Finisher Swine Research Articles

128 Lysine Titration for Intact Males and Gilts During the Grower-Finisher Period in Both Summer and Winter Seasons in a South African Commercial Production System

Abstract The decision as to the optimum amount of dietary balanced protein to feed to commercial grower-finisher pigs should be based on both biology and economics. Terminal sired genotypes are constantly changing due to the selection pressures applied by geneticists on the patrilineal as well as matrilineal animals, as are the relative costs of protein-containing ingredients and the revenue derived from the sale of pork. Thus, the objective of this study was to determine the most efficacy and economical levels of lysine to feed grower finisher swine in both the summer and winter seasons in South Africa. The trial was conducted at the Baynesfield Swine Research Unit at Baynsefield Estate in KwaZulu Natal, South Africa. A total of 528 animals (26.48 ± 0.33 kg initial BW, TN 70 Topig genetics, 70-d of age) were used in an 84-day study, consisting of the grower-finisher period. The house consists of 48 pens each containing 11 pigs with a total of 528 pigs in the house. Pens were randomly allocated to one of six treatments (n = 8 pens). Each diet by phase was formulated with the same NE but with different SID Lys levels (120%, 110%, 100%, 90%, 80%, 70%) of the Topigs Norsvin Tempo Progeny Grower feed manual. All the diets were fed in a four-phase program. Individual body weight and pen feed intake were taken at each phase change. Data was analyzed utilizing Prox MIX (SAS, 2021). Pigs had ad libitum access to feed and water. Feed intake and body eight were measured at every phase change. Additionally, the carcass variables of percent lean, grade, cold carcass weight, and yield were measured at slaughter. The economic variables of feed cost, carcass value, mofc, and cost per gain were calculated to make a comparison. Statistical analysis was conducted in SAS (2021) utilizing the Proc GLM model for the average effects within each period and connection letter calculated with Fisher’s test. Yield and grade were optimized when pigs were fed the 100% SID Lysine diet. Pigs fed the 120% SID Lysine diet had the best overall gain and slaughter BW in both seasons (Table 1). Pigs that were fed the 120% SID Lys diet had the greatest average daily gain when compared with other treatments for the winter trial but during the summer trial the pigs that were fed the 100% SID Lys diets showed the greatest average daily gain. However, the greatest margin over feed cost during both summer and winter was obtained from the 90% SID lysine treatment. In conclusion, raw ingredient costs and seasonality are critical components when optimizing SID lysine for more than just gain but profitability.

The effect of standardized ileal digestible isoleucine:lysine in diets containing 20% dried distillers grains with solubles on finishing pig performance and carcass characteristics.

In order to determine the standardized ileal digestible (SID) Ile:Lys requirement in finishing diets containing 20% DDGS, a 56-d study was conducted utilizing 2,268 pigs (DNA 600 x Topigs Norsvin 70, initially 82.3 kg). A total of six dietary treatments were fed, including a standard corn-soybean meal (SBM) diet and five diets containing 20% DDGS with SID Ile:Lys ratios of 55%, 60%, 65%, 70%, and 75%. Dietary treatments were assigned to pens, incompletely balancing for previous treatment, with each treatment being replicated 14 times. Pair-wise comparisons were used to evaluate the impact of dietary treatment on performance and carcass traits, whereas single degree of freedom orthogonal polynomials were used to evaluate dose response of SID Ile:Lys in 20% DDGS diets. Increasing the SID Ile:Lys ratio in diets containing 20% DDGS did not impact pig growth performance criteria in a quadratic or linear fashion (P ≥ 0.18). However, increasing the SID Ile:Lys ratio in 20% DDGS diets resulted in decreased back fat (BF; Quadratic, P = 0.01), increased loin depth (Quadratic, P = 0.03), and tended to increase percent lean (Quadratic, P = 0.07) with optimal carcass parameters occurring when 65% SID Ile:Lys was supplied in 20% DDGS diets. Pigs fed the corn-SBM diet had a similar final body weight (BW; P = 0.26) and cumulative average daily gain (ADG; P = 0.12) compared to pigs fed a 20% DDGS diet containing 70% SID Ile:Lys ratio and 3% greater cumulative average daily feed intake (ADFI) compared to pigs receiving diets with SID Ile:Lys ratios of 65% and 75% (P ≤ 0.01). In conclusion, these results suggest that when feeding 20% DDGS in late finishing swine diets, a SID Ile:Lys ratio of 70% should be utilized when attempting to achieve similar overall growth performance relative to a corn-SBM diet.

