls.
2. Group animals by calf age.
A tight calving pattern will take time to achieve. In the meantime, group animals by calf age to prevent exposure of newborn animals to older animals. Ideally, this should be done prior to birth.
3. Ensure good hygiene in sheds.
Careful attention should be paid to bedding management, drainage and ventilation to provide a clean environment, especially at birth and in the first 2 weeks of life. If necessary, a creep area can be provided to provide a clean resting area for calves.
5. Ensure good hygiene at pasture.
Although generally at lower risk, calves born outside can still be affected by scours. Attention should be paid to high traffic areas such as around feeders or gateways. One effective approach is to regularly move the cows which have not calved onto fresh pasture, leaving behind groups of cows with calves of a similar age.