Market Hogs Research Articles

Dietary supplementation of magnesium sulfate and sodium bicarbonate and its effect on pork quality during environmental stress

Market hogs ( n = 160) were allotted to four dietary treatments to evaluate the effectiveness of magnesium sulfate (MgSO 4) and sodium bicarbonate (NaHCO 3) on improving pork quality during times of environmental stress. The experiment was conducted in four different months (Trial) to evaluate temperature as an environmental stressor. The dietary treatments were: 1) control 2) control + 3.2 g⁎pig-1⁎d-1 of MgSO 4 for a minimum of 14 days prior to slaughter, 3) control + 1.5% NaHCO 3 fed for 48 h prior to slaughter, and 4) control + 3.2 g⁎pig-1⁎d-1 MgSO 4 + 1.5% NaHCO 3. No differences ( P > 0.05) in pork quality were found between dietary treatments. Live weight, carcass weight and dressing percentage did not differ ( P > 0.05) by Trial whereas measures of pork quality (24 h pH, L, a, and b values, NPPC color scores, drip loss, and Warner Bratzler shear force [WBSF]) values were affected ( P < 0.05) by Trial. Time in lairage increased ( P < 0.05) dressing percentage and impacted ( P < 0.05) initial loin pH, 24 h ham pH, ham a values, and WBSF. Although dietary treatment had no effect on pork quality, the month of the year when pigs were slaughtered played a relevant role in pork quality.

Incidence and severity of Arcanobacterium pyogenes injection site abscesses with needle or needle-free injection methods (2009)

A total of 198 nursery age pigs were used to evaluate the difference in the occurrence of injection site abscesses between needle-free jet injection and conventional needle-and-syringe injection systems. Pigs were fed for 21 d prior to treatment administration to acclimate the pigs to the environment of the Kansas State University Segregated Early Weaning Unit. On d 21, each pig received 4 injections of aluminum hydroxide adjuvant, 1 in the neck and 1 in the ham by needle-free jet injection (Pulse Needle-Free Systems, Lenexa, KS) on 1 side and 1 in the neck and 1 in the ham on the opposite side by conventional needle-and-syringe injection. Immediately prior to injection, the external surface of the injection sites was contaminated with an inoculum of Arcanobacterium pyogenes. The pigs were then fed for a period of 27 and 28 d. On d 27 and 28, the pigs were humanely euthanized and sent to the Kansas State University Veterinary Diagnostics Laboratory, where necropsies were performed and the injection sites underwent histopathological evaluation. The needle-free jet injection system was associated with more injection site abscesses than the conventional needle-and-syringe injection method for both the neck (P = 0.06) and ham (P = 0.03) injection sites. Twelve abscesses were found at needle-free injection sites, whereas only 1 abscess was found where a conventional needle injection method was used. Five abscesses were found at the neck injection sites, and 8 abscesses were observed at the ham injection sites. Of the 13 abscesses found, 10 developed on the left side of the animal, and only 3 were on the right side. In summary, the implementation of needle-free jet injection systems in market hog production will be beneficial by eliminating the potential for needles and needle fragments in meat products, but it may increase the occurrence of injection site abscesses in pork carcasses that will need to be trimmed in pork processing plants.; Swine Day, Manhattan, KS, November 19, 2009

Effects of management, environmental and temporal factors on mortality and feed consumption in integrated swine fattening farms

