Parity Effects on Pigs Weaned

In this follow-up to our last column, "The Effect of Parity on Weaned Pig Average," (Oct. 19, 2011 Weekly Preview posted at, we will again use the 94 farms selected from the Swine Management Services database. These farms are located in the United States and Canada, have 20+ weaned pigs/mated female/year (PW/MF/Y) for the last 52 weeks, and have a mature female parity structure. Several different genetic lines are represented. The database includes 222,362 sows, with a farm average of 2,365 females.

For the last 52 weeks, these 94 farms averaged 25.70 PW/MF/Y. The top 21 farms, averaging 3,129 females, averaged more than 27 PW/MF/Y.

This article will focus on reproductive traits, broken out by parity, such as wean-to-first service interval, percent repeat services, percent multiple matings and percent farrowing rate.

In Chart 1, sows are broken out by parity 1 through 7+ and wean-to-first service interval. The busy chart reinforces there is lots of variation among farms. Average days to return to heat for all the farms was 6.57 days for the last 52 weeks and slightly less, 6.34 days, for the 21 farms that averaged 27+ pigs.

As one would expect, the biggest variation is in Parity 1 (P1) females, which averaged 8.82 days and ranged from 5.1 to over 14 days; 27.7% of the farms averaged less than six days for weaned females to cycle.

As weaning age increases, the trend has been to decrease the days to cycle. However, as producers tried to lower feed costs in lactation using more distiller's dried grains with solubles (DDGS) at varying energy levels and less animal fat is fed due to cost, we have seen more variation in days to cycle. The farms that are getting more sows to cycle by Day 7 after weaning have increased daily feed intake in lactation by feeding sows more times per day, increasing feed intake sooner after farrowing and adding ad-lib feed delivery systems so sows can eat all they want, when they want.

Chart 2 shows that as wean-to-first service interval drops, PW/MF/Y usually increases. There is a relationship between days to cycle after weaning, farrowing rate and subsequent total pigs born in the next parity.

Chart 3 shows a lot of variation in percent of repeat services. In this dataset, average percent repeat service was 5.2%. The charts show several farms have low repeats do to higher farrowing rates. Some farms cull all repeats.

We also looked at percent multiple matings by parity and the effect on PW/MF/Y in Charts 4 and 5. Most farms try to mate females multiple times. The 94 farms averaged 90.8% multiple matings, while the top 21 farms averaged up to 93%.

The most variation is replacement gilts (P0), with some farms dropping to 70% multiple matings. Farms that have the highest farrowing rate for P0 females generally average two or more matings. With P0 females having shorter heat cycles than weaned sows, some farms have gone to breeding P0 females, returns and late weaners twice the first day they are in heat with AM/PM matings to reduce the number of single matings. Chart 5 shows that most of the higher producing farms get most of their females mated multiple times, which usually increases farrowing rate and total pigs born.

As you see in Charts 6 and 7, we broke the farms out by farrowing rate. Again, there was lots of variation, with P1 at 85.8%, P2 at 87.4%, P3 at 88.4%, P4 at 88.0%, P5 at 86.5%, P6 at 85% and P7+ at 82.5%. The average of all farms was at 86.6%. The top 21 farms averaged more than 27 PW/MF/Y, which was 2% higher than the average. That 2% higher farrowing rate equals about 0.70 more pigs/sow/year.

Chart 7 shows farrowing rate variation on the 94 farms ranging from 70% to 95%. The trend line shows that as farrowing rate improves so does the PW/MF/Y. The 94 farms ranged in farm size from 200 sows to more than 7,000 sows, averaging 2,362 sows.

Chart 8 reinforces that as farm size increases the trend line for PW/MF/Y also increases. There are still many farms with less than 1,000 sows that average more than 25 PW/MF/Y. Three farms, with 6,000+ sows are now averaging more than 27 PW/MF/Y.

In Chart 9, the data is broken down by Total Born/Female Farrowed and Farm Size. Trend lines show total also increases with farm size. But there is still a lot of variation by farm size.

We are beginning to see more improvement in PW/MF/Y in the larger farms. These farms are adopting more of the newer ideas on how to produce and save more pigs. They are concentrating on gilt development, skipping heats, providing extended care in the farrowing rooms to lower stillborns and preweaning death loss to improve piglet survival.

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: [email protected] or [email protected].

Click to view graphs.

Mark Rix and Ron Ketchem
Swine Management Services LLC