**Costs - What if?**

A **What if? **
programme is extremely helpful when making decisions on farms.

However, there are a lot of different standards for calculations on farms and the effects of any parameter change vary between advisors.

Batching allows What if? calculations to be made easier as the farm output can be pre-determined.

The spreadsheet below provides a guide only to a cost analysis approach.

Note the actual results on your farm may differ. For example, the spreadsheet assumes that there is space for any extra pig meat produced.

The spreadsheet assumes that all the pigs are sold in the top matrix in the slaughterhouse - which is very unlikely.

At the bottom of the spreadsheet, there is a brief explanation of the calculation method. Obviously we would welcome any comments on our technique. ([email protected])

Always discuss any proposed changes with the whole farm health team.

**Explanation of the calculations
made:**

The calculations do work in whole animals - so numbers are rounded-down or up where appropriate.

The costs are calculated with the assumption that the "fixed" costs - the none food related costs do not change. However, with more pigs it is likely that there will be more health costs, but the impact is normally small compared to the food cost.

**The effect of
numbers weaned, post-weaning mortality and liveweight increase- is:**

[Current cost of production + Fixed costs associated with new production] divided by the new production deadweight.

Note there are legal stocking rate requirements in various parts of the world which increases in liveweight may infringe upon.

For example if the average weight of the pigs in the EU is above 110kg, they must be supplied with 1 sq m - an increase of 30% floor space!

**Killing out %**

Extra weight at the same cost/current total deadweight

**Lean meat %**

The "bonus" paid for each % lean meat over the current deadweight

**Food Conversion
Ratio (FCR)**

(The difference in food consumed between the current and new option* the cost of the food eaten)/current deadweight

**Grams per day and
the days to finish**

[Liveweight - birthweight (assumed to be 1.2kg)]/growth rate parameter

Note the space assumptions and comments are calculated around the batch time in weeks. Thus to the farm there is no real difference between 150 and 152 days growth rate - in a one week batch farm both require 22 weeks of space.

Other calculations are required to determine the spread of the weights and slaughterhouse suitability for finishing pigs.

Similarly the impact of any sow related parameter (litters per sow per year, pigs per sow per year) are minimal in a batching system as the number of sows is not the determining factor. In fact the herd size should change with the seasons to accommodate varying seasonal and predictable farrowing rates.