The purpose of this study was to assess the effects of management, environmental and temporal factors of farms and batches on mortality and feed consumed per market hog. Information of management, environmental and temporal factors from 158 all-in all-out finishing batches completed in 27 integrated fattening farms in Galicia (Spain) were collected from 1999 to 2002. Multilevel random effects models were used to determine the factors associated with the mortality and the average amount of feed provided per marketed hog. The level 1 unit was the finishing batch (batch level). At the level 2 the fattening farm where the batch of pigs was developed was introduced as random effects. A bad level of care provided by the farmer to the pigs increased the risk of mortality ( P = 0.03). The mortality of the fattening batch was associated with the supplier sow farm ( P < 0.01). The level of mortality of the batches of piglets entered the fattening farms both between January and April and October and December was higher than for batches incorporated from May to August ( P < 0.01). The year when the piglets entered the farm was significantly associated with mortality ( P < 0.01). The introduction of such variables in the multilevel model for mortality reduced the total unexplained variation by 41.06%. The proportion of the variation of the mortality attributable to the fattening farms was small (3.65%). The variability of mortality was higher when the placement of piglets was from September to December ( P = 0.01). Higher consumption of feed was recorded when the feed was provided in a non-pellet form ( P < 0.01). The introduction of piglets between September and December was associated with a higher consumption of feed ( P < 0.01). The average final weight of the hogs was positively associated with the feed consumed per hog of the fattening batch ( P < 0.01). The amount of feed provided per hog was statistically different among the years and these effects were modified by the level of mortality recorded in the batch and by the average weight of the marketed hogs. After introducing all the fixed effects in the multilevel model for feed provided per hog the unexplained variation at the farm and batch level was reduced by 47.72% and 85.35%, respectively. A considerable amount of variation of feed provided per hog resided at the fattening farm (32.50%). When the piglets were placed on September–December the variability of feed consumed was higher than in the other two periods of the year ( P = 0.02). In conclusion, our study shows that specific factors of the batches are the main contributors to explain mortality. On the other hand, by improving permanent farm characteristics a substantial profit is expected in the long run as a result of lower feed costs.

Factors associated with fatigued, injured, and dead pig frequency during transport and lairage at a commercial abattoir1

The objective of this study was to identify environmental and management factors that are associated with the frequency of fatigued, injured, and dead pigs on arrival and in resting pens during lairage at a commercial Midwest abattoir. The terms transport losses or total losses refer to pigs that die or become nonambulatory at any stage of the marketing process. In this study, fatigued, injured, and dead pigs were summed into a variable termed total losses. Relative humidity (%), temperature ( degrees C), wind speed (m/s), and dew point ( degrees C) data were collected on 12,333 trailer loads of pigs. Week, sort from barn (first or third pig removal from barn), farm, normal vs. split load type (from 1 or multiple barns), load crew, driver, trailer, and wind direction were used as fixed effects in the model for the analysis of losses per load using generalized mixed models for Poisson distributions. Seven temperature-humidity indices (THI) were calculated and compared as model covariates. Load time per pig, trailer density (pigs per trailer x average BW/trailer space; kg/m(2)), wait time before unloading at the abattoir, and wind speed were used as model covariates. The log of the number of hogs per trailer was used to standardize the response variable. The linear covariate density accounted for the greatest portion of variance (based on F-value) followed by the fixed effect sort from barn, the fixed effect load type (pigs from 1 or multiple barns within a farm), load time per pig linear covariate, and THI. Pigs transported to the abattoir from June through July experienced fewer losses (P < 0.001) when compared with pigs that were transported from November through December. Keeping other factors constant, the log of total losses (%) per load increased by 0.0102x + 0.000541x(2) per unit of THI and 0.0191 kg/m(2) of density. Similarly, of 9 farms, the poorest-performing farm in regards to total loss percentage experienced 0.93% more losses per load when compared with the farm with the least loss percentage. This study demonstrates that multiple environment and management factors influence the incidence of market hog transport losses.

Effects of Slaughter Date, On-Farm Handling, Transport Stocking Density, and Time in Lairage on Digestive Tract Temperature, Serum Cortisol Concentrations, and Pork Lean Quality of Market Hogs

The objective of this study was to evaluate the effect of on-farm handling intensity (conventional vs. passive), transport stocking density: (high vs. low), and preslaughter lairage time (45min vs. 3h) on digestive tract temperature, serum cortisol concentrations, and pork quality of market pigs slaughtered in November (NOV; n = 111), February (FEB; n = 113), and August (AUG; n = 112). Pigs slaughtered in FEB had greater (P ≤ 0.027) digestive tract temperatures before loadout than pigs slaughtered in NOV or AUG. The digestive tract temperature of pigs slaughtered in AUG was greater (P ≤ 0.027) during than before loadout. Pigs afforded 3h of lairage tended to have greater (P = 0.068) digestive tract temperatures than pigs given 45min of lairage. When pigs were slaughtered in AUG and NOV, those afforded 3h of lairage had greater (P = 0.042) cortisol concentrations than pigs given only 45min of lairage. Carcasses of pigs slaughtered in AUG had a paler (P ≤ 0.032) LM than carcasses of pigs slaughtered in NOV and FEB, and greater (P ≤ 0.032) LM purge losses than pigs slaughtered in FEB. Pigs given a 45min lairage had greater (P = 0.036) 30-h LM pH values, darker LM (P = 0.008), greater (P = 0.012) subjective color scores, and tended (P = 0.069) to have lower purge loss percentages than pigs given a 3-h lairage. Results indicated that pigs should have less than 3h of lairage when the day\\s low ambient temperature is ≤ 22°C to decrease antemortem stress and improve lean quality.

