Exponential growth of male and female free-range chickens during the rearing phase in mixed floor-raised batches
The productive cycle of free-range chickens includes a confined breeding phase followed by a rearing and finishing phase with access to open air. The objective of this study was to evaluate the effects of sex and genotype on the growth dynamics of two populations of free-range chickens during the br...
Guardado en:
| Autores principales: | , , |
|---|---|
| Formato: | Artículo revista |
| Lenguaje: | Español |
| Publicado: |
Universidad Nacional del Nordeste
2025
|
| Materias: | |
| Acceso en línea: | https://revistas.unne.edu.ar/index.php/vet/article/view/8214 |
| Aporte de: |
| Sumario: | The productive cycle of free-range chickens includes a confined breeding phase followed by a rearing and finishing phase with access to open air. The objective of this study was to evaluate the effects of sex and genotype on the growth dynamics of two populations of free-range chickens during the breeding phase. Campero Casilda (CC: founding population) and Campero Bonaerense INTA (CBI: synthetic population under stabilization) birds were evaluated. They were identified at birth with a numbered wing band and raised in a mixed batch as a single group, with ad libitum feeding and individual weekly body weight recording until 35 days of age, when they were sexed based on the development of sexual ornaments. Body weight versus chronological age data from birth to week 6 of a random sample of 60 birds per group and sex were fitted using non-linear regression with an exponential model and the absolute sexual dimorphism (ASD= male weight - female weight) and relative (RSD= male weight/female weight) were estimated for the average weekly body weight over the same period. No interaction effect on the exponential growth rate was observed (p= 0.294) while both genetic group (p= 0.022) and sex (p
<0.0001) effects were significant, with higher values corresponding to CBI and males, respectively. ASD values were fitted using an exponential function and the hypothesis of a common curve for both genotypes was rejected (p= 0.004), with higher values in CBI. RSD values were fitted using linear regression, showing a higher slope in CBI (p= 0.030). It is concluded that the evaluated groups exhibit the typical sexual dimorphism of the species from an early age and that the synthetic population in stabilization shows a more advantageous growth pattern during the breeding phase as a dual-purpose bird, given its higher ASD and RSD values.> |
|---|