Community Research and Development Information Service - CORDIS

Identification of optimum feeding and management strategies to deliver CLA-enriched ovine milk

Feeding dairy sheep relies substantially on grazing. Native and cultivated grass and legume based pastures are the main feed sources being either grown as monocultures or mixtures. With reference to this result, the BIOCLA consortium has recently worked to:
- Identify the FA composition of some relevant Mediterranean forage species during vegetative and reproductive phases with particular reference to CLA precursors;

- Identify the milk CLA profile of sheep fed these forages either as monocultures or mixtures;

- Find out periods in which CLA concentration in milk falls and the factors that are underlying these drops;

- Envisaging and testing feeding techniques such as supplementation with fat-enriched concentrates or complementary grazing of CLA precursor-rich forages able to fill the above gaps.

The body of knowledge accumulated so far allows us to point out that the concentration of milk CLA of pasture-fed sheep tends to increase along with the proportion of green herbage in the diet.

In sheep fed fresh forages only, milk CLA content is related to two main factors: the forage genotype (species and cultivar) and the phenological phase of forages which in turn affects the dietary proportion of leaves. Both these factors are under the control of grazing management.

Four experiments and a survey have been undertaken within this project to investigate this. On the basis of the results, a feeding and management strategy aimed at maximizing CLA concentration in ovine milk is put forward. It lays on the following guidelines:
- Choose preferably mixtures of grass and legumes or sequential grazing of legume and grass pastures. Legumes such as burr medic and subclover can be preferable to sulla. Daisy forbs rich in linoleic acid such as safflower or Chrysanthemum coronarium can be conveniently included in lactating sheep diets.

- Graze at moderate to high intensity, particularly during the fast growth spring period in order to keep pasture leafy as long as possible, hence maintaining at good level the CLA precursors’ concentration in the grazed herbage.

- Minimize the use of use of non-fat enriched supplements unless the quality of the pasture forage is poor. They usually have substitution effects and may also exert a dilution effect on most beneficial PUFA.

- Consider offering fat-enriched supplements, particularly when the intake of green forage is expected to be low. This is an area, which deserves further multi-disciplinary studies involving the evaluation of technological and sensory properties of ovine dairy produce.

All this information is currently being submitted for publication in peer-refereed journals and will be disseminated at farm scale via technical papers and ad hoc meetings with farmers, advisers and cheese manufacturers. Technological implementation could include compound feed manufacture companies being interested in the development of novel concentrate production lines based on the above outcome.

Related information

Reported by

Istituto Zootecnico e Caseario per la Sardegna (IZCS)
Località Bonassai, Olmedo, SARDEGNA
07040 Sassari
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