Search Results

You are looking at 1 - 10 of 12 items for

  • Author or Editor: William E. Marsh x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective—To evaluate reproductive and financial performance for commercial swine herds grouped on the basis of pattern of removal of female swine.

Design—Cohort study.

Sample Population—25 swine herds.

Procedures—Lifetime reproductive productivity was summarized as number of pigs weaned per herd day per mated female and as number of herd days per pig weaned per mated female. Factors associated with these 2 measures were determined by use of linear regression. Financial data from a commercial database were used to estimate maximum number of parities at removal associated with profitability. Sensitivity analysis was used to simulate how variations in daily maintenance cost and value per weaned pig would influence profitability.

Results—Mean number of pigs weaned per herd day per mated female was 0.054; mean number of herd days per pig weaned per mated female was 20.2. Both these measures were associated with proportion of nonproductive days during herd life, preweaning mortality rate per litter weaned, mean lifetime number of pigs born alive per litter weaned, and mean lifetime lactation duration. Maximum parity at time of removal associated with profitability ranged from 5 to 8. Daily maintenance costs per female had a greater impact on lifetime profitability than did value per weaned pig.

Conclusions and Clinical Relevance—Results suggest that lifetime reproductive and financial performance is optimized among swine herds that have higher proportions of high-parity females. (J Am Vet Med Assoc 2000;216:1802–1809)

Full access
in Journal of the American Veterinary Medical Association

Objective

To develop estimates of lifetime productivity for breeding female swine calculated longitudinally during time in the breeding herd, and to compare estimates of lifetime productivity for female swine removed from the herd at different parities.

Design

Retrospective cohort study.

Animals

9,416 breeding female swine from 29 herds.

Procedure

A frequency distribution for parity at the time of removal was generated. Estimates of lifetime productivity (lifetime nonproductive days [NPD], lifetime NPD as a proportion of herd life, total number of pigs born per litter weaned, number of pigs born alive per litter weaned, number of pigs weaned per litter weaned, number of NPD per year in the herd, number of litters weaned per year in the herd, and number of pigs weaned per year in the herd) were calculated for females with parity ≥ 1 at the time of removal.

Results

For 58% of all females, parity at the time of removal was ≤ 3. On average, 20.7% of herd life was spent in nonproductive activities, but the proportion of herd life that was nonproductive decreased significantly as parity at the time of removal increased. Number of NPD per year in the herd decreased and number of litters weaned per year in the herd and number of pigs weaned per year in the herd increased significantly as parity at the time of removal increased.

Clinical Implications

Higher parity at the time of removal from the herd is associated with improved lifetime productivity for female swine. Parity at time of removal is commonly used as an approximation for lifetime productivity, but it does not take into account the impact of NPD, especially NPD during early reproductive cycles. (J Am Vet Med Assoc 1999;214: 1056–1059)

Free access
in Journal of the American Veterinary Medical Association

Objective—

To determine whether lactation length was associated with reproductive performance or longevity of sows.

Design—

Cohort study.

Sample Population—

Data collected between 1986 and 1992 for sows in 15 breeding herds in Minnesota and Iowa.

Procedure—

Sows were grouped into 4 genetic line categories according to their sources and 6 parity categories (1, 2, 3, 4, 5 or 6, and ≥ 7). Multivariate regression analysis of reproductive performance was conducted, using the general linear model procedure. Logistic regression was conducted with a dichotomous response variable for sow longevity (ie, removal from or retention in the herds). Odds ratios were obtained from estimated coefficients of the regression.

Results—

Herd, genetic line, parity, year, month, and lactation length were significant in statistical models for litter (eg, number of live pigs/litter) and interval (eg, weaning-to-mating interval) traits. Interactions between lactation length and year, lactation length and genetic line, lactation length and parity, and lactation length and genetic line and parity were also significant. Sows removed from herds had a significantly shorter lactation length than did sows of the same parity that were retained in the herds. Sows that had shorter lactation lengths were at higher risk of being removed from the herds than were those that had longer lactation lengths.

