Everything I didn’t know about Cows.

Ok guys, we’re really down the rabbit hole on this one. I made it to Spokane and it’s cold and rainy, so while I am waiting for my cousin to get done with class, I parked myself at the campus Starbucks and resolved to get some of my questions answered about cows that I asked myself on the drive through Montana and North Dakota.

There’s a lot to know about cows, and quite a bit of math involved.

I quickly found that I had to refocus my inquiry. I had started by asking questions about range cattle, which is contrasted with feedlot cattle. This gets at a frequently held conversation about the virtues of grass fed beef versus grain fed.

Those interested in sustainable farming practice frequently come down on the side of grass fed, because it conserves grain protein that can be used for human consumption. I have read conflicting statistics on the fact, but it seems that it requires 20-25 pounds of grain protien to produce 1 pound of beef protein. People can’t eat grass, so this seems like a win-win, yeah?

On the other side, those that support feedlots, point out that while, yes, grass fed beef is cheaper as far as feed, the expenses associated with keeping such large plots of land that support fewer animals (specifically property tax) are also cost prohibitive. In a feedlot, advocates say, you can streamline the process and produce meat that is more tender, and looks more uniform.

GIven some recent reading about the average American’s habits when buying food, I buy the “uniform look” argument a whole bunch. An ungodly amount of food waste comes into play at the retailer and consumer level based solely around the cosemetic features of food. But that will be a whole other post.

Back to range cattle. Proponets of grass fed say that the key to addressing issues of taste and tenderness all come back to pasture management. Everything I have read about how to manage your herd of beef cattle comes down to how to optimize their weight gain.

Calves are weened at about 5-7 months, with the goal of being about one full month of pasture grazing before cold weather forces the switch to hay. A few sources I read suggested two full summers of pasture grazing to get a cow to its ideal weight before slaughter, and industry standard suggests a preference for 900-1,200 pounds, depending on the breed.

A healthy pasture consists of mixed cover of both legumes and grasses. Legumes like alfalfa fix nitrogen in the ground, as well as provide a strong root system which all contribute to soil health. Grasses help to prevent animals from bloating on an all legume diet, as well as dry out faster when hay is cut. The beekeeper in me would like to point out that alfalfa and orchard grass are excellent food for the bees, provided they are pesticide free.

So how much pasture do you need to sustain your cows? The goal here is to keep the cows fed so they can gain weight but not strip the pasture of its ability to regrow itself. Healthy pasture reduces feed costs, helps mitigate drought, and can even feed the bees.

So, how many cows can you keep on your acrage? Remember when I talked about math earlier? Here it is. Time to figure out your carry capacity, which is the maximum population of a given animal that can survive indefinitely in a given environment. This is where the sustainability folks really shine. You can read about the impact on economics of carrying capacity from the folks at the Sustainable Scale Project here. Carrying capacity is a function of both the resources available on the land and the consumption habits of the species in question. In this case, cows.

The first step is figuring out what your Animal Unit (AU) is, in the case of beef cattle, one dry (non-nursing) heifer, 1. A 2,000-lb mature bull may be considered 2 AU. 1,300 lb wet heifer can be considered 1.4-1.6, depending on how far the calf has been weened. So, you add all of this together to get your total AU of your herd.

So how many animals can a farmer support. Let’s look at the formula:

Number of animals =  (pounds of dry forage/acre) x (number of acres) x % utilization

                              (Animal weight x Percentage intake) x number of days

Dizzy yet? Let’s look at the numerator. Pounds of dry forage/acre is determined by literally measuring how tall the plant cover is. Say, you have 10 inches of growth in the pasture, and you need to stop your cattle from grazing at 4 inches, you have 6 inches of forage over that acre. There are tables to help people figure out how many pounds of forage there are per inch per acre. Multiply that by how many acres you have, and how much of it is actually growing. For example, if a quarter of your pasture is bare, you only have 75% utilization.

From there, you are going to want to figure out your paddock rotation. While some operations employ a continous grazing system, to avoid exhausting the pasture itself.  You’ll need to figure out how large of a paddock you’ll need and how long your cows can stay there, and how long the pasture will need to recover.

There is more math and more tables to help you figure that out. So here I have been reading and typing for about 2 hours, and I haven’t even touched on breeds and breeding, feedlot cattle, the market share, and how to get your cow from eating grass to people eating your cows. Down the rabbit hole, indeed.


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