Trial of human laser epilation technology for permanent wool removal in Merino sheep

Objective To assess whether human laser epilation technology can permanently prevent wool growth in sheep. Design An observational study. Methods Two commercial human epilation lasers ( S harplan alexandrite 755 nm laser, and L umenis L ight S heer® 800 nm diode laser) were tested at energies between 10 and 100 J/cm 2 and pulse widths from 2 to 400 ms. Wool was clipped from flank, breech, pizzle and around the eyes of superfine M erino sheep with O ster clippers. After initial laser removal of residual wool to reveal bare skin, individual skin sites were treated with up to 15 cycles of laser irradiation. Behavioural responses during treatment, skin temperature immediately after treatment and skin and wool responses for 3 months after treatment were monitored. Results A clear transudate was evident on the skin surface within minutes. A dry superficial scab developed by 24 h and remained adherent for at least 6 weeks. When scabs were shed, there was evidence of scarring at sites receiving multiple treatment cycles and normal wool growth in unscarred skin. There was no evidence of laser energy level or pulse width affecting the response of skin and wool to treatment and no evidence of permanent inhibition of wool growth by laser treatment. Laser treatment was well tolerated by the sheep. Conclusions Treatment of woolled skin with laser parameters that induce epilation by selective photothermolysis in humans failed to induce permanent inhibition of wool growth in sheep. Absence of melanin in wool may have contributed to the result.