What’s driving the surge in sow mortality?
Sow mortality in US herds has trended upward in recent years, and identifying the reasons has frustrated producers and veterinarians alike.
“We can define some of the conditions associated with sow mortality, but they are vague and often multifactorial,” Clayton Johnson, DVM, Carthage Veterinary Service, told Pig Health Today. “We haven’t found the root cause of the increase; we don’t know what’s driving it.”
In fact, no patterns have surfaced — no age or genetic links, seasonal trends, management risk factors, dietary or health issues. “First-litter gilts may have a higher risk, but we haven’t seen any particular group that’s over-represented,” Johnson added. The lack of trends has prevented producers and veterinarians from identifying treatment strategies.
Sow-mortality causes are commonly classified as sudden death, unknown death, lameness or downed animals. The recent uptick has included a significant rise in uterine prolapses. Sudden and unknown deaths are the vaguest causes and suggest that an underlying condition in the sow went undetected.
“Lameness is probably the most complex,” Johnson said, “because we don’t know if the lameness caused death or if it was due to other factors triggered by lameness. Also, we don’t know if the prevalence of lameness is any different from 5 years ago.”
More aggressive on-farm euthanasia also is contributing to the rise in sow mortality. This is tied to the expansion of animal well-being audits and producers’ commitment to complying with timely euthanasia protocols. “Records show that the percentage of euthanasia as compared to total deads is going up,” Johnson noted.
There is an all-out industry effort to find answers to the sow-mortality uptick, not just because of the financial costs involved but also to ensure animal well-being. The National Pork Board has organized a working group to investigate the issue, including collecting more epidemiological data to identify risk factors. “We have to collect more data to do a root-cause analysis and generate some hypotheses to test,” Johnson said. “We have to find out what’s different about farms that are over- or under-performing in sow-mortality rates.”
An equally important, but sometimes underappreciated, cost to the current sow-mortality trend is how demoralizing it is for the farm staff. “Anytime you tell someone they have a problem and you don’t know what to do about it, it’s demoralizing,” Johnson said. That’s not to mention the safety challenges of removing dead sows from a facility and biosecurity risks.
For now, the added attention and commitment to find answers is a positive, long-term trend.