Suspected intoxication by Kikuyu grass (Cenchrus clandestinus) of dairy cattle in the Azores, Portugal

ABSTRACT

Case history:

An outbreak of suspected Kikuyu grass (Cenchrus clandestinus) intoxication among dairy cattle occurred on the island of Terceira in the Azores (Portugal), in October 2022. The animals affected were non-lactating dairy cows and heifers from five small farms grazing (free or tethered) a Kikuyu-dominant pasture. Of the 29 animals exposed, 17 were affected, and eight (five heifers and three adult cows) died, resulting in a morbidity rate of 58%, a mortality rate of 28% and a case mortality rate of 47%.

Clinical findings and treatment:

The clinical signs were non-specific and inconsistent, and included dry faeces, some with dark red blood; apathy and prostration; abdominal dilatation; tachycardia; tachypnoea; pale or jaundiced mucous membranes; sham drinking; sialorrhoea; and moderate to severe dehydration. Symptomatic treatment was provided but was ineffective. Haematology and serum biochemistry revealed an acute inflammatory leukogram, increased alkaline phosphatase (ALP) activity, decreased gamma-glutamyl transferase (GGT) activity, and azotaemia.

The most consistent necropsy findings were haemorrhages in the epicardium and endocardium, an enlarged liver with rounded edges, non-perforated abomasal ulcers, and haemorrhagic lesions in the small and large intestines. Histopathology indicated myocarditis, hepatitis, interstitial nephritis, enteritis and colitis.

Several fungal species were isolated from grass samples taken from affected pastures including several Fusarium spp., the genus implicated in Kikuyu toxicosis. Immediate removal of the animals from the pasture with Kikuyu was the only measure that prevented new cases and resulted in the recovery of some of the less affected animals.

Diagnosis:

The epidemiological features of this outbreak and the clinical signs and micro– and macroscopic lesions observed were highly suggestive of Kikuyu grass poisoning.

Clinical relevance:

Although the weather conditions varied from other published cases, the grazing conditions (almost exclusive Kikuyu grass) and the post-mortem findings were very similar to those described in the literature, particularly the haemorrhages in the epicardium and endocardium. Kikuyu grass is very invasive and presents many desirable characteristics as cattle feed. Thus, an increase in cases of intoxication may be expected. Practitioners and farmers in areas where Kikuyu grass is abundant should be aware of the potential risks of grazing cattle exclusively on these pastures. They should also be aware of the early and subtle signs of Kikuyu intoxication to allow for timely removal of the animals from pasture.

KEYWORDS:

• Kikuyu grass intoxication
• cattle
• mycotoxins
• fungi
• Terceira Island
• Azores

Introduction

Kikuyu grass (Cenchrus clandestinus, formerly Pennisetum clandestinum), known in the Azores as “quicuio” grass or Australian grass, is a perennial, creeping, rhizomatous herbaceous plant, with extensive branched stems. Vegetative stems can reach up to 30 cm in height. It flourishes in warm and humid conditions (Bourke 2007) but is moderately drought resistant and can reproduce sexually (dozens of seeds/plant/year) and asexually (stolons) facilitating spread and hindering control. It can quickly form dense carpets that hinder the growth of other plants, either by shading or by producing herbicidal toxins.

Because it is easy to cultivate and forms a mat, it is favoured for lawns, although it can be sown as pastures, as in Australia and New Zealand. Recently introduced to the Azores for lawns and gardens, Kikuyu quickly spread to grazing areas such that, in Terceira, there are now pastures exclusively comprised of Kikuyu (personal observation).

The Azores archipelago consists of nine islands located in the North Atlantic. The climate is classified as humid mesothermic, with high humidity, mild temperatures, low insolation rates, regular and abundant rainfall, and sustained, strong winds (Morais et al. 2018; de Almeida et al. 2021). Dairy products are the main agricultural products, but most farms are small (average 9 ha), strongly atomised, and family-owned (de Almeida et al. 2021). Dairy cows, predominantly Holstein-Friesian, graze pasture year-round, supplemented with maize silage, ryegrass haylage and concentrate. Rotational grazing, frequently strip grazing with electric fences, is common and allows for intensive use of pasture (Morais et al. 2018; de Almeida et al. 2021).

