Causes of respiratory challenges in calves

By Leonardo Bringhenti, DVM, PhD – Technical Services Consultant

Bovine respiratory challenges (BRD) are within the major and unremitting concerns when raising replacement heifers because of the high incidence and long-term health effects associated with these challenges. These disorders are considered to be multifactorial and commonly polymicrobial syndromes involving complex interactions among the host immune system, pathogens and the production stages of dairy and beef systems.

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 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. Mannheimia haemolytica, Pasteurella multocida, Mycoplasma bovis and Histophilus somni are the main species of bacteria that have been associated with pneumonia, and those agents are considered ubiquitous in the upper respiratory tract of dairy calves. 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, we find: stressful situations generated by environmental changes such as feeding, variations in temperature, humidity and ventilation, and comingled animals from different origins. Lastly, housing environments with poor air exchange may also favour the accumulation of pathogenic bacteria and pollutants, such as dust and ammonia. Temperature and humidity are important factors that can affect the health of the animal with negative impacts 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 cut down the onset of respiratory challenges it is important to guarantee calves a well-ventilated environment with no drafts. The environment must be clean, comfortable and dry, especially during the colder months, allowing the animals to maintain their body temperature without draining their reserves of energy. Therefore, this energy can be better spent in the essentials needs, such as 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 in the calf respiratory tract also allows to cut down the spread of respiratory pathogens between calves. Even though most of the bacteria present in the air are not pathogenic, continuous exposure can be a burden on the defenses of the respiratory system especially if related to poor housing conditions (not only structures and poor ventilation, but also, for example, caused by overcrowding).

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 increases 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, commingling and transport of animals.

The proactive use of AHV Respi

To overcome the respiratory challenges imposed in a calf raising facility, the use of Respi is highly recommended.

Respi contains bioactive ingredients responsible for the biofilm breakdown in the respiratory tract and mucus dissolving function, improving the respiratory tract health of calves.

Respi can be administered once a day, on a dose of 10-20g mixed with the milk feeding. It is recommended to use Respi at least 7 days prior and 7 days after the respiratory issues happens in a farm independently of the calves’ age. Therefore, if the calves are facing most of their respiratory challenges at around 25 days of age, Respi should be administered from day 25 until day 32. The concomitant use of Respi with Calf Bolus and Aspi is also highly recommended when the reactive approach is necessary.

In summary

To take a proactive approach for optimal respiratory health in calves, is very important to cut down risk factors but also support the immune system of calves. If you would like to know more about how AHV products can help your calves, please contact your local AHV Advisor in your region for tailor-made advice.