Estudio de las comunidades de interés pascícola en un puerto de montaña: II evolución en la intensidad de selección del pasto por dos razas ovinas (Churra y Merina)

Abstract

In order to know how the grazing period during summer affects to the degree of food selection in mountain areas and consistency of this differences in Churro and Merino genotypes an experiment on "Nardus" grass was carried out Four oesophageal fistulated wether lambs of each breed were used during the last week of June, July, August and September 1990 and the leaf and steam were separated in each sample. There were no differences (P>0.05) between breed in the proportion of extrusa leaves (88.3 and 85.3% for Churra and Merino respectively). The effect of period was significatively different (P<0.01) for the proportion of leaf, with a lower value (78%) in the second period (driest state of grass). There were no differences (p<0.01) in selection index (% of leaves in the extrusa / % of leaves in the grass) among periods. For the Merino genotype the selection index was lower (P<0.01) during June and July periods than august and September values. For the Churra breed the value of index of food selection at June period was lower (P<0.01) than the other three periods.