by Inga Garrelfs
Without the help of man – wild horses have always been able to find all essential nutrients in their natural habitat. Domesticated horses, however, are dealing with nutritional deficits, despite the access to pasture. These can be prevented by keeping in mind a few simple rules.
The quality of a pasture is influenced by several factors. Some of them are changes in the grass’ structure in certain areas or during certain time periods, the availability of herbs, the different kinds of plants, and defence mechanisms of plants. But also the current state of the grazing animal is a factor which needs to be considered (Andrew J. Rook et al. 2002). If any of these factors are not optimal they can result in consequences like lack of different herbages, too much or not enough grass, or a soil which is to acidic.
To save pastures from any type of problem you need a management suitable for it. Apart from the specific organisation of the animals on your pasture, the consideration of the general health of the animals as well as the maintenance of the soil condition and the sward structure play an imported role when deciding on the right strategy.
First of all it needs to be taken care of an even sward structure. Regarding this need it is advisable to mulch the pasture. This practice reduces corrosion which is caused by faeces on the pasture. Other appropriate steps for maintenance are towing and rolling of the surface in early spring; if necessary some additional seeding should be undertaken (FN, n.d.). The pasture should be mowed on a regular basis to cut plants, avoided by horses, and allow them to grow new stems.
To allow the pasture to be used for the purpose of grazing, the support of optimal plant growth is important. Fertilizers provide helpful elements such as: Nitrogen, Calcium (Ahlswede et al. 1991), Phosphor, Potassium, and Magnesium (Diepolder et al. 2004). Further relevant for soil that allows good plant growth is its pH-value. To maintain the right value (boggy soil 4.5, sandy soil between 5 and 5.5 and loamy- and clay soil between 6 and 6.5 (Ahlswede et al. 1991)) it is advisable to lime the pasture every three years with a type of carbonate; and in regions, where soil is low in magnesium, it is common to spread out magnesium lime every other year (Diepolder et al. 2004). The exact frequency of fertilizing (and liming) grass fields as well as the type of fertilizer should be determined by a professional.
But not only treatment can increase effectiveness. The use of your land can determine much of its quality. Depending on the circumstances different ways of organising a pasture are possible. Rational-, rotational or continuous grazing are the most common practiced strategies.
Rational grazing is to first allow the animals to graze on part of the land. Then, daily, the fence can be moved to allow more and more space to be used. A motivation for this strategy, besides the periods of rest for soil and plant, can be a need to control feed-intake of the animals.
When speaking about rotational grazing it is meant that animals rotate from one pasture to another. The basic reason for this is to give plants a time of rest to re-grow. This period of rest should last approximately 20 days or longer (Landesberger et al., 2007). However, in countries like the Netherlands this strategy is only of limited possibility due to a lack of available land.
A practice often followed by these countries is permanent grazing. Permanent grazing is simply the daily use of the same pasture. This usually has many negative effects on the land. The quality of soil and plants, for example, is strongly decreased due to lack of resting periods. Manure, containing ammonia, can be a strong factor in low quality (Fleurance et al. 2006). And the risk of infections by several types of parasites is very high; higher even with too many horses residing on one pasture.
To prevent parasitism in your animals, anthelmintic therapies (worm therapy) should be administered in intervals of three months (Rhein-Kreis Neuss, 2006). The collection of dung from the pasture can be effective and necessary, but not very cost-efficient since it is a quite time-consuming activity. Another possibility to reduce the “worm problem” is to carefully consider the number of horses grazing in one pasture.
Unfortunately, it is very difficult to estimate the space that is reasonable for a particular number of horses. This decision should be made keeping factors in mind like the horses’ use and breed, individual horses’ herd behaviour, soil quality, fertilisation, and climate (Ahlswede et al. 1991). Considering the size of the animal for example, one hectare of permanent pasture is acceptable for approximately three to four ponies or two horses (Ahlswede et al. 1991). Too many horses on a pasture can not only cause parasitism, but also a damaged sward structure triggered by the impact of their hoofs, when moving, stopping, and turning. The damaged places then allow room for weeds to grow rapidly (U. Pollmann et al. 2005).
An additional possibility of maintaining a pasture is to establish mixed grazing, meaning that the land is grazed on by horses and cows. This can be done either at the same time or consecutively (FN, n.d.). Both of these alternatives have many advantages.
Cattle are ruminants and their digestive system is apt to digest older, stammy grasses and plants better than horses. Sorrel (Rumex acevosa), for example, is a plant eaten by cattle but avoided by horses; Firstly, simply because it is toxic for them and secondly because it is growing next to their faeces. The latter can be explained by the research “Selection of feeding sites by horses at pasture: Testing the anti-parasite theory” (Fleurance et al. 2006) which has shown that a natural instinct, working like an anti-parasite strategy, makes horses keep a distance of at least one meter to their faeces.
Cattle do not only eat plants, avoided by horses but are also resistant to most of the parasites infecting horses. When they eat eggs and larvae that adhere to the grass, a natural waste management eventuates. The same cycle happens when horses eat grass with parasites affecting cattle.
Another supporting argument for keeping cows and horses in one pasture is that it provides a fast regeneration of the grass. The hooves of cattle maintain the sward by activating tillering. This natural action leads to an aggregation of plants resulting in a denser sward (Diepolder et al. 2004).
Many different factors concerning pasture management are of importance. Which particular type an owner or manager should focus on always depends on the individual circumstances. A right combination has to be selected for each pasture’s specific attributes. If there is a possibility for a horse keeper to integrate cattle in the management system, it should be made use of. This strategy mixed with common technical and artificial helpers will not only provide well nourished but also healthy horses.
M. Diepolder, St. Hartmann (2004), Herausgeber: Bayerische Landesanstalt für Landwirtschaft (LfL), 2. Auflage April / 2004
Available from <http://www.LfL.bayern.de
FN (Deutsche reiterliche Vereinigung, rubric: Wissen rund ums Pferd, Article: Weidehaltung von Pferden, Available from < http://www.horses.ch/scripts/modules/news/news.asp?
K. Landesberger; B. Brunner (2007), Bayerischer Rundfunk, Broadcast „Unser Land“, rubric Landwirtschaft und Verbraucherschutz, Topic: Was Pferde Wünschen – Ein Offenstall
Andrew J. Rook; Jeremy R.B. Tallowin (2003), Soils, Environmental and Ecological Science Department, Institute of Grassland and Environmental Research, North Wyke, Okehampton, Devon EX20 2SB, UK [online]
Fleurance, G. et al., Selection of feeding sites by horses at pasture: Testing the anti-parasite theory, Appl. Anim. Behav. Sci. (2006), doi: 10.1016/j.applanim.2006.11.019 [online]
Rhein-Kreis Neuss (2006), News From Veterinary Office, Topic: Pferde auf der Weide
Available from < http://www.kreis-neuss.de/C1256C1B0039A97E/barrierfree/9C2CBB75729D1FFDC1256E6E00363C2D?Open&mnn=buerger&nav=fb_51&ds0=PresseSingleBF&r0=DBC1256A02004D8723IDCB5566BBF52D4039C125718000455F64
Dr. L. Ahlswede; Dr. H. Pirkelmann; Dr. M. Schäfer; Prof. Dr. U. Schatzmann; Dr. Heinz Schulz, Published by Dr. H. Pirkelmann, Pferdehaltung: Verhalten, Arbeitswirtschaft, Ställe, Fütterung und Krankheiten, Stuttgart: Ulmer 1991 (Tierzuchtbücherei).