Comment by groby_b | Hacker News Reader

Comment by groby_b | Hacker News Reader

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That data (1000 gallons for a gallon of milk) comes from Natural News, which is... not a very precise source. A cow consumes, worst case (2000 lbs, lactating, it's hot) ~80 gallons per day. That same cow produces 3-4 gallons of milk a day.

On top of that, most of that water is excreted again - otherwise, your cow would gain 640lbs a day. Or, with the 1000 gallons/gallon of milk scenario, some 12,000 lbs/day

Assuming that that water is tap water is also... well, a most pessimistic assumption.

If you wish a quick sanity check of your numbers, US milk production is ~25 bln gallons/year. Roughly ~70 mln gallon/day. Assuming it took one day at 10kW for a gallon of milk, that'd be 700GW continuous energy consumption for our annual milk production. This is a substantial part of the total US energy production.

Second check: Assuming really cheap energy ($0.09/kWh, 10kW, 24h), that gives us a milk energy price of ~$21.00/gallon. Just the energy. This does not quite match, either. $14/gallon if you go exclusively with wind energy, which is IIRC the cheapest right now.

> comes from Natural News, which is... not a very precise source.

Now that's an understatement. Every time I get sent some info from that site I know I'm going to spend the next 15-20 minutes debunking it with real sources and explaining that while it looks like they source their info, all their links go to blogs that either aren't sourced, source each other, or misinterpret the data.

Actually, now that I think about it, it's amazingly similar to what the fake news and Russian sites did in 2016, but Natural News has been doing it for at least 6-7 years, as that's when I started noticing them. Could be longer.

> That same cow produces 3-4 gallons of milk a day.

Does that only include the periods when the cow is lactating or is it an average that takes the cow's entire lifespan into account?

> On top of that, most of that water is excreted again - otherwise, your cow would gain 640lbs a day.

Wait. Is the 80 gallons per day figure referring to the water that is consumed by the cow directly, or does it include the water used to produce the cow's food?

80 gallons is direct cow consumption. Note that OP treated energy for feed generation separately as well. (And, again, most of that water passes through the cow, it's not actually absorbed)

And 3-4 gallons/day is a rough average. Lactating cows produce 6-7 gallons of milk, for about 10 months after calving. And after 12 months, they calve again. (But really, all these numbers are very rough estimates. It doesn't matter because they're used as a ballpark sanity check for OPs post, not as accurate numbers)

> On top of that, most of that water is excreted again

This seems pretty important in discussions of resource use : how the waste is handled / recycled etc.

> A cow consumes, worst case ~80 gallons per day.

I assume most of the water needed to sustain cows is spent on the plants they eat.

Irrigation systems don't use potable tap water; they use rainwater, or ditches, or in some cases wells. None of these consume marketed energy at anything like the rate given above for tap water. (Wells often need water pumps, but the energy use of the pump is tiny compared to a municipal potable water system.)

This may well be. But at least in the case of the diary farmers that surrounded my home town, all the water used to grow the cattle feed fell from the sky.

Irrigation systems can be buried, so sometimes watering is not as obvious as it may seem.

Milk costs about $3.50 per gallon in the USA.

If approximately 73% of the milk price is subsidized, that is about $12.96. Also, oil is heavily subsidized, which is the main cost of plastic bottled milk dispatched by oil using trucks.

That'd still assume cows, land and labor are free. Which I'll just go ahead and say is probably an invalid assumption :)

And if you read the actual data[1], you'll realize that 73% of the returns come through subsidies. Or $0.35(cdn)/liter, so ~$1.40/gallon.

Really, that energy/water consumption number in the OP is bogus. There's no way around that. It doesn't mean that milk is particularly environmentally friendly, but neither is it anywhere near as devastating as OP made it out to be.

[1] https://www.realagriculture.com/2018/02/u-s-dairy-subsidies-...

Wow, in Australia it’s about 1 AUD or 70c USD per litre. So about the same price, but no subsidies as far as I know.

That said we recently had to fund raise for farmers due to too dry weather and supermarkets increased the price a little bit explicitly to help them out.

Counterpoints / sidenotes: that price is really, really low. We probably should pay more for milk but the industry was dereguated in 2001.

https://www.dairyaustralia.com.au/industry/prices/farmgate-m...

Would that not breach anti cartel laws?

I assume Australia has some?

> supermarkets increased the price a little bit explicitly to help them out

How is this different from normal supply and demand?

Because the supermarkets are a oligopsony. This distorts the market.

I thought you'd spelled oligopoly incorrectly, then I googled.

I've done a business studies degree so surprised I hadn't come across the term.

TIL.

https://en.m.wikipedia.org/wiki/Oligopsony

Actually I looked more closely today and they sell two supermarket branded milk cartons: one with the donation of 10% added to the price and the regular milk. Same stuff inside I presume!

No, that’s not how oil subsidies work. Plastics aren’t receiving extra discounts below the market oil rates.

The subsidies they received are baked into the current market prices you see for a barrel of oil.

Milk costs about $3.50 per gallon in the USA.

Milk prices vary wildly from market to market in the U.S.

Where I live, where cows are rare, it's $2.39/gallon. In greener regions nearby it's closer to $1.89/gallon.

When I lived in Ohio, the hypermarkets always had it for 99¢/gallon as a loss-leader.

I can only assume that $3.50/gallon is normal for... San Francisco, maybe? Or if you're buying organic, free-range, ultra-filtered, sustainable milk.

Average price is $3.27/gallon in December.

Source: https://www.ams.usda.gov/sites/default/files/media/RetailMil...

Wow, that's cheap!

In Quebec, it's illegal to sell milk for less than US$4.89/gallon.

> San Francisco, maybe? Or if you're buying organic, free-range, ultra-filtered, sustainable milk

I don't think it's legal to sell regular milk there - it has to be either nut milk or raw milk.

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