O isolamento de Salmonella enterica em suínos abatidos tem sido reportado no sul do Brasil, o que torna a carne suína uma fonte potencial de contaminação para os consumidores. Nesse contexto, o trabalho propôs estimar o risco da ocorrência de infecção alimentar pelo consumo de lingüiça frescal suína, através da análise de dados de prevalência, quantificação, cinética de crescimento e destruição e de surtos alimentares que envolveram Salmonella no Rio Grande do Sul. Das 336 amostras de lingüiça frescal de carne suína adquiridas no comércio, 24,4% apresentaram Salmonella sp. com contagens variando entre 0,03 e 460 Número mais Provável (NMP).g-1, com mediana de 0,23 NMP.g-1. Os sorovares mais prevalentes foram Brandenburg, Derby, Panama e Typhimurium. Em simulações de crescimento e destruição realizadas em caldo nutriente, isolados dos 12 sorovares encontrados no produto, apresentaram cinética de crescimento semelhante em temperatura ambiente. Até duas horas todos os sorotipos permaneceram em fase lag e, após, iniciou-se a fase exponencial. Em temperatura de refrigeração, todos os isolados mantiveram a contagem inicial até 30 dias. A destruição térmica em 60°C ocorreu após 20 minutos em todos os ensaios. As mesmas simulações foram conduzidas em amostras do produto contaminadas artificialmente com Salmonella sp. não havendo alterações significativas nas quantidades de Salmonella em temperatura ambiente e de refrigeração durante todo o período de observação. Após a preparação em forno (200°C), por 15 minutos, a população total inoculada foi destruída. Nos surtos ocorridos por Salmonella, os alimentos a base de ovos, maionese e frango predominaram. Os resultados obtidos na quantificação variaram de <3 NMP até 4,6x109.g-1desses alimentos, com mediana de 4,6x106.g-1. S. Enteritidis foi o sorovar identificado em todos os surtos, apresentando um único perfil de macro-restrição. Os dados obtidos foram utilizados para simular diferentes cenários no programa @Risk. Considerando-se o costume da população estudada de ingerir este produto após tratamento térmico, o risco encontrado foi muito baixo (6,12 x 10-7). Para uma pequena parte da população que costuma ingerir o produto sem qualquer tratamento térmico, em uma simulação realizada com 10.000 refeições, poderá haver 8,78 casos da doença, considerando a ingestão de uma única unidade. Em um perfil típico de preparação e consumo de lingüiça frescal de carne suína pela população de Porto Alegre, ou seja, como acompanhamento de churrasco, após tratamento térmico mínimo de 15 minutos, calculou-se a probabilidade de ocorrência de doença.Dentre os 3.354.716,98 churrascos estimados consumidos mensalmente em Porto Alegre, o resultado do modelo indicou um mínimo de 0,01, média de 2,05 e máximo de 11,08 casos de doença por mês. Esse cenário infere que a lingüiça frescal de carne suína pode estar causando um baixo número de casos isolados em Porto Alegre, os quais podem estar sendo subnotificados. / In Southern Brazil, a high prevalence of Salmonella isolation has been reported in slaughter pigs, indicating that pork may represent a hazard to the consumers. In this sense, this study aimed to conduct a risk analysis of the consumption of pork sausage in Southern Brazil. For this purpose, Salmonella prevalence on pork sausages collected at retail level was estimated, growth and death curves for representative porcine Salmonella strains were constructed, the consumption patterns of pork sausages by the population were investigated, and foods involved in salmonellosis outbreaks were analysed. From a total of 336 samples of fresh pork sausage examined, Salmonella enterica was detected in 82 (24.4%) of the samples, with a Most Probable Number count ranging from 0.03 (MPN).g-1 to 460 MPN.g-1, and a median of 0.23 MPN .g-1. Strains belonging to serovars Brandenburg, Panama, Derby and Typhimurium were the most prevalent. Growth and death curves of 12 strains representing Salmonella serovars isolated in this study were similar in assays conducted in nutrient broth. At room temperature, all Salmonella serovars started the exponential phase after a two hours period of lag phase. Under refrigeration, all isolates mantained the initial population counts up to 