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Seasonal lambing distribution of the Romanov breed in northwestern Croatia during five consecutive years

Objectives. The aim of this study was to investigate the lambing distribution of the Romanov breed in northwestern Croatia during five consecutive years. Most European breeds of sheep are seasonal breeders in the moderate climate region ; however, the Romanov breed is a meat breed that is aseasonally polyoestrous. Romanov sheep are considered to be highly fertile, with a fecundity rate of 230% or more. In Croatia, the lambing season is primarily in the winter and spring for seasonal breeders. Materials and methods. During five consecutive years (December 2011 to November 2016) at eight medium-scale sheep farms in northwestern Croatia, there were 5379 mattings with 5046 successful conceptions i.e. lambings. Ewes were kept at pasture, which primarily provided area for exercise, with access to stables during the night, in a semi-intensive environment. According to standard farming practices, animals had free access to good quality meadow hay (about 1.8 kg per doe daily), adequate concentrate and drinking water. Results. Fertility was 93.81%. The seasonal distribution of lambings in this study was: 47.64% of ewes delivered in winter (n=2422), 23.37% in spring (n=1179), 18.82% in summer (n=950) and 9.81% in autumn (n=495). The winter season refers to the period of December to February. Sexual activity was lowest was during spring and early summer (March to June) with a peak of sexual activity from August to October. Litter size was greater during spring and winter than in other seasons (1.67 vs.1.36) though birth weight was lower in larger than in smaller litters (2.64±0.65 vs. 2.87±0.61). Conclusions. More lambs during lambing season and a higher percentage of multiple births (triplets, quadruplets, etc.) was expected during the optimal breeding season, as seen in most European sheep breeds. Despite being aseasonally polyoestrous, the distribution of mating and lambing was not uniform through the seasons for the Romanov breed.

Seasonal lambing distribution ; Sheep ; Romanov breed ; Northwestern Croatia

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