Horsetalk.co.nz ‘Senior’ performance horses may need a little more TLC Share As horses age, some physiological functions start to decline, and they require extra care to maintain their overall health and condition. Image by Alexas_Fotos From a veterinary perspective, horses can be considered “middle-aged” by 13 years of age, and “seniors” by 20 years of age. Although many sport horses may just be coming into their prime for training and competing during these years, horses show signs of ageing at different rates just like humans do. As horses age, some physiological functions start to decline, and they require extra care to maintain their overall health and condition.