30 days. The heat destruction was observed after 20 minutes in all assays. Similar assays conducted in fresh pork sausages inoculated with Salmonella demonstrated that no growth of Salmonella sp. could be detected at room temperature and under refrigeration troughout the observation period. After cooking in the oven (200°C) for 15 minutes the inoculated Salmonella population was completely destroyed. Foods containing eggs, mayonnaise or chicken were the most implicated in outbreaks investigated in Rio Grande do Sul. Salmonella counts variaded from <3 MPN to 4.6x109.g-1 of foods involved in these outbreaks, with a median value of 4.6x106.g-1. All strains were identified as S. Enteritidis, and presented a unique macrorestriction profile, demonstrating the predominance of one clonal group in foods involved in the salmonellosis outbreaks. Data obtained in the conducted assays were used to simulate different cenarios, using the @Risk software. Considering that the population usually consums pork sausage after termic treatment (roasting), the estimated risk was very low (6.12 x 10-7). Another simulation, conducted for the low percentage of the population (3%) that declared to consum raw pork sausage, indicated that for 10,000 meal consumption events of one sausage, the probability is 8.78 disease cases. Finally, considering the typical consumption pattern of pork sausage by the population of Porto Alegre city (roasted for at least 15 minutes during a barbecue called “churrasco”) the number of disease cases was simulated. Among 3,354,716.98 “churrascos” prepared monthly in Porto Alegre city, the model indicated a probability of a minimum of 0.01 cases, a media of 2.05 and a maximum of 11.08 disease cases occurring each month. Results of risk assessment show that fresh pork sausage may have been a cause of few undernotificated individual salmonellosis cases in Porto Alegre city.

Fresh pork loins were cut for three replications and randomly assigned to one of seven treatments: 1) polyvinylchloride (PVC) packaged, 2) vacuum packaged (Vac-pack), 3) 0.2 mL of Tris-Buffer, 4) 0.2 mL of high leghemoglobin high pH (HLbHpH), 5) 0.2 mL of high leghemoglobin low pH (HLbLpH), 6) 0.2 mL of low leghemoglobin high pH (LLbHpH), and 7) 0.2 mL of low leghemoglobin low pH (LLbLpH). Treatments 3 through 7 also were vacuum packaged. Leghemoglobin (Lb) protein treatments improved (P<0.05) the visual color of vacuum packaged pork at the point of purchase. CIE L* values were not affected by HLbHpH, LLbHpH or LLbLpH treatments. However, the HLbLpH treatment was lighter (P<0.05) than the vacuum packaged control treatments on days 3, 4, and 5. High Lb (HLb) treatments had a positive effect (P=0.0116) on the CIE a* values on the day of manufacture. HLbLpH treatment eIE b* values were higher (P<0.05) than Vac-pack and buffer controls from day 0 to day 5. On the day of processing, HLb treatments were higher (P=0.0637) in oxymyoglobin than low Lb treatments. Metmyoglobin of HLb treatments was higher (P<0.05) than the Vac-pack and the buffer treatments on the day of manufacture. pH did not affect (P>0.05) sensory or objective color, pigment state, purge or total psychrotrophic aerobic bacterial counts (TPC) throughout the study. Lb treatments TPC were lower (P<0.0l) than nontreated samples at all assessment times. / Master of Science

Master of Science

Thesis (MScAgric) -- Stellenbosch University, 1987. / INLEIDING: Van al die plaasdiere, is die vark die enigste spesie wat slegs vir vleisprodukte aangehou word. Alhoewel daar verskeie varkrasse in Suid-Afrika bemark word, word hierdie varke, ongeag die ras, hoofsaaklik in die vleisbedryf vir twee doeleindes aangewend. Die ligter varkkarkasse (karkasmassa onder 50kg word as vleisvarke, en die swaarder varkkarkasse (karkasmassa bo 50kg) word as spekvarke verwerk. In hierdie projek is die doeltreffendheid van verskeie karkaspararneters ondersoek en as onafhanklike veranderlikes, afsonderlik of in kombinasie, in lineêre regressievergelykings gebruik, om sodoende regressievergelykings te verkry wat 'n hoë voorspellingswaarde van die varkkarkassamestelling i.t.v. vleis, vet en been sowel as van die groothandelsnitopbrengs en -samestelling van die karkasse besit.