Diagnostic specificity of a real-time RT-PCR in cattle for foot-and-mouth disease and swine for foot-and-mouth disease and classical swine fever based on non-invasive specimen collection

Foot-and-mouth disease virus (FMDV) and classical swine fever virus (CSFV) are highly contagious and can cause great economic losses when introduced into disease-free regions. Accurate estimates of diagnostic specificity (Sp) are important when considering the implementation of surveillance for these agents. The purpose of this study was to estimate diagnostic Sp of a real-time reverse-transcriptase PCR assay developed for detection of FMDV in cattle and domestic swine and CSFV in domestic swine based on non-invasive specimen collection. One thousand and eighty-eight range beef cattle were sampled from thirteen geographic locations throughout Texas. One thousand and one hundred market hogs and cull sows were sampled. Results for both FMDV and CSFV were considered positive if amplification occurred at or before 40 PCR cycles, inconclusive between 40 and 45 cycles and negative otherwise. Ten cattle had nonspecific PCR amplifications for FMDV, but none were classified as positive and only one as inconclusive. Specificity (95% confidence interval) was estimated as 100% (99.7, 100). There were 19 nonspecific PCR amplifications for FMDV in sampled swine with 1 classified as positive, 6 as inconclusive, and 12 as negative. Specificity (95% confidence interval) was estimated as 99.9% (99.5, 100). There were 21 nonspecific PCR amplifications for CSFV, and 1 was classified as positive. Specificity (95% confidence interval) was estimated as 99.9% (99.5, 100). These assays have high Sp, but nonspecific PCR amplifications can occur.

Effect of introducing piglets from farrow-to-finish breeding farms into all-in all-out fattening batches in Spain on productive parameters and economic profit

A prospective study was conducted to assess the effect of introduction of piglets from farrow-to-finish farms on the global performance of all-in all-out fattening batches in Galicia (NW Spain). Two hundred and thirty-nine fattening batches from 48 fattening farms integrated in a cooperative were used in the study. All-in all-out fattening batches were classified according to the category of farm that supplied the piglets. Origin F was a fattening batch where all feeder piglets came from one or more farrow to feeder units versus origin FF, in case a group of piglets or all piglets of the batch came from farrow-to-finish farms. Productive parameters of fattening batches included in the study were recorded. Crude comparisons of performance of 37 fattening batches from origin F and 202 from origin FF were made. Mixed multiple linear regression models were used to assess the association between type of origin of feeder piglets and the following parameters: feed consumed per market hog, percentage of deaths (mortality) and time to slaughter. In all models, variables with presumable relationships with the outcomes were offered to the models as well as the biologically plausible interaction terms. Mortality was higher in fattening batches with piglets coming from farrow-to-finish farms (0.67% higher than origin F; P < 0.05). Time to slaughter was longer when feeder piglets were from origin FF (3.1 days longer; P < 0.05). We found a significant effect of type of origin on feed consumed per marketed hog. Additionally, a significant interaction was found: feed consumed per marketed hog was higher for fattening batches with all piglets from farrow-to-finish farms if slaughtered before 109 days and vice versa. A Monte Carlo simulation model was used to assess the economic impact of using origin F or FF as source of piglets. Results of the model indicated that the difference in expected profit per marketed hog between the types of sources of piglets was small (€11.50, S.D. 1.79 for origin F versus €10.44, S.D. 2.72, for origin FF).

Regional Impacts of a U.S. Hog Slaughter Plant Closing: The Thorn Apple Valley Case

As the 1998 U.S. hog market collapse unfolded, Thorn Apple Valley ceased hog slaughter operations at its Detroit, Michigan plant. We examine the impacts on Michigan live hog prices relative to Eastern Corn Belt hog prices. Results indicate that Michigan producers' relative price advantage diminished after the closure as procurement competition changed. As the impacts of the 1998 hog market collapse were absorbed, Michigan producers' relative price advantage became consistently negative. Examination of Michigan's market hog production distribution indicates postclosure shifts away from production in areas geographically near to Thorn Apple Valley and growth in counties geographically closer to alternative packers.

