Parity Affects Pigs Weaned/Mated Female/Year

This third and final article on female parity effects on weaned pig averages will focus on several production parameters - weaning age, pigs weaned/female farrowed, female death loss percentage, female culling percentage, sow herd parity structure and farm size.

We selected 94 farms from the Swine Management Services database, located in Canada and the United States. To be part of the dataset, farms must have weaned at least 20 pigs weaned/mated female/year (PW/MF/Y) the last 52 weeks and have a mature sow farm. Several different genetic lines were represented.

The 94 farms represented 222, 362 females, averaging 2,364 females/farm. These farms reported 25.70 PW/MF/Y, on average, for the 52-week period. The top 21 farms, averaging 3,129 females, produced 27 PW/MF/Y.

Chart 1 shows average weaning age, by parity. The average weaning age for all farms was 19.68 days. The top 21 farms averaged 19.17 days at weaning. The chart shows the weaning age ranged from 20.11 days for Parity 1 sows to 19.10 days for P7+ females. The top 21 farms ranged from 19.74 days of age at weaning for Parity 1 sows and 18.41 days for Parity 7+ females. In this dataset, 45% of farms weaned pigs between 19 and 21 days of age, with a range of 17.1 to 24.1 days of age.

Chart 2 shows most of the high producing farms are weaning pigs at 17 to 21 days of age, with top farm weaning at 20.9 days. The data shows you do not have to wean pigs at 21+ days of age to attain top production. This allows the use of farrowing facilities to be used to their fullest. However, as we wean more and larger pigs, farrowing crate design will probably have to be updated. In the future, I see farrowing crates being 8 ft. long and 6 ft. wide.

Charts 3 and 4 show pigs weaned/female farrowed. Chart 3 shows the vast variation among the farms in the data set. The average pigs weaned/female farrowed for all farms was 10.57 pigs. By parity, females averaged 10.78 in Parity 1, 11.08 in Parity 2, 10.89 in Parity 3, 10.60 in Parity 4, 10.31 in Parity 5, 10.03 in Parity 6, and 9.64 in Parity 7 and above.

For the top 21 farms, pigs weaned/females farrowed for Parities 1 through 6 were 11.42, 11.70, 11.41, 11.14, 10.84, 10.60, respectively, and 10.27 pigs for Parity 7+. All females averaged 11.19 pigs.

To get to 30+ PW/MF/Y, you need to wean 12+ pigs/litter with 2.50 litters/mated female/year. Chart 4 shows that increasing pigs weaned/female farrowed had a direct effect on PW/MF/Y. The top farm in the dataset weaned 12.45 pigs/female farrowed. To get top production, you must push females to nurse larger litters and they must wean a large percentage of those pigs at a desirable age and weight.

Sow Death Loss' Effect on PW/MF/Y
We also took a look at female death loss for the 94 farms. In Chart 5, percent female death loss is broken down by parity. Clearly, there is a lot of variation from farm to farm.

Average death loss for all farms was 7.6% and slightly less (7%) for the top 21 farms for the 52-week period. When broken down by parity, we see a death loss of 11.4% for Parity 0 (gilts), then 18.2%, 14.1%, 13.9%, 12.9%, 11.6%, 8.5% for Parities 1 through 6, respectively, while Parity 7+ mortalities came in at 6.3%.

Chart 6, displaying percent female death loss by PW/MF/Y, shows a range of 2.3 to 17.2% (all farms). The trend line shows that lower female death loss generally means the number of pigs weaned is higher. As a rule of thumb - each 1% change (Improvement) in female death loss increases PW/MF/Y by 0.25 pigs. Therefore, a 4% decrease in female death loss increases production by one pig.

How Sow Culling Affects PW/MF/Y
To look at female culling percent, we took the 99,093 females that were culled from the 94 farms and broke them down by parity. As Chart 7 shows, culling increases in later parities - 28.6% were culled at Parity 7 and higher, 12.9% of culls were Parity 6 sows.

For all farms, 44.5% of sows (all parities) were culled. The culling rate was even higher for the top 21 farms at 50.7%. The chart shows the top farms cull more gilts and Parity 1 females and fewer of the older parity females, with only 22.3% being Parity 7 or higher.

Chart 8 (all parities) shows a range of culling from 21 to 68%. We feel replacement rate is more affected by the price paid for culled females than it is by a designed replacement plan.

Chart 9 looks at PW/MF/Y by farm size. In the past, most of the top producing farms had less than 1,000 sows. However over the last two years, some of the larger farms produced some of the highest numbers. As you see, three farms with over 6,000 sows are now at 27 PW/MF/Y or higher. Apparently, the larger farms are better able to adopt more of the management changes that increase total pigs born. They do a better job of developing gilts as well as extending the number of hours someone is available to attend farrowing and assist sows when needed. They have fewer stillbirths, dry pigs immediately after birth to reduce chilling and split suckle pigs the first 24 hours to make sure each pig gets a share of the colostrum.

Best Holiday Wishes
We hope that our monthly articles are interesting and valuable to Weekly Preview readers. We are grateful to the farms that work with Swine Management Services and allow us to utilize their farm data in our composite database. If you have a topic you’d like to have us address, please drop us a note or give us a call. We wish you and your families a happy and safe holiday season.

Key Performance Indicators
Tables 1 and 2 (below) provide 52-week and 13-week rolling averages for key performance indicators (KPI) of breeding herd performance. These tables reflect the most current quarterly data available and are presented with each column. The KPI's can be used as general guidelines to measure the productivity of your herd compared to the top 10% and top 25% of farms, the average performance for all farms, and the bottom 25% of farms in the SMS database.

If you have questions or comments about these columns, or if you have a specific performance measurement that you would like to see benchmarked in our database, please address them to: or

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