# Pig calculations that change based on when gilts are entered into the record program

September 4, 2015

We continue to get questions from farms and groups on how calculations are being made in different record programs. They want to understand why there are variations from farm to farm and record program to record program in some of the numbers. Since we deal with as many as 24 different sow record programs now being used in the industry, we see where some of the confusion comes from.

We were asked if entry day to first service for gilts affects some of the calculation being made in record programs. For this column, we selected 324 farms, 568,821 females, over 24 pigs weaned per mated female per year and eliminated all farms with major disease, startups, depopulations, repopulations and farms that transferred females between farms. We selected three areas to look at and how the numbers are calculated based on the equations listed with each area.

• Females death loss percent: ([Females died in period / days in period] * 365 days) / Average female inventory in period

• Female culling percent: ([Females culled in period / days in period] * 365 days) / Average female inventory in period

• Average parity: Sum of female parities / Female inventory

Table 1 summarizes the farms by entry to first service interval; 50 days and over, 40 days to under 50 days, 30 days to under 40 days, 20 days to under 30 days, 10 days to under 20 days, five days to under 10 days and under five days. That data shows that there are not significant differences in pigs weaned per mated female per year and total born per mated female per year between the seven breakdowns. This was a surprise to us since some farms have gilt in inventory for 60+ days.

The reason many farms use for not entering females when they arrive or when they are selected in the grower is increased cost for their record program by 5% to 10%. We feel by not entering the gilts when they arrive or are selected does not allow for tracking death loss and culling for gilts before they are bred, most farms do not know their true fallout of females before they are entered into the record program. It is important to know the true fallout to determine the effectiveness of your gilt selection and development program.

## Death loss variations

Female Death Loss Percent, Chart 1, shows the large variation in death loss with a range of 1.2% to 13.7%. The trend line shows as the entry to first service interval days increases so does female death loss. Parity 0 death loss ranges from 0.1% to 4.3% and increases as entry to first services increases. This does make logical sense as the farm with longer entry to first service interval days have larger female inventories would have more gilt deaths.

Female culling percent, Chart 2, again shows the variation is large between farms with a range of 35.1% to 59.9% but the trend line is flat as the entry to first service interval increases. Parity 0’s trend line does increase as entry to first service interval increases. Once again these farms have larger female inventories on the farm allowing for more of these gilts to be injured, have feet and leg issues, etc., which would be reasons for removal from the gilt pool.

## Average parity from farm-to-farm

Average parity, Chart 3, does go down as entry to first service interval goes up. Once again there is a lot of farm-to-farm variation in average parity. I know of several farms that have higher entry to first service interval that feel gilts development is a key to improved farm performance.

These farms are active in the Gilt Development Unit area, making sure all gilts that have a recorded heat no service date and, if possible, crate exposure before being bred. Both these procedures have been shown to improve total pigs born for that first litter.

In conclusion without knowing how gilts are entered into the record program, comparisons between farms are difficult. It is important that within systems gilts are entered uniformly so numbers used to compare these farms are more accurate. At Swine Management Services we would like to see all the farm data we get be in the same format, but we know that is not going to be done in the near future. We know that a few of the numbers such as female death loss percent, female culling percent and average parity in Table 2 are not as good of comparable between farms as we would like.

## SMS Production Index

Table 2 provides the 52-week rolling averages for 11 production numbers represented in the SMS Production Index. The numbers are separated by 90-100%, the 70-90%, the 50-70%, the 30-50% and the 0-30% groups. We also included the 13-week, 26-week and 12-quarter averages. These numbers represent what we feel are the key production numbers to look at to evaluate the farm’s performance.

At SMS, our mission statement is to provide “Information solutions for the swine industry.” We feel with the creation of different SMS Benchmarking databases for all production areas we now have more-detailed information to share with the swine industry. We enjoy being a part of the National Hog Farmer Weekly Preview team.