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Number of Matings, Services Impacts Reproductive Performance

To continue our review on improving farrowing rate, we will take a closer look at how the number of matings (per heat cycle) or number of services (repeat cycles) affects this key performance indicator.

To continue our review on improving farrowing rate, we will take a closer look at how the number of matings (per heat cycle) or number of services (repeat cycles) affects this key performance indicator. At the outset, we have broken the data out by the number of matings or number of services, by parity. It is important to look at how this number affects farrowing rate, total pigs born/female, and total liveborn pigs/female.

Although most recordkeeping systems allow you to enter all breeding information, it is sometimes very difficult to retrieve the data needed for effective analysis. Critical information that must be recorded includes all the matings, identity of AI technician, boar identification or semen batch code, and the time of day the insemination took place – in military time – not just AM or PM. This detailed information is needed to fine-tune breeding procedures and culling decisions.

Performance by Number of Matings
Table 1 and Chart 1 show performance by number of matings, by parity. Data is broken down by one, two and three or more matings, showing the impact on farrowing rate, total pigs born/female, total liveborn/female and stillborns/female.

The data shows 96% of sows were mated more than once, which is very good. To improve performance of this high average, look at the data closer. Parity 0 females (gilts) have a 94% multiple matings, but those that were mated only once had a farrowing rate of 71.6%; gilts bred twice had an 85.2% farrowing rate, and gilts bred three or more times had a farrowing rate of 87.5%. Because gilts have a shorter estrous cycles, more AM/PM or PM/AM matings should be considered, with a third mating if the gilt is still in standing heat. Afternoon heat checking and breeding are critical with gilts.

Studying the impact of mating frequency on farrowing rate of subsequent parities shows a single mating of Parity 1 females at a low 53.3%, two matings yields a farrowing rate of 88.6%, and three or more matings pushes the average to 92%.

Some experts say that having 20-30% of females with three or more matings is normal. We feel that a third mating should only be made if the female is in rock solid standing heat. In some units, a third mating can lower farrowing rate because the females are going out of heat or may not be in heat at all. Past data has shown that a third mating would help increase total pigs born, but have very little effect on farrowing rate. The data in Table 1 shows no difference in total born, live born or stillborn, based on number of matings.

In summary, it is important to review data to see the effect of number of matings on performance. In some units, a few changes in the standard operating procedures (SOPs) for breeding could improve farrowing rate and reduce semen costs by closely monitoring the number of matings.

Performance by Number of Services
Table 2 and Chart 2 show reproductive performance by number of services (estrous cycles). First service females have a farrowing rate of 89.6% farrowing rate, second service females have a 70.2% farrowing rate, and females that cycle a third time, and are mated, have a 61.5% a farrowing rate.

It is normal to see a drop of 15-25% in farrowing rate from first to second service, with another 8-15% drop from the second to third service. The lower farrowing rate is accompanied by a drop in total born from 12.85 pigs to 11.67 pigs from first to second service, and another 1.64 pig drop from second to third service.

With the large investment in breeding females, it is important to give them every chance to get pregnant. Our suggestion is to cull repeat cycling females after two services no matter what parity they are in. It is helpful to print a monthly list of females with 2+ services so the breeding crew can cull any cycle again.

If you want to improve farrowing rate, you must scrutinize mating and service data and use it to finetune your SOPs in the breeding barn. A 4% improvement in farrowing rate can increase pigs/sow/year by 1.35 pigs.

Key Performance Indicators
Tables 3 and 4 (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

Mark Rix and Ron Ketchem
Swine Management Services LLC

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