Posted by & filed under Animal Forage, Livestock, Working Animals.

By Mariette van den Berg B.(Hons), MSc. (Equine Nutrition)


This photograph © copyright Craig Mackintosh

Introduction

Within the Equine industry there is next to no research based on alternate feeding sources such as forage trees and shrubs for horses. Adding trees in and around pastures can be beneficial for a number of reasons; it not only plays a major role in the hydration of the land and the control of erosion, but it can also provide shade, shelter and fodder. Many of you may be familiar with feeding tree and shrub forage to livestock but not a lot of horse owners know about the use of fodder tree and shrub for horses. In this article I will describe the benefits of trees and scrubs as a fodder and will give a small selection of potential forage trees and shrubs for horses.

Primarily grazer or mixed feeder?

We recognize that horses evolved primarily as grazing herbivores, but they may also be categorised as mixed feeders depending on the feed availability and selection.
The evolution of the horse, Equus ferus caballus, has occurred for approximately 55 million years. From studies of fossils, we derived knowledge about the phylogeny of the horse as an herbivore. It shows that the first 35 million years (Eocene to early Miocene) of equine phylogeny are characterized by browsing species with a relative small body size (~10-50 kg). The remaining 20 million years (middle Miocene until the present day) are characterized by either primarily browsing/grazing or mixed feeders with a large diversification in body size (~50-500kg).

In addition, studies that observed the feeding behaviour of our present day wild horses and other equus species (e.g. zebras and wild asses) reported that equus species show grazing as well as browsing behaviour. In a natural system horses and other equus species browse various shrubs, trees and water plants to balance macro nutrients (energy, protein, water etc), minerals and vitamins requirements. Even our domesticated horses in a confined pasture environment will show this browsing behaviour if various types of foliage are present.


Horse eating leaves of a tree

Choosing the right trees and shrubs

It is important to select the right tree and scrub species for each pasture or paddock. There are various native and several introduced species to choose from, but species differ in their site requirements and ideal soil type.

Some tree and shrubs species are toxic to horses and should be avoided around and within horse pastures/paddock. Plants have co-evolved with and are eaten by bacteria, insects, fungi and grazing animals. Because of these interactions plants have developed a range of defense mechanisms to help their survival. Tree legumes often have thorns, fibrous foliage and high tree crowns. Many plants also produce chemicals which are not directly involved in the process of plant growth – and are therefore called secondary compounds. These chemicals can protect the tree or scrub against insect and fungal attack. However, these compounds also affect animals and modify the nutritive value of forages. Mycotoxins which are produced by certain types of fungi are also a potential source of toxins in forages. The effects of both secondary compounds and mycotoxins differ with animal species. Non-ruminants (e.g. pigs, poultry and horses) are usually more susceptible to these toxins than ruminants which have the capacity to denature potential toxins in the rumen.

Another concern that you may need to consider when selecting trees is the potential risk of housing populations of flying foxes which may spread the Hendra virus. Flying foxes are attracted to trees with blossoms (nectar), soft fruits, figs, berries, stone fruits such as mangos. However flying foxes can roost in any type of tree so it is advised to look at your property lay-out or farm design when planting (forage) trees.

Nutritive value of forage trees and shrubs for horses

Forage trees and shrubs must have nutritive value to be useful as forage. The nutritive value of trees and shrubs forage is determined by its ability to provide the nutrient required by an animal to balance requirements. Tree and shrub forage have been primarily used as feed for ruminants (cattle, goats, sheep), although there are some reports of their inclusion in the diet of non-ruminants (poultry and pigs). There is not much known about the feeding value and palatability of tree and scrub forage for horses. Most of the reports on plants and trees focus on the toxicity for horses.

