Managing Grazing

for Pasture, Soil and Animal Health

Herbivores co-evolved with mixed grassland and forb ecosystems to build some of the most fertile landscapes on our planet. While grazing animals are an integral part in such communities, it is the plants, along with their microbial associates, that ultimately underpin the health and productivity of living systems. One only has to think of the amount of life in a desert compared to a rich prairie. The implications of grazing animals, in an environment, are largely correlated to the effect they have on the plant community.

In order to grow herbivores, livestock farmers are essentially in the game of growing forage. We benefit when our management of animals fosters better plant growth, but animal management that compromises plant systems is detrimental, economically and environmentally. If we focus on using our livestock as a tool to enhance the development of diverse and robust plant communities, we will be rewarded with better forage, and animal production and health outcomes. Our ability to do so increases our capacity to run animals without damaging our resource base.

Ecosystem Services

Performed by Grazing Animals

Vegetation, as we know, generates the carbohydrates that are both the fuel source and building blocks for the organic organisation we call life, in all of its functionality. As a plant matures and starts to set seed, leaf growth, photosynthesis and root exudation subside. A timely prune switches its hormone system back into a vegetative mode, so that they can regrow. In this way, grazing events can initiate another round of vegetative growth, with higher photosynthesis and carbohydrate production.

Living plants also slough off, or release, a quota of microbial stimulating root exudates when grazed, instigating a surge of beneficial biological activity in the soil.

When forage sets seed and senesces, plant nutrients get locked up in lignified material, and are no longer being utilised for plant growth. Over time, some carbon (energy) and nitrogen (protein) are also lost back to the atmosphere with weathering.

Herbivores host a robust population of microbes in their digestive system that can break down fibrous plant material. In the process, they release and deposit the inherent nutrients, as manure and urine, on the soil, where they are available once again, to be used for plant growth.

Bunches of larger animals’ trample standing forage and residue into the soil, within reach of decomposers that are then able to break it down. In the process, nutrients and organic compounds are incorporated and released into the soil environment.

The deposits of nitrogen rich manure and urine on the carbon-based plant residue improves the carbon to nitrogen balance, making for more efficient decomposition.

Herbivore manure also contains a range of microbes that perform beneficial services in the soil environment, and non-nutrient compounds that promote plant growth and stimulate microbiological activity.

The seeds of certain plant species are spread by animals, to hedge their bets in different locations. Some types of seeds remain viable when ingested, and are deposited with manure. Others attach to hair etc... and drop off over time.

Herbivore hooves create divots or pockets on the soil surface that become collection points for seed, organic materials and water, aiding the germination and the establishment of more plants.

As animals are mobile, they get around, performing their services, through the landscape.

Environmental Risks

Associated with Grazing Animals

When grazing livestock aren't managed properly, they can cause a range of environmental issues

Plants need to put on good vegetative growth in order to harvest energy from the sun, and develop decent root systems to acquire nutrients and water from the soil. This equips them with the infrastructure and reserves needed to survive the various circumstances encountered in their growing environment.

If animals graze plants when they are too young, it sets the plants back significantly, and can be fatal.

When a significant portion of their foliage has been removed, plants have to draw upon reserves to support themselves through a phase of initial regrowth.

If a recovering plant is re-grazed too soon, reserves are further exhausted, diminishing its capacity for regrowth. This also hinders the development of deep root systems, which compromises a plants ability to withstand drought and recover nutrients from deeper in the soil.

Overgrazing has more to do with how soon we graze a plant than how much of it is grazed.

If given the choice, herbivores will selectively graze the most desirable species first and preferentially graze tender regrowth before consuming less palatable species. This puts our best species at a significant disadvantage. Some herbaceous plant species, especially those with terminal growing points, may struggle to grow on and reproduce after a graze. Grazing animals consume the flowers and seed heads of many plants. Annual species will not persist in plant communities unless they are able to set seed. Over time, all of this leaves us with less of the good plants, and lower diversity.

