Prevalence of gastrointestinal parasitism in Oklahoma swine

The prevalence of swine gastrointestinal parasites was determined from all listed large swine operations (28) and a geographically representative sample (70) of the population of small hog farm operations in Oklahoma. Fecal samples (n = 975) were collected from 98 farms. From the 98 farms, parasites were recovered in pig feces as follows: Ascaris, 53.0%, strongyles, 53.1%, Trichuris, 35.7%, spirurids, 6.1%, Strongyloides, 19.4%, coccidia, 57.1%, and Balantidium, 55.1%. A higher percentage (16.5%) of hogs maintained on cement floors were positive for Ascaris than were those on either dirt lots (11.9%) or slatted floors (9.9%), but pigs on dirt lots were more often positive with a higher percentage of coccidia (21.0%) than those on either cement or slatted floors (8.5% and 6.0%, respectively). Prevalence of Trichuris was essentially the same (6.8% to 11.3%) in hogs from all 3 management practices.     

Nutrient composition of Kansas swine lagoons and hoop barn manure

A total of 312 samples in two experiments were analyzed to determine mean nutrient concentrations of swine lagoons and hoop barns in Kansas. First, in a retrospective study (Exp. 1), we obtained 41 sample analyses from the Kansas Department of Agriculture of sow, nursery, wean-to-finish, finish, and farrow-to-finish operations in 1999. The average total N concentration was 899 ppm (SD = 584 ppm), while the total P concentration was 163 ppm (SD = 241 ppm). In an attempt to reduce the variation, we conducted a prospective experiment standardizing collection procedure, laboratory techniques, phase of production, and season of year to more accurately determine the nutrient concentrations of swine lagoons in Kansas. In Exp. 2, we used 236 lagoon and 35 hoop barn manure samples taken in 2000 from Kansas swine operations to determine the impacts of production phase and season of the year on nutrient concentration. The different operations with swine lagoons were: 1) sow; 2) nursery; 3) wean-to-finish; 4) finish; and 5) farrow-to-finish, with a total of 9, 8, 7, 10, and 8 lagoons sampled from each phase of production, respectively. The total N and P concentrations from lagoons were 1,402 and 204 ppm, respectively, averaged over all samples. Concentrations of total N were higher in wean-to-finish and finishing lagoons (P < 0.05) compared with sow and farrow-to-finish lagoons. Lagoon analyses also revealed that N concentrations decreased (linear, P < 0.05) during the summer and fall compared with winter and early spring. The concentration of P was greater (P < 0.05) for wean-to-finish compared with farrow-to-finish lagoons. Phosphorus concentrations for all lagoons increased (quadratic, P < 0.05) from February until June, but then declined steady throughout the remainder of the year. Average total N and P in hoop barns were 8,678 and 4,364 ppm, respectively. No seasonal changes in N and P concentrations were observed in manure from hoop barns. Season and type of production phase affect the nutrient content of Kansas swine lagoons, and producers will benefit from obtaining individual analyses from their lagoons when developing nutrient management plans rather than utilizing published reference values.     

Epidemiological approach to the association between economic efficiency and productivity on swine farms in Prince Edward Island.

Regression analysis was used to determine the ability of a number of biological parameters to predict economic efficiency. Detailed feed, financial, and production records were maintained by a random sample of eighteen Prince Edward Island (PEI) swine producers (each producing over 1000 market hogs per year). Relative economic efficiency of the operations was measured using return to management and labor (RML). Of the routinely monitored biological parameters, RML on PEI farrow-finish operations was best predicted (R2 = 64.8%) by: marketed per square meter per year (p = 0.008) and marketed per sow per year (p = 0.096). Regression of fixed costs revealed that biological parameters had limited ability to predict fixed costs per hog on farrow-finish operations (R2 = 30.7%). The only parameter contributing to the prediction of the fixed cost component of RML was feeder hog density (p = 0.077). The variable cost component of RML on farrow-finish operations was predicted (R2 = 94.3%) by feed cost per kg gain (p = 0.000), and marketed per sow per year (p = 0.044). The routinely recorded biological parameters on feeder farms had only limited ability to predict RML in this study (R2 = 43.7%). The only parameter of any importance was marketed per square meter per year (p = 0.106). Prediction of the fixed cost component of RML on feeder farms (R2 = 67.4%) was best realized by measuring feeder hog density (p = 0.045). The variable cost component of RML on feeder farms was reasonably well predicted (R2 = 74.7%) by feed cost per kg gain (p = 0.012). Although this parameter is difficult to monitor from records currently maintained on most farms, it points out the need to monitor feed consumption on swine farms.     

