Respiratory challenges in calves

By Dr. Andre Rigo – Technical Team Manager

Cattle are more prone than other species to develop respiratory challenges due to some specific anatomical and physiological features, such as lung size compared to body mass and lung clearance. Respiratory challenges in calves are the second most common challenge for pre-weaned calves, after intestinal challenges. Respiratory challenges in calves are responsible for significant economic losses, delays in growth and production performance, as well as early development of longer lasting challenges in animals and increased management costs.

Causes of respiratory challenges

The highest rate of onset of respiratory challenges is recorded in the period from birth to six months of age, as the functional maturity of the respiratory system is not reached before the first year of life of the animal. Respiratory challenges are caused by different factors such as microbial agents, but also by environmental and animal factors. Among the etiological agents we find unfavourable bacteria. Respiratory challenges have a seasonal trend; they are more present in autumn and winter, due to the greater presence of predisposing factors such as low temperatures and high ambient humidity. The presence in spring and summer months is relatively scarce. Within the factors that can be attributed to the animal, we find: Its state of general condition, the degree of immunity achieved and its state of maturity. Among the environmental factors, able to modulate the prevalence and severity of the challenge, we find: Stressful situations generated by environmental changes such as feeding, as well as induced by variations in temperature, humidity and ventilation, the mixing of animals from different origins and the size of the herd. Lastly, housing environments with poor air exchange may also favour the accumulation of unfavourable bacteria and pollutants, such as dust and ammonia. Temperature and humidity greatly affect the health of the animal with the negative impact on the mucociliary activity and functionality of the pulmonary arteries.

Measure of proactive approach

To take a proactive approach for optimal respiratory health, it is very important to limit the exposure of the animal to the risk factors that cause challenges.

Hygiene and housing

To reduce the onset of respiratory challenges it is important to guarantee calves a well-ventilated environment with no drafts. The litter must be clean, comfortable, dry and abundant -especially during the colder months, such as to allow the animal to maintain its body temperature without draining the reserves of energy it has. Instead, this energy is better spent at the essentials: growth and the development of the immune system. The presence of dividers between calves makes it possible to limit direct contact between animals and therefore the transfer of unfavourable bacteria between challenged and healthy calves. Maintaining a good bacterial balance inside the calf also allows to reduce the spread of respiratory challenges inside the calf. Despite the fact that most of the bacteria present in the air are not dangerous, continuous exposure can be a burden on the defences of the respiratory system especially if related to poor housing conditions (not only structures and poor ventilation, but also, for example, caused by overcrowding). Animals should be raised in small groups (less than 10 animals per group), as the greater the number of animals, the more their space is restricted and with that, increase the chance of spreading the challenge even further. Finally, it is essential to ensure the correct administration of food and water because nutritional deficits favour the onset of respiratory challenges.

Calf immunity

Support the immunity of the calf starting from a good colostrum procedure. At birth, maternal antibodies play a protective role against respiratory challenges in the first weeks of the calf’s life: an inadequate transfer of maternal immunity with colostrum doubles the risk of developing respiratory challenges in the calf. In order not to compromise the immunity of the calf it is important to reduce the situations during which stress can be expected before and after weaning, mixing and movement of animals.

In summary

To take a proactive approach for optimal respiratory health in calves, is very important to reduce risk factors but also support the immune system of calves.

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