Importance of humidity and temperature in breech strike of Merino sheep
J. C. Greeff![https://orcid.org/0000-0003-4457-8448](/media/client/orcid_16x16.png)
A Department of Primary Industries and Regional Development, Perth, WA 6151, Australia.
B Retired.
C School of Agriculture and Environment, University of Western Australia, Crawley, WA 6009, Australia.
D Institute of Agriculture, University of Western Australia, Crawley, WA 6009, Australia.
E 11 Holman Way, Orange, NSW 2800, Australia.
Animal Production Science 63(5) 480-488 https://doi.org/10.1071/AN21579
Submitted: 29 November 2021 Accepted: 4 October 2022 Published: 18 November 2022
© 2023 The Author(s) (or their employer(s)). Published by CSIRO Publishing
Abstract
Context: Breech strike is a serious disease particularly in wool sheep. Skin wrinkle and dags are known predisposing factors for breech strike, although a large part of the variation between sheep is unexplained.
Aims: We used sensor buttons to determine whether there were differences in humidity and temperature in the breech area of Merino sheep exposed to blowflies without traditional preventive measures being used in the flock.
Methods: Sixty-two Merino rams and 62 Merino ewes that had high or low breeding values for breech strike were each fitted with a sensor button to record hourly temperature and humidity in the breech over 49 days. The sensors were fitted before the onset of the blowfly season. The sensor was tied to a wool staple close to the skin in the breech and was removed when a sheep was struck. All remaining buttons were removed prior to shearing. Breech wrinkle, neck wrinkle, breech cover and faecal soiling (dags) were recorded on all the sheep. A total of 98 213 hourly temperature and humidity records were analysed with cubic smoothing splines to assess how humidity and temperature differed between struck and unstruck sheep, and whether the breech indicator traits affect temperature and humidity in the breech.
Results: Time of day and day-to-day variation prior to being struck explained most of the variation of temperature and humidity in the breech of the sheep. Humidity and temperature increased with an increase in breech cover. The humidity in the breech area was, on average, 2% higher in struck sheep prior to being struck. There was a sharp increase in humidity in struck sheep in the 8 days leading up to detection of breech strike relative to unstruck animals, most probably due to exudate from the wound.
Conclusions: Sheep prone to be struck have higher humidity in the breech than sheep less prone to be struck.
Implications: Temperature in the breech does not qualify as a potential indicator trait for breech strike in wool sheep, whereas humidity needs further research to determine its effectiveness as a potential indicator trait.
Keywords: blowfly, breech, breech humidity, cutaneous myiasis, flystrike, Lucilia cuprina, Merino, sheep, wool.
References
AWI (2007) ‘Visual sheep scores.’ (Australian Wool Innovation and Meat and Livestock Australia: Sydney)Belschner HG (1953) ‘Sheep management and diseases.’ (Angus and Robertson: Sydney)
Bird-Gardiner T (2015) Genetic analysis of breech strike in sheep. MSc thesis, School of Environmental and Rural Science, University of New England, Armidale.
Brodie BS, Babcock T, Gries R, Benn A, Gries G (2016) Acquired smell? Mature females of the common green bottle fly shift semiochemical preferences from feces feeding sites to carrion oviposition sites. Journal of Chemical Ecology 42, 40–50.
| Acquired smell? Mature females of the common green bottle fly shift semiochemical preferences from feces feeding sites to carrion oviposition sites.Crossref | GoogleScholarGoogle Scholar |
Davies L (1948) Observations on the development of Lucilia sericata (Mg.) eggs in sheep fleeces. Journal of Experimental Biology 25, 86–102.
| Observations on the development of Lucilia sericata (Mg.) eggs in sheep fleeces.Crossref | GoogleScholarGoogle Scholar |
GHD (2015) Final Report for Project B.AHE.0010. Priority list of endemic diseases for the red meat industries. Meat and Livestock Australia Limited, Locked Bag 991, NSW 2059, North Sydney.
Gherardi SG (1981) Blowfly strike and the skin-fleece microenvironment in sheep. Master of Philosophy thesis, Murdoch University.
Gilmour AR, Gogel BJ, Cullis BR, Welham SJ, Thompson R (2015) ‘ASReml user guide release 4.1 functional specification.’ (VSN International Ltd: Hemel Hempstead, UK). Available at www.vsni.co.uk
Greeff JC, Biggs A, Grewar W, Crumblin P, Karlsson LJE, Schlink AC, Smith J (2013) Dogs can differentiate between odours from sheep that are resistant or susceptible to breech strike. In ‘Proceedings of the 20th congress of the association for the advancement of animal breeding and genetics’. Held 20–23 October 2013 in Napier, New Zealand. pp. 397–400. (Association for the Advancement of Animal Breeding and Genetics)
Greeff JC, Karlsson LJE, Schlink AC (2014) Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment. Animal Production Science 54, 125–140.
| Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment.Crossref | GoogleScholarGoogle Scholar |
Greeff JC, Karlsson LJE, Schlink AC, Gilmour AR (2018a) Factors explaining the incidence of breech strike in a Mediterranean environment in unmulesed and uncrutched Merino sheep. Animal Production Science 58, 1279–1288.
