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Bamford NJ, Stewart AJ, El-Hage CM, Bertin FR, Bailey SR. Investigation of breed differences in plasma adrenocorticotropic hormone concentrations among healthy horses and ponies. Vet J 2023; 296-297:105995. [PMID: 37207985 DOI: 10.1016/j.tvjl.2023.105995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 04/06/2023] [Accepted: 05/16/2023] [Indexed: 05/21/2023]
Abstract
Plasma adrenocorticotropic hormone (ACTH) concentration is commonly measured to diagnose pituitary pars intermedia dysfunction (PPID). Several intrinsic and extrinsic factors affect ACTH concentrations, including breed. The objective of this study was to prospectively compare plasma ACTH concentrations among different breeds of mature horses and ponies. Three breed groups comprised Thoroughbred horses (n = 127), Shetland ponies (n = 131) and ponies of non-Shetland breeds (n = 141). Enrolled animals did not show any signs of illness, lameness or clinical signs consistent with PPID. Blood samples were collected 6 months apart, around the autumn equinox and spring equinox, and plasma concentrations of ACTH were measured by chemiluminescent immunoassay. Pairwise breed comparisons within each season were performed on log transformed data using the Tukey test. Estimated mean differences in ACTH concentrations were expressed as fold difference with 95 % confidence intervals (CI). Reference intervals for each breed group per season were calculated using non-parametric methods. In autumn, higher ACTH concentrations were found among non-Shetland pony breeds compared with Thoroughbreds (1.55 fold higher; 95 % CI, 1.35-1.77; P < 0.001), and in Shetland ponies compared with Thoroughbreds (2.67 fold higher; 95 % CI, 2.33-3.08; P < 0.001) and non-Shetland pony breeds (1.73 fold higher; 95 % CI, 1.51-1.98; P < 0.001). In spring, no differences were identified among breed groups (all P > 0.05). Reference intervals were similar among breed groups in spring, but upper limits for ACTH concentrations were markedly different between Thoroughbred horses and pony breeds in autumn. These findings emphasise that breed should be accounted for when determining and interpreting reference intervals for ACTH concentrations among healthy horses and ponies in autumn.
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Affiliation(s)
- N J Bamford
- Melbourne Veterinary School, The Universtiy of Melbourne, Building 400, Parkville, Victoria 3010, Australia.
| | - A J Stewart
- School of Veterinary Science, The University of Queensland, Building 4114, Gatton, Queensland 4343, Australia
| | - C M El-Hage
- Melbourne Veterinary School, The Universtiy of Melbourne, Building 400, Parkville, Victoria 3010, Australia
| | - F R Bertin
- School of Veterinary Science, The University of Queensland, Building 4114, Gatton, Queensland 4343, Australia
| | - S R Bailey
- Melbourne Veterinary School, The Universtiy of Melbourne, Building 400, Parkville, Victoria 3010, Australia
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Akter R, Stent AW, Sansom FM, Gilkerson JR, Burden C, Devlin JM, Legione AR, El-Hage CM. Chlamydia psittaci: a suspected cause of reproductive loss in three Victorian horses. Aust Vet J 2020; 98:570-573. [PMID: 32830314 DOI: 10.1111/avj.13010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/24/2020] [Indexed: 11/28/2022]
Abstract
Chlamydia psittaci was detected by PCR in the lung and equine foetal membranes of two aborted equine foetuses and one weak foal from two different studs in Victoria, Australia. The abortions occurred in September 2019 in two mares sharing a paddock northeast of Melbourne. The weak foal was born in October 2019 in a similar geographical region and died soon after birth despite receiving veterinary care. The detection of C. psittaci DNA in the lung and equine foetal membranes of the aborted or weak foals and the absence of any other factors that are commonly associated with abortion or neonatal death suggest that this pathogen may be the cause of the reproductive loss. The detection of C. psittaci in these cases is consistent with the recent detection of C. psittaci in association with equine abortion in New South Wales. These cases in Victoria show that C. psittaci, and the zoonotic risk it poses, should be considered in association with equine reproductive loss in other areas of Australia.