Welfare Index and Reproductive Performance in the Sow

To study the relationship between on-farm welfare and reproductive performance in the sow, the TGI 35L Animal Needs Index was modified for use in Finnish pig production. The modified index had a maximal total score of 100. It was comprised of six categories: 'locomotion' (maximal score 21 for dry sows and 11 for lactating sows), 'social interaction' (12/8), 'floor quality' (16/9), 'stable climate' (16/21), 'feeding' (16/23) and 'health and stockmanship' (19/29). Index scorings were performed separately in farrowing, breeding and gestation units on 28 representative Finnish sow farms. One-year production parameters were collected. Multiple linear regression was used for statistical analysis. Total ANI-points varied between 36.5-68.0 for lactating and 39.5-86.0 for dry sows. Litter size increased with increasing scores for 'feeding' in the dry sow unit. Controlling for breed, high scores for 'health and stockmanship' and 'floor quality' shortened the reproductive cycle, probably because of good leg health. The number of weaned piglets per sow per year (PSY) increased with increasing scores for dry sow 'health and stockmanship', 'floor quality' and an interaction of 'feeding' in the farrowing and mating units. PSY increased with decreasing scores for farrowing pen 'climate'. High-quality floors and stockmanship appear to correlate positively with reproductive performance in the sow. Effects of a welfare-promoting feeding strategy on reproduction are contradictory.     

Sow wastage: reasons for and effect on productivity.

The purpose of this study was to examine the reasons for, the rate and the effect of sow culling on productivity. Sow removal or wastage was investigated by means of producer questionnaires and by detailed production data recorded on 30 swine farms for two years. The sow removal rate was high (mean = 44.2%) with a wide herd-to-herd variation (range = 16% to 100%), and correlated negatively with litter size. Reproductive failure was the most common cause of culling cited by producers. It was concluded that sows on many Ontario farms were being culled prior to reaching their reproductive potential.     

Evaluation of environmental and management-related risk factors associated with chronic mastitis in sows

OBJECTIVE: To evaluate environmental and management-related risk factors associated with chronic mastitis in sows. ANIMALS: 1,254 sows from 76 herds. PROCEDURE: Prevalence of chronic mastitis was determined by a veterinarian who performed clinical examinations at the time of weaning and approximately 1 week later in a sample of the sow population on each farm. Information concerning environmental factors and management practices was collected. In addition, the herd veterinarian made an assessment of the farmer's skills in swine production. RESULTS: Use of partly slatted floors in the farrowing pens, use of disinfectants between batches in the farrowing and breeding areas, feeding lactating sows whey, and avoiding cutting or grinding of the piglets' teeth were significantly associated with a decreased risk of chronic mastitis. A high hygienic standard on the farm, as determined by the herd veterinarian, was associated with a significant reduction in the prevalence of mastitis. CONCLUSIONS AND CLINICAL RELEVANCE: Chronic mastitis in sows is a common disease that has a negative influence on productivity. Results indicate that certain management practices and environmental factors influenced the development of mastitis, which may contribute to the development of methods useful for controlling the disease.     

A Delphi exercise used to identify potential causes of variation in litter size of Ontario swine

Forty-eight people, considered to the swine experts, were asked to collaborate in a Delphi exercise to identify the factors which they believed affect litter size in Ontario swine. The panel included 16 animal scientists, 16 pork producers, and 16 veterinarians in swine practice. The ten factors with the highest ratings were parity of the sow, mycotoxins in the feed, infections with porcine parvovirus or Leptospira spp., breeding gilts on their second versus first observed estrus, the timing of breeding with respect to the onset of estrus, purebred versus crossbred sows, boar overuse (bred by a boar that was mated more than six times per week), pen versus hand mating, age of gilt when first bred, and body condition of the sow at the time of conception. The experts did not agree about the effect on litter size of the sow's previous lactation, factors ensuring adequate nutrient intake during lactation, health of the sow and the boar, breed of a purebred sow, or the ease of mating the sow.