U.S. Food Safety and Inspection Service Testing for Salmonella in Selected Raw Meat and Poultry Products in the United States, 1998 through 2003: An Establishment-Level Analysis

The U.S. Food Safety and Inspection Service (FSIS) pathogen reduction–hazard analysis critical control point systems final rule, published in 1996, established Salmonella performance standards for broiler chicken, cow and bull, market hog, and steer and heifer carcasses and for ground beef, chicken, and turkey meat. In 1998, the FSIS began testing to verify that establishments are meeting performance standards. Samples are collected in sets in which the number of samples is defined but varies according to product class. A sample set fails when the number of positive Salmonella samples exceeds the maximum number of positive samples allowed under the performance standard. Salmonella sample sets collected at 1,584 establishments from 1998 through 2003 were examined to identify factors associated with failure of one or more sets. Overall, 1,282 (80.9%) of establishments never had failed sets. In establishments that did experience set failure(s), generally the failed sets were collected early in the establishment testing history, with the exception of broiler establishments where failure(s) occurred both early and late in the course of testing. Small establishments were more likely to have experienced a set failure than were large or very small establishments, and broiler establishments were more likely to have failed than were ground beef, market hog, or steer-heifer establishments. Agency response to failed Salmonella sample sets in the form of in-depth verification reviews and related establishment-initiated corrective actions have likely contributed to declines in the number of establishments that failed sets. A focus on food safety measures in small establishments and broiler processing establishments should further reduce the number of sample sets that fail to meet the Salmonella performance standard.

U.S. Food Safety and Inspection Service Testing for Salmonella in Selected Raw Meat and Poultry Products in the United States, 1998 through 2003: Analysis of Set Results

The U.S. Food Safety and Inspection Service (FSIS) tests sets of samples of selected raw meat and poultry products for Salmonella to ensure that federally inspected establishments meet performance standards defined in the pathogen reduction–hazard analysis and critical control point system (PR-HACCP) final rule. In the present report, sample set results are described and associations between set failure and set and establishment characteristics are identified for 4,607 sample sets collected from 1998 through 2003. Sample sets were obtained from seven product classes: broiler chicken carcasses (n = 1,010), cow and bull carcasses (n = 240), market hog carcasses (n = 560), steer and heifer carcasses (n = 123), ground beef (n = 2,527), ground chicken (n = 31), and ground turkey (n = 116). Of these 4,607 sample sets, 92% (4,255) were collected as part of random testing efforts (A sets), and 93% (4,166) passed. However, the percentage of positive samples relative to the maximum number of positive results allowable in a set increased over time for broilers but decreased or stayed the same for the other product classes. Three factors associated with set failure were identified: establishment size, product class, and year. Set failures were more likely early in the testing program (relative to 2003). Small and very small establishments were more likely to fail than large ones. Set failure was less likely in ground beef than in other product classes. Despite an overall decline in set failures through 2003, these results highlight the need for continued vigilance to reduce Salmonella contamination in broiler chicken and continued implementation of programs designed to assist small and very small establishments with PR-HACCP compliance issues.

The influence of creatine and a high glycemic carbohydrate on the growth performance and meat quality of market hogs fed ractopamine hydrochloride

Crossbred barrows ( n = 128; 85 ± 0.91 kg) were randomly allotted to one of four dietary treatments. A pelleted corn-soybean diet containing 5 ppm Paylean ® (PAY) was tested against a negative control (NCON) diet formulated to meet or exceed the National Research Council’s requirements for the growing pig, a pelleted corn-soybean diet containing 0.92% creatine and 2.75% dextrose (COMBO), and a pelleted corn-soybean diet containing a combination of 5 ppm Paylean ®, 0.92% creatine, and 2.75% dextrose (PAYPLUS). No treatment differences were noted when comparing ADG ( P = 0.66) and hot carcass weight ( P = 0.75). Over the 27 d test, barrows fed PAY and PAYPLUS produced loins with a larger ( P < 0.01) loin muscle area (LMA) than those fed NCON or COMBO diets. Barrows fed the NCON diet were fatter at the 10th-rib ( P < 0.01) than those animals fed the remaining dietary treatments. Dietary treatment did not affect the ultimate pH ( P = 0.87), Japanese color score ( P = 0.25) or Minolta L ∗ ( P = 0.61) and b ∗ ( P = 0.56) values of the loin. Loin chops from NCON, COMBO and PAYPLUS tended ( P = 0.07) to contain a higher intramuscular fat content than those from barrows fed PAY. Additionally, loin chops from the NCON and COMBO fed animals were more red (higher a ∗-value) than those chops coming from animals fed the PAY diet ( P < 0.01).

