Customised Genetics - A Case History
With processors’ specifications becoming more and more specialized, US-based Andrew Coates, PIC’s Technical Services Director for Genetics, describes how a custom selection index can be designed to deliver to the most exacting contracts.
The scenario
The phone rings and you answer it. The
buyer of your pigs wants to set an
appointment to agree your contract for
next year. The good news is they are
changing their payment contract but the
bad news is that your pigs are too light,
too fat and not enough eye muscle depth
for their new requirements. Sounds
familiar?
At the meeting, more specific details are
provided: carcass weight needs to
increase by 4-5kg; backfat needs to be
lower by 3mm; and eye muscle depth
should increase by 5mm. He warns that
you have six months to make some
improvement, and the other six months
on your first new contract to continue
those improvements.
This was a real-live wake-up call for a US
customer a few years ago. How could PIC
help him? The production system
consisted of nearly 15,000 sows in total,
spread over several herds varying in size
from 600 – 2400 sows and nearly all were
farrow-to-finish.
Short-term change – PIC’s nutrition
services team performed an audit of the
feed system from manufacture in the
home-mill, diet formulation, analysis of
complete feeds, feeding mechanisms and
pig consumption. The first priority was to
achieve greater consistency of diets
produced in the several feed-mills, plus
consistency of the diets provided at the
different stages of growth. Changes were
made to diet formulations to accelerate
lean growth to produce heavier and
leaner pigs.

Medium-term change – PIC’s genetic
services team carried out an audit of the
male and female products being used by
the customer. They found that through
the ups and downs of profitability there
was a wide variety of terminal sires still
being used.
Figure 1. The relative weightings of each
trait in the tailored selection index.![]() |
The bold decision was taken to move to a central boar stud for all terminal sire needs; by removing all on-farm AI ‘labs’ and the majority of old boars (leaving only heat detection males). The PIC337 was chosen as the terminal sire for all farms, to improve the potential for sustained lean growth to heavy weights. The quality of boars continued to improve with each new delivery of boars (Table 1).
PIC’s genetic services team designed a custom selection index that emphasized low backfat and high eye-muscle depth. The index included the effects of several gene markers, like PT1 for lower backfat. (Figure 1). The index was applied to the boars then in the stud inventory and to all subsequent replacement boars. Under an agreement with the stud, these boars were custom-housed and semen collected and processed for delivery to the customer.
Long-term change - Similarly with the sow herd, the average age of many females was high with replacement gilts often having been derived from the terminal generation. Longer term improvements were planned by reducing the substantial genetic lag in their gilt multiplication system. GP males were turned over and new boars were also ranked on the custom index. The replacement of older GP sows and those of the ‘wrong’ breed composition was also stepped up through the introduction of new GP females.
The Results
Initially, over the first four months
average carcass weight was increased by
2-3kg (see Figure 2), without serious
increases in backfat. A further 2-3kg was
also added over the next six months. After
the first 4-5 months, backfat began to
decrease and loin depth to increase
(Figures 3 & 4). Trends that were
sustained more or less over the next two
years, as steps were implemented and
their effects reached the market pigs.

The process that this company went through shows that change is not immediate.
Nevertheless, significant changes to the traits of core commercial importance can be
made in a relatively short time-frame. It is vital to consider a multi-faceted approach – a
combination of understanding the on-farm performance; tailoring the genetics;
realising that there are bold decisions to be taken; and seeing through the
implementation of a new farm strategy with the unit staff.

The Priorities in Customized Sire Selection
Select the breed/product for the market
- The first step to consistency
- Set the objectives and criteria for Custom Selection Index
- Include DNA marker information for trait improvement
- Maximize genetic potential
- Keep the product closest to latest developments
- Cost of a dose of semen is NOT the vital issue