Managed grazing

From Triple Performance
Technical articles - Conserwa
Targeted grazing Orchard grazing Practicing cover and regrowth grazing Ecological grazing

Targeted grazing (also called prescribed or managed grazing) is a complementary solution to weed control methods. Animals are used as weed control tools to weaken weeds, reduce their reproductive capacity, and decrease their presence over time. This specific goal is achieved through planning and controlling 4 parameters:

  • the animal species grazing
  • the grazing period
  • the duration and intensity of grazing.

Difference between conventional grazing and targeted grazing

Conventional grazing Targeted grazing
Main objective Feed the animals Manage vegetation by defoliation or trampling
Impact on weeds Consumed secondarily Animals are used as weed control tools
Planning Grazing depends on UAA and herd size. Grazing determined according to the weed (limited in time, targeted in space, adjusted in intensity)

Role of different species

Each species has specific feeding behavior.

Cattle

Cattle mainly consume grasses and are less selective under high grazing pressure.

They are useful for:

  • reducing overall biomass
  • limiting grass dominance
  • preparing the ground for other species.

However, caution is needed because they:

  • may trample weeds that sheep and goats might eat
  • are heavy and can compact the soil depending on climatic conditions.

Sheep

Sheep are more selective but have some advantages:

  • they can be used to graze cereal plots at early tillering and/or cover crops between crops
  • they have good precision on targeted areas.

Goats

Goats consume woody plants and less palatable species.

They are suited for:

  • brush
  • brambles
  • invasive woody plants
  • difficult perennial weeds.

Feeding learning

Animals must learn to feed on weeds. This involves:

  • feeding training, i.e., exposing young animals to weeds so they learn to consume these plants.
  • leader animals
  • high-intensity grazing for a short time which encourages animals to graze much less selectively.

Grazing period

Weed palatability

The plant stage is decisive; indeed, some weeds lose palatability as they develop. It is therefore important for farmers to know the weeds to identify periods when they are most sensitive to grazing.

Grazing is more effective when weeds are more palatable than other plants, i.e., when they are young and before flowering or seed set.

Effects of grazing on weeds

Targeted grazing can damage weeds in several ways depending on the timing:

  • in early spring, it allows elimination of new weed growth; over a long period, the plant is weakened and eventually dies
  • later in the spring season, it can prevent flowering and thus seed formation
  • during the weed growing season, grazing can stress the weed and reduce its competition with desired plant species
  • in autumn, it can disrupt nutrient flow to roots and crowns, which reduces carbohydrate reserves necessary for weed growth.

Grazing intensity and duration

Insufficient intensity

  • Weeds are selected
  • Palatable plants disappear
  • Resistant weeds dominate

Excessive intensity

  • Risk of overgrazing
  • Soil degradation (compaction and erosion)

Conclusion

The goal is to establish a strong but short pressure followed by a rest period so desired plants can develop. It is thus important to list the weeds present on the plot and estimate their quantity to plan appropriate pressure and duration.

Advantages

  • Improves water infiltration and use
  • Possible maintenance of riparian zones, high-altitude or hard-to-access areas
  • Fertilization provided by animals
  • Nutrient recycling
  • Improvement of soil structure
  • Reduction of chemical and mechanical treatments
  • Possible yield increase, notably thanks to sheep grazing winter cereals.[1]
  • Alternative method on plots limited in phytosanitary products.

Limitations

  • Late grazing could disseminate weed seeds (via animal droppings or hair)
  • Grazing depends on climatic conditions; animals can only work on load-bearing soil
  • Animal welfare must be monitored as some weeds can be toxic. Studies show complementary feed can reduce effects of some toxins (terpenes, tannins, oxalates, etc.)
  • It is essential to know the weed flora well to establish a precise targeted grazing plan
  • Risk of overgrazing, hence the importance of precise targeted grazing management.