Cases of Kikuyu intoxication in cattle, sheep and goats grazing Kikuyu pastures have been reported occasionally since the early 1960s in New Zealand (Busch et al. 1969; Parton and Bruere 2002; Bourke 2007), Kenya, Zimbabwe, South Africa (Bourke 2007) and Australia (Gabbedy et al. 1974; Wong et al. 1987; Ryley et al. 2007). Outbreaks occur sporadically, arise suddenly, are of short duration, and are very restricted geographically (Bourke 2007; Ryley et al. 2007). This unpredictability and rapidity make it difficult to study the causes and pathogenesis of poisoning cases.

Currently, the main suspected agent in Kikuyu intoxication is the fungal endophyte Fusarium torulosum, which is often found in the leaves on pastures where intoxication has occurred (Ryley et al. 2007), but a causal relationship has not been fully established. There are reports of intoxication from which F. torulosum could not be isolated (Botha et al. 2014). This fungus is known to produce wortmannin (Abbas et al. 1991; Thrane and Hansen 1995; Ryley et al. 2007), which is toxic to cattle in doses as small as 4 mg/kg and affects the digestive tract and heart (Bourke 2007). The fungus also produces butenolide toxin, which is lethal to cattle at doses of 40 mg/kg (Tookey et al. 1972; Ryley et al. 2007), as well as eniatin and moniliformin (Desjardins 2006). The effects of wortmannin and butenolide are consistent with the lesions reported in previously described cases of animals that died from intoxication in Kikuyu pasture.

The predisposing factors leading to toxicity are still uncertain; however, there are the few risk factors described in the literature include the summer–autumn transition period (corresponding with abundant rainfall after long dry periods); grazing 2–3 weeks after heavy rain; consumption of pastures left ungrazed for a long period of time; and plant stressors (e.g. insect herbivory, nitrates, oxalates). Although cattle are most affected by Kikuyu poisoning, sheep and goats are also susceptible (Martinovich and Smith 1972) but there are no known breed, sex or age predispositions (Larkins 2019).

Outbreaks of Kikuyu grass poisoning are acute but brief and limited geographically (Bourke 2007). Animals show non-specific clinical signs 1–8 (mean 3) days after entering toxic pastures. The first signs are severe abdominal dilatation and voluminous dry stools, despite the animals grazing on green pasture. Later, ptyalism and sometimes paralysis and protrusion of the tongue, are noted. Animals may show “sham drinking” (Larkins 2019), muscle weakness, incoordination, staggering, a high-stepping gait and intermittent periods of recumbency, as well as signs of abdominal pain (Bourke 2007). A rise in rectal temperature occurs in some cases. In the final stage of the illness, ruminal distension causes rapid and shallow breathing, tachycardia and weak pulses (Bourke 2007).

In an exposed herd, morbidity and mortality range from 14 to 64% and 9 to 32%, respectively with 17–96% of affected animals dying (Bourke 2007). Clinical signs and deaths can continue for 1–8 (mean 4) days once animals are removed from pasture (Bourke 2007; Larkins 2019).

Non-specific necropsy findings include rumen dilatation with massive accumulation of grass and fluid; inflammation and sloughing of the mucosa of the forestomachs, an empty small intestine, and abnormally dry large intestinal contents (Parton and Bruere 2002; Bourke 2007). Haemorrhages in the epicardium and endocardium, giving a blackened appearance to the heart when the pericardial sac is opened, are a more specific finding.

There is no known treatment for Kikuyu intoxication. However, some animals that have ingested small amounts of the toxin will recover if they are removed from the toxic pasture. Prevention must be based on the avoidance of risk factors. This includes careful selection of pastures during the transition from the dry to wet season, especially if Kikuyu is growing rapidly. Pastures that have not been grazed for a long time should be avoided or used by less valuable (tracer) animals. Farmers should be aware of the first signs of intoxication (abdominal distension, dry and bulky stools) and any animal showing these signs should be immediately removed from pasture with Kikuyu grass and offered other feed.

This report describes an outbreak of Kikuyu toxicity among several small dairy herds that occurred in 2022 on the island of Terceira, Azores, and which the authors believe to be the first described in Europe.

Case history

The outbreak occurred between 5 and 12 October 2022. At the time the outbreak was detected, the authors were aware of a similar outbreak on the island of Faial, which killed at least 15 animals, and another on the island of Pico, both in the Azores.