When selecting forage trees and shrubs you must take into account that you may find limited information about the use of trees and shrubs for horses, moreover there are many contradictions in the literature regarding the acceptability of fodder from trees and shrubs. This may be explained by the following aspects:

  • Acceptability can change during the year. Animals may select only young leaves. With maturing of the leave the secondary compounds may increase and animals may not like the taste of the leaves anymore.
  • In some cases it may take some time for animals to accept a new feed, but once accustomed they may consume it readily.
  • Preference for one feed over another does not mean that they will not eat it when it is the choice is limited.
  • Within a single species, differences can exist between varieties, individual trees and even between parts of the same tree. Acceptability can be influenced by climate and soil conditions.
  • There is limited information about the nutritive value, palatability and toxicity of various parts of plants for horses.

Benefits and selection of forage trees and shrubs for horses

Trees and shrubs can potentially supplement the quantity and quality of pastures for grazing horses. They can function as a substitute when there is seasonal shortage or risk of drought. Tree fodder systems also deliver additional benefits such as shelter, soil conservation, rough timber and habitat.

There are various trees and shrubs that horses can safely browse. The leaves, stems, pods and fruits can be used as a supplement to their other feed. Tree and shrub fodder as a sole diet is not suitable for horses. More research is necessary to determine the feed value and even the toxicity levels for horses. Moreover, like with many other feed products, gradually introduce you horse to the fodder and don’t over feed. It is recognized that horses may browse the following tree/shrub species in Australia.


Old Man Saltbush (Atriplex Nummularia)

Saltbush (Atriplex spp.) is a halophytic (‘salt tolerant’) shrub and has a long-term survival on moderately saline and waterlogged soils. It is drought tolerant and can be used as a fodder with other feeds. A number of Atriplex species are native to Australia. Old Man saltbush (Atriplex Nummularia), River saltbush (Atriplex Amnicola), Wavy-leaf saltbush (Atriplex undulate; introduced from Argentina) and Quailbush (Atriplex lentiformis) show the best results in environmental tolerance (salinity, drought, frost, water logging and flooding), palatability and recovery after grazing. Ruminants tend to prefer it more than horses. Most of the research that studied the nutritive values of saltbush species for animals is also focused on ruminants especially sheep. Saltbush spp contain oxalates and nitrates which may cause poisoning when consumed in high levels by cattle and sheep. It is recognized that if saltbush is present in the pastures, horses may browse the shrubs. However, limited information is available about the nutritive value, palatability and toxicity of the various species for horses.


Hop bitter pea (Daviesia latifolia)

Bitter pea (Daviesia spp.)– are several native shrubs that belong to Fabacea (pea) family. They can be found in most states. The fruits have a pleasant bitter flavour and various animals are fond of them. It is reported that livestock and horses prefer the leaves and young twigs of two kinds of species; Clustered bitter pea (Daviesia corymbosa) and Hop bitter pea (Daviesia latifolia). Limited information was available about the nutritive value, palatability and toxicity of bitter peas for livestock and horses.


Dogwood (Jacksonia scoparia)

Dogwood (Jacksonia scoparia) is a native pea-flowered shrub or small tree that reaches about 4 metres high. It belongs to the Fabacea (pea) family and is found in south east of Queensland and eastern New South Wales. Dogwood can be used as a drought fodder and is reported to be relished by cattle and horses. Limited information was available about the nutritive value, palatability and toxicity of bitter peas for livestock and horses.

Tagasaste (Chamaecytisus palmensis) or Tree Lucerne is a small spreading evergreen tree that grows to a height and crown diameter of about 5 m. It is a member of the Fabaceae (pea) family and is indigenous to the Canary Islands (Spain).


Tagasaste (Chamaecytisus palmensis)

Tagasaste has been grown in Australia, New Zealand and many other countries as fodder crop. The trees can have long drooping or upright, leafy branches. The white flowers develop into flattened pods about 5 cm long which can contain about 10 seeds. The nutritive value of leaves is similar to that of lucerne (Medicago sativa). The crude protein content can vary from 18% to 25% for tips and 8% for stems. Leaves are high in vitamin A and reported as highly palatable. However, animals take a little time to get used to it as a feed. There seems to be no reports of tagasaste containing compounds toxic to animals. Levels of tannins are low. The trees are extremely drought tolerant, fast growing and frost tolerant. Limitations are that they will not tolerate poor drainage or water logging. Tagasaste can become an invasive and over grow bushland if it is allowed to set seed.


