When you have established the feed requirements of your goats, you will need to determine the quality and quantity of forage and/or supplements required to fulfil these requirements and the availability and consistency of your forage supply. This article guides you through forage assessment, management and grazing strategies for temperate pastures and for rangelands.
Quality and quantity.
The standard unit of measurement for feed quantity is kilograms of dry matter (kg DM). Moisture content varies widely between different feed sources, and with time of year. To enable comparison between feed sources, quantity figures are always quoted in terms of dry matter.
Feed quality refers to the nutrient content of the feed source and these figures are always related back to dry matter. There are many ways to measure feed quality. Some of the most common units of measurement are;
This information can be obtained via laboratory analysis of a feed sample. Many commercial fodder suppliers will have this information readily available for each of their products.
Palatability is also something that will influence a goat’s grazing habits and feed preferences. The article Palatability of plants commonly eaten by goats contains further information.
Another issue to consider is plant toxicities. Some plants can be toxic to goats. Toxicity levels vary and the effect on the grazing animal may depend on how much of the plant material that they consume. Refer to the article Plants toxic to goats for more information.
Maintaining your feed base.
Maintaining your feedbase is good grazing management. Before you commence thinking about grazing strategies, you should first be aware of some of the grazing habits displayed by goats that are different from the grazing habits of cattle and of sheep;
- Goats are able to utilise the foliage of trees and shrubs, and will eat a wide variety of forage plants.
- Given the opportunity, goats are very selective in the way that they graze.
- Goats are inquisitive and will sample new things.
- They will select the most energy-dense parts of a plant eg seedheads.
- Goats show more of a preference for roughage than other domestic livestock.
Understanding your goats’ requirements and their grazing preferences is only part of the information to base your grazing strategies upon. The other critical element is understanding the growth habits of plants and how they respond to grazing.
To ensure plant persistence, you need to be aware of how hard a particular type of plant can be grazed and how long the plant will take to replenish its reserves and grow back to a suitable size for grazing. Constant heavy grazing will have a deleterious effect on most plants and may lead to palatable plants being grazed out of a pasture mix.
Plant growth is driven by photosynthesis: a process where sunlight is intercepted by the plant’s leaves, converted into carbohydrates and used for the production of plant material. The factors impacting on plant growth are;
- Soil temperature.
- Soil conditions.
- Sunlight – leaf area.
The main factors that landholders can influence are nutrient availability, capture of sunlight and to some degree soil conditions; acidity, drainage and compaction. Moisture, without irrigation, and soil temperature are largely out of the farmer’s control.
Nutrient availability can be influenced by fertiliser application and strategies which promote a healthy environment for soil microbes eg. improving soil conditions.
Soil conditions can be altered by drainage, the addition of soil ameliorants such as lime and gypsum, tillage reduction, trash/ground cover conservation and careful management of stock to prevent pugging.
The amount of sunlight captured is relevant to the management of leaf area. The more leaf area, the more sunlight is intercepted, the more carbohydrates are produced, and the more leaf material is generated. Grazing and cutting are the main methods of manipulating leaf area, and this is where management can have a significant impact.
Grazing temperate pastures.
In temperate grass-based pastures it is common to think about pasture growth in terms of the number of green leaves. Grass tillers are only able to maintain a certain number of green leaves before the oldest leaf starts to decay. Decaying leaves are of low feed quality and lower palatability, and thus represent wasted production. The aim is to graze as many green leaves as possible and minimise decay.
For example, perennial ryegrass has, at most, three active green leaves per tiller: the fourth leaf onward will be decaying. So the aim is to commence grazing when there is an average of three green leaves per tiller. Other common temperate grass species function similarly and hence a similar grazing strategy is appropriate; phalaris has a maximum of four active green leaves and cocksfoot and fescue have at most five active green leaves.
Having determined when to commence grazing, the next questions are when to take stock out and how long to spell the paddock before the next grazing. This is governed by the rate of plant recovery and growth. The recovery of temperate pasture grasses after heavy grazing is initially quite slow the rate of growth rapidly increasing as more leaves appear, reaching a plateau, and then declining as decay begins to surpass new growth.
- Very short pasture.
- Low leaf area, very little interception of sunlight.
- Initial regrowth is often driven from plant energy reserves.
- Slow pasture growth.
- High-quality feed, low quantity.
- Phase of greatest pasture growth.
- Increasing leaf area allows increased photosynthesis and thus increased biomass production and replenishment of plant energy reserves.
- Good quality and quantity.
- High leaf area, but shading of lower leaves and decay, reduces the growth rate.
- High quantity, low quality.
The aim of grazing management is to spend as much time in phase II as possible. This is where you get the greatest pasture growth, striking a good balance been feed quality and quantity. As you can see in the diagram, the lower the level of leaf area remaining at the end of grazing, the slower the rate of plant recovery. It is advisable to retain some leaf area at the end of the grazing period.
If pastures are subject to frequent heavy grazing, and are continuously kept in phase I, individual plants will begin to suffer, and some will be killed. Loss of desirable plant species opens up the pasture to weed invasion. Also with reduced plant cover, the soil surface is exposed, increasing the risk of erosion.
