EFFECT OF WEATHER CONDITIONS ON A PASTURE QUALITY AND ITS USE FOR PRODUCTION OF LAMB

Lambing was advanced on spring months in group of ewes, merino crossbreeds. Lambs grazed together with mothers without addition of concentrate to the end of pasture season. Trial group of 24 ewes (12 ewes with one lamb and 12 ewes with two lambs) was grazed separately in fenced pasture with average quality of grazing plants. During this experiment a synoptic situation showing variability of meteorological parameters (air temperature, rainfall, sunshine, wind speed) and their extremes, which are related to animal comfort or discomfort on the pasture. Their importance consists in an effect on the surface of the earth, which is warmed during a day and cooled over the night due to radiation. It influences minimal ground temperature. Heat loss due to cooling by the wind is also important. Persistent rain or torrential rain is unfavorable especially for young animals. However, pasture had positive effect on the course of lactation curve, when the peak was achieved during the 8th week of lactation and average daily gain of live weight reached 295 g in the group of single lambs and 213 g in the group of twins. Average slaughter weight at 5 months of age represented 31.5 kg in single lambs and 27 kg in twins.