Bovis ISSN 2398-2993

Brassica spp

Synonym(s): Brassic oleracea, Brassica rapa, Brassica juncea, Brassica nigra, Brassica elongata

Contributor(s): Nicola Bates , Mike Reynolds

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Introduction

  • Cause: ingestion of brassicas, particularly with the exclusion of other fodder.
  • Signs: weakness, hypothyroidism, gastrointestinal signs, respiratory distress.
  • Diagnosis: history and clinical signs.
  • Treatment: supportive.
  • Prognosis: depends on severity of signs and the syndrome exhibited.
  • Brassica toxicosis is associated with a number of different syndromes with various names.
    • Usually only one syndrome is present in a single animal or herd, but sometimes multiple syndromes may occur.
  • Brassicas can also accumulate nitrates and cause nitrate poisoning.

Pathogenesis

Etiology

  • Toxic effects are more likely to occur when animals are fed only Brassica crops.
  • They are usually used as a winter feed source  when other forage is unavailable.
  • The concentrations of glucosinolates vary with the species, variety, season and environmental conditions.

Pathophysiology

Hemolytic anemia/Heinz body anemia

  • Brassicas contains S-methylcysteine sulphoxide (SMCO) which is converted during normal fermentation in the rumen to dimethyl disulphide. This is toxic to red blood cells and oxidises hemoglobin leading to Heinz body formation and hemolytic anemia.
  • Hemolysis of cells occurs as a result of oxidative damage.

Glucosinolate toxicity  

  • Brassicas contain numerous glucosinolates. These sulphur-containing compounds are hydrolysed by myrosinase (an enzyme in plant tissue) or in the ruminal environment to isothiocyanates, thiocyanates, nitriles and related compounds.
    • Isothiocyanates are irritant to mucus membranes and have an antithyroid effect.
    • Nitriles depress growth and are toxic to the liver and kidneys.
    • Thiocyanates have an antithyroid effect.
    • Oxazolidine-2-thiones are related to isothiocyanates. They also have an antithyroid effect.
  • Effects on the thyroid include blocking tyrosine iodination an inhibition of T4 production (due to goitrin, a breakdown product of thiooxazolidine) and inhibition of thyroid iodine uptake due to thiocyanate formation.

Pulmonary emphysema/Acute respiratory distress syndrome

  • Brassicas contain a high concentration of tryptophan which is converted in the rumen to 3-methylindole.
  • This binds with the protein of type I cells in the pulmonary airways resulting in acute pulmonary edema and emphysema.

Polioencephalomalacia (PEM)/cerebrocortical necrosis (CCN)

  • Polioencephalomalacia is uncommon in ruminants grazing brassica crops. Polioencephalomalacia
  • The cause of brassica-induced polioencephalomalacia is unknown but may be due to the high sulphur content of brassicas.
  • Sulphate is reduced to sulphide in the rumen, it then reacts with sulphite and may act as a thiaminase but it is more likely that the neurotoxic effects are due to additional direct effects in the brain via lipid peroxidation. There are minimal changes in tissue concentration of thiamine.
  • The high sulphur content may also reduce bioavailability of copper leading to copper deficiency.

Blindness

Photosensitization Photosensitization.

  • In cattle, brassica-related photosensitivity is a secondary photosensitivity associated with hepatocellular toxicity.
  • The identity of the toxic compounds in photosensitivity in cattle is unknown. It may be nitrile derivatives of glucosinolates.

Bloat

  • There is limited information on the cause of brassica-related bloat.
  • The free gaseous bloat may be due to the rapid accumulation of free gas. Ruminal bloat

Reproductive effects

  • Poor health and reproductive failure in animals eating large quantities of brassicas, without other foodstuffs in the diet, is usually due to a combination of effects: anemia, low copper concentrations, irritation of mucous membranes and antithyroid effects.

Timecourse

Hemolytic anemia/Heinz body anemia

  • Usually after 1-4 weeks of feeding.

Glucosinolate toxicity  

  • Gastrointestinal signs can occur within a few days of feeding.
  • The development of a goiter only occurs after weeks of feeding.

Pulmonary emphysema/Acute respiratory distress syndrome

  • This usually occurs 7-10 days after animals begin to graze, sometimes as early as 5 days or up to 4 weeks.

Polioencephalomalacia (PEM)/cerebrocortical necrosis (CCN)

  • Usually after days or weeks of feeding.

Blindness

  • After several weeks of feeding.

Photosensitization

Bloat

  • Can occur at any time but may occur within hours of ingestion.

Reproductive effects

  • After weeks of feeding.

