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The Sow Stall Debate Continues

This Quarterly Benchmarking review offers some clues on how gestating sows performed in four different housing systems. Additionally, this fourth article in the Benchmarking series continues to study the key performance indicators (KPIs) summarized from herds working with Swine Management Services (SMS, Fremont, NE). This data set, from the third quarter of 2007 and featuring our traditional 52-week

This Quarterly Benchmarking review offers some clues on how gestating sows performed in four different housing systems.

Additionally, this fourth article in the Benchmarking series continues to study the key performance indicators (KPIs) summarized from herds working with Swine Management Services (SMS, Fremont, NE).

This data set, from the third quarter of 2007 and featuring our traditional 52-week and 13-week breakout periods, allows producers to track how KPIs change with seasons, management and a variety of other factors (Table 1).

This periodic review reinforces the importance of effectively collecting and utilizing accurate production records in your daily management, and offers tips that can help you squeeze greater efficiencies out of your production system.

Sow Housing Focus

All producers are keenly aware that some of the largest pork production operations in the United States and Canada have decided to move away from individual gestation stalls in favor of alternative gestation housing systems. Most notably, those concerned with the well-being of gestating sows favor some type of penning system.

Few comparisons of stalls vs. pens have been made under similar management systems, comparable genetics and a host of other factors.

Likewise, comparisons between different types of gestation systems are virtually non-existent in the scientific literature.

SMS has segmented their reproductive performance data where the type of gestation housing was known. The four different types include:

  • Pen gestation housing with a computerized feeder;

  • Pen gestation system without an electronic feeder;

  • A combination of pen and stall gestation housing (free stall); and

  • Individual gestation stall housing.

First, a word of caution before examining the production differences between these different types of gestation housing systems. The adjoining tables represent field data, collected without “control” groups for comparison.

Management capabilities can have a considerable impact on field data, especially when measuring reproductive traits. For example, some of the differences could reflect parity differences.

None of the farms employed more than one gestation housing system in an attempt to compare the reproductive performance of like genetics and nutritional programs on a single site using different environments. Therefore, these data must be reviewed cautiously.

That said, many would argue that the best evidence comes from data collected in a “real world” setting. For lack of controlled tests, these field data can help advance the discussion about gestation housing options.

Field Data Reviewed

In the current data available for comparison, the breakout of different gestation housing options was:

  • Five farms with a total of 4,788 sows utilized pens and computerized sow feeders;

  • Two farms with a total of 1,300 sows utilized pen gestation only;

  • Fifteen farms, totaling 22,273 sows, utilized a combination of gestation crates and pens; and

  • Twenty-seven farms with a total of 70,677 sows used gestation stalls only.

Read more on Page 2

These data came from farms within the SMS database in which gestation system type was clearly defined. Consequently, the total number of farms and sows in the SMS database does not match the totals in the entire database.

Table 2 summarizes the differences of the 10 KPIs reported under the four gestation housing types defined above. Our discussion will focus on the most important traits — pigs weaned/mated female/year (PW/MF/Y), farrowing rate, number of pigs born alive and average mated female mortality. Other traits are important, certainly, but most are encompassed in these traits.

The data reinforces that the most widely used gestation housing system is individual stalls, and their average PW/MF/Y is 24.57. All of the other gestation housing options from this data set had lower PW/MF/Y: 22.6 for the farms with a combination of stalls and pens; 21.9 for operations with gestation pens only; and 22.3 for operations with gestation pens and computerized feeding stations.

Noteworthy is the difference between sow gestation stalls and the other three options which range from 1.96 to 2.65 pigs weaned per mated female, annually. Clearly, the alternatives to the gestation stall appear to cut into the profit potential of the operations utilizing them.

Farrowing rate was the best in operations utilizing individual gestation stalls (85.2%), followed closely by operations using gestation pens only (84.7%). Pens with computerized feeding stations or a combination of pens and stalls had similar farrowing rates — both slightly higher than 80%.

Similar trends were seen in the number of pigs born alive. Operations using gestation stalls led the way, averaging 11.3 pigs born alive/litter, while all other gestation housing options had poorer performance, averaging from ¼ to ½ fewer pigs born alive/female farrowed (Table 2).

The one advantage that pens and pens with feeding stations had over individual sows stalls and the stall-pen combination was in the area of sow mortality.