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Affiliation(s)
- R Akter
- Asia Pacific Centre for Animal Health, The Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, 3010, Australia.,Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - A W Stent
- The Melbourne Veterinary School, The University of Melbourne, Werribee, Victoria, 3030, Australia
| | - F M Sansom
- Asia Pacific Centre for Animal Health, The Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - J R Gilkerson
- Asia Pacific Centre for Animal Health, The Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - C Burden
- Goulburn Valley Equine Hospital, Congupna, Victoria, 3633, Australia
| | - J M Devlin
- Asia Pacific Centre for Animal Health, The Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - A R Legione
- Asia Pacific Centre for Animal Health, The Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - C M El-Hage
- Asia Pacific Centre for Animal Health, The Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria, 3010, Australia
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El-Hage CM, Bannai H, Wiethoelter AK, Firestone SM, Heislers CM, Allen JL, Waller AS, Gilkerson JR. Serological responses of Australian horses using a commercial duplex indirect ELISA following vaccination against strangles. Aust Vet J 2019; 97:220-224. [PMID: 31236928 DOI: 10.1111/avj.12825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/22/2019] [Accepted: 02/18/2019] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine the nature of serological responses in Australian horses using a commercial duplex indirect ELISA (iELISA) following vaccination against strangles. DESIGN A group (n = 19) of client-owned horses from five properties were recruited to receive a primary course of a Streptococcus equi subsp. equi (S. equi) extract vaccine. Serological responses were determined by duplex iELISA incorporating S. equi-specific fragments of two cell wall proteins, SEQ2190 and SeM (antigens (Ag) A and C, respectively). METHODS The horses were administered a primary strangles vaccination course. Blood was collected immediately prior to each of the three vaccinations at 2-week intervals and additionally at 28 and 56 days following the 3rd vaccination (V3). RESULTS Significant increases in mean antibody levels of horses following vaccination were limited only to AgC, which was significantly increased at T2/V3, 14 days following V2 (ratio of geometric means = 3.7; 95% confidence interval (CI): 1.6, 8.4; P = 0.003). There was no increase in mean antibody to Ag A (ratio of geometric means = 1.4; 95% CI: 0.6, 3.2; P = 0.39). Four horses (22%) exceeded the test cut-off for AgC following vaccination. CONCLUSION Vaccination of Australian horses is unlikely to interfere greatly with detection of strangles using the duplex iELISA. No responses would be anticipated to AgA following vaccination with Equivac© S/Equivac© 2in1 and only a minority are likely to respond to AgC. We conclude that the results of this study validate the usefulness of the duplex iELISA to assist control measures for strangles outbreaks in Australian horse populations.
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Affiliation(s)
- C M El-Hage
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - H Bannai
- Equine Research Institute, Japan Racing Association Tochigi, Japan
| | - A K Wiethoelter
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - S M Firestone
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - C M Heislers
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - J L Allen
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
| | - A S Waller
- Animal Health Trust, Kennett, Newmarket, UK
| | - J R Gilkerson
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, 3010, Australia
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Bacci B, Whiteley PL, Barrow M, Phillips PH, Dalziel J, El-Hage CM. Chronic phalaris toxicity in eastern grey kangaroos (Macropus giganteus). Aust Vet J 2014; 92:504-8. [PMID: 25424766 DOI: 10.1111/avj.12272] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2014] [Indexed: 11/26/2022]
Abstract
CASE REPORT Seven eastern grey kangaroos (Macropus giganteus) grazing pastures including Phalaris spp. in Victoria showed neurological deficits characterised by ataxia, head tremors and collapse. Gross examination of the brains and spinal cords of affected kangaroos showed a greenish discolouration in several regions of the grey matter. Histologically, intracytoplasmic accumulation of pigment granules was detected in the neurons, most prominently in the thalamus, brainstem and ventral horns of the spinal cord. Pigment granules were positive to stains used for identification of melanin, including Fontana-Masson stain and Schmorl's reaction. CONCLUSION The combination of clinical signs and obvious neuronal pigmentation is consistent with chronic Phalaris spp. toxicity, a condition well documented in domestic ruminants.