Predicting the time to detect moderately virulent African swine fever virus in finisher swine herds using a stochastic disease transmission model

BackgroundAfrican swine fever (ASF) is a highly contagious and devastating pig disease that has caused extensive global economic losses. Understanding ASF virus (ASFV) transmission dynamics within a herd is necessary in order to prepare for and respond to an outbreak in the United States. Although the transmission parameters for the highly virulent ASF strains have been estimated in several articles, there are relatively few studies focused on moderately virulent strains. Using an approximate Bayesian computation algorithm in conjunction with Monte Carlo simulation, we have estimated the adequate contact rate for moderately virulent ASFV strains and determined the statistical distributions for the durations of mild and severe clinical signs using individual, pig-level data. A discrete individual based disease transmission model was then used to estimate the time to detect ASF infection based on increased mild clinical signs, severe clinical signs, or daily mortality.ResultsOur results indicate that it may take two weeks or longer to detect ASF in a finisher swine herd via mild clinical signs or increased mortality beyond levels expected in routine production. A key factor contributing to the extended time to detect ASF in a herd is the fairly long latently infected period for an individual pig (mean 4.5, 95% P.I., 2.4 - 7.2 days).ConclusionThese transmission model parameter estimates and estimated time to detection via clinical signs provide valuable information that can be used not only to support emergency preparedness but also to inform other simulation models of evaluating regional disease spread.

Assessing the value of PCR assays in oral fluid samples for detecting African swine fever, classical swine fever, and foot-and-mouth disease in U.S. swine.

IntroductionOral fluid sampling and testing offers a convenient, unobtrusive mechanism for evaluating the health status of swine, especially grower and finisher swine. This assessment evaluates the potential testing of oral fluid samples with real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) to detect African swine fever, classical swine fever, or foot-and-mouth disease for surveillance during a disease outbreak and early detection in a disease-free setting.MethodsWe used a series of logical arguments, informed assumptions, and a range of parameter values from literature and industry practices to examine the cost and value of information provided by oral fluid sampling and rRT-PCR testing for the swine foreign animal disease surveillance objectives outlined above.ResultsBased on the evaluation, oral fluid testing demonstrated value for both settings evaluated. The greatest value was in an outbreak scenario, where using oral fluids would minimize disruption of animal and farm activities, reduce sample sizes by 23%-40%, and decrease resource requirements relative to current individual animal sampling plans. For an early detection system, sampling every 3 days met the designed prevalence detection threshold with 0.95 probability, but was quite costly.LimitationsImplementation of oral fluid testing for African swine fever, classical swine fever, or foot-and-mouth disease surveillance is not yet possible due to several limitations and information gaps. The gaps include validation of PCR diagnostic protocols and kits for African swine fever, classical swine fever, or foot-and-mouth disease on swine oral fluid samples; minimal information on test performance in a field setting; detection windows with low virulence strains of some foreign animal disease viruses; and the need for confirmatory testing protocol development.

Mortality Patterns in a Commercial Wean-To Finish Swine Production System.

Modern commercial pig production is a complex process that requires successful producers to understand and resolve factors associated with perturbations in production. One important perturbation is inventory loss due to mortality. In this study, data on 60 lots of approximately 2000 weaned pigs (n = 115,213) from one commercial production system were collected through the wean-to-finish (WTF) cycle with the objective of establishing patterns of mortality, estimating differences in profit/loss among patterns of mortality, and identifying production practices associated with mortality patterns. Information provided by the production system included the number of pigs in each lot at the time of placement (beginning inventory), weaning weight, barn dimensions, number of dead pigs (NDP) daily, capacity placed (proportion pigs actually placed versus what had been planned to be placed) and average weight sold. Analysis of NDP revealed three mortality patterns (clusters I, II, III) composed of 6, 40, and 14 lots, respectively, that differed in the temporal onset and/or level of mortality. Average daily gain (ADG) and feed conversion ratio (FCR) were calculated by growth phase for each cluster. An economic model showed profit differences among clusters due to poor biological performance by clusters I and III in the late finishing phase. Cluster II (n = 40) had fewer dead pigs and the highest profit compared to clusters I (n = 6) and III (n = 14). Area per pig (stocking density) was the only factor associated with the differences in mortality patterns. Routine monitoring and the analysis of mortality patterns for associations with production and management factors can help swine producers improve biological performance and improve profit.