Key items in the use of the Delphi technique to arrive at a consensus are discussed.

     

Assimilation Versus Accumulation of Macro- and Micronutrients in Soils: Relations to Livestock and Poultry Feeding Operations

Nutrient management is an integral part of profitable agrisystems, but in some areas of the United States, continued applications of fertilizer and manure nutrients in excess of crop requirements have led to a buildup of nutrient concentrations that are of environmental concern. Proper use of nutrients in livestock manures is becoming more critical for sustainability of concentrated animal feeding operations (CAFO) because new environmental regulations require that nutrients be properly applied and managed. Losses of nutrients, such as N and P can be reduced by refining the rations fed, increasing nutrient retention by livestock, moving manures from areas of surplus to deficiency, finding alternative uses for manure, using cropping and haying systems that remove excess nutrients, and using conservation practices, such as limited tillage, buffer strips, and cover crops to limit runoff and leaching. Whole farm nutrient balances are useful for educating producers about quantities of nutrients being managed and the flow of nutrients, but they can also be misleading because of spatial factors, such as uneven nutrient application that introduce environmental risks that may not be noted with a whole-farm nutrient balance. Manure utilization plans also need to deal with nutrients that potentially leave the field or production area in route to sensitive ecosystems.     

A survey of biological productivity of Prince Edward Island swine herds.

Sow and feeder pig productivity were measured on a random sample of 32 Prince Edward Island swine farms (each producing over 1000 market hogs per year). Productivity parameters could be arranged in a hierarchy, with the highest level on farrow-finish operations represented by pigs weaned per sow per year. The 17 farrow-finish farms in this study averaged 19.6 (+/- 2.2 SD) pigs weaned per sow per year. Large variation between farms was observed with a range from 16.2 to 24.9 pigs weaned per sow per year. The major opportunities for improving productivity, as compared to reviewed targets, lie in reducing the average weaning age, reducing preweaning mortality, and reducing non-productive sow days per parity. The 14 feeder operations were characterized by 0.58 +/- 0.07 kg average daily gain. Average daily gain was negatively correlated with mortality (r = -0.662, p = 0.010), suggesting that herds that achieved a high rate of gain also had lower mortality.     

Herd factors affecting the selection and success of intervention strategies in the program for eradication of pseudorabies (Aujeszky's disease) virus from Illinois swine farms

The program for eradication of pseudorabies virus (PrV) from swine herds in Illinois was evaluated with respect to compliance with Livestock Conservation Institute (LCI) guidelines for selection of intervention strategies and for the effectiveness of these interventions under different herd conditions. The sample consisted of 395 swine operations quarantined between 1988 and 1994. These herds were followed until the end of 1996. The association of herd characteristics (number of sows, sow PrV seroprevalence, type of housing, number of PrV-seropositive farms within 1.5 mi) at the time of quarantine with the producer's selection of an initial intervention strategy (vaccination, offspring segregation, test-and-removal, depopulation-and-repopulation) was analyzed using logistic multiple regression. The interaction of herd characteristics with intervention strategies to affect the duration of quarantine was analyzed using multivariable Cox regression.

Factors favoring selection of vaccination were increased herd size, higher sow PrV seroprevalence, and more PrV-seropositive farms within 1.5 mi. Offspring segregation was preferred when sow PrV seroprevalence was higher, and test-and-removal was preferred when seroprevalence was lower. Depopulation-and-repopulation was more likely in outdoor operations. Except for depopulation-and-repopulation, selection of an intervention strategy was in accordance with LCI guidelines.

