Managing our flocks to reduce risk of infection

By Sahlie P. Lacson

In the wake of the recent African Swine Fever (ASF) that beset the hog industry starting in the third quarter of 2019, the volume of poultry production in the Philippines, in turn, grew 8.48% to 465,150 metric tons. According to the Philippine Statistics Authority (PSA), the chicken industry accounted for 14.72% of the total value of agriculture output, equivalent to R25.941 billion. During the same quarter of 2017 and 2018, the industry accounted for 13.27% and 13.96%, respectively. Last year’s increase in percentage can be associated to consumer’s tendency to shift their consumption from pork to chicken. But how can we prevent the same fate as ASF when it comes to our flocks in order to answer the increase in demand?

Whether for eggs or for meat, in order to have success with small or large poultry farms, we need to make sure to start and end with a healthy flock. This is best done through proper management and preventive practices. However, as a livestock owner, it’s likely one will have to deal with sick animals at some point. Being able to identify a disease issue in our flock will also aid us in the decision-making process and in preventing continued outbreaks. With an extensive number of diseases and disorders that could affect our chickens, it is best to have a guide on how to prevent, treat, and control some of the major diseases that could impact our flocks.

In a seminar conducted by Dr. Renato Rollan, a poultry consultant, during the recent International Farmer’s Summit, he enumerated the key factors in reducing risks of infections.

As it is, the current system of poultry raising in the Philippines has focused more on yield. The high stacking density commonly found in housed poultries contributes to the flock’s susceptibility to infectious, as well as metabolic diseases, and which causes these agents to spread quickly. The failure to provide the correct growing conditions or factors such as temperature, relative humidity, air composition, air speed and air movement, light, water, feeds, space, and immunization, all contribute to endemic diseases in poultry.

To date, the Philippines had experienced the following poultry diseases: Newcastle disease (ND), infectious bronchitis (IB), infectious bursal disease (IBD), infectious laryngotracheitis (ILT), mycoplasma, and fowl cholera, among others. Why? The high density of poultry population in a given area seemed to be the main causative factor. Add to this the below standard levels of farm biosecurity measures especially in backyard farms, layer, grow-out, and pullet farms. The presence of multi-species at the farm, inadequate quarantine or vaccination also largely contributes to disease worsening.

As a consequence, breeders are heavily vaccinated for viral diseases in order to contain them. What can happen then? It could further result in the continuous build-up of pathogens. Also, the nutrients are diverted to immune response which may possibly result in poor production efficiency. The immune system, in the long run, cannot process or dispose off the pathogens caused by severe vaccination reaction. Worst, they could eventually succumb to disease.

The summer season or hot weather, which is from the second to third quarter of the year, are usually the most difficult times for poultry operations. The hot and humid conditions during May to October result in the high level of mycotoxins in raw materials, which has a major effect on production efficiencies and a predisposing factor for diseases, which could result in outbreaks.

Reducing risks of infection 

First on the list in reducing risks of infection is cleaning and disinfection. Hygiene or quarantine and isolation remove an average of 80% dirt and pathogens among flock since this minimizes exposure or restrict access. Establish a separation to distinguish the farm from the outside world.

An important reminder by Dr. Rollan is to not forget to apply rat poison or insecticide to the surroundings since it will be useless to disinfect the farm or premise without rodent and insect control. Remember that a pair of rats and its progenies can produce 1,500 to 2,000 rats in a year.

Other important points to remember: Bacteria survive longer than viruses because they can replicate outside of the hosts; bacteria can survive longer on hard surfaces than on cloth; and bacteria and viruses can survive longer in moist environments.

In cases of possible human contamination, determine if you are exposed. If there is a possibility of exposure, resort to 72 hours quarantine policy and wear a mask to prevent transmission of pathogens lodged in your nasal passages.

Second, give your chicks a good start, that is, start with healthy chicks. This can ensure 50% of the flock’s success. Prioritize their needs: oxygen, light, heat, and vaccination.

Give your chicks a good start, that is, start with healthy chicks. This can ensure 50% of the flock’s success. Prioritize their needs: oxygen, light, heat, and vaccination.

Third, maintain gut health. Gut health refers to the balance of microorganisms that live in the digestive tract. The use of gut active compounds, which include probiotics/prebiotics, organic acids, acidifiers, monoglycerides, and fermentable fibers result in early development.

Fourth, maintain a correct adaptive vaccination program. Here, variables should be determined first: type of poultry production (whether broiler, layer, or breeder); density of poultry population in the area; disease risk of field challenge; degree of level of maternal antibodies; timing of vaccination; resources available (route of administration and the level of stress at the time of vaccination); need for booster; and post vaccination reasons or complications.

The types of vaccines that may be used in poultry are attenuated live, close attenuated live, inactivated (killed) vaccines, vector vaccines, and immune complex. These types of vaccines are used differently, say, in order to protect birds from early infection and onwards (that is, for day-old chicks), killed vaccine may be used to protect against ND, vector vaccine and immune complex for IBD.

Moreover, vaccines are considered part of biosecurity: the vaccine must be given and provide protection by the time the bird gets exposed to the field virus.

Fifth is monitoring. This means the early recognition of the disease. Included in the flock monitoring programs are daily check of the flock (production parameters, feeds and water intake, general appearance, and clinical signs), and regular necropsy (blood sampling of laboratory analyses, and blood titers).

Sixth, assist the birds during times of stress. Environmental sources of stress could be ambient heat stress, relative humidity, poor ventilation, and lack of growing space. Heat stress has an effect on feed intake, weight gain, blood pH, and survival. It is important to provide them with electrolytes, sodium, potassium, chloride, vitamin C, and ascorbic acid to aid with its different functions.

Last is adaptive medication. This means the responsible use of antibiotics for sick animals only rather than for prevention or growth promotion. It is important to know what you are treating, to use as little as possible or as much as necessary with correct dosage and timing.

There is a saying that an ounce of prevention is better than a pound of cure. Here, preventing birds from getting sick will prove to be more cost-efficient than treating sick birds.

This appeared in Agriculture Monthly’s April 2020 issue. 

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