Factors Associated with Salmonella Prevalence in U.S. Swine Grower-Finisher Operations, 2012.

Nontyphoidal Salmonella is an important foodborne pathogen with diverse serotypes occurring in animal and human populations. The prevalence of the organism on swine farms has been associated with numerous risk factors, and although there are strong veterinary public health controls for preventing Salmonella from entering food, there remains interest in eradicating or controlling the organism in the preharvest environment. In this study, using data collected via the U.S. Department of Agriculture (USDA) National Animal Health Monitoring System Swine 2012 study, we describe nontyphoidal Salmonella and specific serotype prevalence on U.S. grower-finisher swine operations and investigate associations between Salmonella detection and numerous factors via multiple correspondence analysis (MCA) and regression analysis. MCA plots, complementary to univariate analyses, display relationships between covariates and Salmonella detection at the farm level. In the univariate analysis, Salmonella detection varied with feed characteristics and farm management practices, reports of diseases on farms and vaccinations administered, and administration of certain antimicrobials. Results from the univariate analysis reinforce the importance of biosecurity in managing diseases and pathogens such as Salmonella on farms. All multivariable regression models for the likelihood of Salmonella detection were strongly affected by multicollinearity among variables, and only one variable, pelleted feed preparation, remained in the final model. The study was limited by its cross-sectional nature, timelines of data collection, and reliance on operator-reported data via a convenience sample.

Genome-Wide Association of Myoglobin Concentrations in Pork Loins

Lean color is a major focus for identifying pork loins for export markets, and myoglobin is the primary pigment driving pork color. Thus, increasing myoglobin concentration should increase redness of pork products and the number of loins acceptable for exportation. Therefore, understanding genetic variation and parameters affecting myoglobin concentration is critical for improving pork color. The objective of this study was to identify genetic markers associated with myoglobin concentration in pork loin muscle. Ultimate pH and myoglobin concentrations were measured in longissimus thoracis et lumborum samples of pigs (n = 599) from two different commercial finishing swine facilities. A Bayes-C model implemented in GenSel identified regions within 7 chromosomes that explained greater than 63% of the genetic variance in myoglobin concentration. Chromosome 7 had 1 significant region which accounted for 37% of the genetic variance, while chromosome 14 had 4 significant regions accounting for 9.8% of the genetic variance. Candidate genes in the region on chromosome 7 were involved in iron homeostasis, and genes in the significant regions on chromosome 14 were involved in calcium regulation. Genes identified in this study represent potential biomarkers that could be used to select for higher myoglobin concentrations in pork, which may improve lean meat color.

Evaluation of antibiotic usage in swine reproduction farms in Umbria region based on the quantitative analysis of antimicrobial consumption.

Antibiotic use in food-producing animals has considerable impact on public health, especially with respect to the development and spread of antibiotic resistance. Pigs represent one of the main species in which antibiotics are frequently used for different purposes. Surveillance of antibiotic consumption and dose appropriateness, through novel approaches based on defined daily doses, is strongly needed to assess farms’ antibiotic risk, in terms of spread of antibiotic resistance and possibile presence of residues in meat. In this study, antibiotic consumption was monitored in 14 swine reproduction farms, together with managerial, structural, and health aspects. Most of the controlled farms (65%) were classified as at medium antibiotic risk, 21% at high antibiotic risk, and 14% at low antibiotic risk. Critical aspects of antibiotic administration concerned treatments for suckling and weaner piglets, oral antibiotic administration, treatment and diagnosis of gastroenteric infections, and use of critically important antimicrobials for human medicine, especially colistin. These aspects could be considered critical aspects of antibiotic use in from-farrow-to-wean/finish swine farms in the Umbria region and must be controlled to minimize risks. Even though a small number of farms in Umbria region are at high antibiotic risk, the risk of antibiotic resistance should be minimized, and management and biosecurity of the farms should be improved by extending the use of antimicrobial susceptibility tests and optimizing the diagnostic methods for infectious diseases. Furthermore, farmers’ and veterinarians’ knowledge of antibiotic resistance should be improved and the prudent use of antibiotics encouraged to prevent the development and spread of resistant microorganisms.

