Bovine respiratory syndrome (BRD) has increased dramatically since the 1970s-80s and is now endemic in intensive livestock farms, especially beef farms.
The reason is mainly due to the cattle’s delicate and relatively small lung volume, which under stressful conditions (transport, early weaning, handling, environmental changes) and in a crowded environment with pathogens in the air as is intensive animal husbandry is easily attacked due to decreased cellular immunity.
What are the factors that promote the occurrence of Bovine Respiratory Syndrome in livestock farms?
Environmental factors: temperature and humidity.
Environmental factors can promote the onset of respiratory disease in animals and be the cause of Bovine Respiratory Syndrome.
Let’s look at how high temperature and sudden colds can be related to Bovine Respiratory Syndrome and what to do to avoid it.
High ambient temperature associated with low humidity increases mucus viscosity by decreasing mucociliary activity in the respiratory tree.
Abrupt colds lead not only to a decrease in the cellular capacity to eliminate foreign materials (phagocytosis), but also to vasoconstriction and alterations in lung surfactant (a complex of lipids and proteins that is essential for respiration as it prevents the collapse of smaller alveoli and the over-expansion of larger ones).
Temperature monitoring to prevent bovine respiratory syndrome
Constant monitoring of barn temperature can help prevent Bovine Respiratory Syndrome and intervene both in the event of high temperatures and rising humidity and in the event of sudden drops in temperature.
Chemical Factors
High values of carbon dioxide (CO2), ammonia(NH3), and hydrogen sulfide (H2S) reduce mucociliary activity, the first defense barrier that cattle have against pathogens. In particular, ammonia has a toxic action on mucous membranes, leading to the fall of vibratile cilia and rupture of alveoli, thus making the cattle attackable by bacteria and viruses in the housing environment.
Timeliness is key to saving cattle with respiratory syndrome
Noticing in time the presence of chemical factors that can cause respiratory disease or promote spread in cattle is critical.
The “smell test” (that is, when we smell ammonia) comes too late: at a concentration of 10ppm the first problems begin, and at 20ppm the lung activity of cattle is compromised. That is why constant monitoring of chemical factors such as carbon dioxide (CO2), ammonia(NH3) and hydrogen sulfide (H2S) can greatly lower the mortality rate of animals due to respiratory syndrome.
Sources:
https://www.drovers.com/article/investigate-and-reduce-winter-calf-pneumonia
