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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Fatores que influenciam a temperatura corporal de vacas da raça holandesa lactantes / Factors affecting body temperature in high producing lactating Holstein cows

Drago Filho, Eraldo Laerte [UNESP] 24 July 2017 (has links)
Submitted by Eraldo Laerte Drago Filho null (eraldinhodrago@hotmail.com) on 2017-08-14T02:04:03Z No. of bitstreams: 1 Dissertação Eraldo Pós Defesa final jul 2017.pdf: 735320 bytes, checksum: d7cea9d3ac82606ae1d91cd0853fd717 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-08-18T19:54:39Z (GMT) No. of bitstreams: 1 dragofilho_el_me_bot.pdf: 735320 bytes, checksum: d7cea9d3ac82606ae1d91cd0853fd717 (MD5) / Made available in DSpace on 2017-08-18T19:54:39Z (GMT). No. of bitstreams: 1 dragofilho_el_me_bot.pdf: 735320 bytes, checksum: d7cea9d3ac82606ae1d91cd0853fd717 (MD5) Previous issue date: 2017-07-24 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / O objetivo do experimento foi avaliar a temperatura vaginal em parâmetros produtivos e reprodutivos. Vacas Holandesas lactantes n = 641 (209 primíparas 36,9 ± 6,54 kg de leite / d; 432 multíparas 43,9 ± 9,77 kg de leite / d) tiveram a temperatura vaginal monitorada através de termômetros, anexados a um dispositivo intravaginal como parte de um protocolo de IATF. A temperatura vaginal foi registrada a cada 10 minutos durante três dias. A temperatura ambiente e a umidade relativa (ITU) foram mensuradas usando um termômetro externo colocado dentro do barracão. Os dados foram analisados com SAS 9.4 usando correlação de Pearson, ANOVA e regressão logística. Calculou-se o estresse térmico com base na porcentagem de tempo que a vaca ficou com uma temperatura vaginal ≥ 39,1°C (PCT). As vacas foram classificadas através de quartis (AltaPCT (3º quartil; PCT-60%) e BaixaPCT; PCT-16%) para PCT e o mediana para produção de leite, que eram diferentes para primíparas e multíparas. Houve uma baixa correlação entre ITU e produção de leite com PCT (r = 0,01), indicando maior variação na termorregulação. O BaixaPCT (22,4 e 13,9%) e o AltaPCT (12,6 e 9,7%) reduziram significativamente o P/AI no dia 30 e 52 pós-IA (P < 0,01) e sem interações com ordem, escore de condição corporal e ITU observados. A cor da pelagem e a espessura do couro não influenciaram o PCT (P > 0,1). Entretanto houve interação entre cor de pelagem, PCT e produção de leite, onde independente da PCT e produção de leite, vacas de cor branca apresentaram menor prenhez (P = 0,03). Em resumo, houve uma grande variabilidade em como as vacas respondem individualmente ao estresse térmico. A prenhez foi afetada somente em vacas com alta PCT independente da ordem, produção de leite, ECC. A seleção de animais com controle eficiente da temperatura corporal apesar da alta produção de leite deve ser abordada como uma estratégia para manter a fertilidade adequada. / The aim of the experiment was to evaluate vaginal temperature on productive and reproductive traits and potential genetic contribution to thermomtolerance. Lactating Holstein cows n = 641 (209 primíparous 36,9 ± 6,54 kg milk/d; 432 multíparous 43,9 ± 9,77 kg milk/d) had vaginal temperature monitored using thermometers, attached to an intravaginal device as part of a timed-AI protocol and recorded vaginal temperature every 10 minutes for 3 days. Ambient temperature and relative humidity (THI) were monitored using an external thermometer placed inside the barn. The data were analyzed with SAS 9.4 using Pearson correlation, ANOVA and logistic regression. Heat stress was calculated based on the percentage of time the cow spent with a vaginal temperature ≥39,1°C (PCT). Cows were classified using the 75th percentile threshold (HighPCT and LowPCT) for PCT and the median value for milk, which were different for primiparous and multiparous. There was a low correlation between THI and milk production with PCT (r=0,01) indicating a large variation in thermoregulation. Multiparous LowPCT (22,4 and 13,9%) and HighPCT (12,6 and 9,7%) significantly reduced P/AI on day 30 and 52 post-AI (P < 0,01) and no interactions with parity, body condition score and THI were observed. Coat color and skin thickness did not influenced PCT. However, there was interaction between coat color, where, independent of PCT and milk production, white cows presented lower pregnancy rate (P < 0,03). In summary, there is a large variability on how individual cows respond to heat stress. Pregnancy was just affected in cows with high PCT independent of parity, milk production, BCS. Selection of animals with efficient control of body temperature in spite of high milk production should be further approached as a strategy to maintain adequate fertility. / CNPq: 131628/2015-1
32

