Don't Overlook Population Inventory

By Stephanie Rutten, DVM, University of Minnesota and published by PigCHAMP - When the typical performance monitor report is generated for a sow farm, it is easy to be become overwhelmed with the shear quantity of information.
calendar icon 16 October 2006
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The standard PigCHAMP Performance Monitor, for example, contains data for 43 different items. On more than one occasion, producers have told me they don't know what to look at first. Consequently, they focus on the "biggies" -- number of matings, wean-to-first-service interval, piglets born alive/litter, farrowing rate, pigs weaned/litter, pre-weaning mortality, pigs weaned/mated female/year, and non-productive sow days. Periodic attention is paid to parameters such as replacement rate, culling rate and death rate.

I would argue that the most important measure is often overlooked -- population inventory. There is a limit to which excellent production numbers can compensate for animals that are not in production

Consider the structure behind a herd's inventory. At any given time, females can be classified as bred, lactating or open (waiting to be bred or removed).

In order to produce a specific number of weaned piglets each week, there needs to be a set number of pregnancies to generate live piglets. And, there must be a given number of sows to nurse the piglets to weaning age. Finally, and arguably most importantly, there needs to be a population of open, eligible-to-breed animals large enough to generate sufficient pregnancies to produce live piglets.

Although these concepts seem inherently obvious, it is not uncommon for short-term goals to lead to their violation. For example, if a unit decides to implement rules about animal culling to improve productivity -- such as culling every Parity 4 sow and greater that farrows less than nine live pigs or culling every sow after Parity 7 -- and these rules are implemented before making an adjustment to the number of replacement animals entering the herd, a drop in inventory will occur.

The population most directly impacted by such actions is the open, eligible-to-breed animals. Although increasing replacements in the future will correct the inventory deficit, the unit will be challenged to have sufficient bred animals in the interim.

When herds have difficulty making breeding targets, the first place I look is the inventory. Large fluctuations in inventory often lead to large variations in the size of breed groups. This leads to large variations in the number of sows farrowing, which then leads to large variations in piglet weaning age, the number of sows weaned, the number of weaned sows eligible to be bred, and so on... Simply stated, animals that do not exist cannot be bred.

Determining and adhering to a unit's target inventory are keys to consistent, reliable production.

Reproduced August 2006

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