When livestock are kept in areas for extended periods of time and the forage is continually overgrazed, the plant community becomes stunted and scant. This leaves the soil prone to structural degradation, exposed to the heat, wind and rain, and susceptible to erosion and nutrient loss.

Constant animal traffic compacts the soil, and on wet ground, hard hooves cause pugging, both of which seriously hinder subsequent plant growth.

The build-up of high nutrient excrement in places that animals frequent, such as water sources, can be become a pollution issue

Not enough recovery time risks stunting pasture

White windmill near grass

What’s Best for the Animals

Keep the Rumen Happy

Grazing animals require adequate amounts of protein, energy, fibre, and essential minerals and vitamins to maintain good condition. These requirements vary somewhat between different species and breeds. Ruminant species, such as cows and sheep, have a rumen full of microorganisms that enable them to digest the high amounts of fibre in plants like grass.

The rumen also contains different groups of organisms to digest proteins, sugars, starches and fats. The population dynamics, are influenced by, and calibrate to, the characteristics of the feed intake. A consistent day to day diet makes for higher feed conversion efficiency and happier animals with fewer health problems.

Forage Need to Know

The composition of forage also varies, between plant varieties and species, with stages of growth and in the different parts of a plant.

Image courtesy of Accioly Livestock Industries Services

Image courtesy of Accioly Livestock Industries Services

Cool season plants are higher in protein and sugar and lower in fibre than warm season (C4) grasses. The energy in cool season species is mostly in the form of sugar whereas the energy in C4 grasses is mostly in the form of fats. Leaf matter is higher in protein and energy, and lower in fibre than stem matter. Young growth, is also higher in protein and energy and lower in fibre. As forage ages, it lignifies and becomes more fibrous and the protein and sugar content drop.

Ruminants, in particular, require a fairly high intake of fibre and if the forage that they are eating is too low in fibre, they are prone to scouring, as witnessed by sloppy manure. Supplementing feed with something high in fibre may be necessary to avoid this.

When sugar and/or starch intake is too high, excess lactic acid is produced, causing acidosis, a condition where the pH in the rumen becomes too low for the fibre digesting organisms, and fibre can no longer be effectively digested. You will see undigested fibre and a white crusting forms on the manure.

If consuming lots of high protein forage, such as legumes, immature cool season species or pasture recently fertilised with nitrogen, protein intake may be too high, relative to energy. When this happens, the excess protein is converted to ammonia gas which elevates the pH, causing all sorts of problems. The animals pant excessively when this happens.

On the flip side, if animals are consuming mature forage that is high in fibre and too low in protein, there may not be enough protein to maintain the rumen microbes and they will struggle to keep up with fibre intake, causing constipation, and a loss of appetite. Again, there will be undigested fibre in their manure and the consistency will be on the hard side.

Grazing animals are subject to a variety of health problems when they don’t get enough of all the essential minerals and vitamins they require. They may be selective and/or consume more to try and overcome any deficiencies. Shortages show in younger animals first as their guts are too small to overeat. Animal performance markedly improves with the supplementation of certain minerals and vitamins if they aren’t getting enough from their feed.

Herbivores avoid eating forage growing in patches that they have soiled with their manure and urine, for quite some time. This instinctively keeps them off forage that's probably too high in nitrogen. It also mitigates the spread and build-up of internal parasites through the ingestion of eggs from worms etc… that emerge from the manure, to complete their breeding cycle on pasture.

Grazing Strategies

to Improve Animal, Soil and Pasture Health and Productivity

If you want to have healthy and productive animals, foster strong plant growth and diversity and build soil, you have to manage grazing appropriately.

It’s a case of the how, not the what.

Ideally, we want to manage our grazing so that we:

avoid selective grazing
give grazed plants adequate time for full recovery
maximize forage utilization
provide livestock with a consistently suitable diet
maintain adequate plant cover on the soil
minimize traffic damage
prevent the build-up of internal parasites

What we can manage is:

When we do and don’t graze an area
The space and time allocated to graze events

When we Do and Don’t Graze an Area

The season, topography, shelter and the state of the forage are all things we need to consider when planning our grazing events.

