Swine

How to Improve Sow Lifetime Productivity

Sow : Sow Production

Gawain Willis, Ph.D.

Research & Development Director, Formulation

The U.S. pork industry continues to experience steady genetic growth.

Sows today are genetically able to produce more marketable pounds in a quicker time period than ever before, but are U.S. sows meeting their full genetic potential? Research shows that some sows may not be living up to their genetic capabilities due to shortages in nutrition.

When adequate nutrients are not supplied to sows through their ration, they are unable to meet their optimum sow lifetime productivity (SLP). The National Pork Board defines SLP as the total number of quality pigs weaned during the productive lifetime of a female, from the time she becomes breeding eligible until she leaves the herd. The board indicates that SLP potential is higher today than ever before as sows are genetically capable of producing 30 pigs per sow per year (psy).1

The SLP growth trend can be maximized by focusing on psy rates on the operation and working to enhance the number of Full Potential Pigs produced. Recent work by the Pig Improvement Company shows the potential to produce the goal of 30 psy is possible with the genetics in place today. The researchers estimated the genetic potential of U.S. near 26 psy in 2004. Genetic improvements pushed the potential of typical U.S. sows to 28.5 psy in 2010 and closer to 30 psy today.2

Though most U.S. sows have the potential to produce 30 Full Potential Pigs psy, very few U.S. producers are reaching this production opportunity.3 Research shows that low psy rates on an operation may be attributed to: early exit of sows from the herd and high pre-weaning mortality rates traced back to low birthweights. A focus on sow nutrition can help producers minimize both of these issues.

Early exit of sows from the herd
When sows exit the herd before becoming profitable, a facility’s SLP drops significantly and their bottom line can be impacted. Recent research by Iowa State University shows that sows reach their breakeven point economically during their third parity and are most profitable when they remain in the herd for six to nine parities, depending on variable costs.4

At the Allen D. Leman Swine Conference in St. Paul, Minn., in 2012, Steven Pollman of Murphy Brown LLC, Western Operations in Ames, Iowa, presented information on sow lifetime productivity, explaining that U.S. sows exit the herd on average between parity 3.3 and 3.7 and that sow replacement rates average 50 to 60 percent annually. Due to early herd exit, Pollman said that many P1 and P2 females never reach the 30 psy goal, In fact, approximately 42 percent of all females produce only 19 or fewer Full Potential Pigs in their lifetimes.5 This number can be decreased by feeding these sows for long-term production before their first parity.

“A 30 percent improvement [in sow retention] would result in average herd longevity of 4.6 parities and an increase of 10 to 15 pigs weaned per sow lifetime,” he said, estimating that increasing the average number of litters by one litter per sow in her lifetime would produce a net value of $250 million for the U.S. pork industry.

Pollman added that, if the developmental cost per gilt was $400, a producer’s ability to obtain an extra litter would leverage the cost of the replacement gilt for an overall reduction of cost per weaned pig at $1.90 per head.

To reach this economic potential and improve the longevity of U.S. sows, one must first examine reasons for early exit of sows from the herd. Recent estimates from the USDA’s Animal and Plant Health Inspection Service show that 23.7 percent of U.S. culled sows leave the herd because of poor performance, while only 11 percent are marketed due to old age.6

Primary reasons listed for culling include: small litter size, high pre-weaning mortality, low birth weights, failure to rebreed on schedule and sow health.

Though other issues are often at play, these issues are heavily linked to sow nutrition. As sows begin to produce additional pigs per litter, nutrients provided through the ration need to be ramped to meet the added requirements of production. Calculations on the nutrients required per pig produced (or on pounds of litter weaned) indicate that an extra 200 to 300 pounds of feed is required per pig to sustain today’s increased production as compared to production levels 5 years ago.7 To keep sows in the herd longer and to achieve 30 psy, the ultimate goal, even more nutrients are needed.
 
Real results can be seen when the added nutrients are provided to the sows. For example, one particular herd in Iowa that we work with is striving to achieve 30 psy on its 3,000-sow, farrow-to-finish operation. The biggest advances were seen when ad libitum feeding occurred at farrowing as compared to a restricted feeding strategy. The increase in nutrients consumed allowed this herd reduce culling rates and improve its total pigs born from 24.8 to 26 psy. In addition, birth weights climbed from 2.9 to 3.2 pounds per pig and weaning weights increased nearly half a pound per pig in the one year between the feed change. The added nutrients also played a role in enhancing overall sow health and resulted in fewer days to rebreeding.
 
Increasing Full Potential Pigs
The producer’s transition to a higher plane of nutrition paid dividends through the sows’ ability to produce more Full Potential Pigs. In the farrowing facility, the producer recognized he significant increases in birth weights. Birth weights are heavily impacted by sow nutrition and the nutrients provided during gestation, so the 0.3 pound increase in birth weights is likely linked to the producer’s nutritional transition in the sow facility.
 
