Effects of mulesing and alternative procedures to mulesing on the behaviour and physiology of lambs

Hemsworth, P.H.; Barnett, J.L.; Karlen, Guillermo M.; Fisher, Andrew; Butler, K. L.; Arnold, Naomi A.

doi:10.1016/j.applanim.2008.12.007

Cited by 29 publications

(53 citation statements)

References 19 publications

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“…These findings were similar to those reported in a previous study shown to feed less on day 2 but otherwise no observable behavioural change when compared to the control group. 95 There is some variation in SLS dose and treatment area between the studies however, which is likely to at least partially account for the different findings. Although this study showed a minimal difference in body weight gain between the control and treatment groups, further trials using larger sample sizes would be required to determine if a significant trend exists.…”

Section: General Sheep Observationsmentioning

confidence: 68%

“…95 However SLS treated lambs showed no abnormal postures of discomfort in comparison with the significant behavioural changes noted in mulesed lambs. A similar study confirmed that SLS treated lambs behaved similarly to the control group while their physiological responses were midway between those of the control group and those of the mulesed lambs which received postsurgical topical analgesia.…”

mentioning

confidence: 96%

“…Behavioural responses were similar between the clip-treated and control lambs. 95 Wound healing in clip-treated sheep was quick, however with a lesser wound bed contraction than mulesed sheep and a propensity for formation of skin tags and slippage of clips. 63,96 Field trials demonstrated an incidence of breech strike of 11.3%…”

Section: B Physical and Chemical Alternatives To Surgical Mulesingmentioning

confidence: 99%

“…Intra-dermal sodium lauryl sulfate (SLS) is an attractive candidate as a chemical alternative to surgical mulesing given its ability (in-vivo and in-vitro) to cause cell necrosis through protein denaturation in membranes, 113,114 and the reduction of behavioural changes associated with discomfort after treatment in sheep 95,102 . This forms the basis of the current thesis which investigates the welfare outcomes including behavioural responses to pain, and characterises the macro-and microscopic changes caused by intra-dermal injection of SLS into sheep skin.…”

Section: Aims Of Researchmentioning

confidence: 99%

“…63,95,[102][103][104] The needleless, pneumatically-powered applicator uses air pressure to drive the chemical through the skin and into the underlying subcutis. 105 In comparison with conventional needle-based injections, needleless systems have the following benefits: [105][106][107] 1.…”

Section: B Physical and Chemical Alternatives To Surgical Mulesingmentioning

confidence: 99%

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The mode of action of intra-dermal sodium lauryl sulfate (SLS) as a chemical alternative to mulesing in sheep

Lee¹

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Sheep blowfly strike imposes significant economic costs of $260 million annually from disruptions to farm management operations 1, 2 associated with high labour cost of controlling flystrike, 3 sheep morbidity and mortality, and loss of wool productivity. 4 Mulesing, the surgical removal of skin from the breech which minimises soiling and reduces susceptibility to flystrike, is performed without anaesthetic and is therefore perceived as cruel and painful as reflected by physiological and behavioural alterations in affected lambs. 5,6 Intra-dermal sodium lauryl sulfate (SLS) was trialled in this study as a potential chemical alternative to mulesing. A sound mulesing alternative would ideally provide efficient wound healing and hairless scar formation which increases the bare area of the breech while causing minimal discomfort to the animal.In a sighting study, 3 Merino wethers were given intra-dermal injections of SLS at specific sites on the flank which were biopsied at different time points over 28 days. Assessments were made on gross and histological changes of wound healing as well as early behavioural indicators of pain.Based on the results of the sighting study, the following protocol refinements were made for the main study which used 6 Merino wethers, to:1) reduce biopsy frequency with concentration around specimens of histopathologic interest;2) expand lesion parameters and sharpen the grading process;3) improve SLS delivery using a pressurized needleless applicator; 4) incorporate analysis of SLS's mode of action at the ultrastructural level; 5) improve the approach for pain assessment.Treated sheep showed minimal behavioural or postural indicators of pain or discomfort, their appetite was normal and there was a net gain in body weight, when compared with their untreated cohorts. Gross appearance of the treatment site consisted of initial swelling which subsided by day 14 leaving a firm, slightly raised, crust. At day 21, the treated area was depressed and covered by a scab (eschar) which partially sloughed off by day 28.Histological examination revealed necrosis of soft tissue structures (including hair bulbs, collagen, vessels and nerves) in the subcutis and deep dermis at 2 minutes after treatment, followed by subsequent additional ischaemic necrosis of the superficial dermis and epidermis with progressive inflammation, proliferation and remodelling of the wound. Fibroplasia and angiogenesis were accompanied with reepithelialisation starting at day 7, subjacent to areas of full dermal-epidermal

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Section: General Sheep Observationsmentioning

confidence: 68%

mentioning

confidence: 96%