Canine-specific tail-in, head-out sperm agglutination

Area of Science:

• Veterinary Science
• Reproductive Biology
• Immunology

Background:

• Subfertility in dogs can have various causes, including immunological factors affecting sperm.
• Sperm agglutination is a common indicator of antisperm antibodies, but specific patterns can reveal underlying mechanisms.

Purpose of the Study:

• To investigate an unusual sperm agglutination pattern observed in a subfertile dog.
• To determine if seminal plasma from the affected dog could induce similar agglutination in other animals.

Main Methods:

• Observation of a specific tail-in, head-out sperm agglutination pattern in a Brucella canis seronegative dog.
• Testing the effect of centrifuged seminal plasma from this dog on canine, equine, and ovine ejaculates.
• Assessing the influence of sperm motility and seminal plasma factor concentration on agglutination.

Main Results:

• A distinct tail-in, head-out sperm agglutination pattern was identified in one subfertile dog.
• The dog's seminal plasma induced a similar agglutination pattern in six out of seven dogs tested.
• No agglutination was observed in ejaculates from a stallion or two rams.
• The agglutination was transient and dependent on sperm motility, with intensity influenced by the agglutinating factor's concentration.

Conclusions:

• The findings suggest a novel, species-specific agglutinating factor present in the seminal plasma of the affected dog.
• This factor may play a role in canine reproductive health and warrants further investigation.
• The pattern is distinct from typical immune-mediated agglutination and may be related to sperm surface interactions or motility.