On Terceira, the cases of suspected Kikuyu poisoning were detected on five small farms, with a total of 29 animals exposed (Table 1). Of these, 17 animals were affected (58%) and eight died (Table 2; 28% mortality rate), with a case mortality rate of 47% (8/17).

Table 1. Characteristics of farms and affected cattle involved in a suspected outbreak of Kikuyu grass (Cenchrus clandestinus) intoxication on Terceira Island, Azores, Portugal.

Farm	Grazing type	Herd composition	Affected animals	Blood sample numbers^a
1	Free	6 suckler cows, 1 steer, 4 calves	6 cows, 1 steer	1, 2, 3 (cows); 4 (steer); 5 (unaffected calf)
2	Tethered	3 heifers	1 heifer	6
3	Free	8 heifers	2 heifers	7, 8
4	Free	1 heifer	1 heifer	NC
5	Tethered	6 heifers	6 heifers	NC

^a Number of the blood sample shown in Table 3.

NC = not collected.

Table 2. Characteristecs of cattle that died in a a suspected outbreak of Kikuyu grass (Cenchrus clandestinus) intoxication on Terceira Island, Azores, Portugal.

Case	Farm	Breed	Age and class	Duration of exposure (days)	Necropsied
1	1	Holstein	5-year-old cow, recently calved	2	Yes
2	1	Holstein	6-year-old cow, recently calved	4	No
3	2	Jersey cross	2-year-old heifer	6	Yes
4	3	Jersey cross	7-month-old heifer	2	Yes
5	3	Holstein	7-month-old heifer	2	No
6	4	Holstein	12-month-old heifer	1	No
7	5	Holstein	7-month-old heifer	3	No
8	5	Holstein	7-month-old heifer	3	No

Affected animals, all suckler cows with young calves at foot, or heifers, were grazing pastures with a very high predominance of Kikuyu grass. Animals either had free access to pasture or were tethered and moved periodically during the day as required.

The 2022 growing season (spring–summer) was particularly wet on the island of Terceira, and there was no expected summer drought period (July–September). This led to rapid pasture growth in excess of demand and a build-up of older, senescent pasture at the base of the sward.

Clinical findings and treatment

The first signs of intoxication were voluminous dry stools, abdominal dilation, apathy and a slight drop in milk production. These signs worsened in the following days, with the development of ataxia; a sharp drop in milk production; hypothermia; tachypnoea; tachycardia; pale or jaundiced mucous membranes; fasciculation of the muscles of the head, neck, thoracic limbs and thorax; moderate sialorrhea; marked enophthalmos; sham drinking; a metallic sound on percussion of the upper part of the left abdomen; and stools with melaena or fresh blood. The clinical signs evolved rapidly to permanent lateral recumbency; little or no reaction to stimuli; intense sialorrhea; moaning; hyperthermia or hypothermia; severe dehydration; and very pale or jaundiced mucous membranes. Death occurred 24–48 hours after the first clinical signs were shown.

Symptomatic and supportive treatments (e.g. IV fluids, analgesics) were provided to all affected animals but failed to improve the clinical status in the later stages of the disease. The therapy provided was determined by the same veterinarian. All animals were removed from pasture to safeguard those that were still in the initial stage of intoxication.

Pathological findings

Clinical pathology

Blood was collected from the coccygeal vein of eight animals from three of the affected herds (seven sick animals and one cohabiting bull calf with no clinical signs; Table 1) into blood collecting tubes for haematology (K2 EDTA; BD Vacutainer; Becton Dickinson, Plymouth, UK; n = 6) serum biochemistry analysis (CAT BD Vacutainer; Becton Dickinson; n = 8). The samples were packed in styrofoam boxes and sent under refrigeration to the local laboratory (Laboratório Noronha, Angra do Heroísmo, Terceira, Azores, Portugal). All erythrogram values were normal while leukograms varied but were characterised by mild neutrophilia, and moderate-to-severe lymphopaenia and thrombocytopaenia (Table 3). Serum biochemical analysis results (Table 3) were consistent with azotaemia and mild liver damage. Changes in the activities of liver enzymes were inconsistent as alkaline phosphatase (ALP) was elevated but gamma-glutamyl transferase (GGT) was decreased in most animals. Mildly elevated albumin concentration most probably resulted from the dehydrated state of these animals.

Table 3. Haematology and serum biochemistry analysis results from affected animals involved in a suspected outbreak of Kikuyu grass (Cenchrus clandestinus) intoxication on Terceira Island, Azores, Portugal.

