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- Author or Editor: Robert B. Morrison x
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Abstract
Objective—To determine the association between limb conformation scores in gilts and retention through the second parity.
Animals—961 gilts.
Procedure—Gilts were monitored for 1 year. Baseline data recorded were conformation scores for the forelimbs and hind limbs and backfat thickness. Primary outcome was time to removal from a herd, and the secondary outcome was time to removal as a result of lameness.
Results—662 of 961 (68.89%) females remained in herds through the second parity, whereas 299 (31.11%) were removed before the second parity. Survival time for females on the basis of conformation scores for the forelimbs and hind limbs differed significantly for total sow removals and removals as a result of lameness. Females with poor conformation scores for the hind limbs had an increased risk of being removed, compared with risk for females with better conformation scores. Risk of removal specifically as a result of lameness increased as conformation score for the hind limbs became poorer. Proportion of the total population that was removed and could be attributed to undesirable limb conformation was 16.13% for forelimbs and 12.90% for hind limbs.
Conclusions and Clinical Relevance—Females with undesirable conformation were removed earlier than females with desirable conformation. This was particularly true for females with low conformation scores for the hind limbs. Selection of gilts on the basis of limb conformation may result in reduced attrition of females and improved performance of herds over time.
Abstract
Objective—To assess the role of noncommercial pigs in the epidemiology of porcine reproductive and respiratory syndrome (PRRS) virus.
Design—Seroepidemiologic study and survey study.
Animals—661 pigs from which blood samples were collected at slaughter and 32 pigs from which blood samples were collected longitudinally.
Procedures—Spatial databases of commercial farms and 4-H participation were evaluated by use of commercial geographic information systems software. Information on disease knowledge and management methods of 4-H participants was obtained by mail survey and personal interview. Serum samples for antibody testing by PRRS ELISA were obtained from pigs at slaughter or at county fairs and on farms.
Results—Participation in 4-H swine programs was geographically associated with commercial swine production in Minnesota, and 39% of 4-H participants reared pigs at locations with commercial pigs. High seroprevalence at fairs (49%; range, 29% to 76%) and seroconversion after fairs indicated that PRRS virus exposure was common in pigs shown by 4-H participants and that transmission could occur at fairs.
Conclusions and Clinical Relevance—The small swine population shown by 4-H members (estimated 12,000 pigs) relative to the population of commercial swine in Minnesota (estimated 6.5 million pigs) suggested the former overall was likely of minor importance to PRRS virus epidemiology at present. However, the relative frailty of knowledge of biosecurity practices, evidence that PRRS virus exposure was frequent, common intentions to show pigs at multiple events, and often close interactions with commercial herds suggested that the 4-H community should be involved in regional efforts to control PRRS.
Abstract
OBJECTIVE To measure incidence and estimate temporal and spatial dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) infection in US sow herds.
ANIMALS 371 sow herds in the United States from 14 production companies.
PROCEDURES The exponentially weighted moving average was used to monitor incident PRRSV infections for onset of an epidemic. The spatial scan statistic was used to identify areas at significantly high risk of PRRS epidemics. A χ2 test was used to estimate whether there were significant differences in the quarterly and annual PRRS incidence among time periods, and a bivariable logistic regression model was used to estimate whether PRRSV infection during a given year increased the odds of that herd being infected in the following year.
RESULTS During the 4-year period of this study, 29% (91/319; 2009 to 2010), 33% (106/325; 2010 to 2011), 38% (135/355; 2011 to 2012), and 32% (117/371; 2012 to 2013) of the herds reported new infections. Weekly incidence was low during spring and summer and high during fall and winter. The exponentially weighted moving average signaled the onset of a PRRSV epidemic during the middle 2 weeks of October each year. Disease incidence was spatially clustered. Infection in the previous year increased the odds of infection in 2010 to 2011 and 2011 to 2012.
CONCLUSIONS AND CLINICAL RELEVANCE Results indicated a striking repeatability in annual PRRSV temporal and spatial patterns across 4 years of data among herds from 14 production companies, which suggested that efforts to control PRRSV at a regional level should continue to be supported.