Thesis (PhDAgric)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: The South African pork industry is characterised by low slaughter weights when compared to the rest of the world. This inevitably leads to a smaller number of kilograms produced per unit fixed cost and subsequently the efficiency of production is reduced. A study was conducted with 189 pigs representing three sex types (boar, gilt and castrate) and five commercial genotypes. Pigs entered into the trial at an age of 10 weeks and an average live weight of 27.5±2.5kg. Treatments were according to slaughter weight ranging between 62 and 146kg. Production and carcass characteristics, meat quality and processing characteristics and sensory attributes were assessed. Production characteristics assessed included live weight gains, intake, P2 backfat thickness and feed conversion ratio. Main observed effects were associated with slaughter weight and its interaction with sex type. Rates of change in parameters measured were described. Growth and feed conversion ratio were described using linear models while cumulative feed intake was described using 2nd order polynomials. Carcass characteristics assessed included carcass weight, dressing percentage, carcass length, ham length, ham circumference, chest depth, backfat thickness measurements, muscle depth, eye muscle area, subcutaneous fat area, intramuscular fat area as well as ratios of eye muscle to subcutaneous and intramuscular fat area. The main statistical differences observed were for slaughter weight. Significant sex type differences were observed for dressing percentage and some fat and muscle depth measurements. Meat quality characteristics assessed included colour measurements, tenderness, drip loss and water holding capacity. Main differences observed were for slaughter weight. Carcass yields were assessed in terms of absolute and percentage yields of commercial cuts as well as yield of processable lean meat. In terms of the absolute and percentage yields of the commercial cuts, the main statistical differences observed were for slaughter weight. Changes in cut yield with increased slaughter weight are described using regression analysis. In terms of yields obtained for processable lean meat, the main statistical differences observed were for slaughter weight. Sex type differences were only observed for percentage belly and topside processable lean meat and percentage brine uptake of belly bacon, whole gammon ham and topside gammon. Genotypic differences were observed for percentage yield of processable lean meat of the neck and whole gammon and percentage fresh to smoke losses of back bacon and whole gammon ham. Sensory attributes were assessed using gammon ham, belly bacon and fresh loin. Observed slaughter weight differences were inconsistent and did not appear to change with an increase in slaughter weight. Once meat was processed, most sensory differences were no longer observed. Increased slaughter weight generally led to increased juiciness and decreased tenderness. It is therefore concluded that the current South African pig genotypes have the ability to maintain high growth rates for a much longer time and therefore can be slaughtered at a higher weight without detrimental effect on production efficiency, carcass and meat quality characteristics, yields of commercial and processable lean meat, processing characteristics and ultimately sensory characteristics of the meat produced. / AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse varkbedryf word gekenmerk deur relatiewe lae slagmassas in vergelyking met die res van die wêreld. Dit lei onvermydelik tot ‘n kleiner aantal kilogramme vleis geproduseer per eenheid vaste koste. ’n Studie is gevolglik gedoen met die doel om die tempo’s van verandering van sekere produksie-, karkas-, vleis- en proseseringseienskappe te kwantifiseer ten einde die optimale slagmassa te bepaal wat vir alle rolspelers in die bedryf tot voordeel sal wees. Die studie is gedoen met 189 diere wat vyf kommersiële genotipes en drie geslagstipes (beer, sog en kastraat) verteenwoordig het. Varke is op ’n ouderdom van 10 weke met ’n gemiddelde lewende massa van 27.5±2.5kg in die proef opgeneem. Behandelings was volgens slagmassa en het gevariëer van 62 tot 146kg. Produksieparameters en karkas-, vleiskwaliteits-, en proseseringseienskappe sowel as sensoriese eienskappe, is ëvalueer. Produksieeienskappe wat ëvalueer is sluit in: groei, inname, P2 rugvetdikte en