Friday 24 September 2010

Warm houses in cold climates, dead stock in warm paddocks

Most of us are familiar with David Friedman's beautiful application of fixed and marginal costs to housing. If you live in a warm climate, you spend not too much on insulation. The marginal cost of increasing the internal temperature is then higher, so you keep your house cooler. If you live in a cold climate, you have to incur the insulation cost because the alternative is likely freezing to death indoors. The marginal cost of heating is then lower and so you'll have warm houses in cold climates and cold houses in warm climates.

New Zealand lamb farmers are currently experiencing massive stock losses due to a big snowstorm down south. This isn't exactly unprecedented; it seems like every second or third year since we've been here, there's been a big snow storm during lambing somewhere in the country that has killed a bunch of lambs and ewes. This one seems worse than prior years' though.

These pretty heavy stock losses always puzzled me a bit. I grew up on a mixed farm in southern Manitoba. Our beef cattle calved out starting around the third week in February and finishing in March. If calving went later, then there'd be elevated risk of scours for the calves with the mucky spring thaw and variable temperatures - the calves needed to strengthen up a bit before the spring. And so the first calves often were born on very cold February nights. Daytime highs of -20 celsius or worse; nighttime lows of -40 celsius weren't completely uncommon, though -30 was more typical.

But we never had stock losses like the farmers here have with snowstorms. With about 50 or 60 cows calving out in a season, we might have gotten two or three calves that didn't make it; those deaths were far more typically due to the cow lying on the calf or strangling during an unattended birth than to being born in a snowbank at -40. Here, it's likely hundreds of thousands of lambs that are dying in the snow. Why? Friedman's story. Because the weather was on average terrible, we had to use practices adapted to it. The young cows stayed in a corral near the barn where they could be quickly attended to if things went wrong; the more experienced cows were in another corral also close to the barn. They were all on straw bedding with lots of good hay and alfalfa (lucerne). If they weren't, they'd all have frozen or starved to death in the pastures. So the marginal cost of ramping things up a bit on a really cold night - putting out more fresh straw bedding and being extra sure to go out two or three times overnight if a cow was due instead of once or twice - wasn't that high. But the farmers here have all their stock out in paddocks far from help. The marginal cost of getting them to a paddock close to the house in the very short notice before a serious snowstorm is high, and keeping them all on hay close to the house would waste a lot of winter paddocks.

And so you get dead stock in warm paddocks and relatively happy cows at -40.

It's likely all optimal. But I wonder whether having adapted to this kind of agricultural practice hasn't helped make things like Crafar more likely.


  1. "With about 50 or 60 cows calving out in a season,"

    There's the difference - here there will be around 3,000 ewes lambing with normal stocking rates of about 5 ewes to the acre.

    Stocking rates could be higher with supplementary feed but even so you'd have a lot more stock over a much larger area requiring much more feed than in Manitoba.

  2. We were pasture in summer, feedlots in winter. Because there was no pasture in winter. You could run that system here too, but it would be far less efficient. All the ewes would have to be rounded up and brought into corrals near home during lambing and fed up mostly on hay. But you can't easily take hay off of the high hill country where sheep range, as best I understand things. So total stock numbers would have to be a good deal lower.

  3. We also were very small time as we were a very mixed operation. Bigger cattle producers didn't have higher loss rates, as best I'm aware. At least nothing like folks see here.

  4. Cattle very rarely have mulitple births - 2 or 3 sets of twins per 100. Around 75% of sheep have twins.

    A single calf is more likely to survive than twin lambs.

  5. Oddly enough, we often had enough twins to make up for other losses; we'd try to convince a dead calf's mother to take another's twin.

    I'm not trying to beat up on the pastoral farmers here, Ele. They've optimized, and I can't imagine that they've done it incorrectly. But the optimal production technology here has reasonable risks of a lot of stock deaths. That allows much greater average production and, in good years, happier stock as being out in pasture is far more pleasant than cooped up in a corral for the winter months, as pleasant as you can make a corral.

  6. I think we're comparing apples and oranges - different animals, different climates, different systems, different markets . . .

    Do/did they have subsidies?

    Animals don't always mind being cooped up - farms here which have housing for dairy cows find sometimes the animals prefer to stay inside even thought they're free to go outside.

  7. Of course they're different! The difference in climate is what drives the difference in, for want of a better term, technology (pasture overwinter or corral), which is what drives the difference in cost of responding to a bad weather event. Because Canadian beef farmers have to have their cattle in corrals over winter, it's really easy to deal with blizzards. Because optimal technology here is large herds/flocks dispersed over wide areas, it's impossible to deal with blizzards.

    No subsidies on Cdn beef, lots on Cdn dairy (we were beef), pork varies with strength of marketing boards province by province, chicken / eggs heavily marketing board dominated.

    Our cows and especially the calves seemed very happy in warm fluffy straw in the corrals; they also preferred the barn when the weather was warm. I know less about lamb.

  8. I think we're comparing apples and oranges - different animals, different climates, different systems, different markets .

  9. @Paul: There are also Manitoba sheep farmers (far fewer); they keep their stock in corrals in winter. The difference in climate is what drives the difference in systems.

  10. I'll comment on the architecture bit here. The difference I see is that it would be easier to change the way you manage livestock (with in reason) from year to hear but housing and development has tons of cultural baggage and is slow to repond to things like energy prices. You can easily add a bit of insulation here or there. But when I lived in Florida I was shocked to find most houses didn't have basements and weren't even on a slab but proper up on piers. Excellent for passive cooling but everyone's pipes froze whenever there was the occasional dip, and not as good for active cooling (a/c). So what was optimal is no longer so but a house is still likely around for 50-150 years here in the us 2 or 3 times that elsewhere. So how does this work when the time it takes to change you response is so much slower than the change of conditions? And is that called friction?