Gordura protegida de óleo de palma na alimentação de ovelhas Lacaune em lactação

Bianchi, Anderson Elias 28 February 2014 (has links)
A ovinocultura leiteira, atividade comum nos países europeus e asiáticos, vem crescendo nos últimos anos no Brasil. Além de produzir leite com altos teores de sólidos, os seus derivados são considerados alimentos funcionais, devido os benefícios à saúde. Com isso, o objetivo do trabalho foi avaliar o efeito dos níveis de óleo de palma na forma protegida na alimentação de ovelhas lactantes da raça Lacaune sobre a dinâmica corporal, produção e composição do leite. Foram utilizados quatro tratamentos com nove repetições, sendo os tratamentos constituídos 0,0%; 2,0%; 4,0% e 6,0% de gordura protegida de óleo de palma no concentrado dos animais. A dieta foi balanceada e ajustada por animal após a pesagem do leite, sendo isoproteica, isoenergética e com a mesma relação volumoso/concentrado, utilizando a silagem de milho como volumoso em todos os tratamentos. As pesagens de leite e coleta para análise da composição centesimal foram realizadas semanalmente nas primeiras sete semanas de lactação e a cada quinze dias nas semanas subsequentes, sendo que o período experimental compreendeu toda a lactação de 182 dias. O aumento dos níveis de gordura protegida na dieta resultou em um menor ganho de peso e menor condição corporal dos animais (P<0,05). O tratamento com 6,0% de gordura protegida apresentou a maior produção de leite (P<0,05). O teor de gordura no leite apresentou efeito linear positivo (P<0,05), enquanto que o teor de proteína, lactose e extrato seco desengordurado apresentaram efeito linear negativo (P<0,05). O teor de extrato seco total no leite, não apresentou efeito (P>0,05). Em relação à produção total de sólidos no leite (gordura, proteína, lactose, extrato seco total e extrato seco desengordurado) não houve efeito (P>0,05) em nenhuma variável. A utilização de gordura protegida de óleo de palma se mostrou eficiente para aumento na produção e gordura no leite de ovelhas Lacaune. / The dairy sheep business, common activity in European and Asian countries, has been growing in recent years in Brazil. In addition to producing milk with high solids contents, its derivatives are considered functional foods because of the health benefits. Thus, the objective of this study was to evaluate the levels of palm oil in protected form in the feeding of lactating ewes of the Lacaune breed on body dynamics, production and milk composition. Four treatments were used with nine replications, with treatments consisting of 0.0%, 2.0%, 4.0% and 6.0% fat protected palm oil in concentrated animal. The diet was formulated and adjusted per animal after weighing the milk, isoproteic, isoenergetic with the same forage / concentrate ratio, using corn silage as roughage in all treatments. The weight of milk and collection for analysis of chemical composition seven weeks of lactation and every fortnight in subsequent weeks were performed weekly during the first, and the experimental period comprised the whole lactation period of 182 days. The increased levels of protected fat in the diet resulted in less weight gain and lower body condition of the animals (P<0.05). Treatment with 6% protected fat showed the highest milk yield (P<0.05). The fat content in milk had a positive linear effect (P<0.05), whereas the content of protein, lactose and solids nonfat showed negative linear effect (P< 0.05). The content of total solids in milk, had no effect (P>0.05). In relation to the total production of milk solids (fat, protein, lactose, total solids and solids non fat) had no effect (P>0.05) in any variable. The use of protected fat from palm oil is efficient to increase the production of milk fat and sheep Lacaune. / 5000
33

Gordura protegida de óleo de palma na alimentação de ovelhas Lacaune em lactação

Bianchi, Anderson Elias 28 February 2014 (has links)
A ovinocultura leiteira, atividade comum nos países europeus e asiáticos, vem crescendo nos últimos anos no Brasil. Além de produzir leite com altos teores de sólidos, os seus derivados são considerados alimentos funcionais, devido os benefícios à saúde. Com isso, o objetivo do trabalho foi avaliar o efeito dos níveis de óleo de palma na forma protegida na alimentação de ovelhas lactantes da raça Lacaune sobre a dinâmica corporal, produção e composição do leite. Foram utilizados quatro tratamentos com nove repetições, sendo os tratamentos constituídos 0,0%; 2,0%; 4,0% e 6,0% de gordura protegida de óleo de palma no concentrado dos animais. A dieta foi balanceada e ajustada por animal após a pesagem do leite, sendo isoproteica, isoenergética e com a mesma relação volumoso/concentrado, utilizando a silagem de milho como volumoso em todos os tratamentos. As pesagens de leite e coleta para análise da composição centesimal foram realizadas semanalmente nas primeiras sete semanas de lactação e a cada quinze dias nas semanas subsequentes, sendo que o período experimental compreendeu toda a lactação de 182 dias. O aumento dos níveis de gordura protegida na dieta resultou em um menor ganho de peso e menor condição corporal dos animais (P<0,05). O tratamento com 6,0% de gordura protegida apresentou a maior produção de leite (P<0,05). O teor de gordura no leite apresentou efeito linear positivo (P<0,05), enquanto que o teor de proteína, lactose e extrato seco desengordurado apresentaram efeito linear negativo (P<0,05). O teor de extrato seco total no leite, não apresentou efeito (P>0,05). Em relação à produção total de sólidos no leite (gordura, proteína, lactose, extrato seco total e extrato seco desengordurado) não houve efeito (P>0,05) em nenhuma variável. A utilização de gordura protegida de óleo de palma se mostrou eficiente para aumento na produção e gordura no leite de ovelhas Lacaune. / The dairy sheep business, common activity in European and Asian countries, has been growing in recent years in Brazil. In addition to producing milk with high solids contents, its derivatives are considered functional foods because of the health benefits. Thus, the objective of this study was to evaluate the levels of palm oil in protected form in the feeding of lactating ewes of the Lacaune breed on body dynamics, production and milk composition. Four treatments were used with nine replications, with treatments consisting of 0.0%, 2.0%, 4.0% and 6.0% fat protected palm oil in concentrated animal. The diet was formulated and adjusted per animal after weighing the milk, isoproteic, isoenergetic with the same forage / concentrate ratio, using corn silage as roughage in all treatments. The weight of milk and collection for analysis of chemical composition seven weeks of lactation and every fortnight in subsequent weeks were performed weekly during the first, and the experimental period comprised the whole lactation period of 182 days. The increased levels of protected fat in the diet resulted in less weight gain and lower body condition of the animals (P<0.05). Treatment with 6% protected fat showed the highest milk yield (P<0.05). The fat content in milk had a positive linear effect (P<0.05), whereas the content of protein, lactose and solids nonfat showed negative linear effect (P< 0.05). The content of total solids in milk, had no effect (P>0.05). In relation to the total production of milk solids (fat, protein, lactose, total solids and solids non fat) had no effect (P>0.05) in any variable. The use of protected fat from palm oil is efficient to increase the production of milk fat and sheep Lacaune. / 5000
34

