Nutritional Quality and Socio-Ecological Benefits of Mare Milk Produced under Grazing Management

This review discusses the scientific evidence that supports the nutritional value of mare milk and how its properties are essentially achieved when mares are managed under grazing conditions. Mare milk's similarity with the chemical composition of human milk makes this food and its derived products not only suitable for human consumption but also an interesting food regarding human health. The contribution of horse breeding under grazing management to other socio-ecological benefits generated by equine farms is also highlighted. Both the high added value of mare milk and the socio-ecological benefits derived from pasture-based systems could be explored to improve the performance of equine farms located in arid and semi-arid areas or in regions with moderately harsh environmental conditions as equids have a strong adaptation capacity.

Animal board invited review: Grassland-based livestock farming and biodiversity

Grasslands dominate land cover nationally and globally, and their composition, structure and habitat value are strongly influenced by the actions of domestic and wild grazing animals that feed on them. Different pastures are characterised by varying opportunities for selective feeding by livestock; agronomically improved, sown swards generally consist of a limited range of plant species whereas longer-term leys and semi-natural grasslands are characterised by a more diverse mixture of plants. In the case of botanically diverse permanent pastures/grazing lands, the dietary preferences of different grazers have a more pronounced effect on the botanical composition of the sward in the longer term. Selection of a dominant species within the sward can give less abundant components a chance to compete, increasing community evenness and species richness. Conversely, the selection of minor components reduces sward compositional heterogeneity and hence plant species richness and evenness. Body size, gut type (foregut vs hindgut fermentation), physiological status (growing, pregnant, lactating), metabolic status (extent of body reserves) and environmental conditions all influence the nutrient requirements of a given animal and related foraging priorities. The diet selected is also strongly influenced by the availability of preferred food items, and their vertical and horizontal distribution within the sward. In general, larger animals, such as cattle and horses, are less selective grazers than smaller animals, such as sheep and goats. They are quicker to switch to consuming less-preferred sward components as the availability of preferred resources declines due to their greater forage demands, and as a result can be very effective in controlling competitive plant species consistently avoided by more selective grazers. As a result, low-intensity mixed grazing of cattle and sheep has been shown to improve the diversity and abundance of a range of taxa within grazed ecosystems. Mixed/co-species grazing with different animals exploiting different grassland resources is also associated with increased pasture use efficiency in terms of the use of different sward components and related improvements in nutritional value. In situations where cattle are not available, for example if they are not considered commercially viable, alternative species such as goats, ponies or South American camelids may offer an opportunity to diversify income streams and maintain productive and biodiverse pastures/grazing lands. Stocking rate and timing of grazing also have a considerable role in determining the impact of grazing. Regardless of the species grazing or the pasture grazed, grazing systems are dynamic since selective grazing impacts the future availability of sward components and subsequently dietary choices. New technologies under development provide opportunities to monitor plant/animal interactions more closely and in real time, which will in future support active management to deliver targeted biodiversity gains from specific sites.

Livestock Management for the Delivery of Ecosystem Services in Fire-Prone Shrublands of Atlantic Iberia

In the northwest of the Iberian Peninsula, characterized by its humid climate, large rural areas are being abandoned, mostly in less-favoured areas covered by heathlands, which present a low nutritive quality for livestock production. The high combustibility of these shrublands is driving a high wildfire incidence with negative environmental and economic effects. In this review, some aspects on wildfire occurrence and the potential of grazing livestock to reduce woody phytomass and fire risk in heathland-dominated areas whilst maintaining quality production and preserving biodiversity are summarized. Heathlands may be partially improved—converted to grassland—to better meet animals’ nutritional requirements while acting as ‘natural’ firebreaks. The specific grazing behaviour offers the opportunity to combine different domestic herbivores (mixed grazing) to achieve sustainable systems utilizing heterogeneous resources. Cattle, sheep, goats, and horses may have a role in the provision of different ecosystem services such as food production and biodiversity conservation. Genotype x environment interactions shape the ability of animals to cope with poor vegetation conditions, with smaller species and breeds performing better than larger animals. Goats and horses are indicated to arrest woody encroachment. Sustainable grazing systems are affordable in heathland–grassland mosaics by selecting appropriate livestock species and breeds for quality production, thus favouring rural economies and lowering fire risk.

Decoupling of traditional burnings and grazing regimes alters plant diversity and dominant species competition in high-mountain grasslands

Over millennia, the combination of controlled burnings and extensive grazing has maintained mosaic landscapes and preserved mountain grasslands in southern Europe. In the last century, deep socio-economic changes have led to an abandonment of traditional uses, to a general decline of the domestic herbivory and to a misuse of burning practices. This study aims to quantify how the decoupling of burning and grazing regimes affects in the long-term the structure, diversity and dynamics of high-mountain, shrub-encroached grasslands. In spring 2012, four treatments (burned-grazed, burned-ungrazed, unburned-grazed and unburned-ungrazed) were set up at three sites in the Special Area of Conservation Roncesvalles-Selva de Irati, in southwest Pyrenees. During seven years, we monitored floristic composition and the height of the native tall-grass Brachypodium rupestre in four plots at each site. In the burned plots, we surveyed the resprout of the dominant shrub Ulex gallii and the dynamics of recovering of the herbaceous vegetation. Plant communities evolved differently in grazed and ungrazed plots. Extensive grazing, despite being lower than in previous decades, maintained plant diversity and limited shrub encroachment. The total absence of grazing fostered the encroachment of U. gallii at two sites and the expansion of B. rupestre at the other site. When B. rupestre cover was >60%, the encroachment of U. gallii was reduced. This research highlights the competition that occurs between shrubs and tall-grasses in the absence of grazing, and the modulating effect exerted by the burnings and the site-specific features. Understanding local plant dynamics is the first step to design the most appropriate practices that help to preserve diversity at the landscape and the community level in high-mountain grasslands of south Europe.