Raw cows' milk can transfer Salmonella to calves
Cows' milk may contain pathogens that cause calves problems at a later stage. After all, young calves have little resistance to disease in their first four weeks. Salmonella is also relatively easily transferred from cow to calf.
The Salmonella group comprises some 2000 strains that each bear their own name. The bacteria can be found in the intestines and faeces of a wide range of animals. There are two common types in dairy cattle: Salmonella Dublin and Salmonella Typhimurium. Almost immediately after contamination, infected animals discharge bacteria in their faeces for three to four weeks. Symptoms include high fever (41°C), diarrhoea, abortions and mortality.
Young calves most prone to Salmonella infection
All cattle are prone to Salmonella infection, and young calves in particular. The infection generally occurs unexpectedly, with parallel pathologies:
- A number of sick cows with high fever and/or abortions;
- A number of animals with chronic diarrhoea, sometimes bloody;
- The symptoms are most commonly seen in dairy cows, young cattle and dry cows. In the latter case, weak and/or stillborn calves are the result.
- In a number of cases, sick cows die.
Salmonella symptoms vary greatly
The symptoms can vary greatly, from many severely sick animals to an occasional abortion. The degree of severity of an outbreak likely depends primarily on the resistance in the affected herd. Research clearly suggests that liver fluke infections in particular, but also BVD-virus infections, can seriously reduce resistance to Salmonella. Almost all animals overcome an infection and are free from contamination after some time. Antibodies are then eliminated from the milk and the blood within three to nine months. However, disease restricts growth and holds back development, which is why prevention is so important.
Infection is persistent
The wild card of Salmonella infections is that some cattle become carriers. These individuals fail to overcome the disease fully and can continually, or sometimes sporadically, discharge the Salmonella bacteria in their faeces. Even when milking is clean and hygienic, it is not always possible to avoid getting faeces in the milk. The dairy pasteurizes the milk, eliminating the problem for consumers.
Milk-drinking calves are susceptible for Salmonella
If calves are fed raw milk, they risk infection with Salmonella. It is the young, milk-drinking calves who are extremely susceptible to a Salmonella infection. They can become seriously ill and can even die if not treated quickly. Diarrhoea, lung infections and high fevers are the key indications initially. Therefore, if Salmonella antibodies are detected in the bulk milk, we highly recommend avoiding cows' milk and swapping to milk replacer.
Treatment plan for Salmonella
Once a Salmonella infection has been detected, a treatment plan must be drawn up together with a veterinarian. The contaminated animals must be placed in quarantine, away from the other animals on the farm.
- Maximum hygiene is essential.
- This includes decontamination containers, separate boots and clothing, etc.
- Personal hygiene is also very important. After all, salmonella is an infection that can be transmitted to humans. Ensure therefore that as few family members as possible come into contact with the infected animals. So no children playing in the quarantine area.
- And keep dogs away, too.
- Wash your hands thoroughly after contact with the animals.
- If milk-producing cows are infected, then definitely do not drink their milk raw. Boil the milk thoroughly first, which is always good advice anyway.
Identifying Salmonella carriers
Carriers are found at approximately 2 out of 3 farms following acute Salmonella infection. These are the animals that are infected but not ill, yet still regularly discharge the bacteria in their faeces. These carriers must be traced by testing faecal matter or blood. The best option is to dispose of these animals. Eventually a farm can be declared Salmonella-free through bulk milk testing.