(The following is from my monthly newsletter. This series began in March 2022 and has continued for nearly a year, with its final installment in February 2023. Below is the “better” edited version I initially emailed my followers.)
This post focuses on managing our living organism employees; basically, how to pull together time, area, and these critters to figure out how to manage your pastures. We will discuss the differences between stocking rate and stock densities and how animal impact can help create a desired impact on the land. In part 2, we will discuss the living organisms themselves!
Stocking Rate: About the Animal Unit
Our primary and most apparent employees are our livestock–cattle, sheep, goats, horses, pigs, fowl, and others–which we can manage for the benefit of the land. We can put as many people on the land as we want, but in terms of environmental regeneration (and “sustainability”), we are limited in how long they can stay. If time isn’t a factor but area is (compounded by forage yield), then the number of animals is also a limiting factor.
This is where the stocking rate comes into play. Stocking rate allows you to do one of two things: it helps you find out a) how many animals a specific size of pasture can support or b) how big a pasture is needed for a certain number of animals. Stocking rate changes from year to year due to forage yield supply. (Carrying capacity, not to be confused with stocking rates, is the number of animals a piece of land can sustainably support year after year without causing damage to the environment.)
Therefore, the stocking rate validates the question of how much forage is available for the grazing season by encapsulating it in the ruminant (or non-ruminant) animal itself.
The grazing/browsing herbivore is the key to determining how best to utilize that forage. It’s one thing to do the tedious method of taking random clippings around the pasture, weighing them, drying them down, and weighing them again (the microwave oven works wonders for that, FYI). It’s quite another to transfer that information into how much an animal consumes daily or monthly and, from there, into how a pasture can be properly (and, yes, sustainably) utilized.
The trouble is, not all animals are created equal! As we all know, different species eat different amounts depending on factors, including body weight, the water content of the feed/forage, nutritional demands, and environmental factors. While I’ll spare you the boring history lesson, stocking rates were initially developed around a “standard animal unit” for this reason. This Animal Unit is–and was–created with the baseline animal being one 1000 lb (454 kg) cow with or without a calf that consumes 25 lb (11 kg) of dry matter (DM) forage per day. This equals 1 (one) AU or AUD (animal unit day).
Since stocking rates are primarily based on the monthly consumption of an animal unit (called the Animal Unit Month or AUM), that translates to that exact size cow or cow-calf pair consuming 800 lb (363 kg) of DM forage in one month.
I won’t get into how to calculate the stocking rate for your pastures as I’m currently working on another article about that. There, I’ll talk about what I previously discussed, plus how to arrive at AUM/acre for your area and how to use that information to calculate the two primary questions posed above: how many animals or how much pasture.
One thing is for sure about stocking rates: it provides a great starting point in pasture management. It is not a means to an end nor the sole manner to manage livestock. Your animals are your employees, so you must fully utilize their strengths and capabilities to steward the land. The stocking rate tells you approximately how many of these employees you need for the grazing season or how much land your herd or flock needs. But it doesn’t tell you how to graze them in a mob, how long that great mob can remain in a small area, nor about setting up a grazing plan for adaptive-style rotational grazing.
Nor does stock density.
The Purpose of Stock Density
Stock density is different from stocking rate in that it is the amount of liveweight put on an area at a given time. Stock density allows you to see how much liveweight is on an acre (or hectare), and, from there, determine how high or low stock density will impact the land.
The purpose of stock density is three-fold:
- Get more even plant utilization in that area
- Get more even manure distribution and
- To change the grazing behaviour of the animals.
Low stock density doesn’t guarantee any of those three results, just as high stock density does. High stock density changes the “animal impact” that occurs on the land. Also called the “herd effect,” it’s the least-used tool for reasons I’ll explain next.
The Power Tool of Animal Impact
Animal Impact is the unpopular, weird kid on the block. Compared with rest, it’s not as eagerly capitalized in grazing management circles because of the understandable (yet arguably unfounded) fears surrounding what “too many animals on the land” would do. I hate to say it, but it’s a fear that’s been perpetuated by the conventional scientific community in that way too many animals damage crowns and “decapitate” tillers, damage the soil, and take far too much forage than what the land can support.
It’s not that they’re wrong; it’s just that they failed to consider Time in their messaging to producers.
(We already know that not having “far too many animals” on a piece of ground at a single time isn’t the problem. It’s the time that they linger there. The only time we can definitively determine that there are maybe “too many animals” is if they have to return to the previously grazed area too soon, and the area available to graze is limited. Therefore, time still takes precedence.)
However, having a high to very high (or ultra-high) stock density means that animal impact is being pushed to the point that it is changing the behaviour of the animals from basically “free to go where they please ” to “feeling the competition heating right up with the mob!”
Getting that high animal impact means more significant physical impact to the land and the forage stand via trampling, manuring, salivating, and even rubbing (if they’re mob-grazed in the bush), stimulating regrowth and new plants (and maybe some new species) coming up, getting as much dead material trampled and beaten into the ground as possible, and leaving plenty of manure behind.
The beauty of the herd effect is that it’s almost akin to the predator-prey relationship. The presence of predators, either by sight or smell, instinctively forces prey animals to crowd up together, changing their focus and mentality from eating, suckling, breeding and maintaining hierarchical status to pure safety in numbers. The temporary electric fence doesn’t exactly have that same effect–even though it does control where they are to go and eat, a new bale of hay or a new salt-mineral block certainly does. Even the activity of moving to a new pasture causes that behavioural change. The excitement is seen when that hay or salt lick is put out, and everyone is eager to gravitate towards it to check it out and start chowing down. Another good example is when animals are excited when it’s time for a big move.
Let me put it another way. Grazing animals that aren’t excited (or stressed) and have their focus on eating are pretty careful about where they’re stepping, placing their feet in between tufts of plants, following popular trails, and carefully avoiding places and plants they aren’t keen on eating or tramping on. However, when they are excited for reasons mentioned previously, it’s very much like an “all-out stampede,” where their focus changes drastically, and they don’t care where they place their feet. According to Allan Savory, that is where the magic happens.
The herd effect doesn’t need to be used all the time on every move. But it is a good tool to use in areas that need the most impact. Don’t be afraid to push the limits. But don’t do it all the time because that stress quickly catches up in an ugly way. I don’t want you to have to deal with it too often.
Part 2 Continues!
I’m changing things by adding a part two to this particular Grazing Tool because there’s more to discuss beyond what I’ve shared here. For one, I didn’t want to make this longer than it already is. For another, there are a few interesting details to uncover (pun… intended?) about some living organism employees available to us in our land management adventures. More than just the animals we manage, we also have the many soil organisms and wild fauna of insects, birds, and mammals that act as barometers to our management practices.