		Sample number
Analyte	Reference range	1	2	3	4	5^a	6	7	8
Red blood cells	5–10 × 10^6/µL	7.09 × 10^6	7.24 × 10^6	6.32 × 10^6	7.33 × 10^6	10.65 × 10^6	7.04 × 10^6	–	–
Haemoglobin	80–150 g/L	126	118	120	104	141	147	–	–
Haematocrit	24–46%	36.4	34.2	35.1	30.4	37.4	45.9	–	–
MCV	40–60 fL	51.3	47.2	55.6	41.5	35.1	65.1	–	–
MCH	9–26 pg	17.7	16.3	19.0	14.2	13.3	20.9	–	–
MCHC	300–360 g/L	346	345	342	342	377	320	–	–
RDW	16–24%	23.0	19.1	18.3	22.1	24.8	25.3	–	–
Leukocytes	4–12 × 10^9/L	9	10.3	7.2	9.5	10	2.8	–	–
Neutrophils	0.6–4 × 10^9/L (15–45%)	4.5 (49.6%)	4.7 (45.8%)	4.1 (57.5%)	4.3 (45.3%)	4.4 (43.6%)	0.4 (15.7%)	–	–
Eosinophils	0–0.17 × 10^9/L (2–20%)	0.8 (8.5%)	0.6 (5.5%)	0 (0.3%)	1 (10.5%)	0 (0.2%)	0 (0.9%)	–	–
Basophils	0–0.17 × 10^9/L (0–3%)	0 (0.5%)	0.1 (0.7%)	0.1 (0.7%)	0 (0.4%)	0.1 (0.6%)	0.1 (2.1%)	–	–
Lymphocytes	2.5–7.5 × 10^9/L (45–75%)	0.3 (3.1%)	0.2 (2.3%)	3 (41.2%)	2.8 (29.5%)	5.5 (54.4%)	1.9 (67.9%)	–	–
Monocytes	0.025–0.84 × 10^9/L (2–7%)	3.5 (38.3%)	4.7 (45.7%)	0 (0.3%)	1.4 (14.7%)	0.1 (1.2%)	0.3 (10.7%)	–	–
Platelets	100–800 × 10^3/µL	86 × 10^3	55 × 10^3	116 × 10^3	99 × 10^3	422 × 10^3	117 × 10^3	–	–
Total bilirubin	1.71–10.26 µmol/L	3.25	4.79	3.25	3.08	4.45	3.59	2.57	2.22
Urea	1–3.66 mmol/L	3	2.83	3.5	3.66	3.5	7.16	5.83	6.66
Creatinine	44.2–97.24 µmol/L	106.08	88.4	97.24	79.56	132.6	150.28	132.6	106.08
AST	58–100 U/L	99	90	99	68	53	90	221	177
ALT	25–74 U/L	42	33	28	27	15	40	79	60
ALP	41–116 U/L	60	59	46	59	190	66	147	180
GGT	22–64 U/L	15	16	19	12	19	26	22	20
Total protein	58–75 g/L	74	72	71	68	56	81	75	72
Albumin	24–35 g/L	38	33	33	32	37	43	35	34

^a Sample 5 corresponds to a bull calf from Farm 1 that showed no clinical signs. The remaining samples were from animals that showed clinical signs of intoxication.

ALP = alkaline phosphatase; ALT = alanine aminotransferase; AST  = aspartate aminotransferase; GGT gamma-glutamyl transferase; MCH = mean corpuscular haemoglobin; MCHC = mean corpuscular haemoglobin concentration; MCV = mean corpuscular volume; RDW = red cell distribution width.

Gross pathology

During the outbreak, one 5-year-old cow and two heifers (ages 2 years and 7 months) that died were necropsied and samples were taken for histopathology (Table 2). The selection of animals for necropsy was dependent on the availability of the practitioner and the farmer.

