Improved control of calf cryptosporidiosis is now accessible to all UK dairy and beef producers with the release of new disease management guidelines and a vaccine.
Dr Kat Baxter-Smith from MSD Animal Heath explained that the company’s new five-step calf cryptosporidiosis control planner will help vets and farmers to evaluate and control practices in five key areas: diagnosis, colostrum, environment and management, prevention and treatment.
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1. Diagnosis
Accurate diagnosis is vital for controlling infectious scour on farms.
Dr Baxter-Smith advises using calf scour testing kits to identify common pathogens like C. parvum, rotavirus, coronavirus or E. coli K99, as well as additional tests for coccidia and salmonella if needed.
Visual identification alone is unreliable and may lead to ineffective treatment, delaying recovery and risking improper antibiotic use.
Calf cryptosporidiosis, caused by the protozoan parasite Cryptosporidium parvum is now the most common cause of infectious scour in the UK. The disease is widespread on UK dairy and suckler cattle units and is prevalent throughout the year. The condition is mostly seen in calves seven-14 days of age, but can strike at anytime.
Infection with the parasite causes blunting of the intestinal villi, reducing capacity for nutrient and water absorption. This has a significant impact on a calf’s future productivity. In a recent UK study, cryptosporidiosis in the first 16 days of life significantly reduced weight gain over a six month period, with severe disease calves weighing 34kg less on average than low disease calves. This equated to a £161 reduction in the calf sale price.
2. Colostrum
Dr Katie Denholm from the University of Glasgow Veterinary School explained that proper colostrum management (5Qs: Quantity, Quality, Quickly, Quietly and Quantify) is critical to setting calves up to have the best possible immunity.
What’s more, she added that calf rearers can derive a horde of animal health rewards by feeding high quality colostrum for longer.
“Whilst each farm is unique and a tailored approach to extended colostrum feeding will be required, there is no doubt that the practice will reap calf performance dividends on units that implement it,” she said.
“For example, potential benefits include increasing calf serum immunoglobulin (IgG) concentrations, reduced antimicrobial use, increased immune protection for specific dam vaccinated pathogens (e.g. C. parvum, rotavirus, coronavirus and E. coli K99), the promotion of sound intestinal villi development (which will translate into better daily liveweight gain), reduced calfhood morbidity and mortality, and the improvement of reproductive and lactation outcomes in later life.”
Dr Denholm also stressed that it was important for farmers to recognise that colostrum provides so much more than just immunoglobulins to the calf.
“This liquid gold also contains immune modulators such as oligosaccharides, valuable enzymes, lactoferrin, cytokines, hormones, vitamins, and minerals – all of which are important for long term gut health, function and development.”
Whilst colostrum immunoglobulin concentrations and other immune modulators are highest in the first milking post-partum – so called ‘true colostrum’ – if practically possible, feeding this valuable first milk beyond the first feed over the first five days life and beyond will certainly be beneficial to the young calf.
Concentrations of immunoglobulins and other colostrum specific immune regulators fall with time as the colostrum ‘transitions’ to whole milk in the first 6-8 milkings post-partum. This is known as ‘transition milk’ but is still enormously valuable.
Dr Denholm pointed out that farmers tend to cite supply and storage problems as the main barriers to implementing extended colostrum feeding on farm.
“In the recent survey, farmers told us that it is difficult to harvest enough first milking colostrum to feed this alone in an extended way, so transition milk is practically preferable for longer term feeding,” she said, adding that artificial colostrum replacers and/or supplements are often inferior to maternally derived colostrum and may lack farm specific immunity. These proprietary products can also be expensive.
It is possible to add chemical preservatives to both colostrum and transition milk (e.g. 1% of a 50% potassium sorbate solution) to keep it for longer, or it can be stored at a low temperature.
“In the UK, colostrum is often preserved using low temperature.
Depending on initial contamination levels, refrigeration at 4°C for 2-5 days and freezing in two litre batches at -20°C for up to 12 months will keep bacterial concentrations low and IgG concentrations high.
"But don’t use a microwave to defrost your colostrum in case ‘hot pockets’ form, which could denature the IgG molecules.
"Better to warm the frozen colostrum to around 40°C using hot water baths. Then it will be ready to feed to your calves,” advised Dr Denholm.
3. Environment and management
The cause of any outbreak of infectious calf scour is often multifactorial, according to Dr Kat Baxter-Smith who pointed out that there is not one ‘silver disease control bullet’ available.
“Good biosecurity, vaccination and nutrition policies will all help to minimise disease problems – and implementing scrupulous hygiene practices will also help.
“Muck out, steam clean, disinfect and leave to dry as often as you practically can. Many common farm disinfectants are not effective against C. parvum, so only use those that are licensed to control this pathogen.
"And leave disinfected pens to dry thoroughly because C. parvum does not like dessication.”
4. Prevention
Vaccinating pregnant heifers and cows with the new Bovilis Cryptium vaccine (licensed in Great Britain in August 2024) can provide protection for calves from birth at the start of colostrum feeding – when they are most vulnerable. Active immunisation raises antibodies in colostrum against C. parvum, which will help to reduce clinical signs (i.e. diarrhoea) when calves are fed this fortified colostrum. The primary vaccination course is two doses (4-5 weeks apart, in the third trimester of pregnancy. To be completed at least three weeks before calving). Cattle that have had the primary vaccination course only need a single booster dose during subsequent pregnancies.
“The protection of calves depends on adequate ingestion of colostrum and transition milk from vaccinated cows. It is recommended that all calves are fed colostrum and transition milk during the first five days of life. At least three litres of colostrum should be fed within the first six hours after birth,” explained Dr Baxter-Smith.
5. Treatment
Calves with cryptosporidiosis may still need treatment if infection levels are high. Rehydration and, if needed, pain relief and antibiotics under veterinary guidance are important. Halofuginone lactate, a licensed non-antibiotic treatment, can aid in both prevention and early treatment of affected calves.
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