US Swine Industry Research Articles

Epidemiological study of air filtration systems for preventing PRRSV infection in large sow herds

Porcine reproductive and respiratory syndrome virus (PRRSV) is the most economically significant pathogen in the US swine industry. Aerosol transmission among herds is a major concern in pig dense regions and filtration of incoming air, in combination with standard biosecurity procedures, has been demonstrated to prevent transmission of PRRSV into susceptible herds. To quantify the impact of air filtration on reducing risk of PRRSV outbreaks, we compared the incidence rate of new PRRSV introductions in 20 filtered and 17 non-filtered control sow herds in a swine dense region of North America during a 7year study period. Events of novel virus introduction were ascertained by phylogenetic analysis of PRRSV ORF5 gene sequences. Putative new viruses were defined as exogenous (introduced) based on ORF5 nucleotide sequence differences compared to previous farm isolates. The influence of sequence difference cut-off values ranging from 2 to 10% on case definition and relative risk were evaluated. Non-filtered farms incurred about 0.5 outbreaks per year, with a seasonal increase in risk in cooler periods. Baseline risk, prior to filtration, in treatment farms was approximately 0.75 per year, approximately 50% higher than in control farms. Air filtration significantly reduced risk of PRRSV introduction events to 0.06–0.22 outbreaks per year, depending on the cut-off values used to classify a virus isolate as new to the herd. Overall, air filtration led to an approximately 80% reduction in risk of introduction of novel PRRSV, indicating that on large sow farms with good biosecurity in swine-dense regions, approximately four-fifths of PRRSV outbreaks may be attributable to aerosol transmission.

The effects of dietary ractopamine on the performance and carcass characteristics of late-finishing market pigs with a previous history of porcine circovirus type 2 associated disease (PCVAD)

ABSTRACT Porcine circovirus type 2 associated disease (PCVAD) is a costly disease to the commercial pig industry. Clinically significant PCVAD decreases growth rate and increases mortality in growing pigs. Porcine circovirus type 2 can costs the US swine industry 3 to 4 dollars per pig and in extreme cases as much as $20 per pig because of increased mortality rates and reduced growth performance of infected pigs relative to pigs of higher health. A total of 1,635 barrows and gilts with a known history of PCVAD were used in a randomized complete block design with a 5 × 2 factorial arrangement of the following treatments: no ractopamine hydrochloride (RAC), 5.0 mg/kg of RAC for 21 d, 7.4 mg/kg of RAC for 21 d, 5.0/7.4 mg/kg step-up, or 5.0/10.0 mg/kg step-up feeding program in barrows and gilts. Pigs assigned to the step-up program were fed the initial dose of 5 mg/kg of RAC for the first 14 d of the trial and then stepped-up to the increased dose of 7.4 or 10.0 mg/kg for the final 7 d of the feeding period. Growth performance traits were measured weekly during the 21-d test period, and carcass traits were measured on d 21 at the slaughter facility. Growth advantages of RAC-fed pigs over controls were observed as early as 7 d on trial and persisted throughout the entire live phase of the experiment. Pigs fed RAC gained 18.6% more weight per day than did control-fed pigs (1.02 vs. 0.86 kg/d, P

Assessment of the economic impact of porcine reproductive and respiratory syndrome virus on United States pork producers

Objective: To estimate the current annual economic impact of porcine reproductive and respiratory syndrome virus (PRRSV) on the US swine industry. Materials and methods: Data for the analysis was compiled from the US Department of Agriculture, a survey of swine veterinarians on the incidence and impact of PRRSV, and production records (2005 to 2010) from commercial farms with known PRRSV status. Animal-level economic impact of productivity losses and other costs attributed to PRRSV were estimated using an enterprise budgeting approach and extrapolated to the national level on the basis of the US breeding-herd inventory, number of pigs marketed, and number of pigs imported for growing. Results: The total cost of productivity losses due to PRRSV in the US national breeding and growing-pig herd was estimated at US $664 million annually, an increase from the US $560 million annual cost estimated in 2005. The 2011 study differed most significantly from the 2005 study in the allocation of losses between the breeding and the growing-pig herd. Losses in the breeding herd accounted for 12% of the total cost of PRRSV in the 2005 study, compared to 45% in the current analysis. Implications: Despite over 25 years of experience and research, porcine reproductive and respiratory syndrome remains a costly disease of pigs in the United States. Since 2005, some progress has been made in dealing with the cost of productivity losses due to the disease in the growing pig, but these were offset by greater losses in the breeding herd.

