Every year calf scours knocks the best laid calving plans backwards and sideways. As newborn calves get sick, staff get tied up nursing them while the usual seasonal demands pile up regardless. But Zoetis veterinary technical advisor Dr Clive Bingham said reducing scours starts well before calving with an effective cow vaccination programme.
“We now have some very effective vaccines available and these enable us to pretty much prevent the worst causes of scours, rather than being left trying to wrestle with the problem at a highly stressful time of year.”
Bingham said calf scours are the worst cases to deal with and the most frustrating simply because good vaccination can make them avoidable.
He admitted he was surprised at dairy farmer survey data (Cinta 2013) from last spring that indicated 73% of dairy farmers have not used a scour vaccine in the past three years. A particularly problematic scour disease was rotavirus, which accounted for about 40% of all scour cases encountered on farms.
Estimates are that a rotavirus outbreak on a dairy farm could cost the farm $6000 in treatment, lost calf condition and calf deaths.
In New Zealand there are two strains, G6 and G10. Typically G6 is the most common strain and last spring 100% of rotavirus scour cases that were typed carried the G6, while 14% also carried the G10 strain.
Zoetis launched ScourGuard4 (K) in 2011 as the only vaccine containing both strains of rotavirus, as well as protection against two other common causes of scours, E.coli and coronavirus infection.
Bingham said while vaccines like ScourGuard are highly effective, any dam-administered vaccine requires calves to receive an intake of quality colostrum for antibodies to be effective.
“You can vaccinate but if you do not get the colostrum into the calf, you are wasting your time.”
The best way to ensure that happened was to collect calves twice a day during calving. Farmers should ensure new-born calves received at least two litres of quality colostrum from the cow’s first milking within the first six hours of birth, and four litres within 12 hours.
First-calving heifers required two vaccinations with ScourGuard. These should be given a minimum of three weeks apart with the second vaccination being given two to four weeks before calving.
The interval between the initial vaccinations could be up to nine weeks to fit in with the management of heifers.
Farmers should talk to their vet to determine the best programme for their farm.
The problems with rotavirus could also be experienced on beef units where cows were calved in mobs on breaks.
“There is a risk of infection there too”.
Cow vaccinations to protect calves offered a very effective insurance against rotavirus infection and Bingham welcomed ScourGuard’s “cow-friendly” formulation which produces significantly fewer painful lumps around the injection site.
The formulation’s non-oily, soluble formula was a key reason behind farmers being happy with the results last season.
Bingham said vaccinating with ScourGuard was a good box to tick in the process of rearing good calves to become excellent cows. Calves affected by scours could recover but the illness could be debilitating to their growth rates.
DairyNZ in-calf calculations showed weaning a calf 15% below the 100kg target was likely to incur a loss of $201 to the farmer by the end of its first lactation.
“If that loss of weight was due to a rotavirus infection, allowing for a 25% replacement rate it would cost $20 for each replacement calf to protect against rotavirus.
“Clearly for $200, or a 10:1 return on investment, it is worth doing. That figure assumes no calves were lost during the outbreak.”
