Changes

Also Known As – '''''Cobalamin Deficiency – Vitamin B12 Deficiency – Secondary Vitamin B12 Deficiency - Ill Thrift – Cobalt deficiency anaemia - Wasting Disease – Coastal Disease – Ovine White Liver Disease'''''

Also Known As – '''''Cobalamin Deficiency – Vitamin B12 Deficiency – Secondary Vitamin B12 Deficiency - Ill Thrift – Cobalt deficiency anaemia - Wasting Disease – Coastal Disease – Ovine White Liver Disease - Fatty Liver Disease'''''

==Introduction==

==Introduction==

Cobalt is required by the ruminant for the '''synthesis of Vitamin B12 – Cobalamin – by the rumenal microflora'''. Thus a diet deficient in cobalt causes a '''secondary deficiency in B12''' which is required for the '''metabolism of propionic acid by the liver for energy production'''. Poor utilisation of propionate then leads to '''reduced appetite and subsequent '''"ill thrift"''' - the generic condition in which '''production and growth are impaired''' in affected animals. B12 is also used for the metabolism of some sulphur containing amino acids which are then used for '''wool growth'''. <ref name="Sargison"> Sargison, N (2008) '''Sheep Flock Health: A Planned Approach''', ''Blackwell Publishing, Oxford'', pp207-213</ref> Thus, cobalt deficient animals often also have poor fleece quality.

Cobalt is required by the ruminant for the '''synthesis of Vitamin B12 – Cobalamin – by the rumenal microflora'''. Thus a diet deficient in cobalt causes a '''secondary deficiency in B12''' which is required for the '''metabolism of propionic acid by the liver for energy production''' via the enzyme '''Methylmalonyl CoA mutase'''. Poor utilisation of propionate then leads to '''reduced appetite and subsequent '''"ill thrift"''' - the generic condition in which '''production and growth are impaired''' in affected animals. B12 is also used for the metabolism of some sulphur containing amino acids which are then used for '''wool growth'''. <ref name="Sargison"> Sargison, N (2008) '''Sheep Flock Health: A Planned Approach''', ''Blackwell Publishing, Oxford'', pp207-213</ref> Thus, cobalt deficient animals often also have poor fleece quality. B12 also has roles in the [[Erythropoiesis#Nutritional factors|production of new erythrocytes]].

The concentration of cobalt in '''crops and forages is highly variable''' and depends on a variety of factors including '''soil concentration, plant species rate of growth, soil pH and drainage'''. Soils are generally considered deficient in cobalt if they contain '''less than 2 parts per million'''.<ref> Haskell, S (2008) '''Blackwell’s Five-Minute Veterinary Consult:Ruminant'''. ''Wiley-Blackwell, Oxford'', p89</ref>

The concentration of cobalt in '''crops and forages is highly variable''' and depends on a variety of factors including '''soil concentration, plant species rate of growth, soil pH and drainage'''. Soils are generally considered deficient in cobalt if they contain '''less than 2 parts per million'''.<ref> Haskell, S (2008) '''Blackwell’s Five-Minute Veterinary Consult:Ruminant'''. ''Wiley-Blackwell, Oxford'', p89</ref>

Deficiency in pregnant sheep has been associated with '''poor milk production and high lamb mortality'''.<ref name="Sargison" />

Deficiency in pregnant sheep has been associated with '''poor milk production and high lamb mortality'''.<ref name="Sargison" />

There is also a syndrome known as '''Ovine White Liver Disease''' which causes '''fatty liver degeneration''' which then leads to subsequent liver failure, '''[[Hepatic Encephalopathy|hepatic encephalopathy]] and [[Photosensitisation|photosensitisation]]'''.  

There is also a syndrome known as '''Ovine White Liver Disease''' which causes '''fatty liver degeneration''' which then leads to subsequent liver failure, '''[[Hepatic Encephalopathy|hepatic encephalopathy]] and [[Photosensitisation|photosensitisation]]'''. This is caused by the accumulation of methylmalonic acid in the absence of adequate cobalt, which is then converted into branch chain fatty acids.

==Diagnosis==

==Diagnosis==

Cobalt and Vitamin B12 can both be measured in serum but this is not without difficulty. Because of this, other tests such as '''methylmalonic acid (MMA) in plasma and urine and formimoglutamic acid (FIGLU)''' were developed and are now often used.<ref name="Radostits"> Radostits, O. M., Gay, C. C., Blood, D. C., Hinchcliff, K. W (2000) '''Veterinary Medicine: A Textbook of the Diseases of Cattle, Sheep and Pigs 9th ed'''. ''Elsevier, Edinburgh''</ref>  Fresh or formalin fixed liver and serum can also be sent for '''toxicological analysis''' of cobalt concentrations.  

Cobalt and Vitamin B12 can both be measured in serum but this is not without difficulty. Because of this, other tests such as '''methylmalonic acid (MMA) in plasma and urine and formimoglutamic acid (FIGLU)''' were developed and are now often used.<ref name="Radostits"> Radostits, O. M., Gay, C. C., Blood, D. C., Hinchcliff, K. W (2000) '''Veterinary Medicine: A Textbook of the Diseases of Cattle, Sheep and Pigs 9th ed'''. ''Elsevier, Edinburgh''</ref>  Fresh or formalin fixed liver and serum can also be sent for '''toxicological analysis''' of cobalt concentrations.  

Affected animals are often '''anaemic''' but this may not be evident due to the effects of haemoconcentration on haematology values.  

Affected animals are often '''anaemic''' but this may not be evident due to the effects of haemoconcentration on haematology values. Liver enzymes (GGT and AST) are also often raised.

Signs of '''fatty liver degeneration''' on pathological examination and histopathology may support clinical signs but this is also non-specific and has many other pathogeneses. Carcasses are generally '''emaciated''' and the '''spleen is often dark due to haemosiderin accumulation'''.<ref name="Radostits" />

Signs of '''fatty liver degeneration''' on pathological examination and histopathology may support clinical signs but this is also non-specific and has many other pathogeneses. Carcasses are generally '''emaciated''' and the '''spleen is often dark due to haemosiderin accumulation'''.<ref name="Radostits" />

==References==

==References==

<references/>

<references/>

Merck Veterinary Manual, '''Beef Cattle:Nutritional Requirements''', accessed online 24/07/2011 at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/182303.htm&word=cobalt

Merck Veterinary Manual, '''Beef Cattle:Nutritional Requirements''', accessed online 24/07/2011 at http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/182303.htm&word=cobalt

[[Category:To Do - Manson review]] [[Category: Lymphoreticular and Haematopoietic Diseases - Cattle]]

[[Category:To Do - Manson review]] [[Category: Lymphoreticular and Haematopoietic Diseases - Cattle]]