Best of Leman 2018 series: J. Patterson – Efficiencies of replacement gilt management

We launched a new series on the blog last year. Once a month, we are sharing with you a presentation given at the Allen D. Leman swine conference, on topics that the swine group found interesting, innovative or that lead to great discussions.

We can find all of the presentations selected from last year’s conference on the blog here.

Our fifth presentation is by Jennifer Patterson from the University of Alberta about how we can improve efficiencies of replacement gilt management.

Continue reading “Best of Leman 2018 series: J. Patterson – Efficiencies of replacement gilt management”

What are the acclimation practices for Mycoplasma hyopneumoniae accross the EU?

This new publication in the Porcine Health Management journal is the result of a collaboration between the University of Barcelona in Spain, PIC (Pig improvement Company) and the MycoLab at the University of Minnesota.

321 farms were surveyed across Europe and Russia regarding their practices for gilt acclimation especially in the context of Mycoplasma hyopneumoniae. The farms are spread over 18 countries and this is reflected in the strong variation of the measures taken to acclimate the incoming gilt population.

Among the questions asked, the type of farm as well as the size of the herd were recorded. Regarding the gilts, the researchers took into account receiving schedule as well as origin and age in addition to the acclimation measures.

In the table below, you can see the summary of  the measures taken to acclimate the gilts to Mycoplasma hyopneumoniae. The vast majority of the herds (77%) used vaccination either as a single intervention or coupled with exposure to sows about to be culled.  Another popular option (22.4%) was no intervention at all.

Acclimation methods for Mycoplasma hyopneumoniae across the EU
Number of farms (%)according to the methods used for replacement gilt acclimation in terms of M. hyopneumoniae

Click on the table above to see the full open-access publication.

Abstract

Gilts are considered to play a key role in Mycoplasma hyopneumoniae (M.hyopneumoniae) transmission and control. An effective gilt acclimation program should ideally reduce M. hyopneumoniae shedding at first farrowing, decreasing pre-weaning colonization prevalence and potential respiratory problems in fatteners. However, information on gilt acclimation practices is scarce in Europe. The aim of this study was to identify current acclimation strategies for M. hyopneumoniae in Europe using a questionnaire designed to assess 15 questions focused on gilt replacement status,
acclimation strategies and methods used to ascertain its effect. A total of 321 questionnaires (representing 321 farms) were voluntarily completed by 108 veterinarians (from 18 European countries). From these farms, 280 out of 321 (87.2%) were aware of the health status of gilts on arrival. From these 280 farms, 161 (57.5%) introduced M. hyopneumoniae positive replacements. In addition, 249 out of 321 (77.6%) farms applied an acclimation process using different strategies, being M. hyopneumoniae vaccination (145 out of 249, 58.2%) and the combination of vaccine and
exposure to sows selected for slaughter (53 out of 249, 21.3%) the most commonly used. Notwithstanding, only 53 out of 224 (23.6%) farms, knowing the M. hyopneumoniae initial status and performing acclimation strategies against it, verified the effect of the acclimation by ELISA (22 out of 53, 41.5%), PCR (4 out of 53, 7.5%) or both (27 out of 53, 50.9%). This study showed that three fourths of the farms represented in this European survey have M. hyopneumoniae acclimation strategies for gilts, and one fifth of them verify to some extent the effect of the process. Taking into account that the assessment of acclimation efficacy could help in optimizing replacement gilt introduction into the breeding herd, it seems these practices for M. hyopneumoniae are still poorly developed in Europe.

Link to the full open-access publication

Infection dynamics and genetic variability of Mycoplasma hyopneumoniae in self-replacement gilts

This is a new research paper from the MycoLab under Dr. Maria Pieters’ supervision. In this study, the group looked at the infection dynamics and genetic variability of Mycoplasma hyopneumoniae in self-replacement gilts, in 3 positive herds. Serum samples were taken from the gilts at 150 days of age onward and laryngeal swabs were collected from the gilts and their progeny.

Highlights of this project

  • Genetic variability of M. hyopneumoniae was evaluated using MLVA typing.
  • The highest M. hyopneumoniae prevalence in gilts was detected at 150 days of age.
  • Detection patterns for M.hyopneumoniae were different among farms.
  • Genetic variability was identified within and among farms.

