Are cows using up all the water in the West?

Young bulls enjoying a drink.

It is another overcast morning here in Central Oregon. It is warm by our standards with just a thin sheen of ice over the puddles from the melted snow. Part of morning chores here include a 6 mile drive over to our cow herd. Since we are a small farm we rely on leased land and contract grazing to keep the cows in fodder. Right now our cow herd (about 80 animals total including the cows and this years calves) are earning their keep grazing down an old spent orchardgrass field so we can over seed it in the spring with some New Zealand perennial rye grass. The cows need drinking water and supplemental hay & minerals and with all of this wet weather it is tough to get thru the field and out to the cows without creating deep ruts of mud. Right now our lightest tractor is a little 10hp. Farmall cub and once I can get it started on these cold mornings it is a champ at getting the water and hay out to the cows without tearing up the fields.

1950’s era Farmall Cub

Since we rotationally graze the cattle we have to move temporary fences daily to provide more fresh pasture to the animals. Since we want to tear this field up just a little we keep the paddocks small and move the cows at least once if not twice a day. Moving fences on a pleasant day like this is relaxing and sort of like taking a brisk walk with a little stooping and bending mixed in. On a really frozen day moving fences can be quite the upper body workout as it can be a real struggle to get the fence posts into the frozen ground. Today the ground is soft and the fence moves easy. Moving fence is a good time to do heavy thinking as the fence chore requires little thought and it makes the time pass faster.

Ok, I know I am biased as I like cows. I like watching their culture and mannerisms, I like using them to manage the land and pastures & in the appropriate circumstances I like to eat them. Cows have in recent years been vilified as the destroyers of our climate & our public lands. Somehow as I watch them peacefully graze this winter hayfield I have a hard time believing that cows will be the downfall of our civilization.

Cows eating supplemental hay on an orchardgrass field.

I read something last night that has me thinking again about an old issue - Are cows using up all of the water in the west? Back in the 90’s Newsweek quoted an estimate of 2,500 gallons of water being required to produce 1 pound of beef. Last night I read a statistic in an article by John Robbins that estimated 5,214 gallons of water was used per pound of beef and in the same article an estimate by David Pinmentel, PHD. of an astounding 12,000 gallons of water per pound of beef. Since I claim to be an environmentally friendly farmer and my customers tend to ask me these kinds of questions I thought I had better get my head around this issue. I can’t vouch for a lb. of McDonald’s burger or for feedlot grain or potato fed beef but I find it hard to believe my grass fed Dexter cows could be using anything close to 2,500 gallons of water for a pound of beef let alone anything close to 12,000 gallons of water per lb.

Ok, so here is my attempt at crunching the numbers. I am going to start from what I know. I know that by rotationally grazing on 1 acre I can produce about 1000 lbs. of beef in 2 years. I know this to be true because I have done this before. For this mind experiment I will put 2 Dexter bulls on 1 fenced acre. I will break up this field with electric fences into paddocks so that I can raise part of this acre as hay for winter feeding. At this low stocking rate I won’t worry about Organic Fertilizers other than the manure and Urine the bulls produce during their 2 year stay on the field. Since this field is so tiny the bulls will need to be confined to a comfortable but not a big penned area and fed hay for at least 90 days during winter. As we don’t want waste to run off into the stream we will spread wood chips over the manure in the pen to create a hot composting bed. The compost from this bed will be excellent fertilizer for next fall’s crops. A bull will consume about 14 lbs of hay per day so we will need to put up a little over 2 tons of hay for winter. This will be a stretch on our little 1 acre but I know it is doable because I have done it. The bulls will stay exactly 2 years as we find we get our best beef when we process exactly at 24 months. For convenience lets assume we get no rain this year and all water comes from irrigation. So that I don’t cheat let’s skip trans-evaporation rates & all of the water that returns to the watershed by percolating thru the sandy loam soil. Let’s forget all of the fancy things I do to stretch out water use and assume I use the maximum water allocation permitted (1 acre foot) per year for this little field. An acre foot equals 325,851 gallons. Over 2 years this would equal 651,702 gallons applied by sprinkler to the tiny field. Let’s assume that the bulls drink from a tank fed by a pump. On a really hot day a Dexter bull drinks around 20 gallons per day. Multiply this over 2 years and you use another 14,600 gallons of water. Ok, so now we are up to a total of 666,302 gallons of water. If we go back to our 1000 lb finished beef number we get a total gallon per lb. figure of 666 gallons per pound of beef. Wait a minute….even Newsweek came up with 2,500 gallons of water per lb. of beef. I must be way off somewhere. Ok, It does rain here and rain does make the grass grow. Here in Central Oregon we get around 10 inches of rain per year. An inch of rain equals about 27,154 gallons on our 1 acre field multiplied by 10 inches and 2 years we get a total of 543,080 more gallons of water or another 543 gallons per lb. of beef. Ok so now we are up to around 1,209 gallons per lb. of beef.. Transportation can’t be much as the butcher is only 7 miles away and we sell most of the beef within a 50 mile radius. Processing can’t be more than 1 gallon per Lb. The water needed to produce the 20 gallons of biodiesel to hay the field won’t be much. Let’s assume another 100 gallons per lb. worst case for all of these other “extras”. Ok, Let’s call the total 1,300 gallons of water per lb. of grass fed beef the absolute worst case scenario. That is one heck of a lot of water but not even close to Newsweek’s puny figure of 2,500 gallons per lb. of beef. How the heck does David Pinmentel PHD. come up with 12,000 gallons of water per lb. of beef. The cows better get a daily bath and massage with those kinds of figures. Ok, 12,000 gallons times 1000 lbs. per acre means 12,000,000 gallons of water per acre. Lets go back to our figure of 235,851 gallons per acre foot of water. An acre foot of water equals the number of gallons of water required to flood an acre with water 1 foot deep. Ok so rough estimate 12 million gallons equals about 37 acre feet of water. Divided by 2 years and we are still are looking at more than 18 acre feet per year. Our poor bulls aren’t going to just be really muddy they are going to need life jackets. Where do you buy a lifejacket for a bull? I don’t mean to be disingenuous thru oversimplification and humor and I am sure David Pinmentel PHD, is earnest and does stellar work. I would really like to read his study as I am obviously missing something really big here. So how much water do I really think it takes to produce a pound of our beef? When I take everything I can think of including our management practices, trans-evaporation & soil percolation into account I get a number in the high 400’s and I think there is still room for improvement.

According to a quick web check soybeans & rice both take around 250 gallons of water per lb. of production. I don’t really know what they take as neither successfully grow in production here. This makes the two heaviest plant water users still a full 100% more efficient than our beef production. If nothing else this emphasizes why eating smaller portions of grass fed beef really matters. Why raise beef at all when plants are so much more efficient at water use? I have lots of thoughts here probably better saved for another post as all of the fences have been moved and it is time for me to head up the hill on the Farmall Cub and home for a lunch of corn, rice & grass fed beef roast.

Sean Dodson the FoodieFarmer