Considering the fact that sheep production has an important role in
agriculture of Serbia, lamb performance is essential. Objective of the study
was to investigate effect of year, lambing season, sex and birth type on
growth performances in lambs of MIS breed. Animal data (birth date, birth
type, sex, birth weight -BW0, body weight after 30 days - BW30 and body
weight after 90 days - BW90) are gained from control of productive
parameters maintained from 2011 to 2020. Research was conducted on the
sample of 1592 lambs. Average daily gain from birth to 30 days (ADG1), from
30 to 90 days (ADG2), and from birth until 90 days (ADG3), were calculated
and included in analysis. Calendar year was divided in four seasons, each
season consists from 3 months: winter, spring, summer and autumn. Average
body weights (? standard deviation) at birth, after 30 and 90 days were 4.41
kg (? 0.99), 14.11 kg (? 2.80), 24.05 kg (? 3.86), respectively. Average
daily gains were 319.87 g (? 74.97), 164.98 g (? 35.39) and 216.88 g (?
36.86) for ADG1, ADG2 and ADG3, respectively. Lambing type and sex of the
lambs affected all of the observed traits very significantly (p < 0.01).
Lambing year had very significant effect (p < 0.01) on BW30, on ADG1 and
ADG2, while lambing season significantly (p < 0.05) affected BW90, ADG2 and
ADG3.Based on the results it can be concluded that birth type and sex had
strongest effects in early productive parameters of lambs.