Supplementation:
Feed Supplementation of Ruminants

Objectives The objective is to make up for ration deficits ingested by ruminants by adding a food supplement high in energy, nitrogen or minerals. The aim is to satisfy requirements for maintenance and production of the herd to make the livestock more economic. | Objectives Techniques Costs Targeted Livestock System Impact Context of Application Monitoring: EIA, Indicators References

Supplementation comes in two complementary ways which compete to improve the energy, nitrogen and mineral nutrition of the herd:
a) significant specific additional nutrients to the animal;
b) improved efficiency of microbial flora in the rumen to digest forage.

Techniques

Most livestock areas on natural rangelands, prairies or in agro-pastoral areas show great variations of quantity available and quality of forage resources in both space and time (seasonal or inter-annual) distribution. The capacity of animals to sort out in the grazing land to feed themselves, thanks to their mobility and feeding behaviour, and their physiological ability to utilise and reconstitute their body reserves, is not always sufficient to ensure their continued good health, their reproduction capacity or the productions expected by the farmers. Recourse to supplementation therefore occurs in a context of well defined animal husbandry objectives.

In tropical regions, forage is very frequently deficient in nitrogen and certain minerals, particularly phosphorus, copper and zinc (and in certain areas sulphur, selenium or cobalt). Sodium is also deficient but farmers often have traditional practices for adding salt. It should also be noted that in semi-arid and arid regions, farmers practise salting for preservation: There is a seasonal transhumance to an area where the animals find minerals naturally, either deposits in the soil , in the water with a high mineral content, or in halophytic plants which, as well as sodium, can supply sulphur and magnesium.

The choice of a supplement depends on sufficient knowledge of the forage calendar and the quality of rations, particularly the diagnosis of qualitative and quantitative imbalances between the herd’s resources and its requirements. It also rests on an inventory with calculations (quantities, price of return for the farmer) of food resources of accessible supplements, and if possible, references obtained in similar conditions making it possible to predict livestock response to supplementation.

The priority is to ensure adequate addition of nitrogen and minerals of rumen microbes, an addition from which the host animal of course benefits. Nitrogen supplement can be supplied by any protein food such as oil cakes, cotton seed, brewery dregs, etc., the quantity to add depending on the content of digestible nitrogen matter of the product. These foods also add energy. Nitrogen can also be added in the form of non protein nitrogen, generally urea. It use is optimised when the urea is limited to easily digested energy such as molasses: different forms of molasses-urea mixture and licking minerals (licking wheels) or solid blocks are currently used in countries producing sugar cane.

More generally, nitrogen and mineral supplementation is linked to energy supplement if the objectives require an energy supplement: this is particularly the case for ploughing, milk production and intensive meat production.

One then links oil cakes or seeds, which themselves supply energy, with non protein nitrogen, either from cereals (rarely the seeds themselves) or large quantities of molasses.

Supplementation also includes utilisation of crop residue or forage crops specifically managed to provide a food supplement to specific animals at critical periods: vegetable leaves, forage stocks of legume bushes (Leucaena sp., Gliricidia sp., Calliandra sp.) or large grasses such as Elephant grass (Pennisetum purpureum).

Mineral supplementation can also be done with forage by using fertilisers: this is especially the case for phosphorus, including by using phosphates of mediocre quality which slowly become soluble (natural phosphates). Otherwise, minerals are added directly to the animals in licking stones, or for oligo-elements (copper, zinc) in pellets put in the rumen. Introducing minerals to drinking water carries the risk of poisoning.

Costs

The usual strategy is to use mainly local resources coming from the farm and the surrounding area, regional and national agro-industries, etc. Whatever the product and its method of use, one should take into account, in addition to the market value of the supplements, transport, storage and distribution charges, which, to be implemented on a large scale, necessitate logistics and a marketing organisation which often has to be created from scratch in the livestock farming systems.

The return on investment on inputs depends heavily on possibilities or marketing the products obtained and the relationship of the prices between food supplements and animal products.

Targeted Livestock Systems

Supplementation is practised:

- in grazing systems to enable the animals to cope as well as possible with the forage shortage in the bad season, by utilising agricultural by-products in mixed systems.
- In mixed andindustrial systems to optimise animal productions.

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 | Y | Y | Y

Industrial System

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

Levels of food constraints and their seasonal nature, production objectives, availability of food supplements and economic considerations (cost-benefit) determine the strategy and techniques of supplementation.

Impact

- Positive environmental impact

- security of livestock farming systems and consequently better management of grazing resources.
- Increase in nutrient cycling in regions with nutrient deficit.
- Through animal droppings, return to the land of nutrients from agro-industrial by-products, contributing to maintenance of soil fertility.

- Negative environmental impact

- In extensive systems, cause of an artificial imbalance between natural resources and livestock pressure in zones where pastures are scarce, contributing to overgrazing : particularly obvious in some arid and semi-arid regions.
- In intensive and industrial systems, cause of importation and concentration of nutrients in animal production areas, with the danger of soil and water pollution.
- Use of energy, mainly fossil energy, for transport and processing of supplements.

- Impact on livestock productions
Supplementation (nitrogen, energy, minerals and vitamins) has particular interest in development of the herd:

- in the dry season it enables reduction of weight loss, mortality and preserves growth and reproduction potential of the herd.
- In females, for example, it permits improvement of female fertility and milk production with as a consequence improved feeding of the young. The latter can grow better and reach puberty earlier. Additional milk production can be used for family consumption and marketing.
- distributed to draft animals before and during ploughing periods, food supplements make it possible to optimise efficiency of the draft animals.

- finally, supplementation makes it possible to maintain in stout condition or even to fatten animals destined to speculative marketing in periods of high demand for fattened animals.

Context of Application

- Favourable factors:

- Increased demand for animal products
- High price of livestock products
- Training in supplementation technique
- Subsidies for agro-industry by-products
- Possibility of credit for purchase of concentrates
- Existence of support services for farmers (advice) and organisations supplying concentrates and food substances for livestock

- Existing infrastructures

- Appropriate manure management.

- Unfavourable factors:

- High costs of inputs
- Low price of animal products
- Supply problems for certain inputs
- Competition with other forms of utilisation (energy, for example)
- Insufficient availability or high cost of labour
- Livestock strategies geared to extensive systems or extensification
- High quality of natural pastures

Monitoring: EIA, Indicators

- Statistics on animal products justifying complementation
- Body score of livestock
- Stocking rate in extensive grazing areas
- Nitrate and phosphorus level in soil and water

References

La complémentation minérale. Fiche technique d’élevage tropical n° 9. Ministère français de la coopération et du développement, septembre 1990.

La complémentation minérale. Fiche technique d’élevage tropical n° 12. Ministère français de la coopération et du développement, décembre 1990.

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