Open wounds (3 cm x 1 cm) on the anterior surface of teats in four dairy cattle were irradiated using low level laser therapy (LLLT). The laser used was a helium-neon (HeNe) system with an output of 8.5 mW, continuous wave at 632.8 nm. The 16 teats from 4 dairy cattle were divided into 4 groups using Latin Square design and were subjected to daily doses of LLLT : 3.64 J/cm2 for 15 min (Group A); 2.42 J/cm2 for 10 min (Group B); and 1.21 J/cm2 for 5 min (Group C). Group D served as the control. The durations of healing were 18.5 ± 0.5 days for group A; 19 ± 0.7 days for group B; 23 ± 0.7 days for group C; and 24.5 ± 0.5 days for group D, respectively. The rate of wound healing between Groups A and C, A and D, B and C, and B and D were significantly different (P < 0.01). The difference in the hydroxyproline content between normal and healed specimens from Group A was significantly different from that of Group D (P < 0.05). The cosmetic appearance of healed Groups A and B was significantly better than those of Groups C and D.