In phase III, prolonged periods of infrequent or lax grazing lead to large quantities of very low quality feed. In tall pastures very little light gets down to the growing points at the base of the plants, and lower growing species may be completely shaded. As a consequence, lowgrowing plants often do not survive and the formation of new grass tillers is suppressed, and thus the pasture starts to thin out.
The rate at which each new leaf appears is governed by moisture and soil temperature. If one or both of these is limiting, the rate of appearance of new leaves will be slow. For example in summer, soil temperature is not a limiting factor, but there is often a deficit of moisture, hence summer growth rates are often slow. In spring, when soil temperature and moisture conditions are optimum, pasture growth is very rapid. The frequency of grazing needs to be adjusted accordingly, with long rest periods between grazings when growth rates are slow, and more frequent grazing when growth rates are high.
The key to successful rangeland management is to match goat numbers with feed supply. It is visual cues, such as plant numbers and species present, that indicate how your balance between feed supply and demand is working. This balance will change with the seasons, and may necessitate seasonal adjustments to your stocking rate.
If you are unsure of the average carrying capacity of your area, seek advice from the Pastoral Lands Board or department of agriculture or primary industries in your area. Local graziers knowledge may also be helpful in determining your carrying capacity.
If you have some idea of the dry sheep equivalent or dry stock equivalent rating for your area (dse/ha) then you can estimate the number of goats that can be carried. This table gives some general guidance of the dse rating for goats. These figures are intended as a guide only. The ratings will be affected by production levels, the physiological state of the animal and the animal’s frame size.
Establishing an appropriate stocking rate and length of grazing period is about understanding the quantity of feed on the ground, sometimes referred to as food on offer (FOO). Feed quantity is estimated in kg DM/ha. The ability to accurately estimate feed quantity is a skill that develops with practice. There are a number of publications that provide sets of photo standards to help you with this task. The photos illustrate what different fodder quantities (kg DM/ha) look like in different rangeland environments. You can use these photos as a reference point to help you estimate the kg DM/ha in your paddocks. Training courses are also available that teach fodder assessment skills.
Knowing the amount of feed available and the feed requirements of your stock, refer to goat feed requirements tables in the article Goat Nutrition you can calculate the amount of stock that can be run in a given area, for a given period of time. When making stocking rate decisions, it is important to consider rainfall trends, and factor these into your stocking rate calculations. You also need to take into account the impact of non-domestic animals, feral nad native, that are grazing the area , as they will also be contributing to the demand for feed.
During the initial stages of an enterprise change, from beef or sheep to goats, it is generally the case that the stocking rate can be lifted for the first 12-18 months. The reason that this is possible, is because of the build-up of browse previously untouched by sheep and cattle. Once a distinct browse line becomes apparent, your stocking rate must be reduced to avoid over-grazing.
Fodder utilisation will be strongly influenced by the presence or absence of available water. Goats will graze within range of water points, therefore water points should be located in the centre of grazing paddocks to encourage grazing across the entire area. This becomes particularly important in summer when any surface water has dried up and stock is reliant on defined water points. During these periods, the grazing pressure around watering points will increase, and so monitoring of the feedbase and management of stock numbers is critical.
Monitoring has both an animal and an environmental component:
Is the stock being adequately fed?
Assess weight, condition and behaviour (underfed does with kids at foot may appear staggery and will not stride out).
Is the environment being maintained in a healthy state?
Look at the soil condition and plant growth and look for signs of degradation.
Signs of rangeland degradation are;
- Increasing levels of bare ground. Reduced plant density and low levels of plant litter on the soil surface.
- Lack of feed bulk, even at times when there is usually high plant growth.
- Reduced numbers of perennial plants.
- Increased presence of unpalatable species.
- Increase in the proportion of annual plant species.
- Increase in the proportion of broadleaf weeds.
- Increase in presence of woody plants.
- Lack of regeneration of trees and shrubs.
- Browse line clearly visible at the highest extremes that goats can reach.
A recent Producer Initiated Research and Development project analysed faecal samples to determine the dietary preferences of goats grazing in rangeland conditions in southern Queensland during drought conditions. The results of the study showed that coming out of drought the goats tended to concentrate their diet selection on herbage and browse. This allowed the grass species to regenerate at a far greater rate than those paddocks grazed by sheep and cattle over the same period.
It is important to be able to identify the different types of plants present on your land and understand your goats’ grazing preferences. The species most at risk from overgrazing are the most palatable shrub and inter-shrub species. Refer to the article Palatability of plants commonly eaten by goats.
Monitoring means getting off the track and observing the type and number of plants present, regeneration levels, ground cover, etc. Photo points can provide an excellent means of making comparisons over time. Select several reference points at different locations on your property, and take a photo from that point at the same time each year or each season. Observe the change over time and take action as required.
If degradation is occurring, stocking rates in the area may need to be reduced or the area completely spelled for a period of time to allow for plant regeneration. To encourage regeneration of declining species, spelling will be necessary during the flowering period. The period of spelling should allow time for the plant to set seed, for seed to ripen and then fall to the ground; approximately 6-8 weeks for grasses.