voeromset-verhoudings. Hoofeffekte wat waargeneem is, was vir slagmassa en interaksies van slagmassa met geslag. Tempo van verandering in die parameters gemeet, is beskryf. Groei en voeromsette is beskryf deur die passing van ‘n linieêre model terwyl kumulatiewe voerinname beskryf is deur ‘n 2de orde polinoom. Karkaseienskappe wat ëvalueer is, sluit in: karkasmassa, uitslagpersentasie, karkaslengte, hamlengte, hamomtrek, borsdiepte, rugvetdikte, spierdiepte, oogspieroppervlak, onderhuidse vet-, binnespierse vetoppervlak en verhoudings van oogspier- tot-vetoppervlakke. Die hoof statistiese effekte wat waargeneem is, was vir slagmassa. Betekenisvolle geslagsverskille is waargeneem vir uitslagpersentasie en sommige, vet- en spierdieptemetings. Genotipiese verskille is waargeneem vir sommige vetmetings. Vleiskwaliteiteienskappe wat beoordeel is, het kleur, drupverlies, waterbindingsvermoë en sagtheid ingesluit. Hoofeffekte waargeneem was vir slagmassa. Karkasopbrengste is ëvalueer in terme van absolute en persentasie opbrengste van kommersiële snitte sowel as prosesseerbare maer vleis. In terme van absolute en persentasie opbrengste van kommersiële snitte, was meeste van die variasie beskryf deur slagmassa. Tempo van verandering in die persentasie opbrengste van die snitte word beskryf. In terme van opbrengste vir proseseerbare maer vleis is die hoof statistiese verskille waargeneem vir slagmassa. Geslagverskille is waargeneem vir persentasie streepspek en binneboud maer vleis opbrengs vir prosesering en persentasie pekelopname van streepspek, heel varkboud ham en binneboud ham. Genotipe verskille is waargeneem vir persentasie opbrengs van maer vleis vir prosesering van die nek en heelboud en persentasie vars-tot-klaar-gerook verliese van rugspek en heelboud hamme. Sensoriese eienskappe is ëvalueer vir twee geprosesseerde en een vars snit. Slagmassa-effekte was nie konstant nie en parameters het klaarblyklik nie verander soos slagmassa verander het nie. Sodra vleis geprosesseer is, het die meeste sensoriese verskille verdwyn. Beide sappigheid en taaiheid het toegeneem met ‘n toename in slagmassa. Dit kan dus aanvaar word dat, gegewe die huidige Suid Afrikaanse genotipes, dit moontlik is om swaarder karkasse te produseer sonder noemenswaardige nadelige effekte op karkas-, vleis-, opbrengste-, prosesering- en sensoriese eienskappe van varkvleis.

Master of Science / Food Science / Terry Houser / The objective of this research was to evaluate the effect of natural nitrites on objective color of vacuum packaged fresh pork. Sections of longissimus dorsi muscle (approximately 18 cm) were injected with solutions containing 0, 3, 6, 9 or 12 ppm of natural nitrite. Sections were sliced into chops (2.54 cm) and individually vacuum packaged. Raw chop surface L*, a* and b* values were measured at 1, 5, 15 and 30 days post packaging. At 1, 15 and 30 days post packaging chops were cooked and surface L*, a* and b* values were measured. Hue and Chroma values were calculated for all color measurements. Linear and quadratic contrasts were evaluated on treatments for all measured and calculated color values. A linear (P<0.05) increase was detected on the L* values for days of vacuum storage treatment, all other raw color measurements and calculations for levels of natural nitrite and days of vacuum package storage were found to be quadratic (P<0.05). Cooked L* and Hue values for days of vacuum storage were found to decrease linearly (P<0.05), all other days of storage and levels of nitrite treatments were found to be quadratic (P<0.05) in relationship to the measured and calculated cooked color values. All raw chops containing nitrite had higher a* and Chroma values at all evaluation days than those containing no added nitrite. Raw chops containing nitrite had lower L*, higher b* and Hue values than the 0 ppm chops (P<0.05). Raw chops containing natural nitrite were darker, redder, more yellow and more intense in color than those without nitrite. The longer the chops were vacuum packaged and then cooked, the lower the L* values were (P<0.05). Cooked chops containing nitrite were redder, less yellow and lower in Hue and Chroma values than cooked chops with no added nitrite P(<0.05). These results indicate that low levels of nitrite can alter fresh and cooked pork color during vacuum storage. To balance the increased redness and darkness of the raw chops with the increased redness of the cooked chops, 3 ppm of natural nitrite was found to be the optimal treatment.

