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https://hdl.handle.net/1959.11/42539
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DC Field | Value | Language |
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dc.contributor.author | Lees, A M | en |
dc.contributor.author | Sullivan, M L | en |
dc.contributor.author | Olm, J C W | en |
dc.contributor.author | Cawdell-Smith, A J | en |
dc.contributor.author | Gaughan, J B | en |
dc.date.accessioned | 2022-02-17T02:32:40Z | - |
dc.date.available | 2022-02-17T02:32:40Z | - |
dc.date.issued | 2020 | - |
dc.identifier.citation | Animal Production Science, 60(16), p. 1932-1939 | en |
dc.identifier.issn | 1836-5787 | en |
dc.identifier.issn | 1836-0939 | en |
dc.identifier.uri | https://hdl.handle.net/1959.11/42539 | - |
dc.description.abstract | <p><i><b>Context.</b></i> Australia exports ~2 million sheep annually. On these voyages, sheep can be exposed to rapidly changing ambient conditions within a short time, and sheep may be exposed to periods of excessive heat load.<br/><i><b>Aims.</b></i> The aim of this study was to define the responses of sheep exposed to incremental heat load under simulated live export conditions. The study herein describes the influence of heat load on wool surface temperature, body temperature (rumen temperature (T<sub>RUM</sub>), °C; and rectal temperature (T<sub>REC</sub>), °C) and respiratory dynamics (respiration rate, breaths/min; and panting score (PS)) of sheep under live export conditions. In addition, the relationship between body temperature and respiratory dynamics was investigated.</br><br/><i><b>Methods.</b></i> A total of 144 Merino wethers (44.02 ± 0.32 kg) were used in a 29-day climate controlled study using two cohorts of 72 sheep (<i>n</i> = 2), exposed to two treatments: (1) thermoneutral (TN; ambient temperature was maintained between 18°C and 20°C), and (2) hot (HOT; ambient temperature minimum and maximum were 22.5°C and 38.5°C respectively). Sheep in the HOT treatment were exposed to heat load simulated from live export voyages from Australia to the Middle East. Respiration rate, PS and wool surface temperature (°C) data were collected four times daily, at 3-h intervals between 0800 hours and 1700 hours. Rectal temperatures were collected on five occasions at 7-day intervals. These data were evaluated using a repeated measures model, assuming a compound symmetry covariance structure. Individual T<sub>RUM</sub> were obtained via rumen boluses at 10-min intervals between Days 23 and 29 of Cohort 2. Individual T<sub>RUM</sub> data were collated and converted to an hourly mean T<sub>RUM</sub> for each sheep, these data were then used to determine the hourly mean T<sub>RUM</sub> for TN and HOT, then analysed using a first order autoregressive repeated measures model. Additionally, the relationship between respiratory dynamics and T<sub>RUM</sub> were investigated using a Pearson’s correlation coefficient, a partial correlation coefficient and a multivariate analysis of variance.</br><br/><i><b>Key results.</b></i> The respiration rate of the HOT sheep (140 ± 3.55 breaths/min) was greater (<i>P</i> < 0.01) than that of the TN sheep (75 ± 3.55 breaths/min). Similarly, the PS of the HOT (1.5 ± 0.02) sheep was greater (<i>P</i> = 0.009) compared with the TN sheep (1.2 ± 0.02). Wool surface temperatures and T<sub>REC</sub> were greater (<i>P</i> < 0.05) for the HOT sheep than for the TN sheep. There were treatment (<i>P</i> < 0.0001), hour (<i>P</i> < 0.0001), day (<i>P</i> = 0.038) and treatment · hour (<i>P</i> < 0.0001) effects on the T<sub>RUM</sub> of TN and HOT sheep.</br><br/><i><b>Conclusions.</b></i> The climatic conditions imposed within the HOT treatment were sufficient to disrupt the thermal equilibrium of these sheep, resulting in increased respiration rate, PS, T<sub>REC</sub> and T<sub>RUM</sub>.</br><br/><i><b>Implications.</b></i> These results suggest that the sheep were unable to completely compensate for the imposed heat load via respiration, thus resulting in an increase in T<sub>REC</sub> and T<sub>RUM<sub>.</br></p> | en |
