Prevent spreading disease via cow’s milk!
Every dairy farmer wants to prevent diseases that are prevalent or incubating on his farm from being transmitted to young calves. By not feeding unpasteurised cow’s milk to your calves, you will substantially reduce the risk of spreading disease. It is well known that there are 7 diseases which are easily transmitted by cow’s milk. This is a brief description.
1. Para tuberculosis or Johne’s disease
Para TBC is a chronic infection of the intestines. Young calves are most susceptible to the transmission of Para TBC. However, incubation takes a long time: the symptoms of the disease only manifest after 3 to 6 years. There is no treatment for Para TBC. The first signs of Para TBC are a 10 to 20% downturn in milk production, worsening physical condition and lower birth weight of calves. Ultimately the animal may die from diarrhoea.
The Animal Health Service (GD) advises that only colostrum from the mother cow should be fed followed by the introduction of calf milk powder instead of cow’s milk. Mixing 'colostrum milk' from different cows is absolutely prohibited as is feeding beestings from cows that have tested positive for Para TBC.
Salmonella is also an infection of the intestines. Salmonella can cause violent diarrhoea, pneumonia and high fever. An animal can transmit Salmonella bacteria via manure within 1 to 3 weeks. An analysis of the milk in the tank will diagnose whether there is Salmonella on the farm. Even on the cleanest farm it happens that bacteria find their way into the milk via small particles of manure.
Newly-born calves are most susceptible to Salmonella infection but all animals are prone to catching it. Most animals recover from Salmonella infection, although young calves quite often die from it. It is has been established that substituting calf milk powder for cow’s milk helps to prevent the disease from spreading.
3. BVD: bovine viral diarrhoea
BVD occurs in cattle of all ages throughout the world. At the time of writing this is one of the most contagious cattle diseases in Europe. The most common form of BVD undermines resistance to disease and therefore causes diarrhoea, fever, pneumonia and decline in milk yield.
Half of BVD-carrying animals can be recognised by problems with the eyes, skin, hair growth and brains, but in the other half there is no sign that the animal is carrying the virus. Since 2011 all newly-born calves in Germany are tested for BVF at the same as they are earmarked.
BVD is transmitted by feeding cow’s milk to young calves among other things. The Dutch Animal Health Service therefore recommends switching over to calf milk powder immediately after feeding beestings.
Among other things, Mycoplasma infections cause pneumonia, ear infections and combinations of diseases that are difficult to treat. The Mycoplasma bacterium can also be found in the udders of young calves and may therefore be the source of clinical mastitis at the start of the first lactation. The spread of Mycoplasma mastitis on a farm is the result of inadequate hygiene when milking and feeding calves with mastitis milk and/or cow's milk.
5. Infectious mastitis
Staphylococcus aureus, Streptococcus agalactiae and other mastitis-causing agents can be transmitted by feeding mastitis milk or cow’s milk. These disease agents are not a direct threat to the calf’s health, but can survive in the udder for months and even years. The result can be that a heifer suffers from immediate mastitis problems at the first lactation.
The Staphylococcus aureus bacterium in particular is a tough survivor. Never feed a calf with the 'colostrum milk' from a cow with mastitis and certainly not with milk from cows that have been treated with antibiotics. This may cause digestive problems and result in resistant bacteria developing so it becomes difficult to fight infections at a later age.
6. Bovine leukosis
The Bovine Leukemia virus (BLV) is a retrovirus which can infect all animals and cause bovine leukosis disease. In bovine leukemia one or several tumours may develop in the abomasum resulting in reduced food intake, weight loss and low milk yield. BLV can be transmitted via blood, via the placenta during pregnancy but also via beestings and cow’s milk.
Leptospirosis no longer occurs on Dutch farms thanks to a succesful national campaign, but it does occur in other countries. The disease is produced by the Leptospira Hardjo bacterium and can be transmitted to human beings (milker’s fever). The disease is transmitted via the urine of infected animals and can also be transmitted to calves via cow’s milk.