Respiratory Diseases and the Youngest Herdmates.

 By Jaclyn Krymowski.

 Getting your calves started on the right foot sets them up for a lifetime of success. Though there are many potential hurdles, respiratory issues are one of the most common challenges for the youngest members of the herd.

Unfortunately, the lingering effects of serious infection don’t just go away as a calf ages. Oftentimes they suffer chronic issues resulting in permanent damage or even death to lung tissue that contributes to recurring illness later in life or other respiratory struggles. There is ample research that these animals, sometimes called “lungers” for their chronic conditions, are impacted in both their efficiency and productivity long into their milking years.

Taking this threat seriously, and implementing a plan of action for early intervention, is an important cornerstone to preserving herd health right from the earliest days of your replacement animals.

Widespread, Lingering Issues
Besides lung damage, respiratory issues early in life also weaken the immune system. Bovine Respiratory Disease (BRD) is the term commonly used to describe several common respiratory issues. BRD has both bacterial and viral pathogenic causes.

In her bulletin Prevent Respiratory Disease in Dairy x Beef Calves, associate professor with the University of Wisconsin Division of Extension Sandra Stuttgen cites the four common viruses associated with BRD: Bovine Respiratory Syncytial Virus (BRSV), Infectious Bovine Rhinotracheitis (IBR), Parainfluenza-3 (PI3), and Bovine Viral Diarrhea (BVD).

The damage inflicted by any of these enemies can significantly impact health. A single respiratory episode can damage lung capacity for life.

While healthy calves may be able to fend off pathogens, stressful events can trigger the onset of BVD. Most often, stress and increased exposure to pathogens occur when calves are transported to a new facility or regrouped into new pens.

With each infection, an animal’s body changes.  BVD is especially problematic because it is another immunity suppressor and dehydrator.

BVD should be identified and treated because it can be a continuing, persistent presence if not managed. These cattle, termed persistently infected (PI) cattle, maintain BVD in the herd.

Farmers and their teams should strive to prevent respiratory issues at any level of the dairy because of its ongoing, negative repercussions, not just for the current herd but for any animals brought into the herd down the road.
 
Contributing Factors
BRD is usually triggered by a combination of factors, including stress, primary viral infection, or inhalation of high levels of dust and/or toxins, among others.

“BRD is the second leading cause of death in un-weaned dairy heifers, and the leading cause of death in weaned heifers,” write Joel Phillipe Costa e Souza and Donna Amaral-Phillips in their University of Kentucky extension bulletin, Respiratory Diseases in Dairy Calves. “This complex includes viral and bacterial diseases and is usually a result of combinations of stress, primary viral infection, or inhalation of high levels of dust and/or toxins. The BRD complex has a considerable impact on the economics of a dairy farm. It includes direct costs for treatment and indirect costs associated with reduced growth as seen through reduced daily gain.”

Fortunately, there are several ways that practical, day-to-day protocols can reduce BRD. This includes ensuring the calf receives adequate amounts of colostrum after birth and is also fed milk. Additionally, provide adequate bedding and proper ventilation, ensure ideal group/pen density, and be on the lookout for symptoms of disease early.

Be sure to consider confinement factors as well because poor ventilation and overcrowded pens can compound the issue. Provide adequate ventilation that allows fresh air to move through the facility and enough space for animals to lie down.

Keep in mind that season, weather and environment all influence respiratory issues in their own unique ways. Housing that remains dry and well-ventilated in the summer may be an entirely different story in the spring or autumn. Pay close attention to how the season and weather impact your housing and the incidences of disease that goes with it. Take note and see what adjustments you can make in advance to better navigate next time around.

Another proactive protocol involves biosecurity measures. Make sure to have strict barriers in place that keep mature and older heifers away from those that are pre-weaned.

Be sure to provide an adequate element of separation as infected animals in pens near a pen of healthy animals can still spread disease and put them at risk. Just sharing the same air space can be enough exposure for an animal to become infected or be impacted by a respiratory issue cautions veterinarian Frank O’Sullivan in his article, Respiratory Diseases- Better to prevent than to cure, written for the Agriculture and Food Development Authority.

O’Sullivan notes that this is because pneumonia is a prime example of an air-borne disease that can spread easily if animals are in confined spaces.

As always, farmers should be wary about mixing purchased cattle from different farms or different age groups. In itself, this can lead to respiratory disease problems as the infection spreads to animals that might never have come across the infection, so have little or no immunity to the new pathogen.

The same can be true of moving freshly weaned heifers in with older calves in different housing or a different location on a farm (or even being sent to a heifer raiser.)

An Ounce of Prevention
While reducing the number of cases can reduce the spread, efforts to prevent any cases in the first place are worthwhile.

Careful monitoring of the herd to weed out PI animals in the case of BVD can eliminate the ticking time bomb before it is passed to other animals in the herd. As well, incorporate a vaccination protocol to reduce “the big four” -  BRSV, IBR, PI3, and BVD.

Preventing respiratory diseases reduces not only the expense of treatment but also helps you better manage your time and that of your employees. You will all spend less time tending and caring for sick animals and more time doing the other tasks that help them reach their full potential.

The Bottom Line
In the end, managing to prevent the issue before it starts and generates a better bottom line. Often, it is more profitable to incur upfront expenses for a vaccination protocol and additional proactive actions than to treat sick animals and return them to health.

Be sure to consider the overall picture, advises O’Sullivan in his article. “When trying to estimate the losses incurred due to a respiratory disease outbreak a cost must be put on the loss of animals, the cost of treatment and the loss in lifetime production due to it. One study put the potential cost of treating an individual calf for viral pneumonia as high as €136 ($146 USD).”

But even the best-laid plans sometimes go awry and animals will become infected.

You can rebound by adopting a protocol that enables you to act quickly to care for sick calves and nip respiratory issues in the bud.