What contributes to the birth canal difficulties leading to dystocia in older female guinea pigs?

Fused pubis bones are a significant contributor to birth canal difficulties in older female guinea pigs. As guinea pigs age, the pubic symphysis, which is made up of two pubis bones, can ossify. This fusion narrows the birth canal, making it more challenging for the offspring to pass through during birth. The reduction in canal size means that even normally sized pups can face difficulties during delivery, increasing the risk of dystocia.

Other factors listed, such as age-related hormonal changes, increased body mass, and inadequate nutrition, may also affect a guinea pig's overall health and reproductive success, but the mechanical issue created by fused pubis bones is directly linked to the physical challenges of giving birth in older females. This anatomical change is a well-documented concern for breeding practices in guinea pigs, highlighting the importance of understanding the impact of aging on reproductive anatomy in these animals.