A focus on birth weights is especially important as the industry moves towards larger litters. Estimates show that a pig’s average birth weight drops approximately 0.10 pound for every additional pig in the litter; however, the producer was able to increase birth weights and maximize the sows’ genetic potential for larger litter sizes by focusing on sow nutrition through gestation and lactation.
 
The increased birth weights the producer experienced may not follow industry trends though. Decreased birth weights are especially concerning because the initial birth weight impacts not only survival rates but also the pig’s lifetime performance potential.
 
The road to increased birthweights may begin with sow nutrition. Retrospective studies from large datasets suggest that sows with increased gestation feed intake typically produce pigs with higher average birthweights. For instance, one recent study of eight operations reported by Knol and Mathur showed that sows on farms feeding approximately 100 pounds more feed per year in gestation produced piglets that were an average of 0.47 pounds heavier than the pigs produced by the lesser fed sows.8 The researchers indicate the only differences in management styles between the high and low birthweight farms were the significant difference in sow feed allowance during gestation and a difference in quantify of feed in the interval from weaning to insemination.9
 
To test the theory that sows fed additional nutrients are better able to perform, researchers at Purina Animal Nutrition Center in Gray Summit, Mo., have monitored sows through several parities and analyzed the performance of their progeny.10 Research from an ongoing study shows that sows fed to a higher plane of nutrition are better able to produce heavier-born pigs. In addition to increased sow health, the 1-pound difference in birth weight (3.1 pounds versus 2.1 pounds at birth) can result in twice the pre-weaning survival rate.
 
The study continued to show benefits through the production cycle, including growth rate and feed efficiency improvements in pigs with higher birth weights. After five years and 2,456 litters, the research shows that pigs with initial birth weights of 3.1 pounds weighed 3 more pounds at weaning than those with birth weights of 2.1 pounds. The heavier pigs also reached market weight seven days sooner than the lighter-born pigs.11
 
These improvements can pay significant dividends when tallied together over time. A look at our Swine Profitability Economic Model shows that a pig with an ideal birth weight of 3.1 pounds could bring an additional $1.39 at weaning or $2.72 additional profit at finishing than a pig born weighing 2.1 pounds.12
 
As illustrated through research at Purina Animal Nutrition Center and through on-farm research trials and consultations, the first step in reaching ideal benchmarks for birth weight, pig performance and sow longevity is to increase the level of nutrition offered to the sow during gestation and especially through lactation. The ration fed to a sow through all stages of production can impact the long-term performance of her progeny and her profitability within the herd – helping to entire herd to meet its full genetic potential.
 

1Pollmann, Steven. “Sow lifetime productivity: Importance of monitoring commercial pork production.” Leman Swine Conference Proceedings, 2012.
2Pig Improvement Company. 5-Yr Genetic Trend Study on Full Value Market Pigs Sold/Sow/Year: PIC337 x Camb. 2005-2010. www.birchwoodgenetics.com/index.php/download_file/view/10/. 
3Swine 2006 - Part III: Reference of Swine Health, Productivity, and General Management in the United States, 2006. U.S. Department of Agriculture Animal and Plant Health Inspection Service. National Animal Health Monitoring System, March 2008. http://www.aphis.usda.gov/animal_health/nahms/swine/downloads/swine2006/Swine2006_dr_PartIII.pdf
4“Determining optimal maximum culling parity in commercial swine breeding herds.” Iowa State University Animal Husbandry Report 2010. http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=1598&context=ans_air.  27 September 2012.
5Pollmann, Steven. “Sow lifetime productivity: Importance of monitoring commercial pork production.” Leman Swine Conference Proceedings, 2012.
6Swine 2006 - Part III: Reference of Swine Health, Productivity, and General Management in the United States, 2006. U.S. Department of Agriculture Animal and Plant Health Inspection Service. National Animal Health Monitoring System, March 2008. http://www.aphis.usda.gov/animal_health/nahms/swine/downloads/swine2006/Swine2006_dr_PartIII.pdf
7Miller, Gay, Yanghoon Song and Peter Bahnson. “An economic model for estimating batch finishing system profitability…” American Association of Swine VeterinariansJournal of Swine Health and Production: Volume 9, Number 4.
8Knol and Mahr. “Impact sow farm feed intake.” Optimizing sow breeding management and litter outcomes. Conference proceedings 2011.
9E.F. Knol (2001). Genetic aspects of piglet survival. Ph.D. Thesis, Institute for Pig Genetics and Animal Breeding and Genetics Group, Wageningen Universiteit, The Netherlands.
10De Rodas, Brenda and Gawain Willis. “Litter size and birth weight and its impact on long-term production.” Purina Animal Nutrition LLC, Purina Animal Nutrition Center. 2006-2012.
11De Rodas, Brenda and Gawain Willis. “Litter size and birth weight and its impact on long-term production.” Purina Animal Nutrition LLC, Purina Animal Nutrition Center. 2006-2012.
12Miller, Gay, Yanghoon Song and Peter Bahnson. “An economic model for estimating batch finishing system profitability…” American Association of Swine VeterinariansJournal of Swine Health and Production: Volume 9, Number 4.