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Affiliation(s)
- B Bacci
- Faculty of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria, 3030, Australia.
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Minke JM, El-Hage CM, Tazawa P, Homer D, Lemaitre L, Cozette V, Gilkerson JR, Kirkland PD. Evaluation of the response to an accelerated immunisation schedule using a canarypox-vectored equine influenza vaccine, shortened interdose intervals and vaccination of young foals. Aust Vet J 2011; 89 Suppl 1:137-9. [PMID: 21711312 DOI: 10.1111/j.1751-0813.2011.00767.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The results of an accelerated immunisation schedule for horses used as part of the emergency response plan to contain and eradicate equine influenza in Australia in 2007 is described. The horses studied were vaccinated with a recombinant canarypox-vectored vaccine (ProteqFlu®, Merial) with a shorter interdose interval. Vaccinated horses included foals aged less than 4 months.
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De Mello Costa MF, Anderson GA, Davies HM, El-Hage CM, Slocombe RF. Circulating angiotensin converting enzyme in endurance horses: effect of exercise on blood levels and its value in predicting performance. Equine Vet J 2011:152-4. [PMID: 21058998 DOI: 10.1111/j.2042-3306.2010.00171.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
REASONS FOR PERFORMING STUDY Investigate angiotensin converting enzyme (ACE) activity in equine plasma as a predictor of performance in endurance competitions and the effect of endurance exercise on ACE activity. HYPOTHESIS Precompetition values of ACE activity in equine blood are correlated with performance results and with heart rates pre- and post competition used as indicators of fitness. Endurance exercise increases ACE activity. METHODS Nineteen horses participating in an 80 km endurance competition had venous blood samples collected before and after the ride. ACE activity and total protein were measured in the blood samples and heart rates and finishing positions were recorded. Statistical analysis included paired t tests and Spearman's rank correlation coefficient. RESULTS Of the 19 horses enlisted, only 16 horses completed the ride. Of these 16, another 2 were disqualified at the last veterinary check. When the 16 horses were considered, precompetition heart rate, but not ACE, was correlated with finishing position. When only the 14 horses that were classified were considered, the association disappeared. ACE activity was similar before and after competition. CONCLUSIONS Precompetition ACE activity in endurance horses competing in an 80 km event was not associated with either finishing position or heart rates before or after competition, indicating that the enzyme is not a good predictor of performance in this form of equestrian competition. Endurance competition did not significantly alter ACE activity in this group of horses.
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Affiliation(s)
- M F De Mello Costa
- Faculty of Veterinary Medicine, The University of Melbourne, Werribee, Australia.
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Abstract
Ross River Virus (RRV) was believed to be the cause of acute illness in four horses around the Bellarine peninsula in south-west Victoria, Australia. The horses presented with clinical signs including petechial haemorrhages, lymphadenopathy, distal limb swelling and reluctance to move. Fibrinogen was also elevated in three of the four horses. Whilst no virus was isolated, serological testing revealed elevated RRV IgM titres in all horses indicating acute infection. The outbreak occurred at a time when a known RRV vector, the mosquito Aedes camptorhynchus was recorded at very high levels in the region. This report is one of very few to attribute specific signs of disease to RRV in horses in conjunction with serological evidence of infection.
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Affiliation(s)
- C M El-Hage
- Department of Primary Industries, Geelong, Vic 3220, Australia.
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Affiliation(s)
- C M El-Hage
- Department of Primary Industries, PO Box 103, Geelong, Victoria 3220.
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