Pig respiratory diseases are commonly caused by diseases such as porcine pleuropneumonia, mycoplasmal pneumonia, and influenza. Once respiratory disease occurs, most cases involve mixed infections, have a prolonged course, and recur. Respiratory diseases are conditional diseases; for example, they are more likely to occur in autumn and winter when pigs’ resistance declines, they are under stress, or temperature differences are too great.
1, The harm of respiratory diseases to pig herds
In mild cases, respiratory diseases in pigs can cause growth to stall, weight loss, and reduced feed efficiency; they can also affect the time to market. Breeding pigs may miscarry, and severe cases may result in death.
2, Main clinical signs
Elevated body temperature (most respiratory diseases are accompanied by an elevated body temperature. Only one or two respiratory diseases do not cause fever, such as uncomplicated mycoplasma pneumonia and uncomplicated atrophic rhinitis, which usually do not cause fever), difficulty breathing, depression, reduced appetite, sneezing, frequent coughing, reddening of the skin, or purplish discoloration and congestion of the extremities).
3, What are the causes of respiratory diseases in pigs?
There are many causes of respiratory diseases in pigs:
Environmental factors, such as poor environmental quality, including excessive harmful gases such as ammonia, dust, etc.;
Management factors, such as high stocking density, high temperature and humidity, stress from regrouping, transportation, etc.
Viral factors, such as porcine reproductive and respiratory syndrome virus, pseudorabies virus, swine influenza virus, circovirus, etc.;
Bacterial factors, such as Glaesserella parasuis, Pasteurella, Actinobacillus, Streptococcus, etc.;
4, Reasons why porcine respiratory diseases tend to recur
When respiratory diseases frequently break out on pig farms, pig farmers’ first reaction is not to look for the cause, but to instinctively buy medicine to treat the disease. However, this treats the symptoms but not the root cause, wasting money. On careful reflection, respiratory diseases on pig farms are generally closely related to the following factors:
1. Many diseases are now mixed infections. Respiratory disease infections are accompanied by other viral diseases, which is also a major reason why pig diseases are currently difficult to treat and recover from.
2. Unstable PRRS on the pig farm: If respiratory diseases occur particularly easily on your pig farm, you should consider whether PRRS on your farm is very unstable. Immunosuppression leads to reduced immune function and a lack of immune response. After vaccination, antibodies are produced slowly or insufficiently, resulting in low antibody levels that cannot resist infections from viruses such as classical swine fever, PRRS, and pseudorabies. On the other hand, poor overall disease resistance in the body can lead to diseases caused by opportunistic pathogens, such as Mycoplasma, Haemophilus parasuis, Pasteurella, and Streptococcus.
Preventive measures for porcine respiratory diseases
1, Appropriate environmental control:
Reduce large day-to-night temperature fluctuations. If the herd is in a subhealthy state, even a slight stressor can cause respiratory disease symptoms to appear in the herd.
2, strengthen feeding management:
(1) Balanced feed nutrition: Balanced nutrition is the best veterinary medicine; it is the foundation of pig health.
(2) Ensure good hygiene and disinfection: Maintain good hygiene, keep the housing dry, reduce stress caused by temperature differences, and disinfect on schedule to reduce the concentration of pathogens or dust in the air.
(3) Reduce stocking density: Excessive stocking density can affect pigs’ feed intake, water consumption, and rest, as well as the growth rate of finishing pigs, and makes disease infection more likely.
(4) Reduce stress: Feed changes, mixing groups, moving pigs between pens, sudden weather changes, cold stress, injections, and other factors can cause varying degrees of stress in pigs. Repeated and prolonged stress can make pigs ill. In production, follow operating procedures and minimize the harm caused to pigs by various production-related stressors.
(5) Reduce mycotoxin poisoning: Mycotoxins can reduce herd immunity and easily trigger various infectious diseases. Affected pigs may show false estrus, splayed legs, black spots on the skin of the back, and pale skin. A mycotoxin binder can be added to the feed.
3, vaccination and deworming
Vaccination is the foundation of disease prevention in pig herds. Particular attention should be paid to vaccination against diseases such as classical swine fever, pseudorabies, and porcine circovirus (2) disease. The principle of treating respiratory diseases is to identify the cause first, then select appropriate medications based on clinical signs and pathological findings. When using medication, ensure the drugs are combined appropriately.