Deon Schlechter
WINDHOEK – Namibian farmers are reporting vitamin B1 deficiency in livestock at an alarming rate now that the drought has reached its most critical stage with animals showing signs that could be mistaken for a variety of illnesses, including rabies.
Thiamine (vitamin B1) deficiency-induced polioencephalomalacia, commonly referred to as PEM, has become a major cause of animals weakening to the point of collapse across the rangelands of the country.
“Vitamin thiamine (B1) plays a critical role in all livestock health. Thiamine depletion can happen rapidly from a large number of causes and will lead to death unless promptly remedied by the immediate administration of injectable thiamine,” says Paul van der Merwe, farmer and Molatek representative in Namibia for the past 14 years.
He says thiamine is inexpensive, and every farmer should have a bottle from their vet on hand at all times.
Any time livestock develop foam around the mouth, suffer from low appetite, neurological impairment, looks dazed and confused, have shortness of breath and lie down, a shot of thiamine is worthwhile.
“Thiamine is a safe and useful therapy any time we suspect neurological insult. It can never hurt, and it may help save your animal’s life,” he comments.
Breakdown of a ruminant’s diet begins in the mouth, where it is mixed with saliva and given preliminary, brief chewing before being swallowed down to the reticulum, the first of a series of stomachs. After being later brought back up and chewed leisurely as cud, masticated food finally ends up in the rumen or second stomach.
Microorganisms break down cellulose and other plant fibres and make their energy available to their host ruminant. The microorganisms also produce many substances critical to their host’s survival and well-being, including the vitamin thiamine. Under normal conditions, a ruminant can synthesise all of the thiamine it needs for daily function without supplemental sources. Thiamine is water-soluble and is manufactured constantly in the ruminant gut, as it is being continually depleted in turn. Thiamine plays an important role in energy metabolism for all body cells but is especially critical in brain and heart cells. Without an adequate supply of thiamine, the brain ceases to function properly and begins to physically deteriorate.
Thiamine can be depleted in a myriad number of ways. Cattle may take weeks to show symptoms of PEM after a sudden feed change happens during drought.
Although many cases of PEM in cattle, sheep, goats and pigs happen quite rapidly, prolonged periods of low thiamine availability can also lead to PEM, with animals exhibiting subtle signs of deficiency over an extended period.
PEM may be caused by a change in an animal’s ability to absorb thiamine from the gut, or by the too rapid removal of thiamine from the body. Possible causes for metabolic disruption along these lines include drought, forages and stress levels.
The acute stage of PEM is typically characterised by increased severity of symptoms seen in subacute PEM; blindness; grinding teeth; spasming or arching of the back and neck – the “death arch”; seizures and muscle spasms; recumbency and failure to rise. Untreated acute PEM will lead to coma and death. Veterinarians have recommended a wide variety of treatments ranging from 10mg/kg every three hours until symptoms are gone to 5mg/kg every six hours for 24 hours.