The Sunday News
Mhlupheki Dube
CALF scours is a general term that refers to a calf having a very loose stool. This is a disease of the digestive system characterised by watery feces and increased frequency of bowel movements. The high water content in the feces results in dehydration.
The body also loses electrolytes which are needed to maintain all bodily functions. The loss of electrolytes causes a condition called metabolic acidosis which will kill the calf in less than two days if it is not corrected promptly. Scours itself is not a disease, but a digestive issue resulting in diarrhea that can be caused by a number of different things.
Calf susceptibility to scours varies as they develop and hence causes tend to change as a calf grows. Diarrhea commonly affects newborn calves. Young calves are more prone to diarrhea because of their liquid diet. Signs of scours are:
– Loose stools which result in a dirty tail
– Dehydration which causes sunken eyes
– Depression which is seen with a calf having its head down, ears down, not willing to stand for a long time
– Weakness and the calf is easier to catch, unstable when walking
– Loss of suckle reflex when the disease is at its severe disease
Causes of calf scours can be broadly divided into two namely nutritional and infectious causes. Issues related to nutrition and feeding are a well-recognised cause of calf scours. The digestive system of a calf is not fully developed.
Therefore feed content and methods that are disruptive during digestive development can cause diarrhea.
Two common causes of scours associated with feeding are inappropriate feed or feed mixture for the age of the calf and sudden changes in feed. For example, early access to water and forage aids in the proper development of the rumen and the friendly bacteria and protozoa that it needs for proper digestion. Otherwise during weaning the calf is not ready to properly digest the food that takes the place of milk. This leads to the calf consuming more milk when it should be consuming less resulting in loose, whitish stools from undigested milk.
The second major cause of calf scours is a bacterial, viral or protozoa infection. Generally speaking, a normal healthy calf in a normal environment would not typically be affected by everyday exposure to common microbial threats.
Underdeveloped immune system is one common reason calves are unable to cope with common microorganisms.
An undeveloped immune system may be associated with the calf not receiving enough colostrum during the first few hours of life.
It is only during the first four to eight hours that a calf is capable of receiving and incorporating the all-important antibodies the dam passes along in its first milk for the calf to build its own strong immune system. Without a strong immune system the calf is much more susceptible to becoming ill and having loose stools. Immune system overload is also a reason calves get ill and develop scours. Even a healthy calf that is overexposed to harmful microbes will eventually succumb.
Eventually the immune system is overwhelmed and the calf becomes ill. The viruses and bacteria that cause sickness tend to thrive in wet, cool, muddy conditions, which is an accurate description of many kraals during the rain season.
If the environment is conducive to development of disease causing organisms calves may fall ill. Infectious agents such as bacteria and viruses can attack the lining of the gut, causing water loss through the damaged wall. .
Several infectious agents have been shown to cause diarrhoea in unweaned calves and these include bacteria, such as Escherichia coli and Salmonella especially in newborn calves. Viruses such as Rotavirus and Coronavirus commonly affect calves in their first few weeks of life usually 1 to 3 weeks. Parasites such as Coccidia and Cryptosporidium parvum can cause diarrhoea in young calves.
Some established remedies to reduce infectious scours include ensuring calves receive an adequate volume of colostrum by using a bottle or a feeding tube during the first few hours of life. Additionally, reducing exposure by separating young calves from the general population, who can be carriers of harmful microbes, has shown to be effective. The most effective and efficient approach to resolving calf scours is through preventive action that address root causes. In any large population of animals, a small number are bound to get sick and display symptoms like diarrhoea. When scours starts to affect a significant number of calves, however, then identifying the cause or causes is a critical step in finding a remedy.
The best prevention is to reduce pathogen exposure by providing a clean environment beginning at birth. The calving area should be clean and uncrowded. No amount of colostrum or treatment can make up for excessive exposure to bacteria and viruses in the environment. Provide a balanced mineral programme to the mother cows prior to and after calving to ensure that the cow has the foundation for normal electrolyte balance and milk production. Some organisms, such as Salmonella, Rotavirus, and Coronavirus, can be fought by vaccinating cows during the final trimester of pregnancy. Vaccination will cause the cow to produce immunoglobulins that specifically attack these organisms. Oral electrolytes can be used to reduce acidosis and eventually scours.