dc.language | en | en |
dc.publisher | CSIRO Publishing | en |
dc.relation.ispartof | Animal Production Science | en |
dc.title | The influence of heat load on Merino sheep. 2. Body temperature, wool surface temperature and respiratory dynamics | en |
dc.type | Journal Article | en |
dc.identifier.doi | 10.1071/AN20268 | en |
dc.subject.keywords | panting score | en |
dc.subject.keywords | rectal temperature | en |
dc.subject.keywords | respiration rate | en |
dc.subject.keywords | rumen temperature | en |
dc.subject.keywords | temperature humidity index | en |
dc.subject.keywords | Agriculture, Dairy & Animal Science | en |
dc.subject.keywords | Agriculture | en |
dc.subject.keywords | accumulated heat load | en |
local.contributor.firstname | A M | en |
local.contributor.firstname | M L | en |
local.contributor.firstname | J C W | en |
local.contributor.firstname | A J | en |
local.contributor.firstname | J B | en |
local.profile.school | School of Environmental and Rural Science | en |
local.profile.email | alees4@une.edu.au | en |
local.output.category | C1 | en |
local.record.place | au | en |
local.record.institution | University of New England | en |
local.publisher.place | Australia | en |
local.format.startpage | 1932 | en |
local.format.endpage | 1939 | en |
local.identifier.scopusid | 85091013354 | en |
local.peerreviewed | Yes | en |
local.identifier.volume | 60 | en |
local.identifier.issue | 16 | en |
local.contributor.lastname | Lees | en |
local.contributor.lastname | Sullivan | en |
local.contributor.lastname | Olm | en |
local.contributor.lastname | Cawdell-Smith | en |
local.contributor.lastname | Gaughan | en |
dc.identifier.staff | une-id:alees4 | en |
local.profile.orcid | 0000-0003-4898-2843 | en |
local.profile.role | author | en |
local.profile.role | author | en |
local.profile.role | author | en |
local.profile.role | author | en |
local.profile.role | author | en |
local.identifier.unepublicationid | une:1959.11/42539 | en |
local.date.onlineversion | 2020-07-21 | - |
dc.identifier.academiclevel | Academic | en |
dc.identifier.academiclevel | Academic | en |
dc.identifier.academiclevel | Academic | en |
dc.identifier.academiclevel | Academic | en |
dc.identifier.academiclevel | Academic | en |
local.title.maintitle | The influence of heat load on Merino sheep. 2. Body temperature, wool surface temperature and respiratory dynamics | en |
local.relation.fundingsourcenote | Funding for this study was provided by Meat and Livestock Australia P/L., North Sydney, NSW, Australia; LiveCorp, North Sydney NSW, Australia; and the Australian Federal Government, Canberra, ACT, Australia. Grant number: W.LIV.3017 – Determining temperature/humidity thresholds for sheep exported from Australia to the Middle East. | en |
local.output.categorydescription | C1 Refereed Article in a Scholarly Journal | en |
local.search.author | Lees, A M | en |
local.search.author | Sullivan, M L | en |
local.search.author | Olm, J C W | en |
local.search.author | Cawdell-Smith, A J | en |
local.search.author | Gaughan, J B | en |
local.uneassociation | Yes | en |
local.atsiresearch | No | en |
local.sensitive.cultural | No | en |
local.identifier.wosid | 000550494000001 | en |
local.year.available | 2020 | en |
local.year.published | 2020 | en |
local.fileurl.closedpublished | https://rune.une.edu.au/web/retrieve/92c89e1b-1945-4d20-b60d-a85f20f53631 | en |
local.subject.for2020 | 300302 Animal management | en |
local.subject.for2020 | 300306 Animal welfare | en |
local.subject.seo2020 | 109902 Animal welfare | en |
Appears in Collections: | Journal Article School of Environmental and Rural Science |
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