Carob tree pods & seeds

Carob tree (Ceratonia siliqua) or St John’s Bread is a small to medium sized long-lived evergreen tree with dense foliage that grows up to 10 m tall. It is also a member of the Fabaceae (pea) family and is native to the Mediterranean region. The plants are cultivated for its edible seed pods. The trees develop dark brown flattened pods (fruit) about 10-30 cm long and about 2.5 cm wide. The pods contain pulp that has a sweet, chocolate taste and a number of bean-like seeds. Carob has a long history as a source of food, mainly for humans, but it is well recognised in parts of the world as a source of fodder for animals (goats, cattle, donkeys, horses). The pods of the carob, not the leaves, are consumed. The pods provide 5% crude protein, 70% carbohydrates and 3% crude fat. Because the pods are high in carbohydrates don’t overfeed your horse, especially those horses that are sensitive to developing laminitis. Carob trees are drought and salt tolerant and tolerate any soil except heavy clay.


Bambusa oldhamii

Bamboo is a group of evergreens that belong to the true grass family Poaceae (Subfamily Bambusoideae). There are various species of bamboo that are used for gardens, building materials, paper pulp, textile and the shoots and leaves can also be used as a food source for humans and animals. The non-invasive (clumping) bamboo Bambusa ventricosa and Bambusa oldhamii species have been reported to be relished by livestock and horses. Bamboo is high in fiber and can contain 10-20% crude protein. Large amounts of Bambusa vulgaris (Yellow Bamboo) have shown to be toxic for horses. However more information is necessary to determine the digestibility, nutritive value and toxicity of various bamboo species for horses.

The best place for trees

Planting trees just outside the fence around the pasture boundary is usually adequate. Trees can grow branches, which will extend over the fences and into the pasture to provide shade. For large fields, you can place a few fenced-off patches of trees within pastures or you can have separate blocks of various forage trees. For young trees, fencing is necessary to protect the trees from damage caused by the animals. Fencing will prevent rubbing injury to trees from horses that like to scratch. Even mature, full-grown trees should remain fenced off from horses to ensure survival of the trees. If you have flying fox populations near your property you may want to choose small shrubs and flower-less trees.

How to feed fodder-trees and shrubs

Horses can browse the trees and shrubs while they grazing in the pasture or you can cut the branches and carry it to their pastures or stables. Pod legumes and seed can be collected and fed separately or mixed (for better digestibility you can crush or boil seeds) into the (hard) feed of your horse.

The forage trees and shrubs stated in this article represent a selection; there may be other trees more suitable for your environment (declared status, climate, soil conditions, rain fall etc). Moreover, as noted earlier there is limited information available about the nutritive value, palatability, and toxicity of forage trees and shrubs for horses.

If you have specific information or have observed your horses eating different forage trees or shrubs, can you please comment here so we can all learn from this.

Further Reading:

28 Responses to “Grazing and Browsing? Forage Trees and Shrubs for Horses”

  1. Chloe Wolsey

    I read that some horses enjoy eating blackberries which contain vitamin C. Brambles may be left in hedges many horses enjoy eating the young leaves of these plants. Dandelions are another highly nutritious plant for horses. They are also easy to seed.

    A variety of herbage in the sward is valuable for grazing horses. Deep-rooting ‘weeds’ can bring up all-important minerals from deeper soil layers. Dandelions, for example, are very good at this and are very palatable. Nettles are a good ‘weed’ to have around the edges of the pasture. They act as host to various butterfly species and, when cut, offer wonderful nutrition, including minerals, to horses, being very palatable when wilted.

    Interesting fact on laminitis: ‘Herbicides appear to be very dangerous for horses. We have even had several bad cases of laminitis following application of a common ‘livestock safe’ herbicide to nettles. The problem appears to occur when horses eat the wilting nettles.’ (From: http://www.alternativevet.org/pasture_management.htm)

    Reply
  2. Chris Dixon

    European Gorse was traditionally used here in Cymru (Wales, GB) as a fodder crop. We’ve used it as cut fodder for horses for several years- you can find some details here

    http://www.konsk.co.uk/resource/gorse.htm

    I believe gorse does quite well in an aussie climate (!)