Statistically Designed Survey of Polychlorinated Dibenzo-p-Dioxins, Polychlorinated Dibenzofurans, and Co-Planar Polychlorinated Biphenyls in U. S. Meat and Poultry, 2002−2003: Results, Trends, and Implications

To obtain information on dioxin levels in the human diet, the Food Safety and Inspection Service of the United States Department of Agriculture recently determined levels of dioxin-like compounds (dioxins/dibenzofurans/PCBs) in four major slaughter classes (steers and heifers, market hogs, young chickens, and young turkeys) that comprise over 90% of the meat and poultry production in the United States. The data were analyzed and compared to data from smaller surveys carried out from 1994 to 1996. These surveys were conducted by different laboratories nearly 10 years apart, so a direct comparison of the data was not straightforward. Three approaches were taken: (1) comparison with nondetects set to zero, (2) comparison with nondetects set to half the limit of detection, and (3) comparison applying the earlier surveys' limits of detection to the newer data. The data analyses indicated that dioxin levels appear to have declined in three of the four slaughter classes, with young chickens, market hogs, and young turkeys declining 20-80%, while any declines in cattle dioxin levels, if real, are less than those observed in the other slaughter classes. Further study is needed to examine factors that might explain the differences in dioxin levels and distribution profiles in the four slaughter classes. A small number of market hog and steers/ heifers samples had dioxin toxic equivalency levels (TEQs) greater than 2 pg/g lipid weight. Follow-up investigations for those samples indicated a common source for the market hog samples (a dioxin-contaminated mineral supplement), but no commonality was found for the steers/ heifers samples.

Nationwide Microbiological Baseline Data Collected by Sponge Sampling during 1997 and 1998 for Cattle, Swine, Turkeys, and Geese

During 1997 and 1998, the U.S. Food Safety and Inspection Service completed nationwide microbiological baseline studies on four separate categories of livestock and poultry. Data were collected by sponge-sampling techniques. These studies were designed to provide nationwide estimates of the prevalence of Salmonella and prevalence and concentrations of Escherichia coli in cattle (n = 1,881), swine (n = 2,127), turkeys (n = 1,396), and geese (n = 102) in establishments under federal inspection. Salmonella prevalence ranged from 1.2% in cattle to 6.9% in swine, 13.7% in geese, and 19.6% in turkeys. The prevalence of E. coli was 16.6% in cattle (geometric mean = 0.26 CFU/cm2), 44.1% in swine (mean = 0.78 CFU/cm2), 92.7% in turkey (mean = 2.46 CFU/cm2), and 96.5% in geese (mean = 1.97 CFU/cm2). These values are similar to or somewhat lower than previous baseline values obtained for steers and heifers, cows and bulls, market hogs, and young turkeys. This study is the first in which nationwide microbiological baseline data have been compiled for geese. These data will be useful to individuals working with hazard analysis critical control point plans and risk assessment and to the research and academic communities.

Using Formula Prices in the Absence of Publicly Reported Prices: An Application for Segregated Early Weaned Pigs

A formula for deriving the price of segregated early weaned pigs using corn, soybean meal, and market hog prices was estimated by equating return on investment for the different phases of production. USDA reported prices were compared with prices derived from this and several other common formulas. Based on several accuracy measures, the estimated formula was better at predicting spot-market prices than other formulas. Producers appear to form price expectations based on futures plus expected basis rather than simply futures or current cash prices. However, the method of choosing price expectations will depend on the risk attitudes of the buyer and seller and their business relationship. Developing pricing formulas based on the framework outlined here (equal returns on investment) has merit for establishing prices in the absence of publicly reported information. However, it is important that users of the formula understand the conceptual framework of how and why it was developed.

