Sexual precocity and productivity of beef cattle female under grazing conditions

Abstract

In view of the importance of female reproductive traits as a key profit indicator in beef-cattle production systems, the objective of the present study was to explore the relationships between female sexual precocity and potential predictive traits of easy and early measurement, related to the productive and reproductive efficiency. Heifers born in 2011 and 2012 (n = 132) from five genetic groups (Angus, Hereford, Angus-Hereford, Hereford-Angus and Argentine Creole) in 2 years (Trial 1 and Trial 2) under grazing conditions were evaluated. After weaning, the presence of corpus luteum, liveweight, body condition score, hip height, rump fat thickness and rib fat thickness were recorded every 28 days, and Longissimus muscle area at 15 months of age. Also, to evaluate the relationships between age at puberty and the subsequent production efficiency, the annual records of 895 cows (217 Angus, 253 Hereford, 125 Creole, 116 Angus-Hereford and 184 Hereford-Angus) born between 1986 and 2009 were studied to estimate the average annual productivity of cows, and its components of (Co)variance, heritability and breeding values. Nutritional conditions immediately after weaning were determinants in reaching puberty. The univariate animal model for average annual productivity showed a heritability of 0.14 ± 0.05. Regression multiple and covariance analyses revealed that the rib fat thickness at 450 days of age was a good predictor of age at puberty, but lose some relevance as early selection criterion. Finally, it is important for future studies to analyse in more detail the existence of critical thresholds of fat deposition for the onset of reproductive activity.

Estimation the genetic parameters for age at first calving in Charolais and Limousine breeds

“…(Swiestra et al, 1977). In others meat breeds, the age at puberty was 464.6 in Angus, 478.6 in Hereford and 493.3 in Creole breed (Pardo et al, 2018).…”

Genome-Wide Association Study Provides Insights into Important Genes for Reproductive Traits in Nelore Cattle

“…The RAB11FIP5 and SFXN5 genes have already been described as associated with shear force [ 56 ], a method used to evaluate the tenderness of meat. There is a high degree of interdependence of puberty traits and growth and body composition [ 57 ]. Pacheco et al [ 58 ] reported that subcutaneous fat thickness is favored when younger animals are slaughtered.…”

Relaciones entre estacionalidad, características corporales y leptina en el inicio de la pubertad en vaquillas Bos taurus taurus y Bos taurus indicus en el trópico mexicano

“…La información disponible indica que se requiere un mínimo de grasa corporal para detonar procesos reproductivos como la PB en vaquillas (9) y un mínimo de CC (54) . En un estudio (55) realizado en vaquillas Nelore, se encontraron altas correlaciones (de 0.82 a 0.93) entre la CC y el GD, y se afirmó que con la CC se puede predecir el GD en ganado B. taurus indicus en las diferentes etapas del ciclo de producción.…”

“…Se ha reportado que las concentraciones circulantes de leptina aumentan durante el desarrollo puberal en vaquillas (8) . La información disponible sugiere que hay un nivel crítico de grasa requerido para el inicio de la actividad reproductiva (9) y que puede haber diferencias en este límite crítico de grasa entre razas (10) , lo que implica que deben existir condiciones para regular la acumulación de energía excedente en forma de grasa corporal. A pesar de que se conocen varios factores que afectan el establecimiento de la pubertad en vaquillas, es escasa la literatura sobre las interacciones entre estos y, particularmente, sobre las diferencias entre B. taurus taurus y B. taurus indicus, en especial si consideramos el factor estacionalidad, que se asocia con el ganado Cebú (3,11,12) .…”