作者: Liliana G. Hidalgo , M. A. Cauhépé
DOI: 10.1111/J.1744-697X.2009.00141.X
关键词:
摘要: The Flooding Pampa natural grasslands are gradually being transformed into croplands to increase the economic returns of ranches. It is therefore becoming necessary for stockmen beef cattle efficiency compete with crops and maintain native grassland its associated fauna. However, during winter have lowest content nutrients year. We intend demonstrate that, breeding weights over 65% cow mature weight, low forage quality rangelands does not a negative effect on reproduction. These higher were obtained by selecting early born female calves grazing annual cultivated pastures. Pregnant Aberdeen Angus yearling heifers (n = 90) evaluated using pregnancy test (May 2005) until second calving (July 2006). At beginning experiment, live weight ranging 360‐514 kg (mean, 425 ± 3.5 SE) used. Cattle grazed (humid mesophytic meadows humid prairie grasslands) old mixed was high (100%), same mean date as in first (227 Julian days). Heifers which calved later year calvers year, resulting relatively constant average dates across animals.