Vaccination: a way to reduce the consumption of antibiotics in poultry

The outbreaks of infectious diseases, especially infectious bronchitis, infectious bursitis, Newcastle disease, and others decreases the overall flock health, in some instances animals must be culled or it might increase the necessity to use antibiotics because of secondary bacterial infection activation. Vaccination is the most effective animal health intervention to prevent dangerous infectious disease outbreaks, decrease overall mortality, economic losses, and antibiotic consumption.

Vaccines in poultry can be applied via drinking water, food, spray, or injection. To ensure a vaccine will provide a desired effect, they have to be stored properly based on the manufacture’s recommendations.

If vaccines are administered via the drinking water line, the line has to be flushed in order to reduce bacterial biofilms and algae formation on its walls. In most cases, appropriate water/vaccine dilution has to be acquired based on the producer’s recommendations. When the correct vaccine dilution for a particular group is prepared, it can be added to an automatic dispenser which is connected to the drinking line. Ensure that the birds do drink the vaccine at the time specified in instruction. For vaccine application via spray attenuate (dilute) the vaccine according to producer or your veterinarian’s instructions and according to your herd needs. Place the prepared working solution in the nebulizer. To improve vaccine correct intake, adjust the droplet size to reach the target tissues. The vaccine should be sprayed systematically and evenly so that each chick receives its dose, but without causing undue stress to the chickens. Check broiler health status after vaccination.

Support the calf to obtain better vaccination results

Farms specialized in bull calf rearing from a very young age often experience high frequencies of respiratory diseases. Specially during the first month after arrival. Calves are often exposed to radical changes and challenges in this period.

Vaccination could be a useful tool to enhance immunity. In other cases, vaccination seems to weaken the calves and trigger outbreaks of disease, often when calves are stressed. Whenever vaccinating, try to create the best possible conditions for the calf and minimize factors negatively affecting their immunity:

  • Opt for short transport time (max. 1-2 hours) to limit dehydration, hypothermia and exhaustion
  • Avoid mixing calves from different farms on the same truck
  • Insert calves in a clean box
  • Keep calves in small groups – preferably in pairs – at least for the first 6 weeks
  • Avoid mixing calves of different origin in the same box
  • Segregate groups of calves by solid walls or panels
  • Make sure all calves have easy access to fresh water – preferably lukewarm water from a bucket or trough
  • Feed sufficient amounts (minimum 6-7 liters/ day) of good quality milk replacer
  • Start milk feeding on the day of arrival
  • Secure good air quality and avoid draught
  • Avoid moving, mixing, feeding changes and other negative factors 3-4 days before and after vaccination

Intra-nasal vaccines can be applied at the day of arrival. Let other vaccinations wait until the calves are in a positive energy balance (e.g. from 2 weeks after arrival).

The prevention and control of mastitis in sheep

Mastitis is a major a problem in dairy farming, being a threat to animal health and welfare, production efficiency, and product quality. Mastitis is the result of contagious pathogens such as Streptococcus agalactiae, Mycoplasma spp. and Staphylococcus aureus, entering the mammary gland via teat canal, establishing an intramammary infection (IMI) and resulting in an inflammatory reactionThe disease can be in a clinical or subclinical form. 

In the subclinical form; milk production decreases, bacteria are present in the secretion, and composition is altered. Transmission of contagious mastitis pathogens mainly occurs during milking. Bedding is also very closely related to the bacteria exposure of the sheep since teats may be in direct contact with bedding materials which are a  primary source of mastitis causing pathogens. 

Tests have to be used to detect the presence of intra-mammary infections (IMI) either directly (culturing of the causative bacterium) of indirectly (by showing inflammatory response including an elevated somatic cell counts-SCC). 

A vaccination program is recommended to be included in the control of mastitis together with hygiene methods in sheep flocks. Mastitis treatment may contribute to reduced transmission of infection, but antimicrobial treatment of mastitis is not always successful. When treatment fails, removal of the infected animals from the flock, to prevent contagious transmission, may be necessary. 

The implementation of biosecurity measures such as: 

  1. good husbandry and milking practice with regular maintenance of the milking machineand 
  2. use of post-milking teat disinfection  

can prevent introduction and transmission of mastitis in dairy ruminants, and consequently, reduce antibiotics usage. 

Enterotoxemia in sheep and lambs

Enterotoxemia is a frequently severe disease of small ruminants of all ages. It is caused by two strains of bacteria called Clostridium perfringens, type C and D. Type C principally produces the β-toxin, which most commonly kills lambs less than 2 weeks of age. A typical symptom of lambs that die from β-toxin is simply sudden death. Type D principally produces the ε-toxin which affects lambs older than 2 weeks of age, particularly those eating diets high in starch. Lambs exposed to high doses of ε-toxin also die very quickly. Fatalities occur particularly in non-vaccinated animals or in newborn lambs whose mother was not vaccinated.

Vaccination of ewes 3-4 weeks before lambing improves passive protection in lambs up to 12 weeks of age, whereas there is no benefit of vaccinating lambs before 6 weeks of age. Since the causative bacteria proliferate in the intestine in response to ingestion of abnormally high levels of starch, sugar, or protein, there are two alternatives:

  • to divide the daily allotment into as many small feedings as is feasible, or
  • to feed roughages such as hay before feeding these higher-risk feeds.

These good practices, vaccination and Smart feeding strategies, can prevent animal losses and improve their welfare. Prevention of enterotoxemia is far more likely to be successful than trying to treat the disease. Treatment of enterotoxemia may not be successful in severe cases.