What factor increases the risk for developing urethral sphincter mechanism incompetence?

The factor that increases the risk for developing urethral sphincter mechanism incompetence is early spaying in larger breeds. When female dogs, especially larger breeds, are spayed early, it can lead to hormonal changes that may affect the development and function of the urethral sphincter. Estrogen plays a crucial role in maintaining the tone and strength of the urethral sphincter, and early spaying reduces estrogen levels, which might contribute to sphincter incompetence. This condition allows for involuntary leakage of urine, particularly under stress or during excitement.

Late spaying, while it may have its own implications, does not carry the same risk as early spaying in larger breeds. Male dogs do not experience the same hormonal changes related to spaying, and while being overweight can contribute to various health issues, including urinary incontinence, it does not specifically pertain to the mechanism of urinary sphincter competence in the same way that early spaying does for females. Therefore, early spaying in larger breeds is a significant risk factor for developing this condition.