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- Author or Editor: John Deen x
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Abstract
Objective—To evaluate the success of removal and replacement decisions in commercial swine herds when sow removal was attributed to problems with fertility, fecundity, or old age.
Design—Retrospective case-control study.
Animals—3,000 sows removed from 3 commercial swine herds (case sows), 3,000 matched control sows retained in the herds, and 3,000 replacement gilts.
Procedures—Control sows were included to generate an estimate of reproductive performance that could have been expected had case sows been retained in the herds. Control sows and replacement gilts were followed up until the next farrowing or until removed from the herd, and reproductive performance, calculated as number of pigs born alive per mated female per year, was compared between groups.
Results—In 2 of the 3 herds, reproductive performance was significantly higher for replacement gilts than for control sows matched with case sows removed for reasons of fertility, and in all 3 herds, reproductive performance was significantly higher for replacement gilts than for control sows matched with case sows removed for reasons of fecundity. In the 2 herds with case sows removed because of age, reproductive performance did not differ significantly between replacement gilts and control sows. The odds of greater performance among replacement gilts relative to control sows ranged from 1.305 to 1.955 for removals attributed to fertility, 1.305 to 1.955 for removals attributed to fecundity, and 1.000 to 3.999 for removals attributed to age.
Conclusions and Clinical Relevance—Results suggested that performance-based removal and replacement programs in commercial swine herds may not yield the anticipated results.
Abstract
Objective—To determine whether there is a relationship between sow injuries and size of gestation stalls relative to sow size.
Design—Prospective study.
Animals—267 pregnant sows.
Procedure—Sows were randomly selected from 4 swine farms. Sow and stall measurements were obtained, and injuries were scored on the basis of location, number, and depth. Ratios of stall length to sow length and stall width to sow height were calculated.
Results—High injury scores were associated with low ratios of stall length to sow length and stall width to sow height.
Conclusions and Clinical Relevance—A small increase in stall dimensions could reduce injuries and improve well-being of sows considerably. (J Am Vet Med Assoc 2002;221:834–836)
Abstract
Objective—To analyze the association of lameness and performance variables on sow longevity by use of time-to-event analysis.
Design—Cohort study.
Animals—674 sows from a commercial breeding herd.
Procedures—A lameness assessment was performed on each sow. Data on farrowing performance and longevity were collected for the sows during 3 or fewer parities from the database of the herd during 2005 and 2006. The association of risk factors with sow longevity within 350 days after lameness assessment was analyzed via Cox regression analysis. Pigs per day, total production days, and survival at 350 days after lameness evaluation were compared between lame and nonlame sows.
Results—Numbers of preweaning baby pig deaths, stillborn pigs, and mummified pigs were negatively associated with sow longevity within 350 days after lameness assessment. A higher number of pigs born alive and younger parity of sows were protective. Lame sows had a higher risk (1.710 times as high) of removal from the herd within 350 days after lameness assessment. The number of pigs born alive per day, survival of sows at 350 days, and total number of days in the herd were lower in lame sows.
Conclusions and Clinical Relevance—Results of this study indicated significant differences in the survivability of lame and nonlame sows in a commercial herd. Parity and farrowing performance variables were factors influencing sow longevity in this herd. Producers need to minimize sow lameness and remove lame sows from a herd early (when treatment is not an option) to minimize economic loss.
Abstract
Objective—To characterize pattens of removal and evaluate the associations among culling because of lameness and sow productivity traits among culled gilts and sows.
Design—Cross-sectional study.
Sample Population—Data from a convenience sample of 11 farms pertaining to the removal of 51,795 gilts and sows from January 1991 to December 2002. Mean culling and mortality (death and euthanasia) rates for all inventoried gilts and sows ranged from 23% to 50% and 4.7% to 9.5%, respectively.
Procedure—An analysis of categories of removal (cull, death, or euthanasia) and reasons for removal of gilts and sows was performed. Multivariate logistic regression was used to determine associations among culling because of lameness and sow productivity traits among culled gilts and sows.
Results—Among sows that were removed, the proportion of parity ≥ 1 sows that died (both death and euthanasia) was > 3 times the proportion of parity ≥ 1 sows that were culled within 20 days after farrowing. Among lame sows that were removed, the proportion of parity ≥ 1 sows that died (death and euthanasia) was higher than the proportion of parity ≥ 1 sows that were culled within 20 days after farrowing. Among sows that were removed, the proportion of sows that died (deaths and euthanasia) was higher during lactation than nonlactation. This was also observed among lame sows that were removed.
