MAESTRI Damian Modesto
congresos y reuniones científicas
Female traits and diet effects on reproductive performance in captive Greater Rheas
CARLA LÁBAQUE; MÓNICA MARTELLA; DAMIÁN MAESTRI; JOAQUÍN NAVARRO
Congreso; XXIV International Ornithological Congress; 2006
The effects of age, weight and diet of Greater rhea (Rhea americana) females on reproductive success was studied as part of a project on the species' conservation and sustainable use. During three breeding seasons (2001/2002, 2002/2003 and 2003/2004) eggs from 15 females of 18, 24 and ³36 months old (at the start of the study) that were marked with numbered tags were identified. The laying date and egg weight, length, width and volume were measured, and up to nine eggs of each female were randomly selected to analyze the specific weight, the proportions of yolk, albumen and shell (based on entire egg weight), protein and lipid contents and fatty acid composition. The remaining the eggs (n = 180) were artificially incubated and monitored until hatching. Females of higher weight started oviposition early and laid more eggs, which were bigger and heavier than those laid by females of lower weight. The latter produced eggs with greater percentage of yolk and lipids, which had higher hatchability. No differences were observed between both female categories with respect to survival of chicks they produced. Diet of females, regardless of their weight and age, produced variations in almost all the egg traits and reproductive parameters. However, changes in hatchability produced by the diet fed to the animals were inversely correlated with chick survival. Age of females influenced only on specific weight and percentage of albumen and arachidonic acid, but not on hatchability or chick survival. Among the variables analysed, weight and diet of females would determine their reproductive success and strategies.