Abstract

ROUVIER, A. M.  and  YANEZ, E. A.. Efecto de la ganancia de peso invernal sobre el desarrollo genital de vaquillas a los 18 meses. Rev. vet. [online]. 2017, vol.28, n.2, pp.93-98. ISSN 1669-6840.

The age for first service in cows is challenging considering breeding conditions for the northeast region of Argentina. The purpose of this work was to determine the effect of different live weight gains (PV) during the first winter in confinement, with natural grassland in summer rearing, on growth, body development and genital score (SG) in eighteen month old cows. For this assay Brangus calves (n=45) were used. During the first part of the assay animals were distributed in three lots and food was administered in different amounts: ad-libitum treatment expected weight gain 800 g/days (T1); 15% food restriction treatment (T2), and 30% food restriction (T3). Later all animals continued grazing altogether. Variables under consideration were PV, SG, hip height, thoracic perimeter, and subcutaneous fat from hip (P8). Design was completely randomized with 3 treatments and 15 repetitions. Results for T1 at the end of confinement and grazing period were: hip height 116.6 and 131.3 cm; thoracic perimeter 153.3 and 158.6 cm; PV 290 and 301.2 kg; P8 5.85 and 3.76 mm; and SG 2.80 and 3.23. These results confirm that they were able to receive the first service. The T2 animals did not show differences compared to T1 for none of the evaluated parameters. T3 was different compared to T1 in all the variables, except for genital score in which statistic differences were not observed being this due to large data variability. The 15% food restriction during winter did not affect heifers body and genital development

Keywords : heifers; growth; genital score; body condition.

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