close
Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jan 11;14(1):11.
doi: 10.1186/s12917-017-1318-7.

Acute-onset high-morbidity primary photosensitisation in sheep associated with consumption of the Casbah and Mauro cultivars of the pasture legume Biserrula

Jane C Quinn  1   2 , Yuchi Chen  1 , Belinda Hackney  2 , Muhammad Shoaib Tufail  1   2 , Leslie A Weston  2 , Panayiotis Loukopoulos  3   4
Affiliations

Acute-onset high-morbidity primary photosensitisation in sheep associated with consumption of the Casbah and Mauro cultivars of the pasture legume Biserrula

Jane C Quinn et al. BMC Vet Res. .

Abstract

Background: Primary photosensitisation (PS) subsequent to ingestion of the pasture legume Biserrula pelecinus L. (biserrula) has recently been confirmed in grazing livestock. Given the potential utility of this pasture species in challenging climates, a grazing trial was undertaken to examine if both varieties 'Casbah' and 'Mauro' were able to cause photosensitisation in livestock, and if this could be mitigated by grazing in winter, or in combination with other common pasture species.

Results: A controlled grazing trial was undertaken in winter in Australia with plots containing a dominant pasture of Biserrula pelecinus L. cv. 'Casbah' or 'Mauro', or mixed biserrula/perennial ryegrass populations. A photosensitisation grading system was established. 167 prime meat ewe lambs were introduced to the plots and monitored twice daily. Mild clinical signs were observed at 72 h on pasture. All animals were removed from biserrula dominant stands at this point. Four animals grazing 'Casbah' dominant pasture rapidly proceeded to severe photosensitisation in the following 12 h. Animals remaining on mixed biserrula/ryegrass stands did not exhibit severe PS but showed an 89% incidence of mild to moderate photosensitisation over the following 14 days. Animals on mixed lucerne showed significantly lower PS score than animals grazing biserrula varieties of any composition. The trial was halted at 14 days as only plots with low biserrula proportion still contained unaffected animals. Necropsy revealed severe multifocal erythematous ulcerations and alopecia of the ear pinnae, severe bilateral periorbital and conjunctival oedema and variably severe subcutaneous facial oedema. No evidence of hepatopathy was present. A diagnosis of acute unseasonal primary photosensitisation caused by biserrula ingestion with no other underlying pathology was confirmed.

Conclusions: We report an unseasonal outbreak of acute photosensitisation in sheep grazing Biserrula pelecinus L cvs.'Casbah' and 'Mauro' with exceedingly high morbidity. A grading system is also proposed as a tool for objective and consistent clinical appraisal of future PS outbreaks. This finding expands our definition of seasonal and temporal risk periods for biserrula photosensitisation, and is the first to identify that both commercial cultivars of biserrula can cause primary photosensitisation in sheep.

Keywords: Biserrula pelecinus L.; Legume; Photosensitisation; Primary; Sheep; Unseasonal.

PubMed Disclaimer

Conflict of interest statement

Ethics approval

All ethical approvals were sought and given prior to establishment of the trial and were fully in alignment with the Charles Sturt University Animal Ethics Committee requirements for use of animals in research. The protocol approval number was 13/018.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Randomised block design of regenerating biserrula pasture plots used for the winter biserrula grazing trial. Two varieties of biserrula were sown in the preceding year: ‘Mauro’ and ‘Casbah’. Plots were established in triplicate with a total of 9 plots per variety. Blue: ‘Casbah’; green: ‘Mauro’. Low Biserrula: Biserrula pastures oversown with annual ryegrass (Lolium rigidum) at a rate of 40 kg/ha. Medium Biserrula: Biserrula pastures oversown with annual ryegrass at a rate of 120 kg/ha. High Biserrula: Biserrula pastures containing no or very low contamination with other pasture species (<10%) and were considered biserrula-dominant
Fig. 2
Fig. 2
Skin lesions associated with primary photosensitisation caused by ingestion of biserrula. a External aspect of left ear pinna: multifocal to coalescing erosion, ulceration and erythema; (b) Inner surface of the tip of the ear: erythema and alopecia (star). Skin covered by ear tags was not affected
Fig. 3
Fig. 3
a Severe bilateral periorbital and conjuctival oedema and variably severe subcutaneous facial oedema. b Severe focally extensive haemorrhage in the nasal subcutaneous tissues. c Severe narrowing of the nasal cavity due to oedema. d No significant changes were observed in the liver and other internal organs
Fig. 4
Fig. 4
Photomicrographs of the alopecic and oedematous areas of the ear pinnae: (a) Low magnification showing severe haemorrhage and oedema in the dermis. H&E, objective × 1.25. b Micropustules containing neutrophils, eosinophils and necrotic debris in the stratum corneum and upper stratum granulosum on the external aspect of the ear pinna. Mild individual cell keratinocyte necrosis, mild acanthosis and haemorrhage in the upper dermis are also shown. H&E, × 200. c Moderate zonal necrosis of the outer layers of the epidermis, which is infiltrated by numerous eosinophils and neutrophils, at places forming small intraepidermal pustules. Keratinocytes show moderate individual cell necrosis. H&E, × 400. (d) Severe epidermal necrosis with obliteration of the follicular epithelial structure and sebaceous gland necrosis (arrows) in the most severely affected section of the ear pinna. Intraepidermal nodular pustules formed by dead and viable neutrophils; eosinophils can be seen multifocally. The dermis is infiltrated by eosinophils and neutrophils, particularly adjacent to necrotic hair follicles. H&E, × 200
See this image and copyright information in PMC

References

    1. Mauldin EA, Peters-Kennedy J. Integumentary System. In: Maxie MG, editor. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals, vol. 1. 6th ed. St. Louis; 2016. p. 577–80.
    1. Quinn JC, Kessell A, Weston LA. Secondary plant products causing photosensitization in grazing herbivores: their structure, activity and regulation. Int J Mol Sci. 2014;15:1441–1465. doi: 10.3390/ijms15011441. - DOI - PMC - PubMed
    1. Santos DS, Silva CCB, Araújo VO, de Fátima Souza M, Lacerda-Lucena PB, Simões SVD, Riet-Correa F, Lucena RB. Primary photosensitization caused by ingestion of Froelichia Humboldtiana by dairy goats. Toxicon. 2017;125:65–69. doi: 10.1016/j.toxicon.2016.11.258. - DOI - PubMed
    1. Kessell AE, Ladmore GE, Quinn JC. An outbreak of primary photosensitisation in lambs secondary to consumption of Biserrula Pelecinus (biserrula) Aust Vet J. 2015;93:174–178. doi: 10.1111/avj.12318. - DOI - PubMed
    1. Puschner B, Chen X, Read R, Affolter VK. Alfalfa hay induced primary photosensitization in horses. Vet J. 2016;211:32–38. doi: 10.1016/j.tvjl.2016.03.004. - DOI - PubMed

LinkOut - more resources