Alternative feed resources and their effects on the quality of meat and milk from small ruminants

The present paper reviews the quality of meat and milk from sheep and goats offered alternative feeds as a replacement for concentrates. Legume seeds and pods, shrubs or local agro-industrial by-products are cheap and easily available in Mediterranean Countries and are suitable to sheep and goat nutrition. Moreover, the exploitation of novel pasture species allows ameliorating pastures quality and availability. In recent years, an increasing number of studies have investigated the effects of these alternative feed resources (AFR) on small ruminants meat and milk quality. Tannin-containing feeds result in meat of a lighter colour. Condensed tannins, present at low or moderate levels in the diet, tend to increase milk yield and protein content, probably because they protect dietary proteins from ruminal degradation. Conjugated linoleic acid (CLA) content in kid meat can be increased by feeding the animals chopped cactus pads. Grazing saltbush (Atriplex spp.) preserves lamb meat colour stability, suggesting that the high level of vitamin E in these shrubs protects myoglobin from oxidation. When olive cake silage is included in ewe diets, meat and milk fatty acid profile can be enriched of linoleic and oleic acids, respectively. The appearance of terpenes in sheep and goat milk is enhanced by grazing on some novel pasture species, such as Galium verum, Cichorium intybus and Chrisantemum coronarium, which modify milk and cheese sensorial profile, in comparison to grazing on conventional forages.