[ Eq(Derivative(x1, t), (1*k19*k1*x1*(1 - x1/k2) + (-1)*k19*k3*x1*x2 + (-1)*k19*k9*x1*x3/(k11 + x3))/k19),
  Eq(Derivative(x2, t), (1*k19*k5 + (-1)*k19*k6*x2 + 1*k19*k7*x1*x2/(k8 + x1) + (-1)*k19*k4*x1*x2 + (-1)*k19*k10*x2*x3/(k12 + x3) + 1*k19*k14)/k19),
  Eq(Derivative(x3, t), ((-1)*k19*k13*x3 + 1*k19*Piecewise((k17/(1/8), Le(t, 1/8)), (Piecewise((k17/(1/8), And(Ge(t, 21), Le(t, 21 + 1/8))), (Piecewise((k17/(1/8), And(Ge(t, 42), Le(t, 42 + 1/8))), (Piecewise((k17/(1/8), And(Ge(t, 63), Le(t, 63 + 1/8))), (Piecewise((k17/(1/8), And(Ge(t, 84), Le(t, 84 + 1/8))), (Piecewise((k17/(1/8), And(Ge(t, 105), Le(t, 105 + 1/8))), (Piecewise((k17/(1/8), And(Ge(t, 126), Le(t, 126 + 1/8))), (0, True)), True)), True)), True)), True)), True)), True)))/k19) ]