Leptospirosis is serious infectious disease of dairy cattle. It is important not only because of its detrimental effects on the health and production of the herd, but also because it is transmissible to humans from cattle. In humans it can cause serious, long-term illness.
A vaccination program can provide long-term immunity in cattle against leptospirosis, thus protecting the herd and humans from the disease.
Leptospira interrogans serovar pomona and Leptospira interrogans serovar hardjo
|Signs of the disease|
L. pomona usually affects calves causing fever, depression, acute anaemia, small blood spots on gums, and redwater; in older cows it can cause abortion, and mastitis with reduction in milk yield and milk discolouration.
L. hardjo usually affects pregnant or lactating cows causing fever, a flabby mastitis with severe drop in milk production, milk discolouration and abortion.
|Potential economic losses|
L. pomona infection:
L. hardjo infection:
Apart from reduced milk production, abortions and calf deaths economic affects include:
|Risks to people|
Leptospirosis in humans causes:
There is no leptospirosis vaccine for people. The best way to prevent leptospirosis in dairy workers is by vaccinating the herd to eradicate the disease from the cattle. Farmers must take responsibility to prevent infection risks to their workers, family, visitors and themselves.
|How the disease spreads|
|Prevention and control|
A vaccination program can provide long-term immunity in cattle against leptospirosis. Vaccinate all susceptible cattle before infection occurs, so that chronic urinary shedding is prevented.
For herds that already have leptospirosis:
The cost to vaccinate a herd can vary significantly. Prices can be affected by:
It is important to compare the different brands and various retailers to ensure you get the most economical vaccination program.
These costs are based on 2003 prices for a 100-cow herd (100 cows, 3 bulls, 25 heifers and 40 replacement heifer calves) and do not include labour, materials or facility costs:
Therefore the program would break-even, if the equivalent of one animal (valued at $1000) was saved every seven years by vaccination against leptospirosis.
Using a seven-in-one vaccine (combined leptospirosis and clostridial vaccine) saves time and labour costs, because it requires only one injection instead of two, to protect the herd against the five clostridial diseases and the two types of leptospirosis
Therefore the program would break-even, if the equivalent of one animal (valued at $1000) was saved (from the effects of any of the clostridial diseases or leptospirosis) every five years by a seven-in-one vaccination.