Clustering forage types according to their feed nutritive value
2016
Villalba, D | Molina, E | Álvarez-Rodríguez, J
The aim of the study was to evaluate the nutritive value of forages produced in the Spanish Pyrenees and whether they may fulfil nutrient requirements of growing beef calves. Forages produced at moun- tain farms (16) were sampled and classified as grassland forage (fresh, n equal to 17; hay, n equal to 35; silage, n equal to 29) or other fibre sources (cereal straw and hulls, n equal to 14). Samples were analysed for dry matter, crude protein (CP), ash, neutral and acid-detergent fibre (NDF and ADF). A cluster analysis was performed to group the forages into homogenous categories according to these variables. The lowest quality group (relative forage value, RFV equal to 75.8 plus minus 3.4) was mainly represented by hays (45 per cent of the total), while the best quality group (RFV equal to 148.6 plus minus 3.7) consisted mainly of pasture silages (60.7 per cent of the total). Forage diets for fattening calves were designed with the three groups, but they differed widely. In case of the poorest forage group (CP 6.6 plus minus 0.6 per cent, RFV 75.8 plus minus 3.4) it was not possible to design a diet including 60 per cent forage due to its low nutritive value. The best quality forages (CP 17.1 plus minus 0.7) met the estimated energy (UFV) requirements but they failed to meet protein requirements (PDIE) of growing-finishing beef calves with high growth potential. In this Pyrenean area, only around one third of the roughages used may allow meeting energy and protein requirements of growing-finishing beef cattle under a forage-based strategy
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