Hematologic, biochemical, hormonal, and redox status alterations during reproductive activity in adult rams of two breeds

Background: Reproduction is a crucial, energy-consuming physiologic activity, which can temporarily disturb the homeostatic balance of the organism. Although rams are commonly placed into intense breeding programs in contemporary sheep farms, the clinicopathologic and redox status alterations have not been adequately studied during reproductive activity. Objectives: The objective was to investigate the clinicopathologic and redox status changes in rams during reproductive activity. Methods: Thirty-seven (19 Chios and 18 Florina breed) adult, healthy rams were individually mated with ten estrus-synchronized ewes of the same breed. Blood samples were collected prior to mating, during mating, and post-mating. CBC (Advia 120), cytologic blood smear evaluation, biochemical analyses (Flexor E, AVL 9180 Electrolyte Analyzer), and thyroxine measurement (Immulite 1000) were performed. Reactive oxygen metabolites (d-ROMs Test), biological antioxidant potential (BAP Test), and oxidative stress index were used to assess redox status. The linear mixed effects model (statistical language R) was used for statistical analyses. Results: Many, mostly breed-independent, clinicopathologic changes were detected during reproductive activity. Conversely, redox status alterations were found to be breed-dependent. Conclusions: Intense reproductive activity was related to mild, acute muscle damage in both breeds and mild oxidative stress in Florina rams, whereas Chios rams exhibited oxidative stress resistance. The observed clinicopathologic and redox status alterations were generally consistent with those reported during various forms of physical activity and exercise in animals and humans. Intense reproductive activity does not seem to be physiologically innocuous; however, it appears to be a relatively mild muscle-damaging physical activity.