umn – Page 105 – Swine in Minnesota

Time-series analysis for porcine reproductive and respiratory syndrome in the United States

Today, we are sharing an open-access publication from Dr. Andreia Arruda, Dr. Ana Alba and members of the MSHMP team in the journal PlosOne.

This study was conducted using data collected from the Morrison Swine Health Monitoring Project. The main objective of this study was to use time-series analysis to investigate whether yearly patterns commonly described for PRRS were in fact conserved across different U.S. states.

Methods

The 268 breeding herds enrolled in this project were the ones that participated in the MSHMP from July 2009 to October 2016. PPRS status of each farm was reported weekly following the AASV guidelines. The five states examined included Minnesota (MN), Iowa (IA), North Carolina (NC), Nebraska (NE), and Illinois (IL).

Results

81 MN farms, 72 IA, 45 NC, 30 NE, 40 from IL, were enrolled in the study with a mean number of animals per site of 2,666; 3,543; 2,342; 4,041; and 4,018 respectively.

journal.pone.0195282.g002 — Graphs showing the prevalence (black line) and upper and lower 95% confidence intervals (grey dotted lines) of PRRS virus positive farms for the five different U.S. states participating in this study: A: Minnesota; B: Iowa; C: Nebraska, D: North Carolina and E: Illinois

The main finding of this study was that PRRS seasonality varies according to geographical region, and the commonly referred “PRRS season” is not necessarily the only time of increase in disease incidence.

Another interesting finding from this study was the presence of an alternating trend for all examined states within of the U.S., except for the state of Iowa, the largest pork producing states in the country (approximately 31.4% of the total US hog and pig inventory), which had an increasing linear trend over the examined years.

In conclusion, PRRS seasonal patterns are not homogeneous across the U.S., with some important pork producing states having biannual PRRS peaks instead of the previously reported winter peak. Findings from this study highlight the importance of coordinating alternative control strategies in different regions considering the prevailing epidemiological patterns, and the need to reinforce strict biosecurity practices beyond the typically described “PRRS season”.

You can also listen to Dr. Arruda present some of these research findings at the 2017 Leman conference.

Abstract

Industry-driven voluntary disease control programs for swine diseases emerged in North America in the early 2000’s, and, since then, those programs have been used for monitoring diseases of economic importance to swine producers. One example of such initiatives is Dr. Morrison’s Swine Health Monitoring Project, a nation-wide monitoring program for swine diseases including the porcine reproductive and respiratory syndrome (PRRS). PRRS has been extensively reported as a seasonal disease in the U.S., with predictable peaks that start in fall and are extended through the winter season. However, formal time series analysis stratified by geographic region has never been conducted for this important disease across the U.S. The main objective of this study was to use approximately seven years of PRRS incidence data in breeding swine herds to conduct time-series analysis in order to describe the temporal patterns of PRRS outbreaks at the farm level for five major swine-producing states across the U.S. including the states of Minnesota, Iowa, North Carolina, Nebraska and Illinois. Data was aggregated retrospectively at the week level for the number of herds containing animals actively shedding PRRS virus. Basic descriptive statistics were conducted followed by autoregressive integrated moving average (ARIMA) modelling, conducted separately for each of the above-mentioned states. Results showed that there was a difference in the nature of PRRS seasonality among states. Of note, when comparing states, the typical seasonal pattern previously described for PRRS could only be detected for farms located in the states of Minnesota, North Carolina and Nebraska. For the other two states, seasonal peaks every six months were detected within a year. In conclusion, we showed that epidemic patterns are not homogeneous across the U.S, with major peaks of disease occurring through the year. These findings highlight the importance of coordinating alternative control strategies in different regions considering the prevailing epidemiological patterns.

NHF: PRRS is also a summer disease

Our latest collaboration with the National Hog Farmer was written by the Morrison Swine Health Monitoring Program team regarding the incidence of PRRS in the summer.

Although our understanding of disease and control methods has improved in recent years, we continue to learn new features of PRRSV epidemiology in part thanks to the Morrison Swine Health Monitoring Project. One of the most recent questions that we have addressed based on enquires from MSHMP participants is whether PRRS incidence during the summer was higher in recent years (i.e. 2016-17) compared to previous years (i.e. 2009-15). We know that PRRSV outbreaks tend to have a seasonal pattern and that they are more frequent during the fall and winter, but we know little about the breaks that happen in the summer and spring.

In order to dig into this question, we analyzed MSHMP data from 2009 to 2017 which included 1,329 outbreaks. Of these, 66% of the breaks occurred during fall and winter and 14% and 20% of the breaks occurred during summer and spring, respectively. Although there were fewer breaks in the spring and summer, the number of breaks in warmer seasons was still significant which represents an on-going frustration to producers because the “PRRSV season” is supposed to be over.

As part of the analysis we learned that between 3% and 6% of the herds break yearly during the summer and spring seasons, respectively. This represents approximately 83 herds out of the 917 reporting in the MSHMP database. If we estimate that the average sow farm has 3,000 sows, then almost a quarter of a million sows break yearly during these two seasons.

Remember, although the risk of PRRSV introduction is lower during the spring and summer, PRRSV breaks still happen, so biosecurity efforts should not be decreased. PRRSV is a sneaky virus so keep your biosecurity up, even in the summer.