The lowest average sow mortality was with the pens-only option at 2.9%. Pens with computerized feeding stations were exactly twice as high with a 5.8% sow mortality rate. Notably, those operations with individual stalls and the stall-pen combination averaged 9% and 9.9%, respectively. The 7% difference in sow mortality with these systems is considerable and deserves further study.

Use Data with Care

As previously noted, some of these data should be taken with a grain of salt. Reports in the scientific literature show sow mortalities increase as farms get larger. Could herd size explain why the lowest mortality was observed in the operations with pens only, averaging 650 sows/farm, in this dataset?

The answer is not clear and cannot be identified from this data alone. The greatest production, from a weaned pig/mated female/year point of view, is from the gestation housing option with the largest number of sows per herd — those with gestation stalls.

However, a look at individual herd data shows that some of the units with sows in pens and equipped with computerized feeding stations are improving. Three of those units recorded over 25 PW/MF/Y for the most current 13-week period in this data set. Updates will confirm whether these improvements are sustainable.

Rethink the Stall

The question needs to be asked: “Have we given up on the gestation stall too early?”

Clearly, if we use sow productivity as a measure of the sows' well-being, then gestation stalls appear to be the favorable choice.

That is not to say that the pen gestation systems cannot work. Our European counterparts, and some U.S. operations, utilize a variety of gestation housing systems with success. Producers will have to evaluate and identify the gestation housing system that fits their genetics and management capabilities best.

Forcing all producers to adopt a pen gestation housing system is probably not the answer to the sow well-being question.

Seeking Feedback

The Benchmarking series will continue to focus on key production indicators in 2008. If you have thoughts or questions about how to best utilize this benchmarking information, contact Ken Stalder at; National Hog Farmer Editor Dale Miller at; or SMS staff Ron Ketchem at or Mark Rix at

Table 1. Third Quarter 2007 Database Benchmarking and Ranking
Key Performance Indicator 13-Week Benchmarking Data 52-Week Benchmarking Data
Top 10% Top 25% All Farms Bottom 25% Top 10% Top 25% All Farms Bottom 25%
Number of farms 42 105 420 104 46 115 463 114
Mated females 52,951 158,939 700,915 158,399 55,396 155,023 782,222 190,100
Pigs weaned/mated female/year 27.50 26.40 22.90 18.28 27.05 26.03 22.57 18.79
Wean-to-1st service interval 5.94 6.25 7.08 8.81 5.94 6.25 7.10 8.20
Farrowing rate, % 88.1 87.8 83.4 77.5 88.4 87.9 82.8 76.5
Total pigs born/female farrowed 13.23 13.05 12.31 11.68 13.06 12.88 12.20 11.73
Pigs born live/female farrowed 12.13 11.94 11.16 10.38 12.01 11.81 11.07 10.49
Pigs weaned/female farrowed 10.93 10.64 9.75 8.68 10.81 10.51 9.63 8.85
Piglet survival, % 84.6 83.3 80.9 77.0 84.8 83.4 80.6 77.1
Avg. age at weaning, days 19.8 18.8 19.0 18.8 19.2 18.8 18.8 18.7
Average parity 2.66 2.89 2.88 2.02 2.58 2.74 2.44 1.90
Avg. parity of farrowed sows 3.15 3.04 3.08 2.84 3.07 3.12 3.15 2.92
Avg. parity of culled sows 3.49 2.95 3.34 2.86 3.01 3.01 3.10 2.89
Source: Swine Management Services, LLC
Table 2. One Year Benchmarking Values by Different Type of Gestation Housing
Benchmarking Data Pens with Feeding Station Pens Only Combination of Crates and Pens Stalls
Number of farms 5 2 15 27
Mated females 4,788 1,300 22,273 70,677
Mated females/farm 958 650 1,485 2,618
Pigs weaned/mated female/year 22.32 21.92 22.61 24.57
Wean-to-1st service interval 7.63 6.65 6.89 5.89
Farrowing rate, % 80.2 84.7 80.7 85.2
Total pigs born/female farrowed 11.84 11.71 12.12 12.35
Pigs born live/female farrowed 10.91 10.78 11.02 11.28
Pigs weaned/female farrowed 9.61 9.39 9.74 10.11
Piglet survival, % 81.0 80.3 81.8 83.6
Average age at weaning, days 17.5 19.25 19.40 18.94
Average parity 2.34 3.03 2.32 2.26
Avg. mated female mortality,% 5.80 2.90 9.90 9.00