First Detection and Clinical Presentation of Porcine Epidemic Diarrhea Virus (Pedv) in Serbia

Abstract During 2015/2016, fecal and intestinal samples from live diseased and/or dead pigs with suspected PEDV and/or TGEV and signs of rotavirus infection were collected from in total seven different farrow-to-finish swine farms located in Northern Serbia region (Vojvodina Province). A total of 14 samples (2 pools per farm) of small intestine with fecal content were submitted to laboratory molecular investigation (multiplex RTPCR). On these farms the clinical signs included the occurrence of diarrhea in suckling and weaned piglets, with weak or no response to the applied antimicrobial therapy. The epidemic of severe diarrhea affecting pigs of all ages on one farrow-to finish swine farm was detected in January 2016. Watery diarrhea in all swine categories was associated with vomiting and a reduction in feed consumption. Diarrheic, gaunt and dehydrated piglets, covered with feces were found in 90% litters. The disease affected most severely the suckling piglets, and the mortality in newborn piglets was up to 35%. In the weaned piglets and fatteners the mortality was up to 2.5% and 1.2%, respectively. The PEDV RNA was detected in pooled feces and samples of small intestines derived from diseased and dead suckling piglets from only one investigated farm. The PEDV positive samples showed to be negative for rotavirus group A and TGEV. The transport vehicles were identified as the main possible route of PEDV introduction. This is the first report demonstrating the presence of PEDV in Serbia.

042 Genome-wide association of myoglobin concentrations in pork loins

Lean color is a major focus for identifying pork loins for export markets, and myoglobin is the primary pigment driving pork color. Thus, increasing myoglobin concentration should increase redness of pork products and the number of loins acceptable for exportation. Therefore, understanding genetic variation and parameters affecting myoglobin concentration is critical for improving pork color. The objective of this study was to identify genetic markers associated with myoglobin concentration in pork loin muscle. Ultimate pH and myoglobin concentrations were measured in longissimus thoracis et lumborum samples of pigs (n = 599) from two different commercial finishing swine facilities. A Bayes-C model implemented in GenSel identified regions within 7 chromosomes that explained greater than 63% of the genetic variance in myoglobin concentration. Chromosome 7 had 1 significant region which accounted for 37% of the genetic variance, while chromosome 14 had 4 significant regions accounting for 9.8% of the genetic variance. Candidate genes in the region on chromosome 7 were involved in iron homeostasis, and genes in the significant regions on chromosome 14 were involved in calcium regulation. Genes identified in this study represent potential biomarkers that could be used to select for higher myoglobin concentrations in pork, which may improve lean meat color.

151 Evaluation of copper source addition in the grow-finish phase

A total of 1167 pigs (66.36 ± 4.10 kg) were used to evaluate differences in 3 copper sources added in the late grow-finish phase. Treatment diets included a control (CON) with no added copper, and the CON diet plus 150 ppm of CuCl2, CON plus 150 ppm of CuSO4, or CON plus 80 ppm of organic copper (Cu Mintrex®, Novus International, Inc., St. Charles, MO). Diet phase changes occurred at d 21 and 32 d post-allotment. Pigs were penned in blocks of either 24 or 25 pigs/pen with a computerized feed system delivering feed to single-sided feeders. There were a total of 12 replications per treatment group. Data were analyzed as a randomized complete block design using the PROC MIXED procedure of SAS with pen as the experimental unit and treatment as a fixed effect. From d 0 to 21 of the study, there were no significant differences (P > 0.24) in performance for the overall effect of CON-fed pigs compared to those fed supplemental copper, regardless of source. During the second phase, there was a tendency for increased ADG (0.84, 0.88, 0.89, and 0.89 kg/d; P = 0.06, respectively) among pigs that were fed supplemental copper, regardless of source or inclusion rate. The inclusion of supplemental copper significantly improved (0.31, 0.34, 0.35, 0.33; P < 0.01, respectively) the G:F, regardless of source or dose. At d 32, all pigs were weighed and first markets occurred. At this point, all pigs were fed a common diet that included ractopamine and all pens remained on study until completely marketed (approximately 35 d after the first market date). There were no differences (0.98, 0.98, 0.98, 0.97; P > 0.27) in the growth performance of pigs during the ractopamine phase. For the overall period (d 0 to market), copper supplementation improved G:F (0.33, 0.34, 0.35, 0.34; P = 0.01, respectively). When organic copper was fed, the response was not significantly different from the CON, but did tend (P = 0.10) to have improved G:F. There also tended to be a decrease in overall ADFI compared to the CON when either CuSO4 or CuCl2 was fed (2.67, 2.46, 2.56 kg/d; P = 0.13, respectively). In conclusion, the addition of supplemental copper, regardless of source, resulted in improved G:F in late finishing swine diets.

