Vaccines available for northern cattle
The following provides a brief discussion on the main diseases in northern Australian beef herds for which vaccines are available and highlight when vaccination is most useful, as well as examples of appropriate programs.
Clostridial vaccinations are relatively cheap. The recommended instruction is for two vaccinations at a minimum of four weeks apart prior to animal husbandry procedures. This provides immunity against five clostridial diseases – tetanus, black leg, black disease, pulpy kidney and malignant oedema.
Black disease is associated with liver fluke so is rarely seen in the north. The practicality and economics of being able to ensure calves in northern Australia receive two shots of vaccine prior to animal husbandry procedures can be challenging, however to ensure strong immunity against the five clostridial diseases two doses are necessary.
Tetanus especially takes about 10 days to exhibit clinical signs, by which time the vaccine has started producing an initial immune response. The natural challenge from the toxin will further stimulate immunity and should provide protection. The risk of tetanus increases with the use of elastrator rings and the Burdizzo.
Black leg is most likely to occur in summer months in flooded areas and after heavy rain when the pastures are highly digestible.
Pulpy kidney is associated with high concentrate feeding and is most likely seen when lot feeding, so even if the benefits are not recognised ‘on farm’, they are realised in a feedlot.
Leptospirosis not only causes abortion in cattle, it can also infect people working with animals (Weil’s Disease). Vaccinating cattle against ‘lepto’ will help protect those working around cattle, as well as the cattle themselves – although other species such as rats and feral pigs are also a high risk factor.
While the organism has been detected all over Australia, outbreaks are more common in dairy cattle, coastal regions and in wet swampy areas. In general, a lepto vaccine is given in conjunction with a clostridial vaccine (as 7-in-1) especially in replacement heifers and breeders. The antibody response tends to wane over twelve months and an annual booster is required. Maximum antibody levels and protection against abortion is achieved if the vaccine is given at mid pregnancy. In practice, this usually occurs at the time of pregnancy diagnosis.
Pinkeye vaccination is one of the control measures that might be considered for beef enterprises where pinkeye occurs, especially given the challenges with treating affected animals. Some Bos taurus breeds are more susceptible.
Only a single vaccine dose is required 3–6 weeks prior to the infection. Where prolonged infection occurs, a booster vaccination after five months may provide pinkeye control. (Note: Inflammation of the eye [keratoconjunctivitis] can be caused by many factors other than the bacterium in the vaccine. If this is the case, vaccination will not be effective).
Pestivirus vaccination is one way to control bovine viral diarrhoea virus (BVDV). The high prevalence of Pestivirus in northern Australian herds was established as far back as 1967. The biggest risk occurs when a carrier animal (often a pregnant cow) is introduced to a naïve breeding herd. An effective vaccination program (an initial two doses with annual boosters) will minimise the impact of BVDV but once commenced, it is likely to be an ongoing commitment in the herd as the herd will become naïve if vaccination is ceased. Therefore, discuss your herd status and the use of Pestigard® in your herd with your veterinarian.
It is highly recommended that studs and seedstock producers implement a sound vaccination program as they need to guarantee that sires sold are not actually carrier animals.
Calf scours is a complex disease with several different organisms including rota virus, corona virus and Escherichia coli bacteria potentially being responsible. However, vaccination is usually effective at decreasing scours, even though the vaccines do not cover all the potential pathogens.
Cows need to be vaccinated pre-calving to ensure adequate colostrum antibody levels to protect young calves. The risk factors appear to be poor seasons (low quality colostrum), maiden heifers and small calves (breeds like Wagyu are more susceptible).
Vibriosis can result in poor reproductive rates. It can be controlled by making sure bulls are properly vaccinated. Bulls should receive two doses of vaccine prior to their first use, followed by annual booster vaccinations.
Vibriosis is very prevalent and the immunity acquired through natural infection can suppress the disease sufficiently for it to go unnoticed. It is a venereal disease and consequently maiden heifers are always naïve and most vulnerable. Vaccination of heifers and cows may be required where bull control is problematic or where herds are found to be infected.
Bovine ephemeral fever
Bovine ephemeral fever (BEF or three-day sickness) is a viral disease in cattle, transmitted by biting insects (primarily by mosquitos and midges). It is endemic in the far north and in coastal regions. Natural infection provides lifetime immunity. The severity of symptoms increases with age and death can eventuate in older, heavier animals. The disease causes mild temporary symptoms in young stock.
The risk increases after a series of dry seasons with low insect activity. The distribution and spread of the disease depends on seasonal conditions and vaccination is the only means of preventing the disease in regions outside the endemic area with two initial doses required.
Botulism is a major problem in northern beef herds, especially in regions acutely deficient in phosphorus. It is probably the biggest factor contributing to breeder mortality in northern Australia. There is no treatment for the disease – vaccination is the only way to protect the breeder herd.
Bone chewing and ingestion of carcase material is a high risk factor. Phosphorus supplementation can reduce the prevalence of botulism. Steers do not usually require vaccination as they are sold at a much younger age and are less prone to bone chewing.
Tick fever is a group of three separate diseases transmitted by cattle ticks. It is localised to the cattle tick endemic area of northern Australia and seldom presents as a problem in these regions as passive immunity followed by natural challenge ensures most animals are protected at an early age.
Bos indicus cattle are more resistant to ticks and the risk of infection. The major risk factors are stock located in the marginal tick areas where the prevalence of ticks may be eliminated during dry seasons.
Producers who wish to move cattle, especially bulls, north of the ‘tick line’ should consider vaccination against tick fever. Cattle should be vaccinated at least four weeks prior to movement into the tick endemic parts of northern Australia to allow time for protective immunity.
Northern cattle disease and vaccination summary
Table 1 includes a summary of the main diseases in northern Australian beef herds for which vaccines are available, and some of the main products on the market as well as the dose rate and cost per dose (click table to zoom in on information).