Interestingly, this appears to be the grow-finish phase in American English? Sounds strange, but this is from the US Environmental Protection Agency... i.e. pretty authoritative.
http://www.epa.gov/oecaagct/ag101/porkphases.html

For information on the common phrasing with an accurate description (in German) see:
http://www.pig-vision.com.
The existing translation was done by a non-native, and I believe Mast was one of the terms in particular that was not translated correctly. For reference, though, it is at www.pig-vision.com/en/
My re-translation of Pig Vision will be up some time soon, hopefully.

Very interestingly
From Defra at: http://www.defra.gov.uk/foodfarm/farmanimal/diseases/vetsurv...

"Some pig farmers may breed and rear their own pigs right through to slaughter. Other farmers may buy in young pigs (‘weaners’) from breeder farms and fatten them (‘finishers’). The majority of commercial pig farmers buy their replacement sows and boars from specialist units, called ‘multipliers’."

So it appears there is a mix. Many intensive farms I've heard of (as is increasingly the norm in the US and some countries in Europe, and coming to the UK - see the Foston pig farm proposal) rear from start to finish.

Note that the sows and boars at multipliers are primarily for that - multiplying. Meat production is the secondary, consequential objective once the animals have outlived their purpose.

Therefore:
The fattening (or as EPA puts it, grow-finish) stage is just that, a stage, and not necessarily an independent industry in itself.

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Note added at 16 hrs (2011-02-12 05:34:35 GMT)
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or "process", even ;) .... which gets quite a few google hits.

...Industry is not terrible if the translation is submitted, but for future reference, this difference should be noted.