Veterinarian shares observation in sow mortality

U.S. hog producers are reporting an increase in sow mortality. The Carthage System discusses mortality trends, sharing data from their hog production systems.

February 16, 2018

3 Min Read
Veterinarian shares observation in sow mortality
National Pork Board

By Megan Schnur, DVM, Integrated Veterinary Network

Sow mortality for the Carthage System (managed by Professional Swine Management) was 9.5% for 2017. Baseline sow death loss has been observed to increase from 6.7% (2006-12) to 9.3% (2013-17). Metafarms’ 2016 annual database reports the bottom 10th percentile of farms experience a 15.8% sow death loss; the 50th percentile, 10.2%; and the 90th percentile, 5.8%.

The observed annual sow mortality increase from 6.7% to 9.3% doesn’t directly correlate with our system sow inventory growth. Other systems across the country have experienced a similar increase in mortality, but it is not reported to be a problem globally.



During the transition between 2006-12 and 2013-17 for the system, overall penned sow gestation space doubled (13% to 26%), but mortality occurring on penned gestation farms more than tripled, from 7.9% to 27.7%.

For the period 2013-17, our system observed Quarter 3 (July-September) to be the highest mortality quarter at 9.2% and Quarter 4 (October-December) to be the lowest mortality quarter at 7.8%. Heat stress during the summer months would be a primary contributor to mortality during Quarter 3.


Parity trend among mortality hasn’t significantly changed during the two periods under consideration. Parity 0 mortality has increased numerically (18.5% to 20.4%), but total losses of young parities (0-3) as a percentage remains unchanged (68.5% vs. 67.3%).


Carthage System farms with the highest sow mortality (six farms, averaging 13.8%) lose a higher percentage of younger-parity animals than farms with the lowest sow mortality (six farms, averaging 8.1%), and they also have a lower culling rate (30.2% vs. 38.5%, respectively). Penned gestation would be represented by farms from both categories. Interestingly, of the 14 “best” PSM farms during 2017 Quarter 3, only two have penned gestation (“best” is defined as better than the system average for the quarter). Of the 14 “worst” farms during that same quarter, seven have penned gestation.

The most common reasons reported for Carthage System sow death loss are “unknown,” “downer,” lameness and prolapse (rectal, vaginal and/or uterine). We have 27 possible reason codes to select from for sow mortality; another system in the United States reports to use over 80 codes. This makes comparison difficult. It is suggested the industry should define a common, more concise, set of reason codes for more accurate comparison and investigation across production systems and regions. The accuracy of reason reporting is largely the outcome of the knowledge, training and experience of the technicians on the farm. “Prolapse” is arguably the most accurate code since it cannot be confused with another condition. Ambiguity is more frequently observed to be highly correlated amongst unknown, downer and lameness.

The number of sows that are euthanized versus found dead has significantly increased from 2006-12 to 2013-17 with an average 35% of mortalities being euthanized. This increase is likely influenced by not only an evolving animal welfare standard but also the severity of lesions/conditions.

A focus on early identification and individualized sow treatments has been a primary focus in our system to reduce sow mortality. Identification of animals needing treatment in the gestation barns is most efficiently carried out at the morning feed drop (while sows are standing). Animals that do not rise can be quickly recognized for follow-up. During this limited window of time, we train our teams to allocate additional staff to quickly walk the back alleys and flag crates with a colored clothespin, using a color-coded system. The primary person administering therapy can then return to his/her treatment vest (stocked with antibiotics/anti-inflammatories, needles, spray paint, red treatment cards, etc.) and more efficiently implement treatments.

Genetics of our sow population over the years has undoubtedly had an impact and is something we need to analyze further.

Nutrition and mycotoxins are additional factors to consider, although the major changes in our system have not directly correlated with the increase in mortality.



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