Evaluation of conditioning time and temperature on gelatinized starch and vitamin retention in a pelleted swine diet.

Two key feed processing parameters, conditioning temperature and time, were altered to determine their effects on concentration of gelatinized starch and vitamin retention in a pelleted finishing swine diet. Diet formulation (corn–soybean meal based with 30% distillers dried grains with solubles) was held constant. Treatments were arranged in a 2 × 3 factorial design plus a control with 2 conditioning temperatures (77 vs. 88°C) and 3 conditioner retention times (15, 30, and 60 s). In addition, a mash diet not subjected to conditioning served as a control for a total of 7 treatments. Samples were collected after conditioning but before pelleting (hot mash), after pelleting but before cooling (hot pellet), and after pelleting and cooling (cold pellet) and analyzed for percentage total starch, percentage gelatinized starch, and riboflavin, niacin, and vitamin D3 concentrations. Total percentage starch was increased by greater conditioning temperature (P = 0.041) but not time (P > 0.10), whereas higher temperature and longer time both increased (P < 0.05) percentage gelatinized starch, with increasing time resulting in a linear increase in percentage starch gelatinization (P = 0.013). The interaction between conditioning temperature and time increased percentage gelatinized starch (P = 0.003) but not percentage total starch (P > 0.10). Sample location also affected both percentage total starch and gelatinized starch (P < 0.05), with the greatest increase in percentage gelatinized starch occurring between hot mash and hot pellet samples. As expected, the pelleting process increased percentage gelatinized starch (P = 0.035; 7.3 vs. 11.7% gelatinized starch for hot mash vs. hot pellet samples, respectively), but there was no difference in total starch concentrations (P > 0.10). Finally, neither conditioning temperature nor time affected riboflavin, niacin, or vitamin D3 concentrations (P > 0.10). In summary, both increasing conditioningtemperature and time effect percentage gelatinized starch, but not to the extent of forcing the diet through a pelleting die.

Genetic diversity of group A rotavirus in swine in Canada

Group A rotaviruses (RVA) in pigs have been poorly investigated in Canada. In a continued effort to fill this gap, ten finisher swine farms in Quebec, Canada, were sampled over a nine-month period. The presence of RVA was detected in healthy pigs on all farms investigated during the entire sampling period. The genotypes detected included G2, G5, G9 and G11; P[6], P[7], P[13], P[27] and P[34]; and I5 and I14. The predominant types were G2, P[13] and I5, which is different from previous global reports. Various fomites were consistently contaminated by RVA, suggesting that a resident viral flora remains in the farm environment and may play a role in the infection of incoming pigs. The results also suggest temporal or geographical specificities regarding strain distribution on pig farms.

Prevalence of Porcine Noroviruses, Molecular Characterization of Emerging Porcine Sapoviruses from Finisher Swine in the United States, and Unified Classification Scheme for Sapoviruses

