Social distancing and self-quarantine are two new terms that have come into use with the COVID-19 pandemic.
While these practices have become central to everyday life, the concepts are not new to those who deal with young calves. Although we can’t make sure that every animal stands two metres away from its immediate neighbour, we have talked about and practiced biosecurity for years.
Biosecurity can be described as management practices that prevent the movement of disease-causing agents between and within livestock operations. Biosecurity involves almost all aspects of farm management, including environmental hygiene and manure management. As a result, many of a producer’s management decisions can have an impact on biosecurity.
One of the biggest changes in management in the cow-calf sector during the last 20 years has been the shift in the calving season. Data from the western Canadian cow-calf surveillance network reflects the new reality with more than 91 percent of the herds that were followed in that study beginning their calving season between April and July.
In fact, almost one-third of the herds in the study reported that their calving season began in June.
We can debate the advantages and disadvantages of various times of calving, but there is no doubt that the risk of cold and inclement weather is dramatically lower at this time of year, and there is less risk of calves becoming chilled or hypothermic.
However, perhaps the most important and often overlooked advantage of later calving is the ability to decrease the stocking density by spreading out cow-calf pairs and thus lowering the risk of calf diarrhea.
It also reduces the need to house calves and cows within a barn during calving. Calving stalls in barns can be a place where infectious organisms concentrate and are also the place where our most vulnerable animals — cows that have recently calved and their newborn offspring — are intensively housed. Intensive housing in barns also allows the aerosol spread of bacteria and viruses that can cause respiratory disease in calves. Avoiding barns and spreading cows out on the calving ground are our best forms of social distancing.
Another form of social distancing practised by many producers is the use of a separate wintering area for cows and then moving the pregnant cows onto a clean, less-contaminated calving area just before calving.
Almost all of the bacteria, parasites and viruses (including the bovine version of a coronavirus) that can cause calf scours are routinely carried in the feces of adult cows. These cows are mostly immune to these infectious organisms and they rarely, if ever, cause disease to occur in adults. However, they continue to harbour these disease-causing agents in their manure.
Using a separate wintering area and a clean calving ground where cows are socially distanced, or spread out, helps to lower the load of infectious organisms that the young and more immunologically vulnerable calves are exposed to.
A second step of social distancing at calving involves separating cow-calf pairs from the cows that have yet to calve and allowing these cow-calf pairs to move to a clean nursery area, which, depending on the operation and the time of year, may be another clean corral, paddock or pasture.
One alternative would be to move cow-calf pairs once they have mothered up to a separate nursery area — a common approach on many ranches.
Another potential alternative is called the Sandhills system, in which cows are also overwintered in a separate area before calving. However, several calving paddocks or pastures are used instead of just one.
In this system, the cows are moved onto the first calving area once calving begins. After a few weeks, the cows that haven’t calved are moved onto the next calving area and the cow-calf pairs are left behind. This procedure continues until the last group of cows have calved.
The Sandhills calving system allows cows to calve on clean calving areas and provides for separation of older calves from younger calves.
These social distancing practices on cow-calf operations are good for more than preventing calf scours. They are also an important component of Johne’s disease control. Most Johne’s bacteria (MAP) transmission occurs from adult-infected animals to young calves through the fecal-oral route.
While we may use diagnostic tests, such as the fecal PCR in adult cows, to find potentially infected cows and cull them, another important aspect of the control program is to try to limit calves’ exposure to feces from adult cows.
Disinfecting and hygiene play a role in preventing calf diarrhea as well.
Calf feeding tubes can efficiently pass bacteria and viruses from an infected calf to another calf. Tubes must be adequately cleaned with hot soapy water between calves or they can become an ideal fomite for inoculating bacteria into the stomach of a newborn calf. I’ve seen several major outbreaks of Salmonella that were probably aided by the contamination of calf feeding tubes.
How cows and calves flow through the calving system and the timing of your calving season are going to be different depending on your facilities and your goals.
Look critically at your ranch and work with your veterinarian to develop a calving system and a biosecurity plan that will work with your facilities.
Minimizing the amount of fecal contamination that the calves are exposed to and minimizing any form of intensive housing are fundamental principles of biosecurity for a cow-calf operation.
John Campbell is a professor in the department of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.
