Mixed Species Herds

Background Degradation (here defined as a change disadvantageous to livestock) of the botanical composition of pastures following prolonged stay by animals. This degradation results from selection by livestock of certain plant species and the avoidance of other species. This results in a change in the mechanisms of inter-species competition, which promotes the growth of plants which are not selected by livestock and a general reduction in the value of the resulting forage. By combining several species of herbivores, either together or successively on the same plot or area of rangeland, it is possible to control changes in the vegetation to some extent. | Background Objectives Techniques Costs Targeted Livestock System Impact Context of Application Monitoring: EIA, Indicators References See Also

Objectives

The principle of mixed herds consists of making use of different feeding habits of domestic herbivore species to manage pasture flora in the best way possible and optimise animal production. For this purpose animals of different species are mixed in the same herd or else herds of different species follow each other on the same piece of land.

Experiments with mixed herds have shown the effects on competition between plant species, particularly on changes and proportions of grass and tree species. Results differ according to eco-climatic situation, either semi-arid or wet tropical zones, or temperate zones.

Techniques

According to the expected impact on vegetation, the rate of browser (small ruminants) on grazer (cattle) can be managed. Generally more browsers will decrease tree population whereas grazers will allow tree regeneration.

Some experiments showed that the length and the period when a ratio is applied has some effect on the result. For example, cattle seem to stimulate tree regeneration at an early stage (seedlings) in semi-arid and semi-humid zones whereas they decrease tree growth later on. According to season and agro-ecological zone, cattle and small ruminant pressure can stimulate or depress grass and tree production.

In the range, greater the heterogeneity in the vegetation and other characteristics, the greater the possibilities for mixed animal type complementarity to express its benefits. In these situations, the lower the dietary overlap between the different animal types, the greater the benefits to animal performance and to range preservation .

In Ireland, sheep and cattle complemented each other in vegetation use, particularly since sheep preferentially grazed cattle dung soiled areas which cattle mostly refused.

Costs

Costs are in fact the additional equipment required by diversification of the herd: adaptation of fencing, buildings, etc.

It should also be remembered that this technique requires on the one hand good knowledge of the forage potential of the area and on the other the feeding behaviour of the herd: additional costs are therefore linked to the acquisition of this knowledge capital (which can be gained by tradition, experimentation or training) and possibly the application of techniques for monitoring the vegetation (use of indicators).

Targeted Livestock System

Grazing and mixed livestock systems.

Grazing System

LGA | LGS1 | LGS2 | LGS3 | LGH1 | LGH2 | LGH3 | LGT1 | LGT2 | LGT3
Y | Y | Y | Y | Y | Y | Y | Y | Y | Y

Mixed System

MCG | MCR | MCC | MFF | MEF
Y | Y | N | N | N

Industrial System

IFP | IPL | IPG | IRM | IDU | ISL | ITN | IMP
N | N | N | N | N | N | N | N

Impacts

- Positive Environmental Impact

- Proper management of vegetation.
- Well balanced pressure on vegetation.
- Protective and productive use of natural range resources.

- Negative Environmental Impact

- The opposite of the objective in case of misutilization or overgrazing.

- Livestock Productivity Impact

- Feed improvement

Context of Application

- Favourable factors: Generally applied in traditional grazing systems.
- Unfavourable factors: Cultural or economic factors against one type of herbivore.

Monitoring: EIA, Indicators

- Tree and grass cover.
- Tree population structure.
- Vegetation biodiversity.
- Livestock population: species, demography.

References

Nolan T., Connolly J., 1989. Mixed v. mono grazing by steers and sheep. Animal production, 48 :519-533.

Nolan T., Connolly J., 1992. Les recherches sur le pâturage mixte par les ovins et les bovins en Irlande. Fourrages, 118:99-114.

Nolan T., Connolly J., Sall C., Toure Fall S., Guerin H., Dione M., Diop T., Diene M., Mandret G., 1993. Mixed animal species in range grazing and preservation. Final Technical Report on EU. Contract TS2 0075-IRL (EDB).

Nolan T., Connolly J., Sall C., Diop T., Vaz Lourenço M.E., Chaves M.M., Zoumana Coulibaly, César J., Hedge N.G., 1998 Natural resource development and utilisation in the Sahel. Final Technical Report on EU. Contract TS3 CT93-0202.

César J., Zoumana Coulibaly, 1999 Les régimes alimentaires des bovins, ovins et caprins dans les savanes de Côte d'Ivoire et leurs effets sur la végétation. Fourrages, 159.

Lambert M.G., Guerin H., 1989 Competitive and complementary effects with different species of herbivore in their utilization of pastures. XVI International Grassland Congress, Nice, France, 1785-89.

See Also

Unconventional Livestock Production

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