Vaccination and offspring segregation were associated with longer times under quarantine, and test-and-removal and depopulation-and-repopulation with shorter times. Test-and-removal was more effective in reducing the duration of quarantine when sow PrV seroprevalence was low. Vaccination increased the duration of quarantine less when sow PrV seroprevalence was high. Vaccination increased the duration of quarantine more when there were one or more PrV-seropositive farms within 1.5 mi than when there were no PrV-seropositive farms within 1.5 mi. It is apparent that herd characteristics affect the duration of quarantine and therefore need to be taken into account in the selection of a PrV-intervention strategy.     

Description of empirical movement data from Canadian swine herds with an application to a disease spread simulation model

We report the methods and findings of a survey of Canadian swine producers summarizing farm-types at-risk of foreign animal disease (FAD) and the routine movement of animals, semen and workers among swine farms, as observed during a 42-day period. Of the 311 producers who returned completed questionnaires, 17% represented swine-herds with no swine or semen movement on or off the farm during the 42 days, 57% were sow herds or farrow-to-finish herds with limited movement onto the farm but movement off the farm, and 26% were swine-herds with movements on and off the farm. A substantial number of premises (>50% in some provinces) with swine also kept other animal species on the same premises. We applied the empirical movement data from the survey in a stochastic simulation model to estimate the number of herds infected and the basic regional distribution of infection that could be expected to occur if the FAD was not detected and routine movements were permitted to occur up to 42 days after infection with a FAD of a single randomly selected herd. Forty-five percent of the simulations did not involve spread beyond the index farm, whereas 34.8% involved spread among five or more farms after 42 days of routine movement.     

Evaluation of the relationship between injuries and size of gestation stalls relative to size of sows

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.     

Risk factors for high sow mortality in French swine herds

Episodes of high sow mortality rates affect profitability of swine farms. However, relevant control actions are difficult to implement. The objective of this study was to identify the risk factors for high levels of sow mortality rate (HM) in French swine herds. A case-control study was carried out in 102 swine herds located in Brittany (western France). Level of sow mortality of a herd was quantified by the annual mortality rate using sow-days as denominator. Fifty-five (53.9%) herds which experienced a sow mortality rate over 5% were classified as HM herds. Logistic regression was used to assess associations of managerial practices and disease prevalence with the odds of HM. High prevalence of urinary tract infections, metritis or lameness were significantly associated with a HM herd status (P < 0.10, OR ranging from 3.4 to 5.2). Multiplying herds were herds at higher risk for sow mortality than commercial farrow-to-finish herds. Providing three meals per day instead of two to dry sows decreased the odds of HM. Feeding plans where the maximum daily amount of feed provided to lactating sows was lower than 8 kg and was reached before 15 d in lactation were related to lower odds of HM (P < 0.10). Average age at weaning of 28 d or more and/or small average litter size at birth (12 piglets or less) were associated with higher odds of experiencing HM.     

Farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals

OBJECTIVE: To identify farm characteristics and management practices associated with development of Rhodococcus equi pneumonia in foals. DESIGN: Prospective case-control study. ANIMALS: 5230 foals on 138 breeding farms with 9136 horses. PROCEDURE: During 2003, participating veterinarians provided data from 1 or 2 farms with > or =1 foal with R equi pneumonia and unaffected farms. Data from affected and unaffected farms were compared by use of logistic regression analysis. RESULTS: A number of variables relating to farm size and desirable management practices were significantly associated with increased odds of farms being affected with R equi pneumonia. By use of multivariate logistic regression, affected farms were determined significantly more likely to have raised Thoroughbreds, housed > or =15 foals, used concrete floors in foaling stalls, and tested foals for passive transfer of immunity than unaffected farms. These results remained significant even after accounting for exposure of foals to other breeding farms during the first month of life. Conclusions and Clinical Relevance-Breeding farms with large acreage and a large number of mares and foals have greater odds of being affected by R equi pneumonia. Clinical relevance of associations with Thoroughbred breed and concrete flooring in foaling stalls remains uncertain. Desirable management factors commonly used on farms were not effective for controlling or preventing development of R equi pneumonia. This finding indicates a need to focus on host factors that influence disease development.     

Swine production.

