Salmonella threat in young calves
Calf scours is a numbers game – about 89% of dairy units had incidents last year
and on 63%the condition was fatal. Worryingly, in 80% of those events the farmers
didn’t seek veterinary advice – a decision which can be costly as a typical case of
calf scours costs £44, excluding labour.
Moreover, losses can continue long after the animal has apparently regained its
health – heifers that had suffered scours as calves typically produce £59 worth less
milk in their first lactation. It is quite possible that early disease creates permanently
‘runty’ stock. Many different pathogens can cause calf scours, and two key ones,
Cryptosporidium parvum and Salmonella, are zoonotic – which means infection can
be transmitted to humans.
Calf health can be boosted by vaccinating cows against salmonellosis with Bovivac®
S in the last four weeks of pregnancy. This reduces shedding of the bacteria at
calving, therefore reducing the challenge to the newborn calf. If needed, the calf can
then be vaccinated from three weeks of age.
Salmonella is one of the main causes of calf scour, which is responsible for 80% of
calf losses before weaning. Each case of scour costs £44/calf in extra labour, vet
time, drugs and reduced liveweight gain. There is also long-term gut damage and
the calf can become more susceptible to other diseases.
The problem with Salmonella is that one of the most common strains – S.
typhimurium – also affects humans, while S. dublin is on the increase, particularly in
bought-in calves. In addition, S. dublin causes septicaemia and meningitis in
weaned calves and abortion in cows. Bovivac S offers effective protection against
both types.
Salmonellosis is often seen at calving because the stress of transition coupled with
the cow’s lower immune system cause her to shed bacteria. Nutritional upsets or
stress such as transport make the calf vulnerable to infection.
Contact the practice for more information on limiting the threat of salmonella in your
herd.