    We use willow extensively as animal fodder here at Penrhos, along with ash and lime. Elm was the traditional one but there’s not much of that left now after Dutch elm disease.

    Reply
  3. Anne Gray

    I am in SE Queensland and have tried to grow tagasasta from seed. The plants got to about 5 ft high and then died. They grew all through the winter and spring an then as soon as summer came that was it. Was it the humidity perhaps?

    Reply
  4. Janice Eaton

    Thanks for the article! Recently had a fabulous hoofcare clinic with Peter Laidely, who emphasized the importance of horses having 5 to 10% browse in their diet. Suitable species include wild roses (which my horses were enthusiastically munching yesterday), and raspberries (Rubus idaeus). When my mare was about to foal she selfmedicated herself by browsing Poplar species (which contain anti-inflammatory populin and salicin) and she had a very easy delivery. I’ve also fed birch browse when horses were dealing with pain. Along the forestry track, the horses browse both gorge and broom and thistles, and though I won’t DELIBERATELY introduce any of those here in NZ, they happily take advantage of the wildlings.

    Reply
  5. A. Jacobs

    I found this article quite interesting, and I myself feed my horses legumes: carob, alfalfa, peas, nettle etc.. as well as browsing. The only thing you may need to check on is the information you gave about carob and laminitis, because is not quite accurate. It has been a proven fact that carob actually helps balances the blood sugar levels and this is one of the reasons why it is used to make diabetic chocolate, hence diabeties is similiar to laminitis etc. None of my equine have ever suffered from laminitis, and I’ve fed my equine on legumes as a main feed for many years. Carob has become more popular in recent years in the equine world, because not only do horses really enjoy eating it, but it’s a very natural source of vitamins and minerals too.

    Reply
  6. Cynthia Cooper

    My horses love to eat willow and sometimes hawthorn trees. They also browse on natives we call ‘Dolly Bush’ and ‘Fireweed’ when out on the trail.
    In their pasture they will eat the black berries, thistle heads, gorse and rushes. A good reason to have native, weedy pastures!
    Thanks for a good article.

    Reply
  7. Moyna Smeaton

    Hi Cynthia…
    my horses eat thistle tops too… very carefully ;-)
    We have Icecream Bean Trees (Inga sp) ‘edulis’ I think… the horses browse these with great relish & once established they are great shade trees. Attractive foliage & pretty flowers.
    Am currently searching for suitable shrubs for wind breaks, hedging that they will NOT eat.
    Thanks also from me for this article.

    Reply
  8. Mariette van den Berg

    Thank you all for your comments and contributions.
    This year I officially started my PhD research on this topic. The main focus of my study is browsing behaviour in horses and the use of fodder trees and shrubs as forage enrichment for domesticated horses in Australia.

    The first step in this study is to conduct a horse industry survey to collect information from horse owners about observed incidences of browsing and types of foliages browsed. This information is valuable for determining the next steps in this research project.
    For more information about this survey and weblink see my new post:

    http://permaculturenews.org/2012/07/18/australian-researchers-look-into-alternative-forages-for-horses/

    Reply
    • simone

      Hi, my mare eats ripe figs right off the tree, she knows which ones are ripe by smelling them first. And a pony i used to own ate both oranges and peachess of the tree, she even spat out the pip :)

      Reply
  9. Alyth Long

    Here in New Zealand I have planted Tree Lucerne (Tagasaste) and found it doesn’t grow rampantly. The seeds need to have 30 seconds in boiling water to enable them to germinate, therefore the seed that is produced does not germinate automatically!! Great fodder for horses, especially in winter.