Review:Transport Losses in Market Weight Pigs: I. A Review of Definitions, Incidence, and Economic Impact

<h2>ABSTRACT</h2> Transport losses (dead and nonambulatory pigs) present animal welfare, legal, and economic challenges to the US swine industry. The objectives of this review are to explore 1) the historical perspective of transport losses; 2) the incidence and economic implications of transport losses; and 3) the symptoms and metabolic characteristics of fatigued pigs. In 1933 and 1934, the incidence of dead and nonambulatory pigs was reported to be 0.08 and 0.16%, respectively. More recently, 23 commercial field trials (n = 6,660,569 pigs) were summarized and the frequency of dead pigs, nonambulatory pigs, and total transport losses at the processing plant were 0.25, 0.44, and 0.69% respectively. In 2006, total economic losses associated with these transport losses were estimated to cost the US pork industry approximately $46 million. Furthermore, 0.37 and 0.05% of the nonambulatory pigs were classified as either fatigued (nonambulatory, noninjured) or injured, respectively, in 18 of these trials (n = 4,966,419 pigs). Fatigued pigs display signs of acute stress (open-mouth breathing, skin discoloration, muscle tremors) and are in a metabolic state of acidosis, characterized by low blood pH and high blood lactate concentrations; however, the majority of fatigued pigs will recover with rest. Transport losses are a multifactorial problem consisting of people, pig, facility design, management, transportation, processing plant, and environmental factors, and, because of these multiple factors, continued research efforts are needed to understand how each of the factors and the relationships among factors affect the well-being of the pig during the marketing process.

The American dream: A quest for high health

There has been at least a decade-long march to improve the health of the US swine industry. This coincided with rapid expansion of many farms and a tremendous change in the ownership structure of the US swine industry (fewer owners having larger sow farms and owning or controlling more pigs). Prior to 1990, the industry consisted of more typical farrow-to-finish farms that would live with chronic diseases such as atrophic rhinitis, Actinobacillus Pleuropneumonia (APP), Swine Dysentery, Mycoplasma pneumonia and a host of enteric organisms. Many of these would persist on an individual farm until either the owner became frustrated, or profitability and production were so poor that depopulation/repopulations were done. This was basically the technology of the 1980s. The late 1980s and early 1990s brought a tremendous amount of new sow farm construction or farm conversion. Nearly all of these were either farrow-to-wean or occasionally farrow-to-feeder pig (25 kg) with off-site finishing. The off-site nurseries and finishers (or recently wean-to-finishers) were built in several different configurations. Some would have 1 week’s worth of pigs on a site, some would have multiple weeks of nursery, some would have multiple weeks of finishing, or some would comingle farms and have only 1 week of nursery or 1 week of finishing on a site.

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.

Agro-Food System Restructuring and the Geographic Concentration of US Swine Production

The US swine industry has dramatically reorganized over the last two decades. Economic concentration in the slaughter sector has increased and hog production has consolidated economically and geographically. Increases in the geographic concentration of hog production have led to water pollution through spills and leakage from high numbers of very large manure storage lagoons centered within limited areas, such as a few counties. The global restructuring of agro-food systems has promoted the development of intensive and concentrated livestock production. However, national, state and local institutions, and dynamics have also influenced the structure of geographic concentration of hog production. Using state-level and national-level time series data from 1975–1996, we find that national-level increases in concentration in the hog-processing sector are positively associated with geographic concentration of production within states. However, we also find that state, and even local, government policy can mitigate, or worsen, the geographic concentration of hog production.

