Monday, February 4, 2013

Cryptosporidia and Calf Health
In the December 2012 issue of the Journal of the American Veterinary Medical Association research was reported on the connection between cryptosporidiosis and how much the calves were fed. (Ollivett, T.L. and Others, "Effect of nutritional plane on health and performance in dairy calves after experimental infection with Cryptosporidium parvum" JAVMA 241:1514-1520)
"After a pathogen challenge, calves maintained hydration, had faster resolution of diarrhea, grew faster, and converted feed with greater efficiency when fed a higher plane of nutrition."
In a nutshell the two feeding programs with non-medicated milk replacer were (a) 20-20 m.r. mixed at 15% solids fed 2 quarts twice daily and (b) 28-20 m.r. mixed at 15% solids fed at 3 quarts twice daily first week and 4 quarts  twice daily for the next two weeks. 
Points of interest for me:
  • Shedding - calves were  handled to prevent natural exposure to Cryptosporium parvum. They were experimentally exposed at their 5th feeding on day 3. Shedding started by four days after exposure. Peak shedding occurred on average on eight days after exposure.  Where we have natural exposure at birth these data suggest we should expect shedding to start around 4 days of age and to peak around 8 days of age.
  • Diarrhea - About one-third of the calves did not have diarrhea. However, about one-third of them had severe diarrhea. Not all calves will respond to a crypto infection the same way - we need to watch these 4 to 8 day old calves very carefully in order to provide appropriate and timely care.
  •  Rate of gain - the calves on "normal" feeding program either stood still or lost weight at the end of 3 weeks. The calves on the high or intensive feeding program ate their way through the infection and averaged just under a pound a day gain at the end of 3 weeks. Well-fed calves can gain weight during the first three weeks of age in spite of cyrptosporidiosis.

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