Farm life

Pasturing Know-How

By Tamsin Cooper

Tamsin Cooper is a smallholder and writer with a keen interest in animal behaviour and welfare

www.goatwriter.com

SHEEP AND GOATS HAVE LEARNED FORAGING TECHNIQUES OVER THE MILLENNIA TO NOURISH AND MEDICATE THEMSELVES. CAN WE STILL TRUST IN THEIR SKILLS IN THE SMALLHOLDING?

In the mountainous landscape of southern and south-central parts of France, shepherds have traditionally accompanied their goats, sheep and cattle up into summer pastures for the growing season and then brought them back down to the valley villages to be barn fed in winter. Such practices allowed animals to learn about all the different plant species and how best to meet their nutritional needs. Goats were led to the steeper parts where they made good use of a large variety of bushes and scrub. All plants contain toxins, but in the right doses and combinations and at the right time, these can actually benefit the consumer. For example, goats have been found to self-medicate on particular plants only when suffering from a worm overload, and the infestation was alleviated as a result. Several studies in different parts of the world have shown similar results. These goats learned by trial and error and then by passing the knowledge from mother to kids and among companions.

Learning to Choose the Right Plants

Animals have a feedback system that puts them off eating a certain food if they subsequently feel ill. Similarly, improved health and pleasant sensations will encourage them to eat a foodstuff again. Herbivores are cautious about eating new plants and will only sample a little until they get feedback from their digestive system. If all goes well, they will eat more. However, this system can be deceived, for example, if a plant gives a hedonic sensation while insinuating its poison, or if a plant’s toxins build up slowly until the damage is done. Social herbivores, such as goats and sheep, reduce the risk of experimentation by observing one another and passing the knowledge on. Animals can adapt to local environments through acquiring traditions from the herd. For example, a female goat in a modern pastoral system in Israel learned to access seed heads of a thistle on a stem two metres high. She grabbed the stem with her mouth and pulled it down in a circular motion. This method has now spread among the flock, beyond her direct descendants. A recent academic paper contends that ‘matrilineal traditions are essential for learning nutritional and medical benefits including sequences that alleviate deleterious effects’. Learning from mother starts in the womb, where flavours of nutrients are sensed in late pregnancy. Milk also carries flavours from plants the dam has been eating. Experiments show that kids preferred plants their mothers were eating while kids were in utero and in the early days pre- and post-weaning. While foraging with mother, kids picked up her browsing habits. When kids were swapped at birth to mothers with different diets, the kids adopted their fosterdams’ strategies. Pastoral kids have also shown that their diets are a combination of what they learned from mother and which plants were prevalent in the year of birth. In rapidly changing environments, this could vary from what was available to older generations. Herd animals also observe each other to locate the freshest, most nutritious patches. They can be influenced by humans, who may add to the feeder a particular plant they want clearing from the field in a bid to accustom the grazers. I found cutting and drying nettles encouraged goats to eat nettles in the field. But, we must take care to introduce them only to plants that are safe to eat.

Why do Grazers Poison Themselves?

If sheep and goats are so smart, why do they sometimes poison themselves? Modern farming systems are very different from the pastoral system where herds had great variety to choose from and large areas to forage. Stable herds and natural rearing on the dam meant that learning could spread among herd members. Goats raised on the bottle or with limited variety of forage will not get the early learning that pastoral herds enjoy. Normally, they stick to safe foods that they know, such as grass and hay. Problems occur when safe foods run out due to shortage or overgrazing. In desperation, an animal may try an unknown plant. Bitter tastes, indicating potential poisons, put them off, but if there is no alternative, they will tolerate the flavour. I have heard of cases when goats started eating a bush they never bothered with before, or lambs gorged themselves on acorns in autumn. These cases can be fatal. With limited land, it can be difficult to avoid shortages, especially in winter.

Solutions for Safe Grazing

Good old-fashioned meadows with a variety of grasses and flowering herbaceous plants are far healthier both for ruminants and the ecology. Herbivores need variety, so they can choose what they need as individuals and for their current circumstances. Goats favour bushes and trees and benefit hugely from their inclusion in the pasture, although you will need to protect the bark of trunks. With variety, herbivores will learn to offset the toxins of one plant against another. Allowing young to be reared by their mother will accelerate learning and minimize dangerous experimentation. Medicinal and nutritional plant knowledge is not just about which plants to combine, but how much, and in which sequence. People with this knowledge can guide their flock, but on the whole, an experienced mother knows best. Where space is limited and during shortages, meadow hay featuring a variety of herbaceous plants makes a good staple, which should be available at all times. Goats can lose interest in their pasture while it still seems plentiful to our eyes. Tired pastures can be refreshed by using rotational systems, in which vegetation is allowed to recover. Strip grazing of small areas for a short time encourages animals to sample all the plants, rather than just picking out their favourites, and this furthers their knowledge of different species. Plant variety and a maternal learning are the keys to browsing success.

These goats learned by trial and error and then by passing the knowledge from mother to kids and among companions Reference: Landau, S.Y. and Provenza, F.D., 2020. Of browse, goats, and men: Contribution to the debate on animal traditions and cultures. Applied Animal Behaviour Science, 105127.