Review/Oorsig Volume 22, Issue 04 | Page 31

Volume 22 • Issue 04 • 2018

As mentioned , the vaccination of young calves , in the presence of maternal antibody , is ineffective . Vic Cortese cautioned us though to , if possible , avoid vaccinating between 3 & 5 weeks of age when the innate immune system is turning on . Feeding milk once a day is an accepted practice , but twice a day would be standard .

Here are two useful websites : Ontario Veal Association – http :// calfcare . ca / Dr . Jim Quigley – http :// www . calfnotes . com /

WG - 15 Jan 2017

The only drug which has any effect on Crypto is Halofuginone ( Halocur ) but it only reduces oocyst shedding and does not treat or prevent disease - I have never actually used it as it is quite expensive and requires 7 days of treatment so is not very convenient to use . It is also not available in SA as far as I know . The most important aspect of treatment , as for all cases of calf diarrhoea , is rehydration . Milk feeding should be continued , especially for crypto as it often takes longer than the viral causes to resolve . The role of antibiotics in calf diarrhoea in general is controversial but they should be kept to a minimum as E . coli will rapidly develop resistance if they are overused - I have cultured multi-resistant E . coli ( including fluoroquinolones and colistin !) from a farm which was injecting every case of diarrhoea with Potencil .

EdP - 25 Nov 2017

I would like some thoughts on the use of Halocur . If we treat the ewes or cows it will help to lessen the losses . But what happens if the mothers do not develop immunity Won ’ t we just postpone the problems ?

CvD - 27 Aug 2018

Something which could become reality in future New tool for fighting crypto in calves Dairy Herd Management

This dairy assailant Cryptosporidium parvum ( C . parvum ), is a parasitic protozoan and primary cause of scours . With four other common causes of scours , many producers often skip testing sick calves and try to manage the symptoms . Multiple research studies have shown that up to 92 percent of calves younger than four months test positive for C . parvum and are shedding the C . parvum organism , with or without clinical signs of disease . It is found in all calf-housing systems and in all regions . C . parvum is transmitted through ingestion of oocysts , or protozoan eggs . Hutches , water and feed supplies can be carriers of C . parvum oocysts , allowing the disease to spread within herds . Researchers have tried to find cures for C . parvum , but most treatments only focused on one stage of the disease . " In the past , researchers focused solely on the oocyst , which is the end infectious stage of protozoans like C . parvum ," says Mark Welter , president of Oragen Technologies Inc . in Des Moines , Iowa . " Oocysts are shed by the animal in their feces . So they tried using oocysts as an antigen to make vaccines , but that didn ' t work ... C . parvum has many life cycle stages , so focusing on one stage is insufficient ."

It ' s not just the calves that are in danger from C . parvum , it is also a threat to humans . The Centers for Disease Control and Prevention says , " Cryptosporidium has become recognized as one of the most common causes of waterborne disease ( recreational water and drinking water ) in humans in the United States . The parasite is found in every region of the United States and throughout the world ."

" The best defense against this disease is to prevent the oocyst ," says Welter , who has been working on a vaccine for C . parvum for close to 18 years . " That ' s what gets into watersheds and infects humans . Since bleach and other filtration systems do not work against C . parvum , it has to be controlled at the source ." A new scientific breakthrough is poised to give producers control of this persistent parasite . Similar to the flu vaccine , Welter has developed and patented a process to generate killed C . parvum proteins in every stage of its life cycle . The killed C . parvum proteins are delivered in a liquid form that can be mixed with milk replacer and fed to calves . It allows the calf an opportunity to produce an immune response without being attacked by the parasite . Then when the parasite is present , the calf will be primed to fight it .

Soon producers will be able to prevent C . parvum induced scours , rather than just react to the symptoms . Preventing the spread of this highly infectious disease will not only help calves stay healthy and strong , but the humans around them too

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