Doctor of Philosophy / Food Science Institute / Kelly J. K. Getty / Salt is used as a preservative in food. Reducing sodium in food, due to its link to hypertension, and replacing NaCl with other types of salt could have an effect on food safety. The main objective was to determine differences in salts and salt substitutes on growth of Listeria monocytogenes in broth and meat and poultry systems. Salts (NaCl, KCl, CaCl2, MgCl2, sea salt, and replacement salt) were added (0.5, 1, and 2.5%) to Listeria monocytogenes (five-strain cocktail) inoculated Listeria enrichment broth at 25 °C and sampled at 0, 24, and 48 h. Results showed that MgCl2, regardless of concentration, caused Listeria monocytogenes populations to grow approximately 0.6 log CFU/mL more (P < 0.05) than the other salts. Fresh ground beef, pork, and turkey with NaCl, KCl, CaCl2, MgCl2, sea salt, and replacement salt (2.0%) were inoculated with Listeria monocytogenes (five-strain cocktail) to determine growth/survival during 5 d at 4 °C to simulate a pre-blend process. Listeria monocytogenes populations significantly decreased (0.41 log CFU/g) during the storage time in beef, however no differences (P > 0.05) were observed over time in pork or turkey. Salt type did not affect (P > 0.05) Listeria monocytogenes populations during pre-blend storage. However, salts (MgCl2 and NaCl) allowed growth (P < 0.05) of aerobic populations during storage. Emulsified beef and pork products were processed with NaCl, KCl, sea salt and a NaCl/KCl blend (2%) and post-processed surface inoculated with Listeria monocytogenes (five-strain cocktail) to determine growth/survival at 4 °C for 28 d. Pork products showed greater (P < 0.05) Listeria monocytogenes population growth at all sampling times (0, 7, 14, 21, and 28 d) than beef products; whereas salt type had no effect on Listeria monocytogenes populations with sampling times pooled for data analysis. Although salt types were not shown to have an impact on Listeria monocytogenes growth/survival in pre-blend and emulsified post-processed surface inoculated meat products, pork and turkey pre-blends and emulsified pork had greater Listeria monocytogenes populations compared to beef products. These studies demonstrate that sodium reduction or replacement may not affect safety of pre-blends and emulsified meat and poultry products.

Consumidor é o agente econômico que faz girar toda e qualquer atividade na sociedade, seja um bem, serviço ou qualquer forma de produção que se possa gerar. Assim, de sua vontade dependem a manutenção, o sucesso ou o fracasso de qualquer uma dessas citadas atividades. Quanto mais os esforços de marketing das empresas estiverem concentrados desde o início no consumidor final que se deseja atingir, maiores serão as chances de que o produto ou serviço seja bem aceito por ele e assim se obtenha sucesso no empreendimento. No entanto, para que se atinja esse objetivo de atender ao consumidor final, é preciso que se saiba quem é esse consumidor final, quais são seus gostos, suas preferências, quais atributos deseja encontrar nos produtos que consome e em quais proporções. E isso só se consegue estudando-o, realizando pesquisas que aliem o estudo científico à realidade empírica, indo até ele e questionando-o a respeito desses assuntos com sólidas bases acadêmicas. O que este trabalho pretendeu foi exatamente realizar um estudo nesse sentido, ou seja, com uma base teórica (a teoria do Comportamento do Consumidor), chegou-se até o consumidor final de carne suína com uma pesquisa estruturada que envolvia questões sobre estilo de vida, atitudes e valores em relação aos produtos e à produção de suínos, além de ocasiões, frequência, locais e maneiras de compra e de consumo de carne suína e produtos feitos à base de carne suína. Esta pesquisa utilizou dados do projeto europeu Q-PorkChains, do qual a pesquisadora do presente estudo e seus orientadores fizeram parte. Utilizaram-se nesta tese dados de apenas um dos cinco módulos do projeto, o módulo que se refere ao Consumo, e apenas a pesquisa aplicada no Brasil. Por tratar-se de um grande questionário que envolvia uma quantidade bastante diversa de assuntos, a tese não incluiu análises de todas as partes do questionário. Estudos posteriores pretendem cobrir as áreas que ainda não foram analisadas, além de se realizarem comparações entre os resultados encontrados na amostra brasileira e aqueles dos países europeus pesquisados e também da China, outro país participante da pesquisa. Foram feitas várias análises estatísticas, porém nem todos os construtos integrantes da pesquisa inicial puderam ser validados na amostra brasileira. A hipótese de que as atitudes dos consumidores brasileiros de carne suína em relação ao meio ambiente e à natureza, à produção industrial de alimentos, ao progresso tecnológico e ao etnocentrismo seriam influenciadas pelos conceitos do FRL e PVQ, que tanto essas atitudes quanto os próprios conceitos influenciariam a maneira como o consumidor vê a produção de suínos, e que, tudo isto somado, seriam gerados os comportamentos de consumo do consumidor final de carne suína no Brasil não se confirmou, uma vez que foi encontrada pouca relação entre os construtos pesquisados e o consumo. Ainda assim, além da importância de se ter a replicação de um estudo europeu no Brasil, esta tese tem como principais contribuições a verificação de uma série de informações que funciona como indicadores de tendências de compra e consumo de