Multifaceted Interplay among Social Dominance, Body Condition, Appetitive and Consummatory Sexual Behaviors, and Semen Quality in Dorper Rams during Out-Of-Season and Transition Periods

Abstract

Dorper rams (n = 24) were evaluated during the sexual resting season to determine their social rank (SR), either high (HSR) or low (LSR), under intensive management conditions in northern Mexico (25° N). Aggressive behaviors were quantified during male-to-male interactions, and appetitive and consummatory sexual behaviors during male-to-female interactions. Morphometric, live weight (LW), and body condition score (BCS) were recorded. During the early reproductive season, male-to-female behaviors were newly itemized simultaneously by seminal quality and quantity sampling. Finally, the dependent variables of the hemogram components were also quantified. Neither LW (61.25 ± 2.4 kg) nor morphometric variables differed between SR groups. However, BCS (2.25 vs. 2.66 u), sexual behaviors (i.e., approaches: 59.6 vs. 21.73 n, mating with ejaculation: 77.7 vs. 42.86 %, latency to ejaculation: 16.6 vs. 143.07 s), ejaculate volume (0.57 vs. 0.23 mL), and hemogram components favored the HSR rams (p < 0.05). Moreover, in their first male-to-female interaction, >50% of the LSR rams failed to display any sexual activity. HSR rams displayed a greater number of threatening behaviors, managing to displace LSR rams when exposed to estrus ewes during the male sexual resting season; more sexual behaviors; and an increased seminal volume in a non-live weight-dependent fashion.

La presencia de cuernos determina el rango social de carneros Dorper

“…A social hierarchy is defined as individuals centred on reciprocal dominance-subordination relationships often determined by a mutual evaluation, ranging from simple recognition to ritualized displays or serious fights (Barroso et al 2000). Social rank is positively associated with differential access to available resources, mainly related to the feeding behaviour of group members (Sifuentes-Lamónt et al 2022). Therefore, dominant males are heavier than subordinate males (Aguirre et al 2007), which implies better productive and reproductive outcomes for high social rank (HSR) than low social rank (LSR) animals (Sifuentes-Lamónt et al 2022).…”

“…Social rank is positively associated with differential access to available resources, mainly related to the feeding behaviour of group members (Sifuentes-Lamónt et al 2022). Therefore, dominant males are heavier than subordinate males (Aguirre et al 2007), which implies better productive and reproductive outcomes for high social rank (HSR) than low social rank (LSR) animals (Sifuentes-Lamónt et al 2022). For example, HSR females have a a higher percentage and duration of estrus, with a higher ovulation rate and corpus luteum size than LSR females (Zuñiga-Garcia et al 2020).…”

“…Hierarchical structure is influenced by several factors, such as the presence of horns, live weight, and age of the animal (Barroso et al 2000, Tölü et al 2007. Morphometrics are among the factors that determine social rank (Sifuentes-Lamónt et al 2022). Horns in ruminants play a role in social behaviour and protection (Simon et al 2022).…”