| Factors explaining the incidence of breech strike in a Mediterranean environment in unmulesed and uncrutched Merino sheep.Crossref | GoogleScholarGoogle Scholar |
Greeff JC, Schlink AC, Karlsson LJE (2018b) Impact of sire on the lifetime susceptibility of their progeny to breech strike in a Mediterranean environment. Animal Production Science 58, 1522–1530.
| Impact of sire on the lifetime susceptibility of their progeny to breech strike in a Mediterranean environment.Crossref | GoogleScholarGoogle Scholar |
Greeff JC, Karlsson LJE, Schlink AC (2019) Are breech strike, dags and breech wrinkle genetically the same trait in crutched, uncrutched and mulesed Merino sheep? Animal Production Science 59, 1777–1782.
| Are breech strike, dags and breech wrinkle genetically the same trait in crutched, uncrutched and mulesed Merino sheep?Crossref | GoogleScholarGoogle Scholar |
Greeff JC, Schlink AC, Karlsson LJE (2021a) Genetic parameters of breech strike, neck wrinkles, dags and breech cover over the lifetime of crutched Merino ewes in a Mediterranean environment. Animal Production Science 61, 1893–1904.
| Genetic parameters of breech strike, neck wrinkles, dags and breech cover over the lifetime of crutched Merino ewes in a Mediterranean environment.Crossref | GoogleScholarGoogle Scholar |
Greeff JC, Paz EA, Munyard K, et al. (2021b) Microbiome analysis of the skin of sheep that are resistant or susceptible to breech flystrike. Animal Production Science 61, 1774–1780.
| Microbiome analysis of the skin of sheep that are resistant or susceptible to breech flystrike.Crossref | GoogleScholarGoogle Scholar |
Henderson CR (1984) ‘Applications of linear models in animal breeding.’ (University of Guelph: Canada)
Joint Blowfly Committee (1933) The sheep blowfly problem in Australia Report. Council for Scientific and Industrial Research (Australia). Pamphlet No. 37. Melbourne, Australia
Karlsson LJE, Greeff JC (2006) Selection response in fecal worm egg counts in the Rylington Merino parasite resistant flock. Australian Journal of Experimental Agriculture 46, 809–811.
| Selection response in fecal worm egg counts in the Rylington Merino parasite resistant flock.Crossref | GoogleScholarGoogle Scholar |
Lipson M (1976) A technique for determining fleece wettability. Wool Technology and Sheep Breeding 24, 10–14.
Lipson M (1978) The significance of certain fleece properties in susceptibility of sheep to fleece rot. Wool Technology and Sheep Breeding 26, 27–32.
Pascoe L (1982) Measurement of fleece wettability in sheep and its relationship to susceptibility to fleece rot and blowfly strike. Australian Journal of Agricultural Research 33, 141–148.
| Measurement of fleece wettability in sheep and its relationship to susceptibility to fleece rot and blowfly strike.Crossref | GoogleScholarGoogle Scholar |
Raadsma HW (1989) Fleece rot and body strike in Merino sheep. III. Significance of fleece moisture following experimental induction of fleece rot. Australian Journal of Agricultural Research 40, 897–912.
| Fleece rot and body strike in Merino sheep. III. Significance of fleece moisture following experimental induction of fleece rot.Crossref | GoogleScholarGoogle Scholar |
Seddon HR (1931) Conditions which predispose sheep to blowfly attack. Agricultural Gazette of New South Wales 42, 581–594.
Smith JL, Brewer HG, Dyall T (2009) Heritability and phenotypic correlations for breech strike and breech strike resistance indicators in Merinos. Proceedings of the Association for the Advancement of Animal Breeding and Genetics 18, 334–337.
Verbyla AP, Cullis BR, Kenward MG, Welham SJ (1999) The analysis of designed experiments and longitudinal data by using smoothing splines. Journal of the Royal Statistical Society: Series C (Applied Statistics) 48, 269–311.
| The analysis of designed experiments and longitudinal data by using smoothing splines.Crossref | GoogleScholarGoogle Scholar |
Vogt WG, Woodburn TL (1980) The influence of temperature and moisture on the survival and duration of the egg stage of the Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Dipteria: Calliphoridae). Bulletin of Entomological Research 70, 665–671.
| The influence of temperature and moisture on the survival and duration of the egg stage of the Australian sheep blowfly, Lucilia cuprina (Wiedemann) (Dipteria: Calliphoridae).Crossref | GoogleScholarGoogle Scholar |
Yan G, Liu S, Schlink AC, Flematti GR, Brodie BS, Bohman B, Greeff JC, Vercoe PE, Hu J, Martin GB (2019) Volatiles from Merino fleece evoke antennal and behavioural responses in the Australian sheep blow fly Lucilia cuprina. Medical and Veterinary Entomology 33, 491–497.
| Volatiles from Merino fleece evoke antennal and behavioural responses in the Australian sheep blow fly Lucilia cuprina.Crossref | GoogleScholarGoogle Scholar |