For instance, we may avoid areas that get too wet and are prone to pugging in the rainy season, but take advantage of the green feed they supply in summer when everything has dried off. At certain times of year, shelter from harsh weather conditions could be a priority, so we’d look to provide animals with paddocks that are protected from the wind or contain trees that provide some shade.

As far as the forage is concerned, we want it to meet the requirements of the animals and be strong enough to handle being grazed.

Forage Quality:

As cool season plant species are generally low in fibre and high in protein and sugar, especially when young, they should be allowed adequate time for establishment, and recovery after being grazed. The feed composition gets better when they have had enough time to put on good growth. Legume stands, particularly, are better grazed when more mature, as they are high in protein relative to energy, and low in fibre when young. If livestock are on young forage, early in the green season, they may need supplementation with some feed that is high in fibre, such as straw.

It is important to make sure that livestock are getting enough protein to utilise the high fibre content in the forage, over the dry season. If not, you can supplement with a source of protein, feed silage/hay, or put them on paddocks where there is a good amount of legume material and/or protein rich seeds.

In the growing season, we want to try and graze paddocks while the forage quality is high. When plants go into reproductive mode, the quality starts to drop off. We can graze maturing plants to initiate the vegetative regrowth of more good forage. At some point, the natural tendency of plants to reproduce annually, seasonally, or at a certain age, gets so strong that they tend to bolt quickly, before there's a chance for much vegetative regrowth. It is best for livestock and pasture health to remove animals before this stage and let these areas recover and go to seed.

You can put aside paddocks in the growing season, and not graze them, to stockpile feed for the non growing season and reduce the need to feed out silage or hay. Areas that weren’t grazed in the green season often make for better dry season feed as there tends to be a greater quota of non-grass species and seeds in the mix and a higher leaf to stem ratio. This also allows a wider diversity of plants to set seed.

Plant Recovery:

By only grazing well established and fully recovered species, we enable plants to build reserves, regrow faster, put more exudates into the soil etc… and the forage has a better nutrient profile, courtesy of more developed root systems. The time taken to recover and rebuild reserves can vary between species, at different stages of growth and with seasonal conditions. In general, perennial species take longer than annuals, and annual forb species are slower to recover, if they recover, than annual grasses. To maintain populations of the various species in a diverse pasture, we must accommodate the recovery requirements of the different species into account. If we want to keep annual species, especially forbs, in the system, they must be left to set seed often enough to maintain a population.

Ideally, we want to move livestock on before parasites, that are deposited with their manure, get a chance to lay eggs on the forage, and then stay away from these areas long enough for the eggs die off, which often conveniently aligns with the recovery needs of plants.

The Space and Time Allocated to Graze Events

In nature, dense and moving grazing herds are an important component in a symbiotic arrangement with the larger living communities of open landscapes, where what works best for the animals is aligned with what is best for the rest.

Space:

There are numerous benefits to be had from sizing our grazing areas (breaks) so the herd density is high enough that they have to eat what's in front of them and trample what they don’t eat onto the soil, in good time.

If animals are allowed to spread out they can pick and choose, selectively grazing young, tender growth and the most desirable species first, and leaving stems, older leaves and less palatable weeds behind. There are a number of issues with this.

On subsequent grazing cycles, remaining stem and leaf material is older, and has lost feed quality.

Selective grazing gives the unwanted weeds an advantage over more desirable forage plants. When the herd density is high enough, anything that’s not eaten is at least stomped to the ground. It can be harder for squashed and bent over plants to recover than those that are grazed, giving the desired plants the upper hand.

When grazing cool season species or younger plants, the extra fibre in the stems and older leaves, might be just what’s needed to prevent acidosis and scouring.

When animals are free to wander they tend to make tracks, and gather and rest in certain spots, making for uneven traffic and poor distribution of dung and urine.

Whilst a significant amount of plant material is stomped to the ground with dense herds, this protects the surface of soil from the elements and provides food for the soil biology. In the dry season, remnant standing material wastes away with weathering, and is much better on the ground where decomposition and mineralisation can take place.

