14 February 2025

Replacement & Culling Rate

Louise Clarke discusses how gilt management impacts sow productivity and farm profitability. With 32% of Irish gilts culled by their third litter, producers face rising costs and declining efficiency. A good culling strategy and good gilt development are key to maximizing herd longevity.

Performance from, and management of gilts has a large impact on sow productivity. Profitability and future reproductive success is directly linked to a strong gilt breeding policy. Gilts do not breakeven in the herd until the 3rd parity and yet currently in Ireland 13% of gilts are culled before the 1st litter and 32% are culled by the 3rd litter. This means that 32% of sows do not cover their rearing costs. It is especially important to ensure that there are sufficient gilts available to serve in the correct condition, at the required time. This enables the planned culling of old or less productive sows and maintenance of the target herd parity profile.

Figure 1: Ideal Parity Distribution

Reason for culling

A sound culling policy is an integral part of herd management. It provides for the removal of less productive sows and the entry of replacement females on a regular basis without disrupting the overall performance of the breeding herd. 

However, data indicates that sows are being culled at a younger age and this has a negative impact on farm profitability. The decision to cull should be taken based on the biological condition of the sow (voluntary culling- performance, age, parity), and a proven healthy sow may in many cases be less of a risk for poor future performance than an unproven replacement gilt. Involuntary culling, on the other hand occurs when the stockperson has no choice over whether to cull the animal, for instance due to a health problem (lameness is the most common), or infertility.

Table 1: Sow culling rate

(Source, Teagasc Profit Monitor)

How many gilts do you need?

Replacement rate and culling rate go hand in hand with each other so if our culling rate increases then we need to make sure we have enough gilts available to replace those animals that we are removing from the herd.

For example, if a 500 sow herd had a replacement rate per year of 52%, they would have 260 replacement females bred per year and be entering 5 gilts into the herd per week. In order to maintain a gilt pool of 12% of the target herd size this would mean the farm would need to have 60 replacement females in stock at all time. It is extremely important to keep an eye on your annual replacement rate and if it is higher than recommended, investigate the factors that may be contributing to this.

High replacement rates mean:

• Larger gilt pool required
• Higher sow feed usage
• Poor parity distribution
• Over-crowding of gilt pens
• Negative impact on herd health & welfare
• Gilts bred below target weights
• Lower weaning weights
• Milk yield and quality reduced
• Less healthy piglets (antibodies and acute phase proteins)
• Staff morale and performance declines
• Costs of biosecurity interventions

Managing sow culling properly is a key factor in maximising profitability in pig production. Sows are being culled at a younger age and this has a negative impact on farm profitability. Strategies to improve sow longevity must be targeted at replacement animals. Gilts must be managed, housed, and fed appropriately during the developmental phase to improve retention and reduce involuntary removals.