Epidemiology

  • Toxic effects are more likely to occur when animals are fed only Brassica crops.
  • The concentrations of glucosinolates vary with the species, variety, season and environmental conditions.
  • Varieties of brassica crops have been developed that are low in glucosinolates.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed Papers

  • Recent references from PubMed and VetMedResource.
  • Collett M G, Stegelmeier B L & Tapper B A (2014) Could nitrile derivatives of turnip (Brassica rapa) glucosinolates be hepato - or cholangiotoxic in cattle? J Agric Food Chem 62 (30), 7370-7375 PubMed.
  • Collett M G (2014) Bile duct lesions associated with turnip (Brassica rapa) photosensitisation compared with those due to sporidesmin toxicosis in dairy cows. Vet Pathol 51 (5), 986-991 PubMed.
  • Collett M G & Matthews Z M (2014) Photosensitivity in cattle grazing Brassica crops. IJPPR 3, 7-22.
  • Do J C, Kim E Y, Kim I K, Cho M H, Kim J K & Park N C (2012) A case of rape poisoning in a Hanwoo. Korean J Vet Sci 35 (1), 53-57.
  • McKenzie R A, Carmichael A M, Schibrowski M L, Duigan J A & Taylor JD (2009) Sulfur-associated polioencephaolmalacia in cattle grazing plants in the Family Brassicaceae. Aust Vet J 87 (1&2), pp 27-32.
  • Kataria A K, Singla B, Ruby K N & Roy P K (2004) Mortality in cattle due to over eating Chinese cabbage. Vet Pract 5, 100-110.
  • Nouri M, Jalali M R, Somti M & Gharaje B (2003) Effects of phosphorus in the prevention of Savoy cabbage poisoning in cattle [abstract]Acta Vet Scand Supl 98, pp 260.
  • Clark C, Radostits O, Petrie L & Allen A (2001) Toxic effect of dairy cattle following the ingestion of a large volume of canola oil. Can Vet J 42, 721-723 PubMed.
  •  Katamoto H, Nishiguchi S, Harada K, Ueyama I et al (2001) Suspected Oriental mustard (Brassica juncea) intoxication in cattle. Vet Rec 149 (7), pp215-6.
  • Semalulu S S & Rousseaux C G (1999) Saskatchewan. Suspected oriental mustard seed (Brassica juncea) poisoning in cattle. Can Vet J 30 (7), pp 595-6.
  • Morton J M & Campbell P H (1997) Disease signs reported in south-eastern Australian dairy cattle while grazing Brassica species. Aust Vet J  75( 2), pp 109-13.
  • Stoewsand G S (1995) Bioactive organosulfur phytochemicals in Brassica oleracea vegetables - a review. Food Chem Toxicol  33 (6), pp 537-43.
  • Prache S (1994) Haemolytic anaemia in ruminants fed forage brassicas: a review. Vet Res 25, pp 497-520.
  • Taljaard T L (1993) Cabbage poisoning in ruminants. J S Afr Vet Assoc 64 (2), pp 96-100.
  • Wikse S E, Leathers C W & Parish S M (1987) Diseases of cattle that graze turnips. Compen Food Animal  9, pp 112-121.
  • Nocerini M R, Honeyfield D C, Carlson J R & Breeze R G (1985) Reduction of 3-methylindole production and prevention of acute bovine pulmonary edema and emphysema with lasalocid. J Anim Sci 60 (1), pp 232-8.
  • Smith R H (1980) Kale poisoning: the brassica anaemia factor. Vet Rec 107 (1), pp 12-15.
  • Papas A, Ingalls J R & Campbell L D (1979) Studies on the effects of rapeseed meal on thyroid status of cattle, glucosinolate and iodine content of milk and other parameters. J Nutr 109 (7), pp 1129-39.
  • Greenhalgh J F D (1969) Kale anaemia. Proc Nutr Soc 28 (2), pp 178-183.
  • Penny R H C, David J S E & Wright A I (1964) Observations on the blood picture of cattle, sheep and rabbits fed on kale. Vet Rec 76, pp 1053-1059.
  • Melrose D R & Brown B B (1962) Some observations on the possible effect of kale feeding on fertility in dairy cattle [abstract]. J Repr Fert 4, pp 232.
  • Dunbar G M & Chambers T A M (1963) Suspected kale poisoning in dairy cows. Vet Rec 75, 566-567.
  • Clegg F G & Evans R K (1962) Haemoglobinaemia of cattle associated with the feeding of Brassicae crops. Vet Rec 74, 1169-1176.
  • Crawshaw H A (1953) Rape blindness. Vet Rec 65 (16), 254.
  • Dalton P J (1953) Rape blindnessVet Rec 65 (19), 298.
  • Cote F T (1944) Rape Poisoning in cattle. Can J Comp Med Vet Sci 8 (2), 38-41.
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Other sources of information

  • Burrows G E & Tyrl R J (2013) Toxic Plants of North America. 2nd edn. Wiley Blackwell, Ames, Iowa. pp 282-307.
  • Casteel S W (2004) Forage-induced photosensitization. In: Clinical Veterinary Toxicology. Mosby, Missouri. pp 427-428.

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