Temporal variations in leaf traits, chemical composition and in vitro true digestibility of four temperate fodder tree species

Abstract

Context Many tree and shrub species are underestimated fodder resources due to insufficient knowledge about their potential feeding value, especially for goats. Aims The present work aimed at assessing productive and nutritional attributes of the foliage of the following four temperate tree species widespread in Europe: Acer pseudoplatanus, Fraxinus excelsior, Salix caprea and Sorbus aucuparia. Methods Leaf length and biomass, proximate composition, fatty acid profile, phenolic composition and in vitro true dry matter digestibility were determined along the vegetative season. Key results The leaf length of the four species was significantly related to leaf biomass and can be considered as a proficient proxy for estimating leaf biomass. The differences found among the species were remarkable, although weakly related to temporal changes, especially when considering fatty acid and phenolic compositions. Fraxinus excelsior sprouts were the most productive, with a mean biomass of 13.2 g dry matter (DM) per sprout at the end of the growing season. Its foliage showed also the lowest phenolic concentrations (average total extractable phenols of 11.25 g/kg DM), resulting in the highest digestibility values (average in vitro true dry matter digestibility of 56.5 g/kg DM). Digestibility of S. aucuparia was similar, but its lower polyunsaturated fatty acid concentration (average value of 62.13 g/kg DM) could reduce the interest for this species as a feeding resource for goat dairy products with healthy properties. The lower digestibility found for A. pseudoplatanus and S. caprea (average values of 43.3 and 46.2 g/kg DM, respectively) may be related to their higher phenolic concentrations (average total extractable phenols of 45.9 and 47.3 g/kg DM, respectively). Conclusions The four species could represent an appealing feedstuff for goat nutrition, due to the valuable and complementary nutritional characteristics of their foliage. Implications The use of the studied species as fodder resource may be particularly relevant during drought periods and in the late summer when herbage quality decreases, especially in terms of crude protein and fatty acid profile.

Temporal Variations in Chemical Composition, In Vitro Digestibility, and Metabolizable Energy of Plant Species Browsed by Goats in Southern Mediterranean Forest Rangeland

“…The chemical traits of browsed species were extremely wide, which are in accordance with previous studies conducted in northern and eastern Mediterranean forest rangelands [ 6 , 12 , 13 , 14 ], deciduous tropical forest [ 35 ], South African rangeland [ 36 ]. In northwestern Italy, Ravetto Enri et al [ 37 ] reported the relevant effect of the vegetative season on chemical composition and in vitro true digestibility of four tree species selected by goats. These wide variations on the nutritional proprieties of plant species could be explained by soil fertility [ 15 , 38 ], environmental conditions, and stage of growth or age [ 14 , 39 ].…”

Seasonal variations in the nutritive value of fifteen multipurpose fodder tree species: A case study of north-western Himalayan mid-hills

“…Concurrently, several variables, including inherent species genotype [ 18 ], seasonal variance [ 19 – 21 ], site capacity, edapho-climatic factors [ 22 ] and management aspects [ 23 ], contribute in determining the nutritional quality dynamics of fodder trees. Among these, temporal fluctuation in the chemical composition and digestibility of tree species may occur as a result of phenological and climatic variations [ 21 ].…”

“…Concurrently, several variables, including inherent species genotype [ 18 ], seasonal variance [ 19 – 21 ], site capacity, edapho-climatic factors [ 22 ] and management aspects [ 23 ], contribute in determining the nutritional quality dynamics of fodder trees. Among these, temporal fluctuation in the chemical composition and digestibility of tree species may occur as a result of phenological and climatic variations [ 21 ]. Thus, knowledge of tree foliage mineral and nutrient fluctuations during the seasons offers considerable potential to provide high-quality ruminant forage [ 19 ], by selecting an appropriate harvesting period for specific tree species in a particular agro-climatic region [ 24 ].…”

Foraging behavior of Highland cattle in silvopastoral systems in the Alps

“…Fraxinus ornus is acknowledged as an important browse species for goats in Mediterranean environments (Papachristou et al 1999 ; Papachristou and Papanastasis 1994 ). Fraxinus excelsior , which has high forage quality (Hejcmanová et al 2014 ; Ravetto Enri et al 2020 ), was positively selected by cows too, except in Torrette study area. The avoidance for this species observed in Torrette may be explained by the age of the plants, as in this paddock there were abundant F. excelsior seedlings about 20-cm tall, whereas in the other sites the trees were mainly adult and the cows fed on their lowest branches.…”