carne suína e produtos derivados, e a utilização de escalas ainda pouco utilizadas no Brasil no setor de agronegócios, como o Food Related Lifestyle (FRL) e o Pictorial Values Questionnaire (PVQ). / Consumer is the economic agent that makes all and every activity in human society run, be it a good, a service or any other form of production that can be generated. In this sense, the success or failure of any of those cited activities depends on his needs and wants. The more the companies\' marketing efforts are concentrated from the beginning on the final consumer, the bigger will be the chances that the good or service is well accepted by this consumer and that it becomes a success. But in order to achieve that objective, it is necessary to know who is the final consumer, which are his tastes, his preferences, which are the attributes he wants to find in the products he consumes and in which proportions. And this can only be achieved by studies that join together scientific knowledge and empirical reality, going directly to the final consumer to ask him about those issues with solid academic basis. This thesis intended to make a study that, based on a theoretical basis (the theory of Consumer Behavior), reached the pork consumer with a structured research that included questions about lifestyle, values and attitudes towards pork products and swine production, and also questions about occasions, frequencies, places and ways of purchase of pork and pork products. This research used data from a comprehensive European project called Q-PorkChains, in which the researcher of this thesis and her advisors made part. This study used data from only one of the five modules of the project, the one that refers to Consumption, and only data from Brazil. Being a big questionnaire that involved a very diverse number of issues, not all parts of the questionnaire were analyzed in this thesis. Further studies should cover the non analyzed areas, and also make comparisons between the results found in the Brazilian sample and the ones found in the European countries and in China, the other country that made part of the research. Many statistical analyses were made but not all of the constructs that made part of the initial study could be validated in the Brazilian sample. The hypothesis that the attitudes of Brazilian pork consumers towards the environment and nature, industrial production of food, technological progress and ethnocentrism were influenced by the constructs of FRL and PVQ, that such attitudes and the concepts both influenced the way the consumer views swine production, and that everything together generated the behavior of the pork consumer in Brazil was not confirmed. In fact, little relation was found between the researched constructs and consumption. Even though, besides the importance of replicating in Brazil an European study, this thesis has as main contributions the verification of a series of information that serve as indicators of tendencies of purchase and consumption of pork and pork products, and the use of scales that have been little used in Brazil in the agribusiness sector, such as the Food Related Lifestyle (FRL) and the Pictorial Values Questionnaire (PVQ).

The purpose of this study was to determine differences between littermate boars and barrows for performance and carcass traits in the Iowa and Northeast Iowa Swine Testing Stations. Data were obtained from 917 litters including 1,804 boars and 917 barrows. The data included 1,086 boars and 581 barrows from the Iowa Station at Ames, Iowa, and 718 boars and 336 barrows from the Northeast Iowa Station at New Hampton, Iowa. The Iowa Station data were obtained over a period of 12 seasons from the fall of 1979 through the fall of 1985, and the data from the Northeast Iowa Station were collected in eight seasons from the fall of 1981 through the spring of 1985. The spring testing season included pigs born from November through March, and the fall testing season included pigs born from May through September. Littermate boars and barrows from the following purebred breeds were used: Berkshire, Chester White, Duroc, Hampshire, Landrace, Poland China, Spotted, and Yorkshire. Boars grew .03 (2.21+/-.20 vs. 2.18+/-.21) and .10 (2.21+/-.18 vs. 2.11+/-.22) pounds/day faster (P<.01) than littermate barrows in the Iowa and Northeast Iowa Stations. Boars had .58 (.80+/-.08 vs. 1.38+/-.20) inches less (P<.01) backfat than littermate barrows (N=581) in the Iowa Station. In the Northeast Iowa Station, boars were significantly (P<.01) leaner than barrows when comparing average backfat of boars with carcass backfat measurements of Ilttermate barrows at the tenth rib (.76+/-.06 vs. 1.06+/-.21) or the average of three carcass backfat measurements (.75+/-.08 vs. 1.29+/-.18 and .79+/-.05 vs. 1.31+/-.19). Boars had .67 (5.49+/-.42 vs. 4.82+/-.67) and .66 (5.62+/-.28 vs. 4.96+/-.65) square inches larger (P<.01) loin eye areas than littermate barrows in the Iowa and Northeast Iowa Stations, respectively. The t test revealed no significant (P>.05) differences between boars and barrows for average daily gain among the eight major breeds in the Iowa Station. However, at the Northeast Iowa Station, the Duroc (2.39+/-.19 vs. 2.12+/-.21) and Hampshire (2.16+/-.17 vs. 2.07+/-.24) boars grew significantly faster (P<.01) than littermate barrows. The t test also revealed that boars averaged seven days (156.00+/-10.78 vs. 163.00+/-12.90) younger (P<.01) at 230 pounds