Effects of Sex and Market Weight on Performance, Carcass Characteristics and Pork Quality of Market Hogs

An experiment was conducted to examine the effects of sex and market weight on performance, carcass characteristics and pork quality. A total of 224 crossbred pigs (initially 26.64 kg BW) were allotted in a 2×4 factorial arrangement in a randomized complete block (RCB) design. The variables were sex (gilts and barrows) and different market weights (100, 110, 120 and 130 kg). Average daily gain (ADG) and average daily feed intake (ADFI) were significantly higher (p<0.01) in barrows than gilts, ADFI and feed conversion ratio (FCR) increased as body weight increased (p<0.05). Gender differences were observed in carcass characteristics. Backfat thickness and drip loss were greater in barrows (p<0.01), while loin eye area (p<0.01), flavor score (p<0.05) and lean content (p<0.001) were higher in gilts. Carcass grade and water holding capacity were the highest in 110 kg market weight pigs. The 100 kg market weight pigs showed lower juiciness, tenderness, shear forces and total palatability than the other market weights (p<0.01). Hunter values (L*, a* and b*) were increased as market weight increased (p<0.05). Hunter a* value was greater in gilts (p<0.01) but L* value and b* value were not affected by sex of pigs. Net profit ((carcass weight×price by carcass grade)-(total feed cost+cost of purchased pig)) was higher in gilts than barrows (p<0.01), and was higher (p<0.05) in the pigs marketed at 110 and 120 kg market weight compared with 100 kg market weight. These results demonstrated that gilts showed higher carcass characteristics, pork quality, feed cost per kg body weight gain and net profit compared with barrows. Moreover, 110 or 120 kg body weight would be the recommended market weight based on pork quality and net profit for swine producers. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 10 : 1452-1458)

Utilizing alternative indices to compare the conformance of market hogs across three packers

Objectives: Generalized Taguchi indices were applied to compare the carcass quality performance of a group of marketed pigs against the quality requirements of three packing companies. Materials and methods: One hundred eighty pigs from a feeding facility were slaughtered at a packing plant. Carcass quality data was collected from the individual carcasses. Most packers determine individual carcass prices from a matrix that references carcass weight and the percent of lean meat in the carcass. Individual packers determine price using different algorithms applied to the matrices. Group carcass measurements were evaluated using three different packer matrices. The ability of the carcass group to perform for the three packers (A, B, and C) was evaluated using measures of quality performance known as sort loss, average lean premium, expected relative loss (Le), and generalized Taguchi performance (C’pm). Revenue was measured as total revenue and average carcass value. Results: The matrix of Packer B developed the smallest Le value (0.125) and the largest C’pm index (0.947), indicating that the carcass requirements of Packer B were best satisfied. Sort loss and average lean premium could not be compared among packers. The values of revenue were comparable and Packer C attained the largest. Discussion: Sort loss and average lean premium implied financial information concerning group conformance that was not comparable among packers. The Le provided a comparable descriptive that was easier to interpret than the C’pm. Implications: Le and C’pm indices may provide a comparison of group carcass quality performance across different packers.

FRESH AND PROCESSED QUALITIES OF COUNTRY‐STYLE CURED HAMS FROM PUREBRED DUROC AND GENETICALLY UNDEFINED MARKET HOGS

ABSTRACTThe objective of this study was to determine country‐style processing differences between hams from purebred Duroc market hogs and market hogs of unknown genetic makeup. Genetically undefined hams purchased from commercial suppliers were sampled the same day as hams from Duroc market hogs. Processing and curing followed standard commercial procedures. After curing, hams were weighed and sliced using a band saw. Slices from the approximate center of the ham were utilized to evaluate cured objective color, moisture content, pH, and salt content. There were no significant differences in cured ham yield between Duroc and genetically undefined market hogs. Intramuscular fat content was greater (P&lt; 0.05) in hams from Duroc market hogs when compared to the hams from genetically undefined pigs. Subjective color, marbling and firmness scores were higher (P&lt; 0.05) in hams from Duroc pigs. Objective color evaluation of cured, center‐slices favored the hams from Duroc market hogs.