After opening the abdominal cavity, the markedly enlarged gallbladder and liver with rounded edges were immediately evident. In two animals, the rumen mucosa was a reddish colour, suggestive of congestion. The rumen contained many Kikuyu seeds (Figure 1) and an abnormally large amount of water, and the mucosa was dark. The reticulum and the omasum also contained large amounts of undigested Kikuyu grass. It is unusual for undigested feed to reach the omasum and the cause in these cases is unclear. Several ulcers, 0.5–4 cm in length were observed on the abomasal mucosa. In all three animals, the mucous membranes of the forestomachs were reddish, suggestive of congestion. The small intestines were mostly empty, containing small amounts of liquid and gas. Petechiae were diffusely distributed on the mucosa, and the serosa had numerous haemorrhagic lesions. In one of the animals, the lumen of the large intestine contained clotted blood, while in the other two there were several extensive haemorrhagic lesions on the mucosa. The kidneys showed signs of nephritis with reddish zones interspersed with pale zones, and a shiny cut-surface, suggestive of congestion and oedema. In one of the animals, the bladder mucosa was hyperaemic, suggestive of inflammation. The hearts of all three animals had disseminated haemorrhagic lesions, on the epicardium and endocardium.

Figure 1. Kikuyu seeds in the ruminal content (arrows) of a cow with suspected Kikuyu grass (Cenchrus clandestinus) intoxication on Terceira Island, Azores.

All these lesions are consistent with the findings described in the literature for Kikuyu poisoning. However, the reddening of the mucosal membranes of the forestomachs, and the haemorrhagic cardiac lesions were indistinguishable from agonal changes associated with death.

Histopathology

Heart, lung and liver samples were collected at the necropsy of the 5-year-old cow from Farm 1. Samples of liver, spleen, abomasum, small intestine, colon, right kidney and bladder were collected at the necropsy of a 2-year-old heifer from Farm 2 (also blood sample 6; Table 3). Samples of liver, spleen, abomasum and kidney were collected at the necrospy of a 7-month-old Jersey cross heifer from Farm 3 (also blood sample 7; Table 3).

The most significant histopathological lesions found were: haemorrhages in the epicardium of both ventricles and moderate inflammatory infiltrate indicative of myocarditis; mild hepatitis (small foci of inflammatory infiltrate, composed of macrophages and lymphocytes); catarrhal enteritis with hyperaemia, haemorrhage and inflammatory infiltrate; ulcerative colitis with multiple foci of necrosis and ulceration of the mucosa and dilation of the lymphatic vessels in the underlying mucosa; congestion of the renal medulla, interstitial nephritis, as well as acute cystitis lesions with erosion of the urothelium. These findings are consistent with an acute generalised inflammatory reaction.

Although all of these lesions are non-specific, they are not usually seen – heart lesions in particular – in other animals necropsied by the present authors in Terceira.

Pasture analysis

A representative sample of approximately 1 kg of pasture was taken from Farms 1, 2 and 3. The grass was cut with scissors, approximately 8 cm from the ground, and packed in a transparent plastic bag. For each sample, grass was collected from 6–8 points, 8–10 steps apart, trying to select places where the grass had been recently grazed and places that were still to be grazed. The samples were refrigerated until they were sent to the Portuguese national veterinary laboratory (Instituto Nacional de Investigação Agrária e Veterinária, Lisbon, Portugal) for detection and identification of phytopathogenic fungi through mycological culture. Samples from Farm 1 showed the following fungi: Microdochium sp., Fusarium sp. (complex sambucinum and incarnatum-equiseti) and F. heterosporum. From Farm 2, Fusarium sp. (complex incarnatum-equiseti), F. graminearum and F. avenaceum were identified. Finally, Pyricularia grisea and Fusarium sp. (complex sambucinum) were isolated from Farm 3.

Fusarium torulosum was not identified and toxicological analysis was not performed.

Discussion

The outbreak of Kikuyu intoxication that occurred on Terceira Island had many similarities with cases described in the literature, particularly regarding the epidemiology, course of the disease, clinical signs and necropsy findings. The affected animals were cows suckling small calves and heifers. This may have been because these are the only classes of animals fed exclusively on pasture without supplementation. Milking cows grazing similar pastures are usually supplemented with concentrate and silage.

The major difference between this outbreak and those reported in the literature is that there was no dry period in Terceira in 2022. The temperature and humidity conditions of a very wet summer/autumn may have favoured the growth of fungi, including that responsible for the intoxication. The absence of a drought before the heavy rainfall season suggests that unidentified plant stressors, or the accumulation of dead material at the base of the sward under wet and warm conditions may have promoted growth of the endophyte or production of the fungal toxin. These conditions are likely to occur elsewhere (e.g. New Zealand) and may increase in frequency with climate change.