    Reply
  10. Ronald Repath

    Over the last 38 years my horses have taught me about their browsing preferences. They seem to be particularly partial to british species that naturally coppice (throw up new shoots from their base) This has led me to believe that browsing and the coppice habit developed together. Hazel, Spanish Chestnut, Hornbeam, Lime, Beech, Birch, Willow and Wilted Ash leaves are all eaten by my horses. They also self medicate on Willow bark (aspirin) and Ash bark which enables them to void worms. Planting such tree species round my paddocks they can browse what ever they wish and as long as a strand of electric fencing prevents them reaching the trunks they can not damage the trees. Browsed below the upper branches grow out to provide shelter and shade. In Northern Europe branches were cut in the late summer to be fed as winter forage.

    Reply
  11. Chris Dixon

    I would recommend looking at F W M Vera’s “Grazing Ecology and Forest History” which provides an alternative approach to the standard model of forest succession. Vera argues that forests in North West Europe developed in the presence of large herbivores, resulting in highly complex and productive forest/grazing systems, not unlike savannnah or park land. Whether this is a more accurate model of historical succession than the conventional one is not really the point- Vera’s model provides us with some excellent opportunities to introduce fodder trees into pasture by way of thorny scrub. Very interesting stuff.

    Reply
  12. Rosalind Dalefield

    When I lived in the USA my stallion always enthusiastically pruned the mulberry trees that grew wild there. I moved home to New Zealand and imported him as well, and am now planning to plant some mulberry trees around my New Zealand acreage so that he can enjoy mulberry again. Horses also enjoy willow and poplar.

    Reply
  13. Michelle

    I am wondering if anyone has any experience in feeding honey locust pods to horses. Apparently it is a good fodder plant for ruminants here in Austraila, and I’d like to know whether it is both palatable and safe for horses.

    Reply
  14. ClaudeA

    Don’t know – but for years I fed it with home-made mash to meat chickens. They grew to 25 lbs!

    Reply
  15. Kerry

    I live in South Louisiana, North America and it seems theres nothing short of my horses pulling leaves from oak trees to figs etc, whatever grows here natively they seem to eat. I feed then feed and hay also keep a mineral block available but im just hoping that these plants, shrubs and trees they are picking from aren’t going to hurt them without my knowledge. Theres been many horses that has lived here and i know of not one that has been poisoned even with what i was told that is toxic to them of the wild cherry trees. Please help give me more information why my horses are pulling leaves and if they will eat poisonious leaves where we live?
    Sincerely
    Kerry

    Reply
  16. Chris Dixon

    I would want to know what species of plants (trees included) grew in my field before I let any grazing/browsing animal in there. I would certainly want to know if any were poisonous. Find a local botanist or ecolgist if you can’t identify tree species from a book.

    Reply
  17. Chris Dixon

    Acorns are poisonous to horses and some can be very sweet, making them more palatable, which is not good as if a hgorse gets a taste they can stuff themselves with usually fatal consequences. Oak leaves are not poisonous as such but are not a suitable fodder for horses due to high tannins, and large quantities can be similarly fatal.

    Reply
  18. Chris Dixon

    Which Ivy? In Britain, our ivy, hedera helix, is very interesting. Potter’s Herbal (rev 2003 C.W.Daniel & Co.Ltd. Edited by Elizabeth M Williamson BSc; Phd; MRPharmS., FLS) backs up the traditional herbal remedies with scientific research which show ivy to have various useful properties including being effective in treating for liver fluke.

    Reply
  19. Sheila

    Hi sorry should have been more specific I was thinking of ground ivy Glechoma hederacea

    Reply
  20. Chris Dixon

    I can find no reference to ground ivy, glechoma hederacea, being poisonous. The book I refer to above describes it as particularly useful for bronchitus and catarrh and it also has anti-inflammatory properties.

    Reply
  21. Chris Dixon

    Wikapedia agrees with the book I refer to in in saying that glechoma hederacea is not poisonous and has various medical uses. We have to be careful making blanket statements about plant species being poisonous or not.

    Reply
    • Sheila

      Sorry Chris I have had another look and under plants poisonous to equines it lists ground ivy I personally wouldn’t like to take the chance.

      Reply

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