Noroviruses (NoVs) and sapoviruses (SaVs) are important human pathogens. Although the involvement of porcine NoVs in disease in pigs is unclear, they are genetically and antigenically closely related to human NoVs. Human NoV-like strains have been detected in pigs, raising public health concerns of potential interspecies transmission. Porcine SaVs are highly diverse and emerging in swine populations. Recently, at least three new genogroups of porcine SaVs have been proposed. In this study, we tested 413 pooled fecal samples collected from apparently healthy finisher pigs in North Carolina swine farms during 2009. Reverse transcription (RT)-PCR coupled hybridization assays were performed to detect known porcine NoVs. The overall prevalence of porcine NoVs determined was 18.9% based on this method. Samples were then tested by RT-PCR targeting the 5' end of the capsid region for genogroup II (GII) NoVs, a group which includes human NoVs, followed by sequence analysis. All NoVs identified belonged to typical porcine NoV genotypes, and no human NoV-like strains were detected in specimens from these pigs. Porcine NoV-negative samples (n = 335) were subsequently screened using universal calicivirus primers, and 17 SaV strains were confirmed by sequencing. Based on the partial RNA-dependent RNA polymerase (RdRp) region, they clustered with GIII, GVII, and GVIII and with currently unclassified SaVs. According to analysis of the complete capsid sequences, 7 representative strains clustered with GVII, GVIII, and GIX? SaVs. We tentatively classified SaVs into 14 genogroups based on the complete capsid protein VP1. In summary, porcine NoVs and highly divergent SaVs were present in North Carolina finisher pigs.

The Association between Sub‐Therapeutic Antibiotics andSalmonellaTyphimurium in Market‐Weight Swine: A Systematic Review and Summation of Evidence from 1950 to 2007

A systematic review approach was used to evaluate the association between sub-therapeutic antibiotics in feed and Salmonella Typhimurium isolation in market-weight finisher swine raised in modern swine production systems. Fourteen challenge trials described the efficacy of different antibiotics after challenge with S. Typhimurium. The studies identified were of limited evidentiary value for the review question because they were not relevant to the review question, i.e. conducted in artificial settings on small numbers of young pigs. None of the studies reported using blinding during outcome assessment. No antibiotic regimen was evaluated more than once. The association between sub-therapeutic antibiotics and Salmonella outcomes in market-weight swine raised in modern production systems cannot be summarized using the currently available literature. Many available studies fail to report critical study design features such as blinding and/or to take into account the data generated from longitudinal studies.

The value of precision feeding technologies for grow–finish swine

Feed and piglet are the largest variable cost items and important factors affecting the profitability of grow–finish pork production in most pork producing countries world-wide. Although a pig's potential to utilize energy and protein depends on its weight, age and genetic line, grow–finish pigs are typically fed with only 1 to 4 diets during the grow–finish phases of production. The goal of this study is to examine whether there are differences in feeding patterns, the timing of slaughter and return on pig space unit between 1) multi-phase feeding in which the quantity and protein content of the feed and the timing of slaughter are optimized on a daily basis, and 2) two-phase feeding in which feed quantity and slaughter decision are optimized daily but feed composition is predetermined for a given weight range. A stochastic dynamic programming model was used to evaluate different scenarios. The model maximizes return on capital invested in production facilities, which is critical for the competitiveness of pork production. The bio-economic model explicitly characterizes the growth process of grow–finish pigs and optimizes the timing of slaughter and daily amounts of protein and energy used in the feed. The growth of lipid mass and protein mass in the pig in a grow–finish group are modelled separately. The results suggest that a switch from the two-phase feeding to the multi-phase feeding shifts feeding regimen towards increased protein inclusion in the diets. It increases annual return on the operation by €1.35–€1.88 per pig space unit.

Supply reductions, export restrictions, and expectations for hog returns in a potential classical swine fever outbreak in the United States

An economic model of pork, swine, and related markets examines effects of hypothetical classical swine fever (CSF) outbreaks in the United States. Equations determine deviations in endogenous variables from observed supply and demand values. The analysis assumes 11 million US hogs are destroyed. Live swine and pork exports are stopped during the outbreak, with full recovery. Pork demand by US consumers is assumed to fall by 1% during the outbreaks, with a gradual recovery. Hog growers adjust expectations of future prices on the basis of current market conditions. One potential CSF outbreak reflects losses in the hog population skewed towards grower and finisher swine, while another outbreak has stronger effects on breeding inventory and the pig crop. The largest effects occur in pork and swine. Effects on other sectors are small. Over 20 quarters, the pork industry returns lose $4 billion. Losses for hogs, including the value of animals destroyed, range from $2.6 billion to $4.1 billion. An assumption of unchanged hog-grower expectations for returns is compared to that when expectations adjust. Unchanged expectations alter the pattern of slaughter and prices because breeding inventory falls less, thus more hogs are available for sale after Quarter 7.