Although clinical signs were indicative of Kikuyu poisoning, the blood count and biochemical analysis did not provide much support for this diagnosis: the inflammatory leukogram and the changes in liver biochemistry could arise in several other situations. Therefore, the authors believe that blood testing should not be the first priority when facing a suspected case of Kikuyu poisoning. In contrast, the necropsy findings largely agree with those reported in other cases of Kikuyu poisoning in cattle. Even though they are not pathognomonic for Kikuyu intoxication, they may reinforce suspicion when considered together with the clinical signs and the rapid but short course of the disease.

Fusarium torulosum is the only species of this genus capable of producing wortmannin toxin (Ryley et al. 2007) and can easily be misidentified as F. sambucinum (Desjardins 2006), which was one of the species identified in grass samples from two affected farms. Therefore, it is possible that the fungi present in the pastures of Terceira may be F. torulosum. However, these results are not sufficient to affirm that the presence of the fungus in the pasture led to intoxication. Unfortunately, toxicological analysis of the rumen fluid was not possible.

The authors acknowledge that this case report has several limitations. However, we believe practitioners will find value in our experience and reflections on how to deal with a situation that is potentially fatal but also unexpected, sudden and short-lived. The lack of a definitive toxicological result made it impossible to confirm Kikuyu intoxication, albeit there was strong clinical evidence. The number of cases was small and those reported were geographically isolated from each other, which did not allow strong conclusions to be drawn regarding epidemiologic features. The short and fulminating course of the outbreak did not allow for the collection of more information or more samples from pasture to confirm the presence of endophytes or for more animals to be necropsied. Regarding pasture samples, it was also unfortunate that retesting for clarification of the Fusarium species present was not possible. The difficulty in identifying the exact fungal species on the pasture samples could have been circumvented by proceeding to direct identification and quantification of the toxins in the rumen. Thus, the collection of ruminal fluid for the identification of Fusarium toxins would have been an interesting and valuable addition towards a definitive diagnosis.

The authors suggest that a methodical and systematic approach should be ensured once the first suspicion of Kikuyu poisoning arises. It should be kept in mind that the time of greatest risk is the summer–autumn transition period, especially after any period of heavy rainfall and when animals will be eating almost exclusively Kikuyu grass.

When facing a suspected outbreak of Kikuyu grass poisoning the first step should be to remove all animals from the toxic pastures and to quickly offer other feed. In an attempt to reach a diagnosis, the authors believe that pasture and rumen fluid sampling are of greater importance than collecting blood samples for haematology and biochemistry. However, the latter can be useful for ruling out other diseases. Rumen fluid can be sampled by orogastric or nasogastric intubation or by percutaneous rumenocentesis (Duffield et al. 2004). Although these are straightforward procedures, they pose some risks for the animal and should be done with proper equipment and care to avoid trauma or peritonitis. The material collected should be sent for fungal identification and toxicological analysis.

If mortality occurs, the necropsy of all dead animals is important. If possible, samples of the organs with the most characteristic lesions – heart, digestive tract and liver – should be collected, as well as rumen contents. Post-mortem findings such as haemorrhages in the epicardium and endocardium, as well as inflammatory and/or ulcerative lesions of the forestomachs and intestines, are highly suggestive of Kikuyu intoxication, although they do not provide a definitive diagnosis.

Conclusions

Epidemiology, clinical signs, macro- and microscopic lesions along with identification of fungi on pasture, strongly support our suspicion of Kikuyu poisoning leading to the death of eight animals in Terceira Island in the space of a few days (plus 15 suspected deaths on another Azorean island). It is clear, however, that very little is known about the aetiology and accurate diagnostic features of Kikuyu poisoning. It is very probable that outbreaks of Kikuyu grass poisoning will become more common in the future. This plant demonstrates great invasive potential, rapid growth and a great ability to compete with other plants. We suggest that climate change, with intense rainfall after drought periods, will also provide ideal conditions for the plant and/or fungi to proliferate.

The authors believe that this case report of a Kikuyu poisoning outbreak that occurred on Terceira Island, Azores, may help practitioners to recognise affected animals and provide additional information about this toxin and its effect on ruminants.

Acknowledgements

We thank UNICOL, Cooperativa Agrícola, C.R.L., Terceira, Azores, and Isabel Mariano and the Instituto Nacional de Investigação Agrária e Veterinária (INIAV).

Disclosure statement

No potential conflict of interest was reported by the author(s).