In an interview in 1930, Ford famously stated his belief that the biggest threat to his business emanated not from outside forces, but from defects within his own organisation. He commented that "only disaster can result when the fundamental principles of business are disregarded". The correct application of fundamental principles was clearly very central to how Ford ran his business way back when. If we look to modern pig production, it would serve us well to replicate Henry Ford's absolute demand for operational excellence in the fundamental areas of our business. In our business, the sow herd is often described as the engine that drives production. If we truly see the sow herd as the engine that drives production then clearly replacement gilts are the components from which the engine is built. Thus it becomes clear, if we use substandard components (gilts) in the assembly of our engine (herd), we can never expect the engine to be durable or efficient. One of the questions most commonly asked in relation to breeding herd management is how many sows should I serve for replacements / how many gilts do I need per week or per batch?
Well, let's assume a 1,000 sow herd as an example and break it down. In order to retain a suitable parity profile in the herd most commentators recommend a target replacement rate of about 50%. So on a 1,000 sow unit we need to introduce 500 gilts annually or in round figures; 10 per week for units on a weekly system. In order to ensure we have 10 gilts farrowing per week, we need to account for losses throughout the system. The components of these losses can be accounted as follows:
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Impact on requirement per 1000 sows |
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Component |
Target level |
Effective number of animals required Annually |
Effective number of animals required Weekly |
Effective number of animals required per 3 week batch |
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Annual Replacement Rate Required (A) |
50% |
500 |
10 |
29 |
|
Plus Production losses |
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|
|
|
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Sub fertile gilts culled before service (B) |
20% |
625 (A / 80%) |
12 |
36 |
|
Gilt Selection Rate (C) |
50% |
1250 (B / 50%) |
24 |
72 |
|
Birth to selection mortality (D) |
12% |
1420 (C / 88%) |
27 |
82 |
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% Gilts born in litter (E) |
50% |
2840 (D / 50%) |
55 |
164 |
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Av Born Alive / Litter (F) |
13.5 |
13.5 |
13.5 |
13.5 |
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Number of sows bred for replacements (G) |
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210 (E / F) |
4 |
12 |
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% of replacements gilts born alive that subsequently farrow |
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35% (A/D) x 100 |
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So, when we break the numbers down; it is clear that replacement gilts represent a significant biological and financial investment on any farm. They represent a biological investment because they will dictate to a large extent, the future direction / productivity of the herd. The financial investment arises not only from cost involved in rearing or buying the stock in; but also from the opportunity cost of additional performance that may be won or lost due to genetic improvement or lag as the case may be. There is a further financial cost associated with replacement gilts insofar as there is a significant amount of 'by-product' to consider. Reject gilts and cohort boars may grow more slowly than terminal line stock in the commercial herd so this should be borne in mind as well. Given the costs involved, the efficiency with which gilts can be introduced into a herd and maintained within it, will have a significant impact on the bottom line. Take some time today to look at your replacement policy and make sure your engine is being built from genuine parts. MO'C.
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