Direct income from cull sows should not be a major factor in determining sow culling policies, said the British Pig Executive in its new culling management guidelines. It should only account for around 2% of total sales income.
Pig producers should instead focus on maintaining an optimum parity profile by regularly replacing older or less productive sows and keeping the herd’s overall performance steady. Sow culling rates have a direct correlation with economic efficiency. “Producers should aim for an average herd parity no greater than 2.8," said BPEX knowledge transfer manager Angela Cliff. "It’s important to understand why individual sows are culled and to manage voluntary or selected culling consistently. Decide what your target maximum parity is for each animal and then stick to it. Voluntary culling is also carried out to remove any sows not performing as well as they should. For example, those that have shown farrowing difficulties, poor litter size or poor lactation and rearing ability.”
At the same time, pig producers should minimize the level of involuntary or forced culling, most commonly caused by fertility problems, lameness or disease. “Pig producers should continually record sow condition and performance and pay close attention to management of gilt selection, feeding strategies and pen and floor condition,” said Cliff.
To find out the economic impact of retaining older, less productive sows, it is worth calculating the cost of ‘empty days’:
- Cost per sow-day = Total annual breeding herd expenditure / (productive sows x 365)
- Cost of reproductive failure = Cost per sow-day x empty days per annum / pigs born alive (sold) per sow per year