According to John Richeson, assistant professor of animal science at West Texas A&M University, BRD has been studied for over 60 years, with millions of research dollars invested. This research has made significant advancements in our overall understanding of BRD, including how the disease is spread as well as access to a wider variety of animal health products.
However, despite improvements in vaccines and antibiotics, the mortality rate of BRD in feedlots is essentially the same as it was 30 years ago.
The “big picture”
In order to improve beef quality and reduce incidence of shipping-related stress and its resulting illnesses, we need to acknowledge beef cattle production is a complex system. We need to look at what is contributing to the problem all the way up the beef supply chain, starting with gestation and ending with our processes at receiving.
According to John Sterman, professor and director of MIT System Dynamics Group (one of the world’s leading business schools), complex systems have these five characteristics:
- The components are tightly coupled; everything influences everything else.
- The components are dynamic; change occurs on various scales.
- The components are policy-resistant; solutions to problems often fail or actually make things worse.
- The components are counterintuitive; cause and effect are distant in time and space.
- They exhibit trade-offs; advantageous short-term behavior is often different or even antagonistic to advantageous long-term behavior.
For example, there is a complex relationship between poor animal performance and epigenetics, genetic expression, cellular changes, nutrition, overall health and environment.
A closer look
Our system makes calves vulnerable from the outset. Richeson says a typical marketing scenario for high-risk calves looks like this:
- Separated from dam on Tuesday morning
- Transported to auction market on Tuesday afternoon
- Handled and sold at auction market on Wednesday (virus transmission)
- Commingled with other calves onto truck on Thursday
- Transported to order buyer facility on Thursday
- Commingled again at order buyer facility on Thursday
- Transported to feedlot Thursday overnight
- Unloaded in a novel environment on Friday morning
- Processed on Saturday
- Chronically stressed with BRD outbreak within 14 days
Freshly weaned calves have multiple stressors and different types of stress. The psychological stress of separation from their dam and herdmates is an obvious one, but also the exposure to new surroundings and noises can add to the stress.
Mixing new calves together can lead to both psychological stress (establishing the new social order) and exposure to new pathogens. The novelty of new water sources and new feedstuffs can cause calves to be unable to find water and feed offered at buyer facilities or receiving pens.
Calves in these common marketing channels may go without water for 24 hours (acute dehydration) or for longer periods over several days (chronic dehydration).
Making improvements
Although we can’t change the complex system in which we produce cattle, Richeson says we can develop novel ways to correct nutritional/metabolic imbalance at receiving as well as correct stress-induced immunosuppression.
“The challenge is when newly received cattle don’t eat or drink well for several days,” says Richeson, who is conducting unique research on a rehydration therapy where water is induced in the chute at receiving with a modified deworming drench gun.
The drenching tube is bored out and connected to a water meter and shutoff valve, and then attached to a water hose. Richeson says the calves respond almost instantly and seem to calm down while they essentially drink the water from a hose as other processing procedures are applied. The technique is showing promise in jump-starting the recovery from shipping stress.
Inadequate water intake can reduce animal performance more quickly than any other nutritional deficiency. Seven to 8 percent dehydration can impair immunity in cattle. Research in human sciences supports this dehydration/immunity interaction as well. Saliva mucosal secretions contain antimicrobial proteins, including amylase and lysozyme, which provide innate immunity in the mucosal surfaces.
In research by Emily Kaufman and others at West Texas A&M University, dehydrated calves (calves that were water-restricted for either 48 hours or alternating 24-hour periods for seven days respectively prior to shipping) were shipped from Arkansas to a feedlot in Canyon, Texas.
The dehydrated calves lost 20 pounds and had decreased ADG for two weeks after arriving at the feedyard compared to calves that weren’t dehydrated. In this study, dehydration didn’t affect antibody titres to BRD vaccine.
Don Hubble, director of the livestock and forestry research station at University of Arkansas, discussed the problem of shipping stress with Richeson when the idea of rehydration therapy came up. Hubble says, “The problem with newly arrived calves is typically they get weaned on the trailer on the way to the sale barn. They don’t have a mama to show them the water, and it takes them a while to overcome the setback of shipping stress.”
Recalling the conversation with Richeson, Hubble told him, “If you could put water in that calf, it could stop dehydration and the associated immunosuppression, provide liquid in the rumen that may stimulate some appetite and awaken the microbes, and help alleviate stress in some way.”
At least one feedlot in Hereford, Texas, uses the rehydration therapy with positive results. In the fall, Hubble and Paul Beck, a University of Arkansas professor of animal science, will be replicating Richeson’s research at the Batesville station using 650 calves in three different groups and incorporating Richeson’s protocol and hydration-therapy apparatus.
Hubble says based on NRC recommendations, they will provide 1 pint of water per 100 pounds of bodyweight, which is equivalent to 2.5 quarts for 500-pound calves.
Add extreme temperatures to the stress of dehydration, and it’s no wonder calves get sick after shipping. Tom Troxel, professor emeritus, University of Arkansas, placed temperature-relative humidity data loggers on the ceilings of four trailer compartments on 12 loads of cattle shipped in June and July to assess the conditions inside commercial trailers in the mid-South.
The objective was to determine whether temperature, relative humidity, dew point and temperature-relative humidity index differed among four different compartments of commercial trailers. The percentage of time the temperature-relative humidity index was in the danger and emergency categories was 93.9 percent for the bottom nose, 86.6 percent of the time for the top deck, 84.2 percent of the time for the belly and 68.3 percent of the time for the tail compartment.
“I know local producers who catch calves the night before and hold them in a pen, then they’re shipped on a truck and off water a minimum 24 hours, if not more, because even if there is water available at the sale barn, it’s not likely the calves find it or drink it if they do find it,” Hubble says.
In a complex system of production, it is attention to details and addressing animal health and well-being that will make the biggest impact on animal performance. 
Melissa Beck is a freelance writer based in Prescott, Arkansas. Email Melissa Beck.