Conclusions and Clinical Relevance—The proportion of death among removed sows, especially lame sows, was higher during lactation than nonlactation. Results indicated that risk of death is not the same for sows throughout their lifetime. (J Am Vet Med Assoc 2005;226:956–961)
Abstract
Objective—To compare the location and severity of injuries in pregnant sows housed in individual gestation stalls with that in pregnant sows housed in dynamic groups in pens with electronic sow feeders.
Design—Prospective study.
Animals—100 pregnant sows of parity 1 to 3 and various body weights.
Procedure—Fifty sows each were randomly allotted to gestation stalls or group pens with electronic sow feeders. Injuries were scored on the basis of location, number, and depth of wounds. Injury scores for sows in both housing systems were compared during a period of 90 days. The influence of factors such as duration of stay in the housing system, parity, and body weight on sow injuries was also examined.
Results—Injury scores were higher in group pens with electronic sow feeders. As body weight increased, injury scores decreased for sows housed in group pens with electronic sow feeders and increased for sows housed in gestation stalls. There was a significant negative association between second parity and total injury scores.
Conclusions and Clinical Relevance—Modifications in housing system design and management procedures are needed to reduce injuries in pregnant sows. (J Am Vet Med Assoc 2003;223:1334–1338)
Abstract
Objective—To compare well-being, performance, and longevity of gestating sows housed in stalls or in pens with an electronic sow feeder (ESF).
Animals—382 pregnant sows of parities 1 through 6.
Procedure—Sows were housed in separate stalls (n = 176) or group pens (206) with an ESF. Well-being of sows was assessed at various time points in terms of injuries, salivary cortisol concentration, and behavior in a novel arena or to a novel object. Farrowing performance and longevity of sows were also assessed.
Results—Total injury scores (TIS) of sows in pens were significantly higher at initial introduction and mixing. In stall-housed sows, TIS was significantly higher during late gestation. The TIS and cortisol concentration were significantly lower in stall-housed sows, compared with values for sows in pens. As parity increased, the likelihood of higher median TIS decreased significantly in pen-housed sows and increased significantly in stall-housed sows. The TIS of sows in pens was negatively correlated with body weight and backfat thickness, whereas these correlations were positive in stall-housed sows. Farrowing performance and results for novel arena or objects did not differ. Proportion of sows removed was significantly higher for pens than for stalls; lameness was the major reason for removal for both systems.
Conclusions and Clinical Relevance—Stalls impose space restrictions for larger sows, resulting in injuries during late gestation. Interventions are needed to minimize aggression during initial introduction and mixing and at the ESF in pens to reduce severe injuries or lameness of gestating sows. (Am J Vet Res 2005;66:1630–1638)
Abstract
Objective—To evaluate retention of porcine reproductive and respiratory syndrome virus (PRRSV) in houseflies for various time frames and temperatures.
Sample Population—Fifteen 2-week-old pigs, two 10-week-old pigs, and laboratory-cultivated houseflies.
Procedure—In an initial experiment, houseflies were exposed to PRRSV; housed at 15°, 20°, 25°, and 30°C; and tested at various time points. In a second experiment to determine dynamics of virus retention, houseflies were exposed to PRRSV and housed under controlled field conditions for 48 hours. Changes in the percentage of PRRSV-positive flies and virus load per fly were assessed over time, and detection of infective virus at 48 hours after exposure was measured. Finally, in a third experiment, virus loads were measured in houseflies allowed to feed on blood, oropharyngeal washings, and nasal washings obtained from experimentally infected pigs.
Results—In experiment 1, PRRSV retention in houseflies was proportional to temperature. In the second experiment, the percentage of PRRSV-positive houseflies and virus load per fly decreased over time; however, infective PRRSV was found in houseflies 48 hours after exposure. In experiment 3, PRRSV was detected in houseflies allowed to feed on all 3 porcine body fluids.
Conclusions and Clinical Relevance—For the conditions of this study, houseflies did not support PRRSV replication. Therefore, retention of PRRSV in houseflies appears to be a function of initial virus load after ingestion and environmental temperature. These factors may impact the risk of insect-borne spread of PRRSV among farms. (Am J Vet Res 2005;66:1517–1525)