Conclusion

  • Targeted grazing is part of integrated weed management
  • It requires detailed knowledge of weed species present and their quantity
  • Its effectiveness depends on a precise grazing plan (period when weeds are palatable, choice of animal species, grazing intensity and duration)

Targeted grazing advice according to weeds present on the plot

A study conducted in the United States[2] established a list of recommendations for targeted grazing of certain weeds, here are some:

Weed Animal Weed growth stage Plant response Number of treatments per year
Canada thistle Sheep Seedling vegetative stages Reduction in vigor, size and flowering Often enough to prevent flowering
Cows, calves and young cattle Seedling, early vegetative stages
Goats All stages
Japanese knotweed Goats (females and kids) Vegetative and flowering stages Reduction in bud number and significant slowing of growth process Several times per year for at least 3 years
Euphorbias Sheep Vegetative stages Decrease in stem density and plant biomass At least twice per season or continuously for a minimum of 4 to 5 years
Goats Vegetative to flowering stages
Musk thistle Sheep From rosette to bolting stage Reduction in vigor, size and flower production Once or twice per year (for at least 3 years) at bud/flowering stage
Goats
Cows and calves
Star thistle Goats and kids All growth stages Reduced growth during treatment year. Rosettes regrow after animal removal One treatment per year at flowering stage (for at least 3 years)
Common couch grass Horses, sheep, cattle and goats Early vegetative stage Reduced plant vigor Continuous grazing until other control methods are applied
Spotted knapweed Sheep (ewes, lambs) All growth stages before flowering Reduction in vigor, density, size, flowering stems and seed production Three treatments per year (for at least 3 years) between rosette and bolting stages and during regrowth
Goats, kids
Centaury Sheep All growth stages before flowering Reduction in vigor, size and flower production Two or three treatments during rosette or bolting stages for 3 to 5 years
Goats
Livestock

Grazing and perennial plants

Orchards

Animals that can be introduced into high-stem orchards are:

  • sheep
  • cattle (stocking rate about 2/ha), mainly used in apple orchards
  • chickens (stocking rate about 500/ha for adults and 1500/ha for young)
  • geese (stocking rate 50 to 100/ha)
  • ducks (stocking rate 100 to 500/ha)
  • pigs
  • equines

It is advised to remove animals 2 to 3 weeks before fruit drop and until the end of harvest.

Spacing between fruit trees for a pre-orchard. Source: Osaé
Species Distance along row Distance between rows Usual density
Apple 10-12 m 10-12 m 90-100 trees/ha
Pear 10-12 m 10-15 m 70-80 trees/ha
Cherry 10-12 m 12-15 m 70-80 trees/ha
Plum-Mirabelle 7-10 m 10-14 m 100-120 trees/ha
Walnut 12-14 m 15-18 m 40-50 trees/ha

Vineyards

In vineyards, grazing is done from November to April generally with sheep (Ouessant and Shropshire sheep preferred), pigs or poultry.

Constraints

  • Monitoring grass quantity on plots so animals do not damage crops
  • Crop protection (wooden fences, metal collars)
  • Remove animals during phyto and copper treatments (toxic for some animals)
  • Additional work time (monitoring, fencing…). Some farmers partner with breeders, allowing them additional quality grazing areas.

Advantages

  • Saves weed control passes (mechanical and chemical). However, care is needed as some animals sort what they eat (e.g., chickens).
  • Animals contribute to prophylaxis by controlling some pests, trampling leaves and fruits, and consuming damaged fruits.
  • Fertilization input
  • Increased biodiversity
  • Increased income diversity
  • Reduced frost risk due to maintaining short or no grass cover beneath trees. This favors heat exchange from soil to atmosphere, reducing nighttime temperature drops.

Feedback

See also

References

  1. ↑ Agrof’île. 2022. Pâturage des céréales : les premières références. [03/02/2026]. https://www.agrofile.fr/wp-content/uploads/2021/12/POSCIF_Fiche_technique_CEREALES.pdf
  2. ↑ Jason C. Davison, Ed Smith and Linda M.Wilson. Livestock Grazing Guidelines for Controlling Noxious Weeds in the Western United States. [03/02/2026]. https://www.weld.gov/files/sharedassets/public/departments/public-works/documents/livestock_graizng_guidelinesdavison_et_al.-2007.pdf
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