The use of high‐energy electrons to depilate the breech of sheep

Abstract

The use of high-energy electrons for permanently depilating areas of sheep skin was evaluated. The most effective dose of electrons for depilation was 17.5Gy. Histological changes in skin treated at this dose were examined in one sheep over 18 months and in 5 sheep over 89 d. Effects of treatment on bodyweight gains and fleece growth were examined by comparing the productivity of a further 5 sheep treated on the breech with high-energy electrons, with that of conventionally mulesed sheep (n = 5) and untreated controls (n = 5). Electron treatment resulted in immediate death of cells in the germinative region of the wool follicle bulbs. Within 10 d of treatment the treated areas were completely depilated. Wool follicle shafts in the treated areas regressed rapidly towards the epidermis and remained quiescent for the whole trial (89 d). A sheep treated 18 months previously has remained largely depilated, although a few sparse fibres are present. Epidermal acanthosis and orthokeratosis were present at 26 d after treatment. The thickened stratum corneum then sloughed off, but the epidermis remained acanthotic for the entire trial. Sweat glands and most sebaceous glands were destroyed by the treatment and were replaced by fibrotic, avascular tissue in the dermis. In all other respects the external appearance of the electron-treated breech was similar to that of mulesed sheep. There were no apparent side-effects of treatment. Neither mulesing nor electron treatment altered weight gains or fleece growth rates.

Sensitivity of spermatogonia to irradiation varies with age in pre-pubertal ram lambs

“…This effect was short term and recovery was apparent within 3 months of irradiation. In contrast, relatively larger irradiation doses (17.5 Gy) intentionally directed within 1 to 2 mm of the ovine skin surface causes long term damage to, and loss of, wool follicles (Sorell et al, 1990). In the present experiments, radiation delivery and damage to the skin surface was calculated precisely and predicted to be minimal.…”

Research into alternatives to mulesing

“…Workers in South Australia 20,21 reported some preliminary results using a linear accelerator to produce ionising radiation that damaged mitotically active cells. Their work suggested that permanent depilation was possible.…”

Animal welfare provision for land‐based livestock industries in Australia

“…Alternatives to mulesing have been investigated in the last 15 years or so, 48,49 but the impetus has increased significantly since the implementation of the campaign by People for the Ethical Treatment of Animals (PETA) 50 . Currently the development of a flystrike vaccine 47 and a needle‐free injection of a protein 51 are ongoing.…”

“…The selection of polled genotypes of sheep would also benefit welfare, because horned rams are at risk of flystrike when fighting causes bleeding around the horns. 47 Alternatives to mulesing have been investigated in the last 15 years or so, 48,49 but the impetus has increased significantly since the implementation of the campaign by People for the Ethical Treatment of Animals (PETA). 50 Currently the development of a flystrike vaccine 47 and a needle-free injection of a protein 51 are ongoing.…”