Effects of stocking rate and feeder-trough space on pig performance in wean-to-finish production systems

Wean-to-finish production, which involves taking pigs from weaning to slaughter in the same building, is becoming widely adopted in the US swine industry. This production system is being advocated largely because of claims of improved animal performance and a decrease in labor needed for animal movement compared to conventional multiple-stage systems. One of the potential disadvantages of this system is the considerable underutilization of floor space during the early growth period if pigs are penned in the group sizes that are appropriate for finishing pigs. However, increasing the stocking rate initially at weaning, with some of these pigs subsequently being moved to another finishing facility, may increase output from the system. Therefore, the objective of this research was to investigate effects of initial stocking rate and of feeder-trough space in commercial wean-to-finish facilities on pig performance from weaning to slaughter.

A new treatment for neonatal scours (1999)

Scours account for significant losses to the US swine industry every year. A common treatment for scours is the administration of broad-spectrum antibiotics, a practice with increasing unpopularity in the eyes of consumers. Currently, no treatment is available to reduce or eliminate the fluid losses associated with scours that is both inexpensive and easy to use. In the present study, a variety of prospective drugs were used to determine if a single compound might inhibit the effects of bacterial toxins in a laboratory setting. The results indicate that a new class of drugs, which we call DASUs, likely will prove useful for the treatment of watery diarrhea. Additional studies are underway to validate this conclusion.; Swine Day, Manhattan, KS, November 18, 1999

Environmental enrichment influences on pig behavior, performance and meat quality

The influence of environmental enrichment and genotype were evaluated for effects on performance, behavior and carcass characteristics in 320 pigs from weaning to slaughter at over 110 kg. Ten treatments were evaluated including two genotypes and five levels of enrichment, arranged factorially. Genotypes were PIC C-15×405 cross (C-15) which is a commonly employed commercial hybrid in the US swine industry and PIC EXP-94×405 cross (EXP-94; one-eighth Meishan). The herd was positive for Porcine Respiratory and Reproductive Syndrome virus which contributed to a high rate of mortality (6–40% death rate within treatments). The five environmental treatments were isolation (NEG), weekly normal handling (NOR), daily normal handling plus the addition of environmental enrichment devices (TOYS), daily normal handling plus 2-min pleasant handling bouts with humans 5 days/week (HUM), and the same as HUM plus TOYS ( T+ H). Averaged over genotypes, growth and efficiency measures were not effected by the range of environmental treatments performed. Enrichment treatments and genotypes tended to interact ( P=0.07) for average daily gain and Feed:Gain ratio. C-15 pigs showed similar ADG and F:G ratio in the five enrichment treatments. However, EXP-94 pigs exposed to the TOYS had improved ADG and F:G ratio ( P<0.05) compared to the HUM, T+ H and NEG treatments. Pigs in the NEG had less backfat opposite the last rib and last lumbar vertebrae ( P<0.05) than pigs in other levels of enrichment. Pork quality measures (pH, Minolta colorimeter, Warner–Bratzler shear force value and taste panel evaluation) were not affected by the range of rearing conditions studied during this experiment. The environmental treatments had no significant effect on the overall duration of the behaviors observed during a 24-h period in finishing (50 to 113 kg body weight), although both treatment and genotype had an effect on behavior patterns in the nursery (weaning at 28 days to 8 weeks of age) stage of production. Animals in NEG took longer to make contact and spent less time in contact with the experimenter during two human-interaction testing periods ( P<0.001). Enrichment treatments did not affect the ability or time required to move or weigh these pigs. Considering a common genotype used in the US swine industry (C-15), we found no improvement in pig performance, ease of handling or meat quality with use of increased environmental enrichment or extensive human handling. Other genotypes may show a positive performance response to environmental enrichment.