title: Grouping previously unknown bucks is a stressor with negative effects on reproduction.
abstract: Grouping previously unknown animals produces social stress, which might have negative effects on reproduction. The aims of the experiment were to determine if grouping unknown bucks (1) triggers a stress response and produces changes in body weight; (2) affects scrotal circumference, testosterone concentration, and semen quality; and (3) has differential effects between resident and introduced bucks. One group of nine Saanen bucks was transported and introduced (introduced bucks, group IG) to a group of eight Saanen bucks (resident bucks, group RG). On day 0, cortisol concentration and rectal temperature were determined, and from day -7 to day 29, body weight, scrotal circumference, and testosterone concentration were recorded and semen quality was determined. The stress response was different between groups: on several moments on day 0, resident bucks had greater cortisol concentration (P < 0.0001), while introduced bucks had higher rectal temperature (P = 0.02). Body weight decreased similarly in both groups from day -7 to day 2 (P < 0.0001), but on day 29, IG bucks were lighter than RG bucks (P = 0.05). Also, the reproductive response differed between groups: introduced bucks had lower scrotal circumference (P < 0.01), lower testosterone concentration (P = 0.02), and lower percentage of motile spermatozoa in the ejaculate (P = 0.05). It was concluded that grouping unknown bucks was stressful and negatively affected the reproduction, being more serious for the introduced than the resident bucks.
authors.affiliation: Departamento de Fisiología, Universidad de la República, Lasplaces 1620, 11600, Montevideo, Uruguay, giriboni02@gmail.com.
authors.forename: Julia
authors.initials: J
authors.lastname: Giriboni
authors.forename: Lorena
authors.initials: L
authors.lastname: Lacuesta
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Damián
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Ungerfeld
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D006041:Goats; D008297:Male; D012098:Reproduction / Q000502:physiology*; D055101:Semen Analysis; D012726:Sexual Behavior, Animal; D013315:Stress, Psychological; D013739:Testosterone / Q000097:blood
chemical_list: D013739:Testosterone