The US swine industry is large and growing. The quantity of pork desired by consumers of US pork is growing at the rate of 1.5%/y. New production systems and new technology have enabled production per sow to grow at a rate of 4% annually in recent years. Consequently, the number of sows in the United States is declining. Because productivity growth is outpacing demand growth, the deflated price of hogs and pork is declining. Hog production and prices continue to exhibit strong seasonal and cyclic patterns. Pork production is usually lowest in the summer and highest in the fall. Production and prices tend to follow 4-year patterns. The US swine industry continues to evolve toward fewer and larger producers who rely on contracts for both hog production and marketing. In 2000, over half of the hogs marketed were from approximately 156 firms marketing more than 50,000 head annually. These producers finished 60% of their production in contract facilities. Over 90% of their marketings were under contract or were owned by a packer. These producers expressed a high level of satisfaction with hog production. Both they and their contract growers were satisfied with production contracts. These large producers were satisfied with their marketing contracts and planned to continue them in the future. The hog industry has changed a great deal in the last decade. There is little reason to believe this rapid rate of change will not continue. This swine industry is highly competitive and profit driven. Profit margins are too small to allow producers the luxury of ignoring new technology and innovative production systems. Consequently, hog production will continue its rapid evolution from traditional agriculture to typical industry.     

Associations between genetics, farm characteristics and clinical disease in field outbreaks of porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome (PRRS) is a disease of domestic swine characterized by exceptionally high clinical variability. This study addresses the question of whether clinical variability in PRRS results from (a) genetic variation among viral isolates and/or (b) variation in management practices among farms on which isolates are found. Genetic data (open reading frame 5 gene sequences) and data on farm characteristics and associated clinical disease signs were collected for 62 PRRS virus (PRRSV) field isolates, representing 52 farms. Clinical disease signs were interrelated — confirming that a true reproductive syndrome exists (involving abortions, infertility in sows, deaths of sows and preweaning mortality).

Pairs of farms experiencing deaths in their sow populations also tended to share viral isolates which were more similar to one another than expected by chance alone. This implies that sow death (one of the more-severe manifestations of PRRS) is under genetic influence. Large herd size was a significant risk factor for the death of sows and for respiratory disease in nursery pigs. All-in–all-out management practices in the nursery were protective against reproductive signs in the sow herd. All-in–all-out management practices in the finishing stages of production were protective against respiratory disease in nursery pigs — but were paradoxically associated with an increased risk of infertility in sows. These results suggest that farm-management practices can also influence which PRRS clinical signs are manifested during an outbreak. In general, signs associated with PRRS appear to result from a combination of genetic factors and herd-management characteristics. The relative contributions of these two influences differ depending on the specific clinical sign in question.     

Prevalence of pseudorabies virus infection and associated infections in six large swine herds in Illinois.

Sera were collected from 6 large farrow-to-finish swine herds infected with pseudorabies virus (PRV) in Illinois. All herds were participating in the Large Herd Cleanup Study, a USDA-initiated project to evaluate the feasibility of eradicating pseudorabies from large farms (greater than 400 sows) by use of a combination of vaccination and management changes. Herd size ranged between 425 and 1,500 breeding females. Between April and July 1990, sera for measurement of PRV antibodies were obtained from 113 to 156 sows and 112 to 162 finishing pigs (body weight greater than 70 kg)/herd. Duplicate sera from 30 sows and 30 market-weight pigs/herd were obtained for measurement of serum antibodies to the following associated organisms: swine influenza virus, transmissible gastroenteritis virus, encephalomyocarditis virus, Actinobacillus pleuropneumoniae, Eperythrozoon suis, and 6 serovars of Leptospira interrogans. Prevalence of PRV antibodies attributable to field virus infection ranged between 53.8 and 100% for sows and between 0.7 and 97.3% for finishing pigs, as determined by the appropriate differential test for the vaccine being used on each farm. In only 1 herd, PRV seroprevalence was increased with higher sow parity. For associated infections, the risk of seropositivity attributable to PRV was not significant (for most infections) on all farms and varied among farms. Thus, pseudorabies did not appear, in general, to increase susceptibility to infection with other disease agents.