Time:

It is most important that animals don’t get the chance to graze any regrowth, as this significantly knocks plants back! Regrowth usually starts around three days after a graze. This is not so applicable in the dry season when plants aren’t actively growing.

Often, larger areas are allocated for grazing events to avoid having to move livestock as regularly. If this happens, they selectively eat the low fibre, high protein/energy forage first, and are left with high fibre, low protein/energy feed towards the end (aside from any regrowth). When they are moved onto a fresh area, they suddenly go back to eating low fibre, high protein/energy feed again. These changes are not good for rumen stability, to say the least. If we are rotating our animals, we want to ensure their day to day dietary intake is fairly consistent, and this involves shorter breaks.

By bunching the animals tighter, in smaller areas, we utilise more of the forage in each graze event, and buy time for recovery in our rotation cycle.

Needless to say, livestock must be moved on before they compact or bare off the soil. Maintaining some residual or living plant cover at all times is essential for soil health.

If we have to keep livestock in an area for an extended period of time, at calving for instance, then it is best to only do so on fully recovered pasture and then allow full recovery afterwards. Sacrificial or otherwise damaged paddocks may need to be renovated, reseeded etc… and again, allowed ample time for plant establishment and recovery.

For all this to work, it has to be done properly.

We have to earn the right to run high stocking rates.

To achieve the desired outcomes, we must be prepared to set up small enough areas to get the necessary herd density, and resolve to rest areas for long enough to get the required recovery.

It is much more effective to set aside some smaller paddocks where you can commit to doing it properly, than take half measures across the whole farm. This will give you a much clearer understanding of what’s involved and what is possible.

Matching area to stock density to get the best pasture utilisation.

Trampled standing feed provides a good mulch over the summer.

Poor pasture profile from prolonged selective grazing.

The next move..

Mobile fencing is a simple way to match grazing area size to mob density for a 2 to 3 day grazing event

Capeweed in pasture can be substantially removed or eliminated through appropriate grazing management.

Making a Case

for High Intensity Grazing Management

High intensity grazing management is all well and good for animal and pasture health and productivity, but what about the cost and time involved?

Putting in the required fencing and water points, combining herds, regular moving of animals etc… it can all be a bit daunting, and is it really worth it?

The benefits that can be achieved when we manage our grazing properly include:

increased growth, and higher quality, feed
more efficient utilisation of forage
greater plant diversity in our pastures
improved soil function and fertility
extended growing seasons
better livestock condition, reproduction and growth
lower hay/silage requirements
less need to seasonally reseed paddocks

So, we can increase our production and lower our input costs if we optimise our grazing management, but our initial set up and daily labour requirements are greater.

How does it stack up?

Obviously, the specifics of our context are part of the equation.

How much capital do we have to invest in setting up?
How much available time/labour do we have to put towards managing livestock?
What does our existing infrastructure look like? How easy is it to modify the current operation?
What’s the size of our enterprise? keeping in mind, it takes about the same amount of time to move a small herd as it does to move a big herd.

The cost of transitioning to a high intensity grazing system is relatively low, compared to the cost of purchasing the real estate needed for equivalent production gains, under standard management.

Once a property has been well set up for high intensity grazing management, the extra cost of in labour is well compensated for by the reduced input costs.

There are numerous environmental benefits associated with this ecologically focused grazing approach, and when we take care of our resource base, we build resilience into our operation.

On a personal level, grazing animals this way can be a very rewarding experience. After all, what beats moving healthy stock onto a fresh paddock and watching them tuck into a luscious stand of top quality forage.

Additional Resources

Managing Grazing Downloadable Summary

This article was produced by 'Talkin' After Hours', the Lower Blackwood Landcare's Online Community & Information Hub

The article was written & collated by Mark Tupman from Productive Ecology to assist land managers in making informed decisions around grazing for Pasture, Soil and Animal Health.

The development of this article was funded through Soil Wise. Soil Wise is funded by the National Landcare Program Smart Farms Small Grants – an Australian Government initiative. It is supported by Healthy Estuaries WA – a State Government program.