Associations Among Antimicrobial Use and Antimicrobial Resistance ofSalmonellaspp. Isolates from 60 Alberta Finishing Swine Farms

The study objectives were to identify potential associations between reported antimicrobial use (AMU) practices and antimicrobial resistance (AMR) of fecal and environmental Salmonella spp. isolates (n = 322 isolates) recovered from 60 Alberta finishing swine farms, and to estimate the amount of pen and farm level variation in AMR. The AMU data were collected through a questionnaire. Separate multilevel logistic regression models were built for six antimicrobials with prevalence of resistance >or=5% using the Generalized Linear Latent and Mixed Model (GLLAMM) procedure. In-feed use of tylosin in finishers was associated with increased odds of resistance in Salmonella isolates to ampicillin (OR = 61.56), streptomycin (OR = 11.70), and multiple antimicrobials (OR = 4.90). Injectable penicillin use in growers was associated with decreased odds of resistance in Salmonella isolates to streptomycin (OR = 0.06), kanamycin (OR = 0.03), and multiple antimicrobials (OR = 0.12). Injectable penicillin use in finishers was associated with decreased odds of resistance in Salmonella isolates to ampicillin (OR = 0.007) and chloramphenicol (OR = 0.04). Overall, these results indicate that AMU in pig production is inconsistently associated with AMR in Salmonella from finishing swine. Variation in AMR prevalence of Salmonella isolates of swine was moderate to high at pen and farm levels for most antimicrobials suggesting that interventions at the pen and farm levels might be beneficial in reducing the emergence of AMR Salmonella in swine populations.

The effect of ractopamine hydrochloride (Paylean ®) on lean carcass yields and pork quality characteristics of heavy pigs fed normal and amino acid fortified diets

Effects of ractopamine hydrochloride (RAC) on carcass parameters in heavy weight (133.24 ± 8.07 kg) finishing pigs ( n = 278) given amino acid fortified (AA) or 16% crude protein (CP) diets were evaluated. A total of seven experimental diets were formulated; RAC was added at 0, 5 and 20 ppm to the 16% CP diets (CP0, CP5 and CP20, respectively) and at 0, 5, 10 and 20 ppm to the AA fortified diets (AA0, AA5, AA10 and AA20, respectively). Carcass, tenderloin, and ham weights were heavier ( P < 0.05) for RAC AA diets vs. AA0. Loin weight was heavier ( P < 0.05) for AA20 vs. AA0 and CP20 vs. CP0. No differences ( P > 0.05) were observed for color or firmness scores. Carcass muscle score, ham weight and protein% were greater ( P < 0.05) for RAC diets. Moisture was greater ( P < 0.05) and fat was lower ( P < 0.05) for AA5 and AA20 vs. AA0 and CP5 and CP20 vs. CP0. Feeding RAC to late finishing swine increases carcass yields and protein% with lower fat% for pigs weighing up to 136 kg.

Efficacy of Vaccination to ReduceSalmonellaPrevalence in Live and Slaughtered Swine: A Systematic Review of Literature from 1979 to 2007

A systematic review was conducted to evaluate the efficacy of vaccination to reduce Salmonella prevalence in market weight finisher swine. A search of online databases and selected conference proceedings was conducted to identify relevant studies. The review process followed relevance screening, methodological quality assessment, and data extraction. Although multiple outcomes were frequently reported, only outcomes describing culture of Salmonella were extracted. Five clinical trials and 23 challenge studies were considered likely relevant to the review as they described vaccination to reduce Salmonella in swine. Five clinical trials reported vaccination was associated with reduced isolation of Salmonella in market weight pigs, however, information required to assess the internal validity of the study was often not described in the manuscripts. All challenge studies assessed vaccine efficacy in pigs aged <15 weeks reducing the relevance of results to the review which focused on market weight pigs. Only five of the 23 challenge studies reported the majority of information necessary to evaluate the quality of vaccine studies. Given large variability in population type, sample size, type of vaccine, dose and dosing regimens, and type of outcomes observed, pooled data analysis was not possible, and therefore, a qualitative synthesis of the studies was conducted. Available evidence suggests that vaccination is associated with reduced Salmonella prevalence in swine at or near harvest; however, this conclusion is based on studies with design and reporting deficiencies that could potentially indicate biases with the outcome.