The first chapter of the Yajurveda-Samhitas (YS) consists of the mantra collections for isti , the fundamental of which is practically to be understood as the new and full moon sacrifice (Darsapurnamasa). Every YS has the section ≪Grazing≫ as its opening. This is the ritual procedures of the so called Upavasatha day, the preceding day of chief offerings are made. There was probably not an exclusive place for the pasture, but the grazing land seems to have been áranya - (a wilderness), the place where no one has his own claim. In this paper, I examine closely the four mantras in this section and the correspondent brahmanas. The mantras are recited for the safety and fertility of the cow grazing in aranya . Comparing the mantras with Rgveda VI 28, 7, which has parallel phrases, we can see an aspect of the nomadic life and trace its change in the Aryan society. It enables us also to confirm how the YV texts were gradually produced and codified.