Economic Losses from Heat Stress by US Livestock Industries

Abstract Economic losses are incurred by the US livestock industries because farm animals are raised in locations and seasons where effective temperature conditions venture outside their zone of thermal comfort. The objective of this review was to estimate economic losses sustained by major US livestock industries from heat stress. Animal classes considered were: dairy cows, dairy heifers (0 to 1 yr and 1 to 2 yr), beef cows, finishing cattle, sows, market hogs, broilers, layers, and turkeys. Economic losses considered were: 1) decreased performance (feed intake, growth, milk, eggs), 2) increased mortality, and 3) decreased reproduction. USDA and industry data were used for monthly inventories of each animal class in each of the contiguous 48 states. Daily weather data from 257 weather stations over a range of 68 to 129 yr were used to estimate mean monthly maximum and minimum temperatures, relative humidity, and their variances and covariances for each state. Animal responses were modeled from literature data using a combination of maximum temperature-humidity index, daily duration of heat stress, and a heat load index. Monte Carlo techniques were used to simulate 1000 times the weather for each month of the year, for each animal class, for each state, and for each of four intensities of heat abatement (minimum, moderate, high, and intensive). Capital and operating costs were accounted for each heat abatement intensity. Without heat abatement (minimum intensity), total losses across animal classes averaged $2.4 billion annually. Optimum heat abatement intensity reduced annual total losses to $1.7 billion. Annual losses averaged $897million, $369million, $299million, and $128million for dairy, beef, swine, and poultry industries, respectively. Across states, Texas, California, Oklahoma, Nebraska, and North Carolina accounted for $728million of annual losses, or 43% of total national losses. Results point to a need for more energy and capital efficient heat abatement systems.

Accelerated chilling of carcasses to improve pork quality.

Our objectives were to determine the optimal accelerated chill time immediately postmortem necessary to improve the quality of pork muscle and to decrease the incidence of pale, soft, and exudative pork. Carcasses from 81 market hogs were cooled either by conventional chill (CC) at 2 degrees C or by accelerated chill (AC) at -32 degrees C for 60, 90, 120, or 150 min, and then placed into a 2 degrees C cooler for the remainder of the 24-h chill period. Loin muscle pH was higher (P < 0.05) for the carcasses that were accelerated chilled longer than 60 min. Although loin visual color, texture, and firmness scores increased (P < 0.05) with AC time, no improvements were noted beyond 60 min. Color, pH, texture, firmness, and CIE L*a*b* values of fresh ham muscles were not (P > 0.05) affected by AC. In addition, AC did not (P > 0.05) affect purge, drip, or thaw loss of fresh products, sensory scores of loins or processed hams (except initial juiciness; P < 0.05), water-holding capacity of processed hams, or processing characteristics of hams. Cooking loss and Warner-Bratzler shear values for hams and loins were not (P > 0.05) affected by AC. Accelerated chilling caused loins to be darker (lower L* value; P < 0.05) and to have lower (P < 0.05) b* values (less yellow) than CC loins. Accelerated chilling increased water-holding capacity in fresh hams, bound water being the greatest (P < 0.05) in the 120- and 150-min AC groups. These results demonstrate that improvements in pork loin quality can be made using freezer-accelerated chilling for carcasses.

PERFORMANCE CHARACTERISTICS AND FATTY ACID COMPOSITION OF PIGS FED A DIET WITH DOCOSAHEXAENOIC ACID

ABSTRACT Market hogs were fed a ration from 22–42 days prior that contained the omega‐3 fatty acid docosahexaenoic acid (DHA) supplemented at 0, 0.125 and 0.250 kg/pig in the form of the microalgae, Schizochythrum sp. There were no differences (P&gt;0.05) between the average daily gain, feed consumption, or feed efficiency of the controls and those that received a DHA supplementation. Of the 21 fatty acids analyzed, the concentration of only five were affected by DHA supplementation. Muscles from the ham, loin, and shoulder of pigs that received 0.250 kg of DHA contained more eicosapentaenoate, docosahexaenoate, and docosapentaenoate n‐6 and n‐3 than either the controls or those that received 0.125 kg. Supplementation of DHA in the ration at 0.125 kg caused an elevation of docosapentaenoate n‐6 and docosahexaenoate. These data suggest that addition of DHA to the diet can elevate the amount of this omega‐3 fatty acid in pork with potential health benefits to consumers.