SCREENING OF DEPIGMENTING COMPOUNDS FOR THE DEVELOPMENT OF AN ALTERNATE METHOD OF BRANDING BEEF-CATTLE

The impetus to find alternative methods to stressful routine managemen t procedures has increased in recent years in the hope of improving an imal welfare. The potential of using depigmenting compounds to create a permanent visible mark was evaluated in two beef heifers. Eight comp ounds (hydroquinone [H], 4-ethoxyphenol [4-EP], 4-methylcatechol [4-MC ], 4-tert-butylcatechol [4-t-BC], 4-methoxyphenol [4-MP], monobenzone [M], hydroquinone bis (2-hydroxyethyl) ether (HHEE), and catechol [C]) were injected intradermally at concentrations of 10 and 20%. These co mpounds were screened in four different carriers (ethanol, glycerol, p ropylene glycol, and liposome cream) to test their effectiveness in pr oducing depigmented hair. Transdermal patches containing 5, 7, and 10% liposome preparations of 4-MC and 4-MP produced depigmentation, but t his depigmentation was not as visible as when the same preparations we re injected. Histological examination of biopsies and observations of the injected sites were compared to sites that were only injected with the carrier solution. Compounds H, 4-EP, 4-MC, 4-t-BC, 4-MP, and M pr oduced visible depigmentation lasting up to 3 mo. The duration of the effect seemed dependent on the hair cycle length and stage of cycle at time of application. None of the depigmenting compounds tested produc ed a permanent depigmenting effect.