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Parity Distribution Will Affect Your Bottom Line

This third article in the benchmarking series focuses on productivity differences among sow parity groups and the cost of a PRRS outbreak. We continue to focus this series on making the best possible use of production records to fine-tune management practices that can squeeze out greater efficiencies and improve profits. Key performance indicators (KPIs), developed by Swine Management Services, LLC

This third article in the benchmarking series focuses on productivity differences among sow parity groups and the cost of a PRRS outbreak.

We continue to focus this series on making the best possible use of production records to fine-tune management practices that can squeeze out greater efficiencies and improve profits.

Key performance indicators (KPIs), developed by Swine Management Services, LLC (SMS), Fremont, NE, serve as a valuable tool in identifying and tracking performance changes during specific time periods. The data presented in Table 1 for a 52-week and a 13-week period was collected and summarized by SMS in the second quarter of 2007. Nearly 729,000 sows are represented in the SMS database.

This quarterly benchmarking review will compare production levels of young sows to older sows — a study of the impact of parity distribution in a breeding herd. We will also examine how an outbreak of porcine reproductive and respiratory syndrome (PRRS) affected sow herd performance in a 2,600-sow, commercial production operation.

Parity Performance

At the outset, we will compare the KPIs from sows of different parities. More specifically, we'll take a look at performance differences between relatively young sows (Parities 1 and 2) with that of more mature sows (Parity 3 and higher).

For a variety of reasons, the KPIs for younger sows are not as good as mature sows. Young animals are still growing, which means they must eat enough to maintain their growth while they nurse their first and second litters.

Sow performance adjustments for various parities, provided in the National Swine Improvement Federation (NSIF) Guidelines for Uniform Swine Improvement Programs (, reveal that a Parity 1 sow receives a +1.2 pigs/litter born alive adjustment when compared to Parity 4 and 5 females, which are considered mature in terms of their productivity. Second and third parity sows receive smaller adjustments (+0.9 and +0.2, respectively) to compare them to their more mature counterparts.

Additionally, we can compare whole herd performance from the values in Table 1. This data is sorted by pigs weaned/mated female/year (PW/MF/Y).

The trend that sticks out in the 52-week data is that the bottom 25% of herds have the lowest average parity (2.11), the lowest average parity of sows farrowed (2.90), and the lowest parity of culled sows (2.83), when ranked on PW/MF/Y (see yellow highlights in Table 1). A similar situation can be seen in the 13-week benchmarking.

There are many reasons why a sow herd may have relatively low parity averages, such as the startup of a herd, repopulation of a herd, a disease outbreak and subsequent replacement of old sows with gilts and a nucleus breeding operation.

It is sufficient to say that if we are culling at a relatively young age or too many sows do not reach their most productive parities (Parity 3-5), the results are reflected in the lower productivity.

Closer examination of the KPIs from Table 1 reveal that, when ranked on PW/MF/Y, the bottom 25% of herds not only have the lowest parity averages, but they also have lower values for other KPIs, such as longer wean-to-first service intervals, poorer farrowing rates and lower piglet survival rates. (See “Piglet Survival — A Key Performance Indicator,” National Hog Farmer, May 15, 2007, page 40).

Breeding herds with the lowest average parity and the lowest average parity of farrowed sows should try to identify the reasons for the young age structure.

If it is a start-up herd, the relatively young average parity is a necessary evil that will have to be overcome as the herd matures. If current culling practices are responsible for a relatively low average parity, then closer examination of culling policies is needed.

In general, we need as many females as possible reaching the mature parities of 3, 4 and 5. The greater percentage of sows that reach those mature parities, preferably all the way to Parity 5, the more productive your herd will be.

Consequences of PRRS

To illustrate the impact of a disease on a breeding herd, Table 2 provides a case study of how a PRRS outbreak affected production and profitability of a 2,600-sow herd. The table compares data for the seven months prior to the PRRS diagnosis to data for seven months after. This outbreak was described as “moderate” based on the following:

  • The loss of 10-20% of weaned pigs;
  • $75-150 loss/sow housed, and
  • Four to eight months recovery time to get back to pre-infection production levels.

These values are arbitrary but pro-vide some definition of the impact of PRRS on the example farm.

Based on the estimates presented in Table 2, this operation experienced a loss of nearly a quarter of a million dollars when 0.8 fewer pigs/female farrowed were weaned. Translated to a “per sow housed” basis, this amounts to $85.

