Animal Health Matters: When should animals practice social distancing?

Russ Daly
Special to the Farm Forum

“Social distancing” – the phrase that will be forever associated with the COVID-19 pandemic.

Signs of social distancing are all over the place. People are standing 6 feet apart from each other in public. News anchors talk to each other from across the set instead of sitting next to each other. The local brewpub even spread out the tables in their taphouse so people wouldn’t be so close to each other.

Of course, social distancing recommendations are meant to decrease the chance people will be exposed to the coronavirus causing COVID-19. This virus affects peoples’ respiratory tracts, so it’s spread between people through what’s called aerosol transmission. Aerosols are the microscopic drops of fluid coming out of us when we exhale or (especially) sneeze or cough. The virus causing COVID-19 uses lung and airway lining cells to reproduce. Viruses leave the respiratory tract by hitching a ride on these microscopic fluid droplets.

The good news is that viruses can’t survive indefinitely on these drops. They need to find cells in a living body in order to reproduce – the fluid in the droplet might protect the virus for a little while but it can’t support its growth.

The bad news is that these aerosols are great ways for viruses to hitch rides between people. But the ride can’t be too long. Aerosols don’t stay suspended in the air for long distances – hence the 6-feet separation recommendation. Of course, if these aerosols land on surfaces like tabletops or doorknobs, the virus could hang out there long enough for someone to pick it up on their hands and transfer it to their nose or mouth.

Since I deal mostly in the animal health world, this notion of social distancing made me think about how we apply – or don’t apply – the same concept in our livestock populations.

I’m not talking about distancing people from livestock – for COVID-19 in particular, there’s no connection between animals and people. But many common livestock viruses are spread through aerosols. How practical is “social distancing” between cattle, pigs, and the like?

You’re already thinking this just isn’t possible given the way we currently (or ever) raise livestock. Ever since farm animals were domesticated, we’ve raised them together with each other: cows in drylots next to the barn, calves in feedlots, and pigs in hog barns. We’ve long known that giving animals more space (as opposed to crowding) helps their health and growth, but maintaining each animal in an isolated 6-foot bubble just doesn’t happen. Caring for animals in an effective and efficient manner means we’re going to feed them together, provide a common water source, and house them out of the elements.

But is “social distancing” between animals or groups of animals sometimes necessary? Yes. If you’ve driven past rows of calf hutches outside a dairy, you’ve witnessed it in action. Young dairy calves are isolated in individual housing to reduce the aerosol virus transmission we’re talking about. This housing also prevents contact with diarrheal germs and allows for individual feeding and care.

One area where “social distancing” for animals should be applied more than it is currently is when new animals enter a herd or return from a show – biosecurity. Providing for some separation (that 6-foot distance actually applies pretty well to cattle and pigs, too) between new animals and the existing herd can prevent the entry of new viruses. The design of SDSU’s new Cow Calf Education Unit demonstrates this by providing an 8-foot blank spot between certain pens – to minimize aerosol transmission between new and existing cattle.

Additionally, it often makes sense for sick animals to be “socially distanced” from healthy animals, too, depending on the disease issue. As is the case with sick people, sick animals release a greater number of infectious germs than do healthy animals.

Because of the time and proximity they necessarily share with each other, our livestock species tend to share germs more readily with each other perhaps even more readily than do our human populations. But we should remember that “social distancing” strategies can sometimes work to keep our animals healthy as well.