Production Impact In Sow Herds, Impact of 1-7-4 PRRSv - Dr. Carl Betlach, from the 2015 Allen D. Leman Swine Conference, September 19-22, 2015, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2015-leman-swine-conference-material

1. Swine Health Monitoring Project
PRRS 1-7-4; TTS & TTBP
Carl Betlacha, Daniel Linharesb,
Bob Morrisona
a University of Minnesota
b Iowa State University

2. Objectives
• To determine TTS and TTBP and associated
risk factors in sow herds infected with PRRS
1-7-4 family
• Preliminary analysis
• Time to 1st negative test (TT1)
• Risk factors

3. Preliminary Conclusions
• TT1 in 62 herds had median of 17.5 weeks
• TT1 was 3.9 weeks shorter in 1-7-4 herds
compared to Linhares et al (p = 0.11).
• Gilt source and % sows housed individually
were associated with TT1 (p<0.10). All other
factors were not associated (p>0.20).

4. Methods
• All SHMP participants having had 1-7-4 family
infection invited to participate
• Questionnaire describing herd history and
management
• Diagnostic data submitted at least monthly
starting 12 weeks post detection
• Production data to be submitted
• Herd inclusion criteria

5. Herd Inclusion Criteria
• Farrow-to-wean herd
• Confirmed to be infected with 1-7-4 family
• PCR monitoring monthly; 30 samples - 6 pools
of 5 (> 2 pools 1st test)

6. 1-7-4 Risk Factors
• Region
• Inventory
• Wean frequency
• Gilt source
• % sows housed individually
• % rooms partially weaned
• # breaks last 3 years
• Herd status at break
• Exposure program
• Antigen exposure to sows and gilts
• Ongoing management of sows and gilts

7. Enrolled & preliminary analysis
Number herds enrolled 149
Number with questionnaires & dx data 128

8. Exposure program after infection
Sows Gilts
MLV MLV 61
Nothing 8
MLV / LVI 2
Nothing Nothing 31
MLV 1
KV KV 8
MLV / KV MLV / KV 5
MLV / LVI / KV 1
MLV / LVI MLV / LVI 5
Feces / tissue Feces / tissue 4
Feces / tissue & KV Feces / tissue & KV 1
Feces / tissue & MLV Feces / tissue & MLV 1
128

9. Analysis
• 62/92 herds had at least one negative test
• Statistical methods
– Univariate analysis
• Kruskal-Wallis ANOVA for categorical factors
• Spearman correlation for continuous factors
– Multi-variable analysis not performed at this time

10. TT1 and TTS were significantly correlated in
data from Linhares et al (2014)
Overall (Spearman) correlation between
TT1 and TTS: +0.49 (p=0.002)

11. Time to 1st negative test was not
significantly different from historical data.
Linhares et al (2014); n=61
1-7-4; n=62

12. Potential risk factors included in this
preliminary analysis
TT1
P-value
Region 0.898
Inventory 0.329
Wean freq 0.455
Gilt source 0.023
% sows housed individually 0.057
% rooms part wean 0.974
# breaks last 3 years 0.409
Herd status at detection 0.944
Whole herd exposure 0.431
Antigen exposure to sows 0.431
Antigen exposure to gilts 0.431
Ongoing management of sows 0.559
Ongoing management of gilts 0.757

13. TT1 vs gilt source
Kruskal-Wallis ANOVA; p=0.023
# herds Median (wks)
Internal - (closed herd) 3 12
External - offsite 9 16
External - onsite 50 20

14. TT1 increased with increasing %
housed in stalls
• Spearman correlation; p=0.057

15. Limitations
• 1st neg test not indicative of reaching stability
• Voluntary cohort
• Regional bias
• Previous/current exposure to other pathogens
was not assessed

16. Stay tuned…
• Continue monitoring Dx data to determine
TTS
• Collect production data to determine TTBP
• Further evaluate associated risk factors

17. Acknowledgements
• Veterinarians and SHMP participants
• Lab – Jennifer Groetsch
• Project funded with support from:
– Swine Health Information Center (SHIC)
– Boehringer Ingelheim Vetmedica PRRS research
award