The largest feedlot in New Zealand is the 5 Star feedlot at Wakanui in Ashburton which holds up to 15,000 head of cattle at a time. It is part-owned by a Japanese company and exists to produce the 'marbled' beef some Japanese prefer. I say 'some' because the eating of fatty meat is an affectation completely at variance with traditional Japanese diet. They acquired it from the Americans - and we have heaps of evidence wobbling around the world of what adherence to US dietary principles and practices results in.
If you want to see Wakanui - you can find it on Google maps.
Animals are brought into the lot at between 14 and 18 months old and stay for for about 8 to 9 months being fed a grain diet to force weight gain. They will double their weight in their time there which is a bit akin to stuffing geese with grain to create pate de foie gras.
A cow's life span is a bit hard to judge because we seldom let them live out their natural lives but we know that its life expectancy, like race horses, is far shorter than its life span. The oldest known cow was 48 at death and ages of 40 are not uncommon. Average life span is reckoned to be around 25 - 35 years. A dairy cow is considered old at about 9.
A cattle beast naturally matures at 4 to 7 years. Old style beef farming let the animal grow to maturity and hung the meat for up to 4 weeks before consumption. Old style beef is a dark brownish meat, completely unlike the bright red, blood and water rich meat from the recently slaughtered immature animals we see in the supermarket.
In some respects the Angus beef cattle that end up in the feedlot are better off than many. They live out on grass until they are old enough and big enough to survive the feedlot.
And these Kiwi cattle are not in such dire straits as those that end up in US feedlots but, confining cattle in barren lots and force feeding them an unnatural (albeit tasty) diet, is hardly designed to ensure healthy, unstressed animals.
In the US feedlots, animals are fed antibiotics prophylactically to counter the inevitable infections - necessary because of the suppression of the immune system by persistently high cortisol levels. I don't know if that is the case in NZ.
The grain diet changes the pH of the rumen and causes liver damage - it is a uncomfortable fact that these animals could not survive in the feedlot for much longer than they are there. The greater acidity of the rumen means that the animals suffer damage to the digestive tract but, also that they carry pathogens which would normally be killed by our high acid stomachs. The way restaurants typically cook feedlot beef is very rare, so the chances of being exposed to acid resistant pathogens from faecal contamination is high. We are not at the stage of the US feedlots which irradiate the meat to kill pathogens and I imagine that the killing room at Wakanui is very clean so maybe faceal contamination is not so much of an issue. And frankly, if people who want to eat feedlot meat get salmonella poisoning as a result, I don't much care.
I make no apology for the fact that I find these arrangements to be abominable. I abhor industrialised farming of any sort and it is a lie that it is the only way we can feed people.
Its greatest efficiency is in making money and its social costs are vast. Typically, the social costs are never borne by those who make the money in the short and medium term. These are long term costs and we bear them - that's all of us. And that's just the monetary costs - there are other less easily quantified 'costs' the discussion of which is drowned in the loud demands for short term economic gain.
Unsustainable intensive farming is a form of extractive industry - and unfortunately we have a government which lacks the vision to see beyond short term profits for the few to the long terms costs to the majority.