To replace or not to replace, that is the question

Blog by Ron Hovenier, Breeding program manager

Longevity is one of the traits in our breeding objectives for dam lines. We define longevity as a sow’s ability to stay in production until at least the start of the fifth cycle.

The importance of this trait from the perspective of whole system profitability is clear: we want to maximize the benefit from the sow’s high production potential in her third to fifth cycle because these are the most productive cycles and produce the best-performing piglets.

Ron Hovenier Topigs Norsvin

Furthermore, the more piglets a sow can produce during her life, the lower production costs of those piglets due to the depreciation of the costs made to produce or purchase a replacement gilt over a higher number of piglets.

However, if we look at the importance of longevity on whole system profitability, there are several other important aspects that should not be underestimated.

First of all, there is the potential loss of slaughter value of the sow to be culled if animals that cannot be shipped to the slaughterhouse are euthanized or in the case of sow death. What if a sow is lost a few days before her expected farrowing? That is estimated to cost €500-€750 per sow that dies just before weaning due to lost carcass value, lost piglets and feed, empty space, etc.

Secondly, the missed opportunity to cull animals voluntary based on their actual production performance. Comparing the average genetic index value of sows that have been culled or died with the average index value for all present sows, shows no difference.* In other words, the animals that have been culled were not culled on the basis of their genetic quality.
*data from the Topigs Norsvin database for the year 2019

Balancing act between four factors

Does this selection for longevity mean that the objective is to minimize the replacement rate at sow farms? No, it does not. There are several factors that determine the optimal replacement rate in a sow farm:

  1. the costs for a replacement gilt;
  2. the carcass value of culled sows;
  3. the production performances for the different parities;
  4. the rate of genetic improvement.

Clearly if the costs for a replacement gilt go down and/or the carcass value of culled sows goes up, it will be more attractive to replace an old sow – with a lower future production expectation – with a young, genetically better gilt. The same is true if sows already achieve top performances in the first and second litter as this will reduce the pay-back time for the investment made for the young gilt.

And last but not least, with increased genetic improvements achieved by modern breeding companies like Topigs Norsvin, the increased margin opportunities of young gilts and their offspring should be seriously taken into account.

If all four of these points are balanced then today’s optimal replacement percentage from an optimal full chain profitability perspective is around 50%.

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