Prolificacy

It is the average of the total piglets born (alive or dead) per litter. Nowadays, hydrid sows normally show a very high prolificacy (they can farrow an average of 12-13 piglets). Nevertheless, there are pure breeds that can have a much lower prolificacy (for instance, the Iberian pig farrows 5-7 live piglets per littter) or a higher prolificacy (for example the Meishan breed). Irt is calculated as follows:

Number of total piglets born (alive and dead) during a certain period of time
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Number of sows that have farrrowed during that same period of time