 

Pieters 2017 infection dynamics Mhyop

Abstract:

The aim of this study was to assess the longitudinal pattern of M. hyopneumoniae detection in self-replacement gilts at various farms and to characterize the genetic diversity among samples. A total of 298 gilts from three M. hyopneumoniae positive farms were selected at 150 days of age (doa). Gilts were tested for M. hyopneumoniae antibodies by ELISA, once in serum at 150 doa and for M. hyopneumoniae detection in laryngeal swabs by real time PCR two or three times. Also, 425 piglets were tested for M. hyopneumoniae detection in laryngeal swabs. A total of 103 samples were characterized by Multiple Locus Variable-number tandem repeats Analysis. Multiple comparison tests were performed and adjusted using Bonferroni correction to compare prevalence of positive gilts by ELISA and real time PCR. Moderate to high prevalence of M. hyopneumoniae in gilts was detected at 150 doa, which decreased over time, and different detection patterns were observed among farms. Dam-to-piglet transmission of M. hyopneumoniae was not detected. The characterization of M. hyopneumoniae showed 17 different variants in all farms, with two identical variants detected in two of the farms. ELISA testing showed high prevalence of seropositive gilts at 150 doa in all farms. Results of this study showed that circulation of M. hyopneumoniae in self-replacement gilts varied among farms, even under similar production and management conditions. In addition, the molecular variability of M. hyopneumoniae detected within farms suggests that in cases of minimal replacement gilt introduction bacterial diversity maybe farm specific.

Access to the full version of the paper

Detection of Mycoplasma hyopneumoniae in naturally infected gilts over time

A longitudinal study to assess Mycoplasma hyopneumoniae natural infection in gilts

This study was conducted by Dr. Karine Takeuti under the supervision of Dr. Maria Pieters from the University of Minnesota, College of Veterinary Medicine. The objective was to sample replacement gilts from 20 days of age until the day before weaning to detect Mycoplasma hyopneumoniae . Laryngeal swabs, tested by PCR, were taken every 30 days at a Mycoplasma positive sow farm. Therefore, the animals were naturally infected.

Gilts were found positive at 110 days, no detection in piglets

11.4% of the gilts were found positive at 110 days whereas all the previous samples came back negative. Positive results peaked at 140 days when 36.4% of the samples were positive for Mycoplasma hyopneumoniae. 27.3% of the gilts got positive results twice or more during the sampling period but 18.2% of the animals remained negative for the duration of the study.  All of the 220 piglets samples were also negative.

Takeuti longitudinal gilt mycoplasma hyopneumoniae 2017
Abstract

Mycoplasma hyopneumoniae causes a chronic respiratory infection in pigs and its transmission occurs mainly by direct contact and by vertical transmission (sow-to-piglet). The objective of this study was to assess the detection dynamics and persistence of M. hyopneumoniae natural infection in replacement gilts. Forty-four twenty-day-old gilts were selected from a M. hyopneumoniae positive farm and followed up to one day prior to their first weaning. Laryngeal swabs were collected every 30 days, starting at day 20, for M. hyopneumoniae detection by real-time PCR, resulting in 12 samplings. Piglets born to selected females were sampled via laryngeal swabs one day prior to weaning to evaluate sow-to-piglet transmission. The M. hyopneumoniae prevalence was estimated at each one of the 12 samplings in gilts and a multiple comparison test and Bonferroni correction were performed. Bacterial detection in gilts started at 110 days of age (doa) and a significant increase (p < 0.05) occurred at 140 doa. The M. hyopneumoniae prevalence remained above 20% from 140 to 230 doa, decreasing thereafter. However, it did not reach 0% at any sampling after 110 doa. In this study, M. hyopneumoniae was not detected in piglets sampled prior to weaning. The M. hyopneumoniae detection pattern showed that in natural infections, gilts were positive for M. hyopneumoniae for one to three months, but occasionally long-term detection may occur. Moreover, the lack of M. hyopneumoniae detection throughout the study in 18.2% of gilts indicated the existence of negative subpopulations in positive herds.

Link to the entire article