The Effect of Parity on Pigs Weaned Average

For the next few articles, we are going to be using 94 farms selected from the farms that Swine Management Services (SMS) consults with on a weekly, monthly or quarterly basis. These farms are located in the United States and Canada. All have weaned 20+ pigs weaned/mated female/year (PW/MF/Y) for the last 52 weeks and have a mature female parity structure. These 94 farms had a total of 222,362 sows (2,365 breeding females, average) representing several different genetic companies.

The 94 farms averaged 25.70 PW/MF/Y the last 52 weeks, with 21 farms averaging over 27 PW/MF/Y. The average size of these 21 farms was 3,129 females.

We made a list of production areas to review over the next few months. This month, we will focus on how parity affects total born, PW/MF/Y, piglet survival, stillborns and preweaning death loss.

Chart 1 shows the 94 farms broken out by Parity (1-7+) and by total born/female farrowed. As you can see this chart is very busy indicating that there is a very large variation in total born by parity among the farms. The 94 farm averages were: P1, 12.90; P2, 13.36; P3, 13.94; P4, 14.02; P5, 13.80; P6, 13.13; and P7+, 12.90 total born/female farrowed, with an overall average of 13.47 pigs/litter.

In parities 1 through 7, the top farm averaged 14.90, 15.90, 16.10, 16.50, 15.70, 15.10 and 14.00 total pigs born/litter, respectively, with an average of 15.3 pigs. The lowest farm in the group, by parity, averaged 10.70, 10.70, 11.10, 11.0, 10.90, 10.30 and 10.00, respectively, with an average 10.80 pigs/litter for all parities. Therefore, the spread for total born/litter from lowest to highest was 4.50 pigs.

Does total born/female farrowed affect PW/MF/Y? Chart 2 is a scatter graph showing PW/MF/Y and total pigs born/female farrowed for the 94 farms in this dataset. As you can see, as the trend line for total born/female farrowed increases, PW/MF/Y follows. It you want to be at 27+ PW/MF/Y, total born/female farrowed needs to be at least 12.50 pigs/litter.

Total born for the Parity 1 female is very important. If she gets off to a good start, the rest of her time in the breeding herd will be more productive. In Chart 3, we separated out the Parity 1 females from the farms in the dataset, which ranged from 10 to16 pigs average total born. If you look at total born/female farrowed in this chart you will see that as that measure goes up, so does PW/MF/Y. To rank as one of the top farms, you must have a good gilt development protocol. (See March 8, 2010 Weekly Preview, “Gilt Development is Key to Increasing Pigs Weaned / Sow,” The key management practices for increasing total born for gilts include acclimatization to farms before breeding, at least one recorded skipped heat, crate exposure before breeding and weighing at least 300 lb.

In Chart 4 you see the trend line on piglet survival increase as PW/MF/Y increases. Remember, piglet survival is a number created by SMS, using this formula: 100% - % stillborn - % preweaning death loss. This is a measure of all of the piglet deaths that could have been viable pigs if management changes were made. Chart 4 shows the large variation piglet survival, by farm, which ranged from 75% to 95%. As total born increases, the trend line for piglet survival decreases (Chart 5).

Chart 6 presents percent stillborn, by parity. The average stillborn rate for the 94 farms is 6.6%. The top farms (27+ pigs) had an average stillborn rate of 6.1%. The best farm averaged 2.4% (P1 females at 1.8% and up to 5% on P7+ females). One farm had a 52-week average stillborn rate of 13.7%. As the charts shows, as sows get older the number of stillborns/sow increases.

Chart 7 reinforces the trend of fewer stillborns in the farms with more PW/MF/Y. To lower stillborn rates, several of these farms have extended the number of hours someone is attending farrowings and several farms now have someone attending farrowings 24 hours/day, seven days a week.

Chart 8 shows the general trend that as total born per litter increases, so does the likelihood of more stillborns.

The other part of piglet survival is preweaning death loss, shown in Charts 9 and 10. Again the trend is clear – as PW/MF/Y increase, preweaning death loss decreases. However, Chart 9 shows a large variation. Top farms have less than 5% preweaning death loss, but several farms recorded over 17% preweaning death loss for the 52 weeks in this dataset.

Also, as one would expect, as total born/female farrowed increases from 10 to16 pigs/litter, the preweaning death loss likewise increases.

What is your farm doing to lower preweaning death loss? Have you tried increasing attended farrowings, towel drying pigs at birth, applying drying agents to pigs to reduce chilling, split suckling of pigs’ at Day 1?

SMS continues to monitor performance of farms by size. In Charts 11 and 12 we looked at 94 farms with average farm size of 2,362 females. The range in size is 200 to over 7,000 sows per farm. We are starting to see a shift from the smaller farms having the highest total born/female farrowed and weaning more PW/MF/Y. More large farms are increasing total born/female farrowed and averaging 27+ PW/MF/Y.

As farm size increases these farms may be able to have more specialized personnel in the breeding and farrowing areas. Most have started to adopt new management concepts of daily heat checks of gilts, better recording of heat cycles, making sure that enough time is spent inseminating to ensure quality matings, minimizing females that inseminated just once, and extending the time someone is attending the sows farrowing. This extra attention reduces stress on sows and pigs and the caring people at the farm are challenged to do better.

Keep in mind, you can never recover from low total born/Parity 1 female farrowed. To achieve top performance, it is important to maximize total born/female farrowed in the first parity. Review your gilt development protocols and adopt the new farrowing management practices needed to wean a higher percentage of the total born.

In the next several articles, we will analyze other production areas for these 94 farms.

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

Click to view graphs.

Mark Rix and Ron Ketchem
Swine Management Services LLC