Patterns of sexual size dimorphism in cattle breeds support Rensch’s rule

Abstract

Rensch's rule describes the pattern of sexual size dimorphism (SSD) claiming that in taxa where males are the larger sex, larger species generally exhibit higher male to female body size ratios. Agreement with Rensch's rule is manifested by the slope of the allometric relationship between male and female body size exceeding one. In this paper we have tested the hypothesis that recent rapid evolutionary changes of body size accompanying domestication process and morphological radiation of domestic breeds follow Rensch's rule. We have analyzed literature data on adult body size of males and females in domestic cows, yaks, buffaloes and other bovines (315, 12, 24 and 2 breeds, respectively) and compared it with SSD in 18 wild species/subspecies of the subfamily Bovinae. Male to female body mass ratio in domestic cows (1.48) was fairly comparable to that found in other species of domestic and wild bovines except domestic buffaloes (1.19). In cows we have demonstrated clear positive allometry of male to female body mass ratio (slope 1.21) predicted by Rensch's rule, however, no such clear relationship was found when body mass was replaced by shoulder height. These findings are in agreement with those we have previously reported in other livestock species, goats and sheep.

Application of multivariate principal component analysis to morphological characterization of indigenous goats in Southern Nigeria

“…The larger values reported for the conformation traits of males compared to females are in agreement with earlier reports on goats (Vargas et al, 2007), sheep (Yakubu and Akinyemi, 2010) and cattle (Polak and Frynta, 2010), respectively. The influence of sex on the body weight and morphometric traits in this study are likely connected with the usual between-sex hormonal action which leads to differential growth rates.…”

Sex influence on genetic expressions of early growth in Afshari lambs

“…In a group of related species, SSD is often larger in larger species and decreases as the size of species decreases. This phenomenon is termed Rensch's rule (Rensch, 1950). In addition, in related species, SSD is normally more pronounced in wild, compared to domestic, species because of the reduced role of male combat in captive herds; the effect of reduced sexual segregation in captivity, where males usually graze together with females in mixed herds; and relaxed intrasexual selection as a result of the femalebiased operational sex ratio (Polak and Frynta, 2009).…”

“…On average, mature Afshari rams are over 25 % heavier than mature ewes (66 vs. 53 kg). Although SSD is apparent in domestic animals such as sheep (Gudex et al, 2009), goat (Polak and Frynta, 2009), pig (Dunshea, 2001), cattle (Polak and Frynta, 2010), rabbit (Eason et al, 2000) and chicken (Maniatis et al, 2013), little effort has been made to investigate its genetic basis and explore its potential use in sheep breeding programs. Accurate estimation of breeding values and the definition and realization of optimal multiple-trait selection response for each sex are challenges when SSD is present in sheep production, especially if heritabilities for measures taken on males and females are unequal and (or) genetic correlations between the sexes are less than unity (Gudex et al, 2009).…”

Andrew meets Rensch: sexual size dimorphism and the inverse of Rensch’s rule in Andrew’s toad (Bufo andrewsi)

“…During recent years, intraspecific tests of Rensch's rule using wild (e.g. Kupfer 2007;Lengkeek et al 2008;Herczeg et al 2010;Kelly et al 2013) and domestic animals (Sutter et al 2008;Polák and Frynta 2010;Remeš and Székely 2010;Frynta et al 2012) have started to emerge. However, most of these studies have focused on taxa with male-biased SSD, and in cases where female-biased SSD has been observed, Rensch's rule has not been supported apparently because positive selection on female body size has been found to be stronger than that on male body size (Teder and Tammaru 2005;Herczeg et al 2010).…”