Sessions

Extensive sheep production relies largely on pasture as the primary source of nutrients, and consequently, animal performance is closely linked to seasonal fluctuations in grass yield and nutritive value. Under such conditions, differences among breeds in growth potential, adaptation to pasture-based environments, and capacity for compensatory growth may influence their fattening performance. In recognition of the importance of this production system, the FAO has designated the year 2026 as the International Year of Rangelands and Pastoralists. In this context, this study examined the growth and fattening performance of sheep under extensive conditions during the primary plant-growing season, from mid-May to mid-October. The study included wether lambs of Hungarian native sheep breeds, with German Mutton Merino (GM) lambs serving as a control group, with 5 individuals per breed. To ensure reliable comparison, live weight and daily gain were adjusted according to the assigned days of life. A one-way ANOVA was then performed, where the breed was included as a fixed effect. Data preparation and statistical analyses were conducted using the software Statistica (version 14, TIBCO). The effect of the age of the individuals was not significant, indicating that the lambs entered the fattening period at a comparable age. Nevertheless, significant differences in initial body weight were observed among breeds, reflecting differences in pre-weaning growth and weight at maturity: the Tsigai, Merino, White Racka and GM lambs had significantly higher initial body weights than the Black Racka and the Dairy Tsigai lambs. During the fattening period, lambs gained weight during the first and final months, but experienced an overall weight loss after arrival and during the intervening summer period. The subsequent recovery of body weight indicates the capacity of the young animals for compensatory growth following the acclimatization period and mid-summer decline in weight. Breed-related differences in body weight observed at the beginning of the experiment remained in the final weight, and were also reflected in the average daily gain during the fattening period.