Clinical Implications—

Lactation length is associated with reproductive performance and longevity, but genetic line and parity playa role as well. Thus, attention should be paid to genetic lines and parity of sows in the herd when implementing an early weaning production practice. (J Am Vet Med Assoc 1997;210:935–938)

Free access
in Journal of the American Veterinary Medical Association

Summary

Seasonal variation oj reproductive performance of female swine was analyzed by use of a data base that included farrowing records from 42 commercial swine herds. Farrowing rates of sows bred during December or January were higher (P < 0.001) than those bred in July or August (79.2 vs 74.1%). The percentage of sows with irregular (prolonged) return-toestrus intervals after mating in December or January (2.63%) was lower (P < 0.01) than those mated in July or August (4.65%). Sows mated in November through January had greater total number of pigs born per litter (11.66 vs 11.19 pigs per litter), more pigs born alive per litter (10.39 vs 9.84 pigs per litter), and greater litter birth weights (15.20 vs 14.28 kg) than sows mated in June through August (P < 0.001). Adjusted 21-day litter weights were lower (P < 0.001) for litters from sows farrowing in July or August (52.04 kg) than sows farrowing in all other months (55.13 kg) except June and September. Sows that had their litters weaned in June through August had longer (P < 0.001) weaning-to-estrus intervals (7.95 days) than sows that had their litters weaned in November through January (6.84 days). The effects of season varied across parities. Primiparous sows had the greatest seasonal variability in weaning-to-estrus interval, whereas multiparous sows had the greatest seasonal variability in total number of pigs born per litter and pigs born alive per litter.

Free access
in Journal of the American Veterinary Medical Association

Summary

Strategies for the elimination of pseudorabies virus (prv) from swine herds include test and removal, offspring segregation, and depopulation/repopulation. The prevalence of prv in a herd is a major factor in selection of the most appropriate strategy. The purpose of the study reported here was to describe the prevalence of prv in adult swine in prv quarantined herds in Minnesota, and to determine herd factors associated with the seroprevalence. Questionnaires describing the health history of the herd, management practices, and design of the swine facilities were obtained from the owners of 142 quarantined herds. Blood was collected from 29 finishing pigs over the age of 4 months, up to 29 adult females, and all herd boars. Factors considered to be significant in a bivariate analysis were combined in a stepwise multiple logistic regression analysis. The prevalence of prv-seropositive adults in each herd was bimodally distributed among the 142 herds. In 42 (30%) of the herds, none of the females tested was seropositive, which represented the lower mode. At least 90% of the adults tested were seropositive in 30 (21%) of the herds and represented the higher mode. The odds of the breeding swine of a given herd having a prv seroprevalence of ≥ 20% as compared with having a seroprevalence of < 20% was 1.654 times higher per 50 adults in the herd, 13.550 times higher if the finishing pigs were seropositive, 2.378 times higher if sows were housed inside during gestation, and 1.481 times lower per number of years since the imposition of quarantine. These findings indicate that a large proportion of quarantined herds may have a low seroprevalence of prv, making them prime candidates for test and removal. Pseudorabies virus might also be eliminated from these low-prevalence herds by a method referred to as management/vaccination, which is described. These methods are inexpensive, compared with offspring segregation or depopulation/repopulation, and represent a substantial cost savings for the swine industry.

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine prevalence of foot lesions, dermatitis, shoulder lesions, mammary gland abnormalities, and visceral lesions, and body condition scores among culled female swine at slaughter.

Design

Observational study.

Animals

Culled gilts and sows killed during a 1-week period at a Midwest slaughterhouse.

Procedure

Carcasses were examined, and lesions were recorded. Body condition was scored on the basis of standard criteria.

Results

58.9% (1,029/1,747) of the carcasses had foot lesions, 67.3% (1,178/1,751) had dermatitis, and 4.6% (80/1,751) had shoulder lesions. Body condition score was significantly associated with detection of dermatitis and shoulder lesions. Mean ± SE number of teats (n = 1,432 carcasses) was 13.86 ± 0.02. Mean numbers of normal-appearing teats in the left and right mammary chains were 6.57 ± 0.02 and 6.58 ± 0.02, respectively. Feet from 48% (688/1,433) of the carcasses were condemned. Visceral lesions were found in 48.8% (624/1,278) of the carcasses; of the carcasses with lesions, 412 (66%) had liver spots, and 268 (42.9%) had pneumonia.

Clinical Implications

Lesions that potentially could have adversely affected production were found in a large percentage of culled gilts and sows at slaughter. Knowledge of lesions commonly found at slaughter may help direct changes in herd health programs. (J Am Vet Med Assoc 1999;214:525–528)

Free access
in Journal of the American Veterinary Medical Association

Objective

To determine attitudes of participating veterinarians toward a standardized slaughter-monitoring program for swine.

Design

Survey by mail questionnaire.

Sample Population

30 of 35 veterinarians in Minnesota who had participated in the program in 1993.

Procedure

Survey was conducted regarding a slaughter-monitoring program. Respondents answered questions related to professional experience, use of slaughter inspections, methods, advantages and disadvantages of the program, effects on clients and business, labor requirements, referral of inspections, confidence in identifying lesions, and usefulness of reports for on-farm decision making.

