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Gilt Development is Key to Increasing Pigs Weaned per Sow

For many years, producers have talked about how a breeding female’s first litter impacts sow lifetime performance. 

For many years, producers have talked about how a breeding female’s first litter impacts sow lifetime performance. Chart 1 shows Swine Management Services’ (SMS) data from 62 farms, displaying total born by parity. At the outset, the data were sorted by the total born/litter for Parity 1 females into four groups – high (13.56 pigs), medium high (12.48 pigs), medium low (11.48 pigs) and low (10.69 pigs). The average for all farms is indicated by the dashed line in the chart.

The data shows that if gilts have a high total born in their first parity, their lifetime performance is improved. The average total born/litter through all parities was 12.56, with the high average of 13.83, and the low average of 11.35 pigs – a difference of 2.48 pigs/female. The SMS database confirms what previous studies have shown.

There are several management areas that influence total pigs born/litter:

• Level and length of lighting in the gilt development area;
• Weight at breeding;
• Backfat level at breeding;
• Age at breeding;
• Age at first boar exposure;
• Number of recorded heat cycles before breeding;
• Environment of gilt development housing;
• Gestation stall exposure before breeding; and
• Genetic potential. SMS has conducted field trials at several farms in which we recorded heat cycles and gestation stall exposure before breeding. At one large sow farm, we looked at the effect on gilts with record heats vs. no recorded heat. The data in Table 1 shows those with recorded heats had a 0.54 pig/litter advantage (11.88 vs. 11.34). The difference between one recorded heat and two or more recorded heats was 0.41 pigs. The total improvement for no recorded heats vs. 2+ recorded heats was 0.83 pigs/litter. Other farms in the SMS database shows the recorded vs. non-recorded heats difference to range from none to 0.91 pigs/litter. Most sow record programs allow you to record heat cycles and conduct your own comparison on your farm.

Whether it is beneficial to expose gilts to gestation stalls before they are bred has been discussed for years. As we have not seen any studies on this question, we conducted a field trial at a large sow farm. Table 2 shows the results of the trial comparing stall exposure vs. no stall exposure before breeding.

Gilts with no gestation stall exposure before breeding had a total born/litter average of 11.37 pigs compared to gilts with stall exposure with a 12.08 pigs/litter average – an improvement of 0.71 pig/litter. Born live averages also favored stall exposure – a 0.84 pig/litter advantage.

In this trial, gilts were placed in gestation stalls for 5-10 days, then placed back into pens and bred on next heat, then they returned to gestation stalls. Ideally, gilts found in heat would be placed in a gestation stall for the next 18-21 days, then bred on the next heat. These procedures will allow gilts to be treated as individuals, controlling feed intake and environment.

To achieve an improvement of a half to a full pig/litter (total born), you must review your gilt development and handling programs and develop written standard operating procedures (SOPs). Commitment to this program requires the proper tools, such as gestation stalls, mature boars, a labor force committed to proper boar exposure, effective heat checking, daily recording of heat cycles, and documentation of all the information into the sow records program. It is very important to provide the results to sow farm employees to reinforce the need to develop replacement gilts properly.

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