Sow losses/cullings: a Tower of Babel (I)

The registration of the sow losses/cullings in the management computer programs is normally something easy, but it is not always given the importance that it really has so, sometimes, the registration is incomplete, with wrong dates and without writing down the cause of the loss/culling. Nevertheless, its correct registration and its later analysis can give us very useful information for the correct technical-financial management of the farm. In this article we will give guidelines for the correct registration of this parameter, leaving for the next article the information that these losses/cullings provide us.

Registration of the losses/cullings

1. Type of loss: we distinguish two main types of losses: the death of a sow in the farm and sending of a sow to the abattoir (culling). Nevertheless, some sows that have been selected to be sent to the abattoir are euthanized in the farm due to different reasons (ie: they cannot be loaded into the truck). In these cases we have two options:

• Include the sows that have been euthanized within the group of sows sent to the abattoir: in this group we would have all sows that we have decided to cull. In this way we will obtain separate information about the dead sows and those sows that the farmer decided to cull. We will also be able to analyze the causes of the decision of culling the sows in the farm.

• Not including those sows in the group of sows sent to the abattoir: in this case they would be considered as dead sows, so on the one hand we will obtain information of the sows that have provided us an economic compensation and on the other hand of the on-farm euthanized sows.

Whatever the chosen option is, the important thing is to stick to it and bear it in mind when performing the study of the losses/cullings in the farm.

2. Moment of the loss/culling: obviously the correct moment of the loss/culling is the day of the loss of the sow (due to its death or to its loading into the truck). Nevertheless this is not always done in this way, because in some farms there is the habit of writing down the loss of the sow in the moment in which we decide to send it to the abattoir, and not on the day in which that sow is loaded into a lorry to be taken to the abattoir. This registration method implies an improvement of the farm data (less non-productive days, a lower productive sow census, a higher number of weaned piglets/sow/year). This policy is incorrect, because this productivity improvement is not real, these sows are still active (they eat feed and occupy a place in the farm). We also lose valuable information, as we can see below:

Table 1.- Breakdown of the NPDs due to losses (deaths or sales) in two farms during a one year period.

In this example we can see that in farm B it takes a little more than a week to send to the abattoir the sows that they decided to cull when weaned, whilst in farm A it takes more than three weeks, with the resulting negative effect on the average of NPDs. If the sows had been "lost/culled" in the register when weaned this difference would have not been seen, and it would have not been possible act appropriately in farm A.

3. Cause of the loss/culling: We can lose a sow due to many reasons, and there are differences between the causes of the loss due to its death or due to its culling.

• Causes of losses due to death: From the example of the causes of death in a typical farm we discuss the most common mistakes.

Table 2.- Sow mortality causes in a farm, one year period.

As we can see, 60% of the losses are due to an "unknown" cause. This is the main problem when making a note of the deaths of the sows. A basic training of the farm staff when carrying out the necropsy for detecting the main causes of death (clostridium, torsion, etc.) helps to reduce this percentage. A basic necropsy does not take too much time and, in exchange, it can give us very useful information.

We can also see that the cause of death of 20% of the sows is the concept "old". We must make clear that in a farm no sow dies due to old age, but there are old sows that die, though there will always be a primary cause. So, it is important to detect (in the case of the deaths and in the case of the sows sent to the abattoir) which is the primary cause of the death/culling of the sow. For example, a sow can have a dystocic farrowing (retained piglets) that causes an infection, with a subsequent metritis. If this sow dies some days later, the cause written down must be a dystocic farrowing, and not a metritis.

• Causes of the sending of a sow to the abattoir: below we show a real example.

Table 3.- Causes of culling (sending to the abattoir) of the sows in a farm, one year period.

Once again we see a great percentage of sows culled due to an "unknown" cause, when all the sows sent to the abattoir should have a cause for its culling.

We can also see a great variety of causes. We recommend the use of a low number of causes for culling sows (10 or 12 at the most) in order to make easier their later study. In the example we could group some of them as, for instance "discharge" and "dirty"; "productivity at farrowing" and "low number of piglets born", etc. We can also see other errors, as the sending of sows to the abattoir due to sudden deaths, or cullings due to abortions without having taken note of the abortion.

As always, the quality of the data that have been written down is essential for their later analysis and the subsequent decision making. The success of a correct registration is to be found in the unification of the criteria by all the people implied in the data collection chain and in the perseverance of all of them. In the next article we will list and define the causes of the losses/cullings for their correct use and in order to avoid problems like the ones described in this article.