Reproductive performance of European-breed ewes in different seasons of the year under mid-latitude.

Abstract

The study evaluated the reproductive performance of Ile de France, Texel, Suffolk and crossbred ewes in different seasons, considering season of mating, age, body condition score and breed. The herd was located at geographic coordinates -25.66114429S, -49.27262198W, in Fazenda Rio Grande, Paraná State, southern Brazil, in a semi-intensive system. 643 mating were evaluated, under natural estrus conditions in 10 consecutive breeding seasons (2015-2019), under a body condition score between 2.5 and 3.5 in 93.9%. Data were analyzed using chi-square tests, binary logistic regression, ANOVA and T test. Considering the breeds and crossbred animals, a pregnancy rate (PR) of 83% (winter), 91% (autumn) and 89% (summer) with no differences between them was obtained, except for 77% PR in spring (p<0.05). Ile de France and crossbred ewes showed similar PR in all four seasons. Suffolk ewes showed similar fertility rates in summer, autumn and winter, but reduced in spring (p<0.05); Texel ewes showed lower PR in summer and spring compared to autumn and winter (p<0.05). The twin PR (TPR) in autumn, winter and spring showed no differences, except for summer (p<0.05). Age did not influence the PR of ewes <2 years, 2 to 8 years and > 8 years in the seasons, except in summer. It was concluded that the reproduction of European ewes breeds under medium latitude, combined with the use of constant management and feeding conditions, resulted in a fertility rate above 77% in all seasons, resulting in constant production of lambs.