Abstract

BANCHERO, Georgget; VAZQUEZ, Andrés; QUINTANS, Graciela  and  CIAPPESONI, Gabriel. Preliminary Study of Growth, Development, and Reproductive Indicators in Females of Six Sheep Biotypes in Uruguay. Agrociencia Uruguay [online]. 2014, vol.18, n.2, pp.117-127. ISSN 1510-0839.

First evaluations of the Prolific Sheep Project of Instituto Nacional de Investigación Agropecuaria (INIA, 2008-2011) demonstrated that the crossbred mothers Corriedale by East Frisian or Corriedale by Finnish Landrace weaned 60 % more lambs than pure Corriedale, and the crossbred mothers East Friesian by Finnish Landrace weaned 85 % more than pure Corriedale. To obtain information regarding the age when puberty begins, the breeding season, and the ovulation rate of these new biotypes, an experiment was carried out with 87 female lambs born the Spring of 2010. Two pure breeds: Corriedale (C.C) and East Friesian (M.M) and the following crosses: Finnish Landrace x Corriedale (F.C), East Friesian x Corriedale (M.C), ¾ East Friesian - ¼ Finnish Landrace (M.(F.M)), ⁷/₈ Finnish Landrace -¹/₈ Corriedale (F.(FxF.C)) were used. Female lambs with more than 75 % of East Friesian blood (M.M and M.(F.M)) had the highests percentages of puberty onset in their first year of life (> 90 %). Their breeding season was the widest with an average ovulation rate of 1.0. F.(FxF.C) lambs followed the previous ones in the percentage reaching puberty and the width of the breeding season with an average ovulation rate of 1.5. Breeding season of hoggets was similar for all biotypes, however, hoggets with Finn blood were outstanding by their high ovulation rate (1.9-2.8) followed by East Friesian (1.5-1.8) and Corriedale (1.3).

Keywords : EWE LAMB; DEVELOPMENT; PUBERTY; BREEDING SEASON; OVULATION RATE.

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