What's lungs got to do with it?

Fall is a busy time for producers weaning calves or receiving stockers. This pivotal time frame is a building block for future success, mediocrity or failure.

I’d like to focus on cattle lungs.

Bovine Respiratory Disease (BRD) is the most costly disease in the U.S. Annually, over $1 billion is lost by producers to this complex, multifaceted illness. Seventy-five percent of feedlot morbidity and around 60 percent of feedlot deaths are attributed directly to BRD. It is easy to pass those numbers off as feedlot problems. However, a majority of those deaths occur within the first 45 days in a feedlot. 

Bovine lungs, just like human lungs, are a complex system of specialized cells that interact together for the purpose of gas exchange - meaning they take in atmospheric air, absorb its oxygen molecules, and trade out carbon dioxide. Lung tissues are spongy so as to be filled with air and are coated in tiny, hairlike structures to filter and protect the animal from airborne particles. Although not part of the lungs, similar filter structures are located in the animal’s nose and throat.

Healthy cattle generally respire (breathe) 26 to 50 times per minute through their nostrils. As air temperatures get hotter, cattle respire more to aid in cooling. Cattle breathing through their mouths is a sign that things are not ideal. Standing still, a thousand-pound cow requires 33 gallons of oxygen per minute. Considering that the air you and I breathe here in Kansas is 21 percent oxygen, that same cow must breathe 157 gallons of air per minute to meet her baseline oxygen requirements!

So, my friend, do you now understand what lungs have to do with it? On the conservative side, calves and stockers in your care require at least 75 gallons of air per minute standing still. As these animals move, become excited or get hot, that number begins trending upward. If your cattle have lungs in pristine condition, there is little to worry about. Unfortunately, lungs are in a constant state of danger from harmful organisms seeking a place to live and an easy meal.

To talk about cattle lungs, you need to discuss lung predators, too. Imagine the creature from the movie "Predator" with its gnarly face munching on your herd’s lungs. That’s pretty much what is happening on a microscopic level, primarily due to predatory viruses and bacteria and, to a lesser extent, lung worms and fungi. Bovine Respiratory Disease is a disease complex of those predators and their effects. Viruses such as Bovine Viral Diarrhea, Infectious Bovine Rhinotracheitis, Parainfluenza 3 and Bovine Respiratory Syncytial Virus are the gateway pathogens that cause initial morbidity, sickness and inflammation. Alone, these viruses are like you and me getting the flu. No one likes it. For a week, you ache from hair to toenails, and you run a high fever. But you survive with some TLC and achieve immunity to the virus. Length and “quality” of immunity are based on the animal’s stress, health, nutrition and previous immunity level.

Once viruses get the party started, bacterials come in and set up shop. Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis and Pasteurella multocida are the fearsome foursome that set up shop. Animals with a current or recent viral infection are weakened hosts whose compromised immune systems offer little deterrence to the bacteria colonizing and spreading within a bovine’s lungs. Once established, bacterials further weaken the animal, suppress immunity and lead to death.

In the long term, BRD leads to diminished growth, reduced feed efficiency, chronic pneumonia, and significant money loss to producers. Death losses, treatment expenses and unthriftiness are three of the greatest threats to profitable margins for calf feeders and backgrounders.

OK, we’ve discussed the problem. Now let us delve into possible solutions. The broadest and most useful tool against BRD is viral and bacterial vaccines. Many animal health companies offer a wide selection of vaccines to the great-eight predators. Some products stack protection into one shot. Pharmaceutical producers have made tremendous strides in enhancing effectiveness and convenience for producers. To maximize immunity and protect against BRD, vaccinate calves while nursing at branding or castration, several weeks prior to weaning, at weaning, and prior to shipping. Stocker operators should vaccinate at receiving (including a booster if required by product label) and prior to shipping or grazing turnout.

Mature cows and bulls should receive at least one BRD vaccine each year. Although mature cattle have stable and generally stronger immune systems, stressors such as breeding, lactation and age can lead to infections. Also, mature animals can harbor infectious agents at subclinical levels and spread pathogens to susceptible calves or weaker animals. As an Extension agent, I recommend that you read and follow product labels. Animal health companies rigorously test their products and draft labels based on what they see working best in studies.

Producers can also influence environmental factors that reduce BRD risk. A comprehensive animal health program covers not only vaccines but also parasites. Reducing lung worms adds to lung integrity and removes one possible foothold from pathogens. Working cattle during cool periods limits their heating and enhanced respiratory workload. Wetting, not flooding, working facilities reduces dust that can make its way into the lungs and irritate lung tissue. Again, the goal is to reduce opportunities for BRD organisms to infect the respiratory tract.

Stocker operators can reduce BRD by limiting commingling of cattle. Granted, stocker operations often thrive on purchasing “mismanaged” cattle from a variety of locations. Upon arrival, group the cattle and remain committed to keeping these groups together, at least until overall herd health is solid and immunity is ready to handle challenges often associated with chronically sick cattle or subclinical infections that dodged a treatment through the chute.

My final points: First, market your cattle accordingly. If you take steps to reduce BRD, make sure all potential buyers are aware of it. Agriculture producers are a notoriously humble lot and avoid self-praise. Presenting herd protocols and management practices is not bragging how fast your pickup truck drives, but is simply stating that it has a diesel engine, power windows and hay bed. Just the facts, as Sgt. Joe Friday would say. There is no shame in recouping cost associated with a highly-sought-after product: a healthy calf ready to eat and grow.

Finally, don’t let loss stymy a future win. By this I mean that when a calf passes away, gain insight into its demise. Invite your veterinarian to conduct a necropsy to determine the cause of death and contributing factors. Your vet can recommend appropriate testing or cultures to see which pathogens are prevalent in your livestock, as well as solutions for the remaining animals. Knowledge is power.

What’s lungs got to do with it? A whole lot! Let me know how I can help you strengthen your herd’s defenses against BRD. We can discuss products, vaccines, protocols and practices that enhance health and make your cattle more attractive to the next production segment.

Anthony Ruiz is an extension agent for livestock production with the Central Kansas Extension District. To contact Ruiz, email him at anruiz@ksu.edu.