than barrows in the Northeast Iowa Station. Although the sample size was small and the differences nonsignificant, there were some breeds in which barrows appeared to grow faster than boars. The I test for boar-barrow differences among breeds revealed that boars had significantly (P<.01) less average backfat than littermate barrows for eight major breeds in the Iowa Station and for seven breeds in the Northeast Iowa Station. For both stations, the differences in backfat thickness between boars and barrows was lowest for the Hampshire breed and the greatest differences were between boars and barrows in the Chester White, Yorkshire, Berkshire and Landrace breeds. The t test for loin eye area revealed that boars had significantly (P<.01 or .05) greater loin eye area than barrows for all breeds except Poland China in the Iowa Station and Landrace in the Northeast Iowa Station. The sex differences between littermate boars and barrows for backfat and loin eye area were significantly different (P<.01) for all years and seasons in the Iowa and Northeast Iowa Stations. The sex differences between littermate boars and barrows for backfat and loin eye area have been increasing in both stations with the largest increase occurring during the last five years. The differences between boars and barrows for days to 230 pounds were significantly different (P<.01) In all years and seasons for both stations. In comparing data for 1981 and 1985, both boars and barrows averaged ten days younger at 230 pounds In 1985 than in 1981. Coefficients of correlation for various measurements of performance and carcass cutability between littermate boars and barrows were determined. In general, there were positive associations between boar and barrow data; however, the correlations were relatively low. The predictive value of the barrow data appears to be of little use In estimating breeding values for boars. Although a limited number of Chester White pens were included in this study, the coefficients of correlation between littermate boars and barrows suggest that castration may have a different effect upon performance and carcass cutability of Chester White than for other breeds. Unfortunately for Chester White breeders, there appears to be a much higher positive correlation between average daily gain and beckfat thickness for Chester White boars and barrows than for other breeds. In other breeds, the correlation between growth rate and backfat is low enough to allow simultaneous progress for improving both traits. A similar desirable low correlation was found between growth rate and loin eye area for other breeds. The coefficients of correlation between backfat and loin eye area were greater for barrows than boars, suggesting that errors of measurement may have been prevalent in the boar data. Large errors In measurement of boar backfat could account for some or all of the increased difference in backfat thickness observed between littermate boars and barrows during recent years.

Market integration testing is important to agricultural marketing, industrial organization, international trade, and international model design. With reliable market integration information, decision makers can undertake appropriate actions to maximize profits, welfare, or both. Level I market analysis, which uses price data solely, has proved unreliable especially in the presence of discontinuous or bidirectional trade, or significant or nonstationary transaction costs. Level II market analysis methods, which incorporate both transactions costs and prices, permit spatial markets to be integrated in some periods and segmented in others, thereby obviating many level I method problems. However, level II methods still fail to distinguish between market integration and spatial market equilibrium. Both level I and level II methods omit the rich information provided by trade flow data. This dissertation develops the first level III method-combining price, transactions costs, and trade flow data, and thus can move beyond the flaws remaining in levels I and II methods. The full information parity bounds model (FIPBM) enables researchers to distinguish between market integration, a concept of market "conduct," and spatial market equilibrium, one of market "performance." FIPBM also shows real promise in signaling the importance of unobservable transactions costs, the frequencly of nontrading periods of competitive disequilibrium likely due to nontariff trade barriers, and the effects of asymmetric trade policies. FIPBM seems better suited to international markets analysis than do other existing methods. This dissertation applies levels I,II, and III methods to analyze price, trade, and market relationships in the product and factor markets of pork industries in key Pacific Rim countries. This empirical work highlights the superiority of the FIPBM approach. FIPBM finds that pork, hog, and feed grain markets between Canada and the United States are almost always integrated. But they are not in competitive equilibrium, implying that there frequently exist positive accounting profits to arbitrage. By contrast, markets between Asian (Taiwan and Japan) and North American countries (Canada and the United States) are integrated less frequently than are intra-North American markets. This reflects greater trans-Pacific transactions costs that reduce tradability. However, markets between Asian and North American countries are commonly in competitive equilibrium.