All of our collaborations with the National Hog Farmer can be found here.

Beer and Bacon conversations: a new session at the Leman swine conference!

The organizing committee of the Allen D. Leman swine conference is proud to present a new session: Beer and Bacon conversations! The goal of this unique session is to invite industry leaders to share personal views and experiences with participants in a fun and relaxed environment.

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This year, we are honored that Dr. Matthew Turner, veterinarian and head of pork live operations at JBS, accepted our invitation.

A graduate of North Carolina State University College of Veterinary Medicine, Dr. Turner joined JBS after being a staff swine veterinarian for Prestage Farms for more than 10 years. He was recognized by the American Association of Swine Veterinarian as the 2014 Swine Practitioner of the year and presented the Dr. Alex Hogg Memorial Lecture at the 2017 AASV annual meeting. Dr. Turner is currently an at large member of the Board of Directors of the Swine Health Information Center (SHIC).

The session will be held at the InterContinental hotel on Sunday, September 16th at 5:15pm. Dr. Marie Culhane will get the conversation started but participation from the audience is more than welcome!

Seating for this event is limited. Do mot miss out by registering today!

Congratulations to the recipients of the Morrison and Pijoan fellowships!

Please, join us in congratulating this year’s recipient of the Pijoan fellowship, Dr. Gustavo Lopez and our first recipient of the Morrison fellowship, Dr. Alyssa Betlach.

Pijoan fellow

Gustavo Lopez was born in Caracas, Venezuela. He obtained his DVM in 2010 from the Universidad Central de Venezuela and did two short internships at the University of Minnesota which influenced him into focusing to swine health and production. Gustavo then moved to Russia to work for the largest meat production company. During his 6-year experience he performed different roles such as wean-to-finish production manager, head of genetic services and head of health services. Currently, Gustavo is pursuing a PhD under the guidance of Dr. Torremorell, focusing our research on swine influenza virus.

“I did not have the opportunity of meeting Dr. Pijoan, but i have seen the legacy he has left in the University of Minnesota swine group and the swine industry itself. For me it is an honor to be awarded this fellowship and i intend to live up to the name, by focusing my research towards finding solutions to economical important swine diseases.”

Morrison fellow

Alyssa_Betlach

This year, as a part of the Morrison legacy initiative at the University of Minnesota, we created a fellowship for graduate students in honor of Dr. Bob Morrison.

Alyssa Betlach is a graduate student at the University of Minnesota and part-time associate veterinarian for Swine Vet Center. She is originally from Owatonna, MN where she first gained an interest in swine production and medicine while working on a 1,500 sow farm. Alyssa obtained her DVM from the University of Minnesota this spring, while concurrently pursuing graduate studies and a certificate in swine medicine. Her graduate thesis focuses on the characterization of M. hyopneumoniae in swine herds using molecular diagnostics and epidemiology under the guidance of Dr. Pieters.

“I am truly humbled and honored to receive the Morrison fellowship award. It was an absolute privilege to have known Dr. Morrison and to have received his mentorship throughout my veterinary education. I hope to continue Bob’s legacy through my collaboration with swine veterinarians, academia, and producers towards the development of science driven resources for swine health and production advancement. I am excited to expand my knowledge of the industry and to experience the opportunities made available by the fellowship. Thank you for selecting me as a recipient of this award and to those that have inspired me during my academic and professional endeavors.”

We are truly excited to have such talented graduate students pursuing high quality work to help solve the swine industry challenges!

Science Page: Effects of gestation pens versus stalls and wet versus dry feed on air contaminants in swine production (Part 1)

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are sharing part of a scientific paper from faculty in the School of Public Health at the University of Minnesota, regarding the effect of gestation pens versus group housing and dry versus wet feed on air contaminants. This week we are sharing the first half of the results, join us next week to read the second part.

Keypoints:

Pollutant levels increased as ventilation rates decreased during the cold months.
Pen housing lead to higher levels of NH3, respirable dust, and endotoxin when compared to stalls.

Objective

Evolving production practices in the swine industry may alter the working environment. This research project characterized the influence of stall versus pen gestation housing on air contaminant concentrations.

Methods

Eight-hour time-weighted ammonia, hydrogen sulfide, respirable dust, respirable endotoxin, and carbon dioxide concentrations and temperature were measured
regularly at stationary locations throughout a year in a facility with parallel gestation stall and open pen housing. Hazard indices were calculated using ammonia,
hydrogen sulfide, and endotoxin concentrations and relevant occupational exposure limits.

Results

Due to reductions in ventilation rates as outdoor temperatures decreased, season affected pollutant levels more than other factors. Concentrations were greater during the
winter than summer (Figure 1). Ammonia, dust, and endotoxin were 25%, 43%, and 67% higher, respectively, on average, in the room with gestation pens than in the room with stalls. While individual contaminant concentrations were generally below regulatory limits, hazard index calculations suggest that the effects of combined exposures on respiratory health may pose a risk to farm workers. Additionally, elevated levels of respirable endotoxin and hydrogen sulfide were detected during power washing.

Conclusions

Ventilation changes in response to seasonal requirements influenced air contaminant concentrations more than production practices, especially housing type.

You can also read the full article on the journal’s website.