Additional costs documented in Table 2 totaled nearly $41,000 or $15.50/sow inventoried. When added to the lost sales of weaned pigs, the PRRS outbreak cost this herd $262,100 or $100.50/sow housed.

These data reinforce the importance of an effective biosecurity program for every herd. Undoubtedly, it is much more cost effective to avoid PRRS or other breeding herd diseases than to deal with the economic consequences of an outbreak. Work with your veterinarian to establish effective biosecurity procedures.

For additional information on the cost of a PRRS outbreak, see the Iowa State University Animal Industry Report at:

Editorial Note: The fourth article in the 2007 benchmarking series will be published in the Nov. 15 issue of National Hog Farmer. The key performance indicators for sows housed in gestation stalls will be compared to sows grouped in gestation pens.

If you have questions about how to best utilize this benchmarking information, contact Stalder at [email protected]; National Hog Farmer Editor Dale Miller at [email protected]; or the SMS staff, Ron Ketchem at [email protected] or Mark Rix at [email protected].

Table 1. Second Quarter 2007 Database Benchmarking and Ranking*
52-Week Benchmarking Data 13-Week Benchmarking Data
Key Performance Indicator Top 10% Top 25% All Farms Bottom 25% Top 10% Top 25% All Farms Bottom 25%
Number of farms 41 103 412 102 38 95 380 94
Mated females 43,990 149,865 728,572 162,878 51,918 144,598 652,482 160,425
Pigs weaned/mated female/year 26.99 25.82 22.50 18.71 27.53 26.46 22.80 18.59
Wean-to-1st service interval, days 6.07 6.22 7.09 8.40 5.76 5.86 6.91 8.62
Farrowing rate, % 88.3 87.4 82.5 75.7 87.5 87.7 82.2 76.1
Total pigs born/female farrowed 13.12 12.83 12.19 11.77 13.29 12.95 12.27 11.73
Pigs born live/female farrowed 12.05 11.76 11.04 10.50 12.19 11.87 11.10 10.34
Pigs weaned/female farrowed 10.78 10.44 9.59 8.82 10.96 10.59 9.66 8.56
Piglet survival, % 84.6 83.3 80.7 78.2 84.7 83.9 80.0 74.4
Avg. age at weaning, days 19.3 18.6 18.9 18.7 19.6 18.5 18.8 18.6
Avg. parity 2.67 2.58 2.46 2.11 2.26 2.42 2.30 2.18
Avg. parity of farrowed sows 3.48 3.28 3.26 2.90 3.26 3.32 3.25 3.11
Avg. parity of culled sows 3.77 3.04 3.01 2.83 2.65 3.03 3.39 3.25
* Source: Swine Management Services, LLC
Table 2. Impact of a “Moderate” PRRS Outbreak from a Midwestern 2,600-Sow Unit
Production Impact of a PRRS Outbreak1
Item Pre-Infection Production Levels Post-Infection Production Levels Percent Change
Farrowing rate, % 85.8 78.3 -8.7
Number born/female farrowed 12.2 12.5 2.5
Number born alive/female farrowed 11.0 10.5 -4.5
Pigs weaned/female farrowed 9.9 9.1 -8.1
Sow mortality, % 6.9 9.1 -31.9
Litters/mated female/year 2.48 2.20 -11.3
Economic Impact of a PRRS Outbreak2
Item Total Loss Estimate Expenses per Sow Housed3 Total Costs of Outbreak
Loss of income on pigs $-221,200 $-85.00
Expenses that changed related to PRRS outbreak
Animal health $-4,900 $-2.00 -
Supplies & misc. $-8,400 $-3.00 -
Other $-1,000 $-0.50 -
Breeding stock purchases $-26,600 $-10.00 -
Total expenses $-40,900 $-15.50 $-15.50
Total losses $-262,100 - $-100.50
1A moderate PRRS outbreak was defined as the loss of 10 to 20% of weaned pigs, loss of $75 to $150/sow housed, and a recovery time of four to eight months in which recovery time is the amount of time it takes to get back to pre-infection production levels and income generation.
2The cost estimates were obtained by comparing the production and economic records seven months prior to and seven months post-diagnosis of a PRRS outbreak in this example.
3Values round to nearest 50¢.