SciELO - Scientific Electronic Library Online

 
vol.39 número1Effects of season and regulated photoperiod on the reproductive performance of sowsGenetic diversity and relationships among indigenous Mozambican cattle breeds índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Articulo

Indicadores

Links relacionados

  • En proceso de indezaciónCitado por Google
  • En proceso de indezaciónSimilares en Google

Compartir


South African Journal of Animal Science

versión On-line ISSN 2221-4062
versión impresa ISSN 0375-1589

Resumen

MAIWASHE, A.; NEPHAWE, K.A.  y  THERON, H.E.. Analysis of stayability in South African Angus cattle using a threshold model. S. Afr. j. anim. sci. [online]. 2009, vol.39, n.1, pp.55-60. ISSN 2221-4062.

The objectives of the study were to estimate genetic parameters for stayability in the South African Angus cattle and to compare the sire and animal threshold models. Data and pedigree information were obtained from the Integrated Registration and Genetic Information System of South Africa. Stayability was defined as a probability that a cow remained in the herd until four (STAY4), five (STAY5), six (STAY6), seven (STAY7) and eight years of age (STAY8), given that she was a dam. Cows that were in the herd by a specific age were assigned a "1" or a "0", otherwise. The proportions of successful stayability were 0.63, 0.57, 0.49, 0.42, and 0.37 for STAY4, STAY5, STAY6, STAY7 and STAY8, respectively. Estimates of genetic parameters were obtained from sire and animal threshold models using AIREML algorithm. The model included the fixed effect of contemporary group and random effects of sire or animal genetic effect and the residual. Heritability estimates from the sire model were 0.26 ± 0.08, 0.26 ± 0.09, 0.30 ± 0.09, 0.24 ± 0.10 and 0.27 ± 0.11 for STAY4, STAY5, STAY6, STAY7 and STAY8, respectively. Corresponding estimates from the animal model were 0.20 ± 0.11, 0.20 ± 0.11, 0.20 ± 0.12, 0.18 ± 0.13 and 0.20 ± 0.14. Estimates from the sire and animal models were consistent. Results from the current study indicate that direct selection for stayability could be effective. However, the long generation interval required to obtain accurate estimates of genetic merit may slow genetic progress for stayability at older ages.

Palabras clave : Genetic parameters; longevity; beef cattle.

        · texto en Inglés     · Inglés ( pdf )

 

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons