This week, we are sharing a literature review based on a collaboration between Drs. John Deen and Perle Zhitnitskiy and the animal welfare team at the University of Wisconsin River Falls, led by Dr. Kurt Vogel. In this open-access publication from the Journal of Translational Animal Science, the authors review the history of captive bolt euthanasia, best practices and current challenges faced by the swine industry including the euthanasia of mature swine.
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Acclimation strategies in gilts to control Mycoplasma hyopneumoniae infection
Today we are sharing a review article regarding the acclimation strategies in gilts to control Mycoplasma hyopneumoniae infection published in Veterinary Microbiology by the University of Barcelona in collaboration with Dr. Maria Pieters.
Key points
- M. hyopneumoniae monitoring should be performed in incoming gilts and recipient herd.
- Gilt acclimation against M. hyopneumoniae aids to maintain farm health stability.
- Vaccination is the main strategy used to acclimate gilts in Europe and North America
Monitoring and diagnosis of M.hyopneumoniae
The article first covers how to assess the M. hyopneumoniae health status of the herd. Various methods of monitoring and diagnosis are detailed and compared with each other.
- Most commonly used: M. hyopneumoniae antibody detection by ELISA but the interpretation of the results can be challenging.
- Most useful technique: PCR on different respiratory tract samples.
- No consensus on sample type to detect bacterial DNA in live pigs.
Classification of the herd based on incoming replacement and recipient herd
Proposed farm classification according to M. hyopneumoniae health status. (aELISA results (negative/positive) could depend on infection pattern in the farm and sampling time point.)
| Classification
|
Clinical signs | Lung lesions | ELISA resulta | PCR result | |
|---|---|---|---|---|---|
| Negative | Not observed | Not observed | Negative | Negative | |
| Provisional negative | Not observed | Not observed | Positive | Negative | |
| Positive | Subclinical infected I | Not observed | Not observed | Positive/Negative | Positive |
| Subclinical infected II | Not observed | Observed | Positive/Negative | Positive | |
| Clinical affected | Observed | Observed | Positive/Negative | Positive | |
-
Prevention and control
Vaccination against M. hyopneumoniae, using commercial vaccines, is the most commonly used strategy to control its associated diseases in worldwide swine production systems.
However, since protection against M. hyopneumoniae infection by commercial vaccines is not complete, antimicrobial treatments are frequently required to control disease outcome. Several antibiotic classes are effective in reducing the incidence and severity of M. hyopneumoniae compatible lung lesions: macrolides, lincosamides, tetracycline, and fluoroquinolones among others.
Acclimation scenarios
Europe
The most common replacement origin used in Europe was external and that most respondents knew M. hyopneumoniae health status of replacement on arrival, being in most of the cases seropositive. Nevertheless, only 28% of respondents verified this theoretical M. hyopneumoniae status given as ELISA test results. Additionally, the most used strategy to acclimate gilt was vaccination alone (58%).
North America
Gilt Development Units are utilized to allow ample time to incoming gilt to gradually adopt the health status of the recipient herd. These acclimation facilities are in most of the cases continuous flow allowing an effective gilt exposure to M. hyopneumoniae. Gilt vaccination in North American swine industry was also recognized as the most common practice used at acclimation.
Natural exposure
Natural exposure was also used in both continents to help acclimate the incoming gilts to M.hyopneumoniae. However, taking into account that pig-to-pig transmission of this bacterium has proven to be extremely slow , the ratio of infected and naïve gilts as well as the time of exposure are crucial and should be considered to achieve an effective exposure.
Abstract
Mycoplasma hyopneumoniae (M. hyopneumoniae) is the primary causative agent of enzootic pneumonia (EP), one of the most economically important infectious disease for the swine industry worldwide. M. hyopneumoniae transmission occurs mainly by direct contact (nose-to-nose) between infected to susceptible pigs as well as from infected dams to their offspring (sow-to-piglet). Since disease severity has been correlated with M. hyopneumoniae prevalence at weaning in some studies, and gilts are considered the main bacterial shedders, an effective gilt acclimation program should help controlling M. hyopneumoniae in swine farms. The present review summarizes the different M. hyopneumoniae monitoring strategies of incoming gilts and recipient herd and proposes a farm classification according to their health statuses. The medication and vaccination programs against M. hyopneumoniae most used in replacement gilts are reviewed as well. Gilt replacement acclimation against M. hyopneumoniae in Europe and North America indicates that vaccination is the main strategy used, but there is a current trend in US to deliberately expose gilts to the pathogen.