Skip to main content
ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #394771
Research Project: Improving Livestock Production by Developing Reproductive and Precision Management Technologies

Location: Livestock Bio-Systems

Title: Yearling bulls have reduced concentrations of sperm after a 28-day breeding season

Author
item Snider, Alexandria - Alex
item MCCARTHY, KACIE - University Of Nebraska
item Wright, Elane
item Ondrak, Jeff
item Oliver, William
item DAHLEN, CARL - North Dakota State University
item Cushman, Robert - Bob
item Crouse, Matthew

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 6/22/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: We hypothesized that after a 28-d breeding season yearling bulls would have reduced concentrations of sperm and increased concentrations of seminal plasma pro-inflammatory cytokine interleukin-8 (IL-8). Yearling bulls (n = 24, 415 days of age) that passed a breeding soundness examination were categorized by concentrations of sperm into one of two breeding groups; 1) bulls with >750 million sperm per mL, which were subsequently exposed to virgin heifers for a 28-d breeding season (BREEDERS, n = 12), or 2) bulls with < 750 million sperm per mL, which were not used for breeding (NON-BREEDERS, n = 12). Blood and semen were collected before and after the 28-day breeding period, with plasma and seminal plasma analyzed for concentrations of cytokines. Data were analyzed using either the MIXED or GLIMMIX procedures with repeated measures in SAS with breeding group, age, and the interaction as fixed effects. Concentrations of sperm per mL of ejaculate were influenced by a day x breeding group interaction (P = 0.04), where BREEDERS had greater concentrations of sperm before the breeding season, but less after the breeding season compared with NON-BREEDERS. Concentrations of seminal plasma IL-8 were also influenced by a day x breeding group interaction (P = 0.005), where BREEDERS and NON-BREEDERS had similar concentrations of seminal plasma before breeding, but BREEDERS had greater concentrations of IL-8 after the breeding season. Taken together, using yearling bulls for a 28-d breeding season resulted in reduced concentrations of sperm and increased inflammatory markers in seminal plasma post-breeding.