Table 2. Mean concentration ± SEM of dopamine by horse age

Age and number of horses
2 to 5 years(n = 6) 6 to 13 years(n = 19) 15 to 24 years(n = 6)
Dopamine (pg/mL) 7.3 ± 2.38 9.0 ± 1.45 10.9 ± 2.31