<div>Background: Osteopontin (OPN) is an extracellular matrix protein with multifunctions and has been identified in the reproductive tract of both males and females. OPN from the seminal plasma (SP) has been closely associated with male fertility in several domestic animals. Different isoforms of OPN has been identified in the SP and sperm membrane in dogs but with unknown functions. The current study investigated the comparison of key canine sperm microscopic parameters and SP markers between dogs exhibiting different fertility potential. 
 
Methods: In this investigation during 2018-2019, 21 dogs coming for breeding soundness examination were selected and divided into fertile (Group I) and hypofertile (Group II). Evaluation included assessment of sperm microscopic characteristics and estimation of OPN, Malondialdehyde (MDA), Catalase (CAT), Glutathione peroxidase (GPx) and Superoxide dismutase (SOD) concentration in the SP. 
 
Result: The OPN level showed positive correlation with all the sperm evaluated characteristics (p&lt;0.01). Linear regression analysis depicted a significant (p&lt;0.001) influence of OPN on the evaluated sperm characteristics. These findings suggest that OPN in the SP along with the microscopic characteristics of the spermatozoa can be used as a potential fertility marker in discriminating fertile from the hypofertile ones.</div>

Seminal Plasma Osteopontin: A Marker for Potential Fertility in Dogs