Pastures that have shrubs and trees are more sustainable, according to new study
Research published in the journal Proceedings of the Royal Society B has identified silvopastoral systems (those that include shrubs and trees with edible leaves or fruits as well as herbage) as being more sustainable than current cattle production methods, improving animal welfare and increasing biodiversity.
Currently, cattle production occurs mostly on cleared pastures with only herbaceous plants grown specifically for cows. This can lead to the removal of trees and shrubs in addition to the use of herbicides which can result in a reduction in biodiversity. Other impacts include contamination of soils and waterways through the use of agricultural chemicals as well as carbon emissions resulting from vehicle use and artificial fertiliser required to maintain the pasture.
Recently, consumers have been demanding more transparency and higher standards of food production, with many people considering environmental impact and welfare of the animal when making purchasing decisions.
The researchers claim that using a diverse group of plants such as that in a silvopastoral landscape can have many benefits, including:
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Promoting healthy soil with better water retention and therefore less run-off
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Encourages predators of harmful animals
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Minimises greenhouse gas emissions
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Improves job satisfaction for farm workers
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Reduces injury and stress in animals and improves their welfare
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Encourages biodiversity using native shrubs and trees
Shrubs and trees with edible leaves and shoots combined with pasture plants produce more food for animals per unit of land than that produced by pasture plants alone. Trees and shrubs have the added benefit of providing shade from the sun as well as shelter from the rain and animals are also able to hide from perceived danger.
Lead researcher Professor Donald Broom of Cambridge University was quoted as saying “the planting as forage plants of both shrubs and trees whose leaves and small branches can be consumed by farmed animals can transform the prospects of obtaining sustainable animal production. Such planting of 'fodder trees' has already been successful in several countries, including the plant Chamaecytisus palmensis which is now widely used for cattle feed in Australia."
In Colombia, mixed planting of the shrub Leucaena with a common pasture grass resulted in a 27% increase in dry matter for food and 64% increase in protein production.
Researchers found that when ruminants such as cows, goats and sheep consumed plants from a silvopastoral system, an increase in growth and milk production was observed. Daily milk production per cow in the Colombian silvopastoral system was 4.13 kg compared to 3.5 kg on a pasture-only system. Quality of milk was found to be greater from cattle on the silvopastoral system.
In total, 33% of the world’s land surface is used for livestock production. The research team argues that if farmers switch to sustainable livestock production methods such as the silvopastoral system, the result would be greater biodiversity with no increase in land use.
Professor Bloom added "It is clear that silvopastoral systems increase biodiversity, improve animal welfare and provide good working conditions while enabling a profitable farming business. The next step is to get farmers to adopt this proven, sustainable model."