Results

27 respondents expressed overall satisfaction with the program. Perceived advantages of the program included use of standardized methods, quality of reports, inspection of more types of lesions, and accumulation of data. Disadvantages predominantly related to increased time commitments for veterinarians. Data considered most useful for on-farm decision making were white spots on livers, nasal turbinate atrophy, and lesions indicative of papular dermatitis and enzootic pneumonia. Respondents perceived positive effects of participating in this program In the areas of recruitment of clients, frequency of visits to clients, recommendations made to clients, satisfaction of client needs, and generation of revenue.

Clinical Implications

A standardized slaughter-monitoring program designed to provide improved information from slaughter inspections may be beneficial to the businesses of participating veterinarians. (J Am Vet Med Assoc 1996;209:123–126)

Free access
in Journal of the American Veterinary Medical Association

Objective—

To determine the benefits that were associated with pregnancy testing by use of transrectal palpation during the period 30 to 65 days after unsuccessful insemination of dairy cows.

Design—

Nonconcurrent, cohort study.

Animals—

Cows in 15 dairy herds in the United States and Canada.

Procedure—

Reproductive records of cows (n = 713) that did not calve within 294 days of first-service insemination and that had been evaluated for pregnancy 30 to 65 days after first-service insemination were examined. Records were analyzed to determine the day of parturition or date of culling and to determine if the probability of a cow being culled or the interval to parturition was related to the number of days after insemination that pregnancy testing was performed.

Results—

For cows that calved more than 294 days after first-service insemination, the interval from first-service insemination until parturition was associated significantly with herd, season, and treatment on the day of pregnancy testing with prostaglandin F or one of its analogues. Cows treated with prostaglandin F on the day of pregnancy testing were less likely to be culled than nontreated cows. For cows pregnancy tested 30 to 65 days after insemination, each additional day after day 30 before pregnancy testing was performed resulted in an increase of 1.09 days in the interval until parturition.

Clinical Implications—

Pregnancy testing by means of transrectal palpation as soon as possible after day 30 after insemination can result in shorter calving intervals.

Free access
in Journal of the American Veterinary Medical Association

Objective

To evaluate agreement between trained veterinarians and a reference inspector when recording gross lesions of lungs, livers, and nasal turbinates of pigs.

Design

Prospective study.

Sample Population

10 veterinarians in workshop 1 and 11 veterinarians in workshop 2.

Procedure

Analysis of data obtained from 2 workshops in which veterinarians evaluated fresh tissues (30 lungs and 30 livers) and 100 slides of nasal turbinates previously evaluated by the reference inspector. Veterinarians independently recorded observations of gross lesions. Agreement was evaluated by percentage agreement, kappa or weighted kappa, and sensitivity and specificity, where relevant.

Results

Agreement between veterinarians and the reference inspector was excellent for detecting consolidation of lung lobes typical of enzootic pneumonia (κ = 0.81 and 0.87 for workshops 1 and 2, respectively) and white spots on livers (κ = 0.76 and 0.78). Estimates of the extent of consolidation as a proportion of lung volume also agreed closely with reference values. Agreement was closer for veterinarians who had undergone repeated training and evaluation. Agreement was good for detecting nasal turbinate atrophy (weighted κ = 0.63 and 0.68) and was poorest for detecting lesions of pleuritis (κ = 0.39 and 0.44).

Clinical Implications

For most of the lesions evaluated, acceptable levels of agreement with reference scores were achieved after training of veterinarians to use standardized methods to record gross lesions. Standardization of veterinarians’ recordings of gross lesions should improve the reliability and usefulness of data collected by inspection of slaughtered pigs. (J Am Vet Med Assoc 1996;209:823–826)

Free access
in Journal of the American Veterinary Medical Association

Abstract

A rapid subjective method for estimating the extent of gross pneumonia lesions in slaughtered pigs was compared with dissection of lungs in 51 slaughtered pigs. After standardization for prevalence in the regional industry, regression analysis indicated that the subjective method was highly predictive of the extent of pneumonic lesions (R 2 · = 0.88). Part of the error with the subjective method was attributed to approximations used for the relative proportions of lung lobes, which result in overestimation of the affected tissue by approximately 20%. Retrospective analysis of data from a slaughter monitoring program revealed strong associations (R 2, 0.54 to 0.91) between prevalence, mean, median, and maximal lung scores in groups of pigs. Maximal lung score was biased by sample size, but prevalence and mean or median lung scores could be used to describe pneumonia severity in groups of pigs. Our results indicate that error in measurement of the extent of pneumonic tissue in slaughtered pigs is unimportant if the time of onset, clinical severity, and duration of disease are not quantified.

Free access
in American Journal of Veterinary Research