One of the most common problems facing many sow farms is high sow death losses. Some herds have reported monthly mortality rates exceeding 15%. PigCHAMP has reported an increase in mortality rate from 4.3% in 1993 to 6.9% in 1999.
A target death rate should be 2%-4%. In a recent survey, John Deen from the University of Minnesota reports no herds had less than 5% annual sow mortality. We commonly see farms with sow mortality rates from 8% to 14%.
Costly Problem Sow mortality is hard on farm morale and is very costly. Reducing it from 10% to 6% would add $4,000/year in income for a 600-sow farm. This converts to 33 cents/weaned pig. Replacement costs plus opportunity costs can be $400-$500/sow.
Increasing sow deaths adds to the cost of production when producers should be lowering costs. Hoping to find a common cause, veterinarians, geneticists, nutritionists and many others have investigated sow deaths. The only common thread they have found is that all farms are different.
Many factors - ranging from farrowing complications to summer heat - contribute to sow death loss. Porcine reproductive and respiratory syndrome (PRRS) and swine influenza virus (SIV) are factors. Veterinarians and producers alike are frustrated as a long-term solution does not appear close.
Case Study No. 1 We were called to a 1,500-sow, farrow-to-wean operation experiencing a 14% death loss. We conducted multiple postmortem examinations on any questionable sow deaths. Postmortems revealed a variety of causes: stomach torsion, splenic torsion, urinary infections, pneumonia and stomach ulcers. The latter was the most frequent cause of death.
Half of the posted sows died of a stomach ulcer. We weren't sure what caused the ulcers, but we felt adding fiber to the diet could decrease the incidence. We added 200 lb./ton of soy hulls through the gestation diet.
This immediately reduced death loss, but mortality rates still continued, for a variety of reasons, at about 12%.
Case Study No. 2 Our second case deals with a report on a research trial given at the American Association of Swine Practitioners (AASP) annual meeting by Deen. It was run on two farms with more than 14% annual sow mortality.
This study analyzed data from a treatment and control group of more than 1,900 sows/group. Lactating sows were fed a diet containing 667 grams/ton chlortetracycline (CTC) for two weeks, then off one week. The control diet received no antibiotic. The medicated diet was fed to alternate farrowing groups to study the impact on sow mortality and reproductive performance.
Adding CTC to sow lactation diets decreased the odds of sows dying by 41%. It also increased the odds of sows farrowing by 8% and decreased the odds of sows being culled by 20%.
The treated sows had 0.1 fewer stillborns and on the next farrowing averaged 0.25 more liveborn pigs. The benefit of treating sows was more than $50/sow/parity; the cost of treatment was less than $1.50/litter.
These results are quite dramatic and aren't likely to be repeatable on every farm. The researchers summarized there wasn't a clear reason for such a dramatic effect. They called for more research to determine the contributors to high sow mortality.
Summary High sow mortality is one of the important challenges facing the U.S. pork industry. Causes of death are multiple and vary from farm to farm.
One fact seems clear about sow deaths. The sows' durability appears to have been compromised from a variety of factors. Sows were challenged by either genetic selection, endemic disease, environmental challenge, nutritional stress or management stress.
During the past two years, many of our farms have been bombarded with disease challenges of PRRS and SIV. These endemic viral infections may play a larger role than we can identify.
With this complex problem, it is likely that two or more factors interrelate yet are likely to be different for each sow farm.
The solutions are different, and hard decisions may need to be made in regards to genetics, herd depopulation or farm management changes. To help sow farms remain competitive, everyone must work together to find a solution.
Each farm must aggressively identify and address their own problems. The plan should include these three key points:
- Identify cause of sow deaths;
- Evaluation and elimination of potential contributing factors; and
- Implementation of both short- and long-term plans for lowering overall sow mortality.
Work with all members of your production team to ensure the success of your action plan.
