Culling a sow is one of the most important management decisions a producer can make. In making the decision, the first consideration should be whether the welfare of the sow is compromised. Should this be the case, then the sow should be hospitalized, destroyed or culled immediately.
However, if the sow’s welfare is not compromised, the second question should be whether there is an additional pregnant gilt that will farrow in the same batch. If not, the sow cannot be culled.
Timing of culling
On many farms, sows are culled at the point of weaning. Perhaps the decision is even made during lactation, but why?
There are three major times when culling should be considered:
* At the end of the breeding week
* At the first heat check
* At the pregnancy check
Keeping cull sows beyond the breeding week
Sows, as they age, need to be culled. Culling sows after breeding provides options for the farm – it does not stop the culling and replacement of old sows.
When we wean on a Thursday, the first day of the new batch should be Friday. Breed all possible sows (including culls) over the breeding week. Then review the number of females which have been mated. If the breeding target has been easily met, remove the cull sows the following Friday.
In addition, retaining the sow for a week, allows the udder to regress and even possibly some lameness/stiffness issues have been corrected.
Sows kept until pregnancy checking
If we retain the sow until pregnancy check, the concept is to ensure that sufficient sows are pregnant before any culling takes place. If sufficient sows are pregnant, do not spend time pregnancy checking the sow marked for culling. The duly culled pregnant sow will not be recognized at slaughter, as 28 day foetuses are extremely small. Culling at this stage brings the additional benefits of recovery from weaning and lactation with the possibility of additional weight recovery.
A possible secondary advantage of these pregnant animals is that through pharmacological abortion, they may be used to fill holes in the breeding program.
Sows culled pre-farrowing
It is not contemplated that extra sows are kept to the point of farrowing. It is assumed that the number of pregnant sows that enters the farrowing pool will equal 110% of available farrowing places – thus for a 10 sow batch farm – 11 pregnant sows will enter the pool.
If you retain all bred sows in excess of 110% to the point of farrowing, welfare problems will arise associated with the overstocking in the farrowing, nursery, grower and finishing areas.
Some sows still need to be culled
Some sows still need to be culled, however, and these include:
* Any sow or gilt which has a welfare problem
* Return sows - even sows or gilts that return once should be culled if possible
* Sows with behavioural issues - sows that kill piglets or low numbers weaned
Which sows should not be automatically culled?
* Sows of a particular age
* Sows with one litter of low numbers
* Sows that look at you funny
Source: wattagnet