Polioencephalomalacia

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We are once again seeing several cases of P.E. (polio encephalomalacia), a nervous disease seen primarily in calves and younger stock.  P.E. is caused by a lack of vitamin B1 (not to be confused with a cobalt deficiency, which is associated with a vitamin B12 deficiency).  P.E. is thought to be nutritionally induced, when there is a sudden change in diet from stalky, higher DM diet, to a lush, low fibre diet.  A high dietary sulphur intake, especially with brassica's, has also been incriminated as a cause of P.E.  Calves with P.E. appear blind, may walk aimlessly, appear wobbly, have muscle tremors and head press.  If calves are treated early in the disease process with a series of vitamin B1 injections, survival rates are good.  In an outbreak situation we have had good success, by prophylactically treating the remaining, unaffected calves, in the group with an oral vitamin B1 drench.  This has proved a very cost effective preventative measure.

Booking In A Pregnancy Testing Date

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Everyone is now fully aware of the tremendous benefits of doing an early aged pregnancy test - these include:

  • Providing information for strategic dry off dates
  • Aiding in early culling decisions for destocking in Autumn
  • Formation of wintering groups for tailored feeding
  • Feed budgeting for the winter period and early lactation
  • Efficiency in time and transport logistics of cows from run-off back to milking platform
  • Detailed reproductive analysis to help guide where continued future improvements may be made
  • Bench marking against the rest of the district
  • Improving the saleability of a herd
  • Identification of cows which have received multiple inseminations but conceived to the first mating
  • Ranking cows for culling
  • Accurately identifying cows which conceived in the early bull mating period
  • Provision of detailed supportive material for possible induction dispensation requests

To provide this information accurately cows should be pregnancy tested 12-15 weeks after the PSM date.  For a herd which started mating on the 23rd of October this would be between the 15th of January and the 5th of February.  The accuracy when dating pregnancies beyond 15 weeks start to diminish.  Herds should have had bulls removed for at least 40 days before an empty diagnosis can be confidently made.

For herds which are limiting their mating period to strictly 10 weeks it would be possible to do a singular test at 15-15.5 weeks after the PSM.  The reality however is that it would not be possible to get all herds tested in the district within this very tight time frame.  We ask therefore that farms stick with the existing program of testing between 12-15 weeks after the PSM.  Cows identified as rechecks can then be simply drafted out for retesting 40 plus days after bulls removal.

Timely Reminders & Handy Hints for November

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  • Pink eye in calves - we are coming up to the Pink Eye season in calves.  A single dose of Piliguard vaccine given 3-6 weeks before the risk period will significantly reduce the risk of an outbreak.
  • Covexin 10 - if you have unexplained deaths in young stock every year despite using 5 in 1 vaccine, you should consider using Covexin 10 in 1 vaccinate, which provides additional protection against two other major clostridial diseases - Clostridium sordelli and Clostridium perfringens type A.
  • Last year we saw a case of several acute deaths in calves which had been worm drenched through the milk.  This is a very timely reminder, not to add worm drench, especially levamisole or abamectin, to milk.  Each season we see 2-3 cases of either levamisole toxicity or abamectin toxicity in calves under 100kg.
  • Poa aquatic (also known as Glyceria maxima) is a grass that proliferates in wet areas of paddocks and drains.  Under the right environmental conditions it can accumulate cyanide - which can be fatal if ingested.  Sudden death in a wet paddock could be potentially due to cyanide.  If you have suspicions contact your vet for identification of the grass.
  • Polioencephalomalacia (P.E.) - this nervous condition of calves is now the most common disease of calves that we see over the summer months.  Polioencephalomalacia (PE or CCN) is considered to be associated with a change of diet from a fibrous stalky diet to a lush, rapidly growing grass diet.  High sulphur intakes have also been incriminated.  P.E. is a vitamin B1 deficiency.  Clinically, calves with P.E. show nervous signs.  They may appear blind, staggery and develop muscle tremors, before becoming recumbent, with severe convulsions and die.  We traditionally see P.E. cases from late November, peaking late Dec/early Jan.

Individual calves, if treated early enough with injectable Vitamin B1, respond well and make a full recovery.  In the face of an 'outbreak', it is well worth considering the prophylactic use of an oral drench of Vitamin B1, for the entire mob of calves.