Healthy Calves For A Healthy Future

Maintaining healthy calves is a result of good nutritional and housing management, along with planned disease prevention and control measures. 

Target growth rates will not be achieved without an effective health management programme.  Scours and respiratory problems tend to be the two main causes of illness.

Generally there are two causes of scour in calves – nutritional and infectious.  Symptoms include a change in faeces, which become liquid, with variable colour and smell.  Affected calves have a dull appearance, with sunken eyes and they are often reluctant to feed or drink.

Causes of nutritional scour include:

• Lack of colostrum – early feeding of colostrum is essential as the calf is unable to absorb antibodies from the intestine after 24 – 36 hours.
• Too much or too concentrated milk being fed – this “overloads” the digestive tract resulting in poor digestion and scouring.
• Milk replacers which are too dilute or not mixed properly – ensure the manufacturers’ mixing and feeding instructions are followed.
• Incorrect milk feeding temperature – whether feeding milk once or twice a day, or through a machine, ensure the milk temperature does not vary from feed to feed.  The optimum temperature is 36 – 42º C (warm) or 15 – 20º C (cool).
• Irregular feeding times – establish a regular feeding routine to reduce the chance of calves becoming hungry and then gorging themselves.
• Cold, damp, draughty or humid housing – ensure housing is suitable to reduce stress on the calves.

Infectious scours can be caused by a number of pathogens including Rotavirus, Cryptosporidia, Coccidia, Coronavirus, E. Coli and Salmonella.  Scouring only occurs when the challenge of the infection is greater than the calf’s resistance.  It is also more likely when the young animal is exposed to more than one type of infection at a time.  Appropriate treatment would include:

• Isolate the affected calf in a clean, dry pen with adequate bedding.
• Monitor the calf’s temperature and ensure it is kept hydrated and warm.
• Stop feeding milk where possible. 
• Feed an electrolyte solution in place of the milk until the faeces have firmed. 
• Seek veterinary advice on the cause of the scour and appropriate treatment.
• After the faeces have firmed, introduce milk gradually back into the feeding regime.

As with other diseases, prevention is better and cure and this is particularly true with scouring.  Include the following measures as part of your calf rearing routine to reduce the risk of scouring becoming a problem:

Ensure that all newborn calves receive adequate colostrum - older cows have been exposed to more infections than first calved heifers and so have higher concentrations of antibodies in their colostrum.  The quality of colostrum is reduced by the presence of dirt or other contaminants.  Ensure the cow’s udder and teats are clean before the first feeding.

Use high quality milk replacer and follow the mixing instructions precisely.
Clean and disinfect calf pens after each batch of calves.
Avoid mixing calves of different ages and from different sources.
Keep the stress from dehorning, vaccination and movement etc. to a minium.
Isolate and treat sick calves.

Pneumonia is a respiratory disease that reduces performance and unless treated effectively will result in the death of the calf.  Symptoms include rapid breathing, coughing, high temperature and excessive discharge from the eyes and nose.  A number of different infectious agents can be involved in the onset of calf pneumonia including viruses (e.g. bovine respiratory syncytical virus), bacteria (e.g. Pasturella) and myoplasmas.

Poor housing and ventilation are among the main causes of pneumonia.  High humidity caused by damp bedding, poor air movement or overcrowding can lead to a ten fold increase in the number of infectious organisms and the time they survive. 

Stress, inadequate colostrum feeding and high levels of atmospheric ammonia are other factors that predispose calves to infection.  Once pneumonia is identified it must be treated promptly and consult your veterinarian about the best course of action.

Steps that should be taken to prevent pneumonia include:

• Ensure adequate colostrum intake.
• Keep bedding dry, with good drainage and frequent cleaning.
• Prevent high humidity with effective ventilation.
• Avoid draughts at calf level.
• Avoid overcrowding.
• Minimise stress

If a particular organism has been identified as the cause of the pneumonia, discuss with your veterinarian whether a vaccination programme is appropriate.

Nutrition and health are two key aspects of your calf-rearing programme.  With these in place you will have the foundation for well-grown heifers resulting in greater performance in terms of higher feed intake, better milk yields, improved fertility and increased longevity.

Tim Harrington,
Ruminant Technical Manager,
Ridley AgriProducts