Due to the amount of time and effort required in measurement, often only a limited number of animals are assessed for individual feed effi­ ciency traits, and this can lower the amount of genetic progress made. Measuring the surface temperatures of the unfeathered areas of turkeys has been proposed as a method to monitor the proportion of feed energy ingested and metabolized. Theoretically, a l...

Better understanding of the mechanisms underlying inter-individual variation in stress responses and their links with production traits is a key issue for sustainable animal breeding. In this study, we searched for QTL controlling the magnitude of the plasma cortisol stress response and compared them to body size traits in five F2 full-sib families issued from two rainbow trout lines divergentl...

1. Immune defence has recently been viewed as a life-history trait that shows trade-offs with other life-history traits. However, studies exploring correlations between different components of immune defence and other life-history traits are scarce. 2. In this study, two measures of immune function, body size, and development time were studied in the Mediterranean Field Cricket, Gryllus bimacul...

The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contr...

Different lineages experience different rates of phenotypic diversification, resulting in greater or lower variance in the expression of phenotypic traits among the species within a lineage. Here, morphological diversification is investigated in 14 different trematode families, based on a dataset comprising morphometric data on body size and 4 anatomical structures (oral sucker, ventral sucker,...

OBJECTIVE (1) To assess the personality profiles of the anabolic androgenic steroid users (AAS) and (2) to determine whether valid premorbid personality traits could be obtained from cross sectional assessment using multisource data. METHODS The first author became a participant-observer in a group of body builders. An experimental group of body builders who had been using AAS for no more tha...

We used a recent passerine phylogeny and comparative method to evaluate the macroevolution of body and egg mass, incubation and fledging periods, time to independence and time with parents of the main passerine lineages. We hypothesised that passerine reproductive traits are affected by adaptation to both past and present environmental factors and phenotypic attributes such as body mass. Our re...

A cross-sectional study was conducted in communal and small-scale Nguni cattle enterprises to determine preferential traits for improvement under low-input cattle breeding programs. Forty-one farmers participated in ranking six specific traits of breeding bulls and cows. Kruskal-Wallis test and ordinal logistic regression were used to determine mean ranks of traits and odds ratios of predictors...

Coloration can play critical roles in a species' biology. The allometry of color patterns may be useful for elucidating the evolutionary mechanisms responsible for shaping the traits. We measured characteristics relating to eight aspects of color patterns from Graptemys oculifera and G. flavimaculata to investigate the allometric differences among male, female, and unsexed juvenile specimens. A...