Características do leite bovino produzido em sistemas de alimentação e de produção com diferentes aportes tecnológicos / Characteristics of bovine milk produced in feeding and production systems with different technological support

Gabbi, Alexandre Mossate January 2012 (has links)
Com o objetivo de determinar a influência dos sistemas de produção e de alimentação sobre as características do leite, dados coletados de produtores de leite do sul do Brasil e de experimentos sobre níveis de restrição alimentar e de atendimento das exigências energéticas de vacas em lactação foram submetidos à análise de fatores principais, de correlação e médias canônicas, agrupamento e comparação de médias dos grupos. Os atributos estudados comuns em todos os sistemas foram produção leiteira diária, componentes lácteos, estabilidade do leite, peso corporal e escore de condição corporal. Na análise dos sistemas de produção, três grupos de produtores foram formados pela análise de agrupamento, com características de sistemas especializados, semi-especializados e não especializados em ambas as regiões avaliadas. Grupos de produtores especializados produziam leite em conformidade com as especificações da Instrução Normativa Nº 62. Enquanto que para os produtores da região sul do Rio Grande do Sul, as estratégias de alimentação foram determinantes para distinção entre os grupos de produtores, no extremo oeste de Santa Catarina a estrutura das propriedades foi mais determinante. Níveis de restrição severos (40 e 50%) alteraram significativamente a produção leiteira diária, os teores de proteína e lactose e a estabilidade do leite. O atendimento das exigências energéticas para vacas em lactação possui uma relação direta com a produção diária de leite, com o teor da lactose e com a estabilidade do leite. A produção leiteira, os componentes lácteos e a estabilidade do leite diferenciam-se entre os sistemas de produção e alimentação. / Aiming to determine the influence of production and feeding systems on milk characteristics, data collected from dairy producers in southern Brazil and experiments on levels of feed restriction and attendance of the energy requirements of lactating cows were subjected to principal factor, correlation and means canonical, cluster analysis and comparison of means between groups. The variables common to all systems were daily milk production, milk components contents, ethanol stability, body weight and body condition score. In the analysis of production systems, three producers groups were formed by cluster analysis, with characteristics of specialized, semi-specialized and unspecialized systems in both regions evaluated. Groups of specialized dairy farmers produced milk in accordance with Normative Instruction Nº 62. While for the producers in southern Rio Grande do Sul, the feeding strategies were crucial to distinguish groups, at the far west of Santa Catarina structure of the properties was more important. Severe feed restriction levels (40 and 50%) altered significantly the daily milk yield, protein and lactose contents and ethanol stability. Attendance of the energy requirements for lactating cows showed a direct relationship with the daily milk production, content of lactose and milk stability. Milk production, milk components and milk stability are different between production and feeding systems.
35

Analýza užitkovosti a plodnosti stáda krav plemene holštýn / Analysis of utility and fertility of a cow herd of Holstein breed

ZETKOVÁ, Jana January 2008 (has links)
The point of the work was to make an analysis of milk production an and fertility and to attest dependence of milk production and fertility in the holstein cattle herd. Background materials were acquired especially from milk production control and cattle accompanying documents. Data of 251 dairy cows were worked up. Big problem of the high producing dairy cows is the low fertility. That is why the work was focused on analysing of milk production and fertility index. Service period, insemination interval and interval were analysed out of the fertility index. Milk production, proteins and fats percentage content represent the efficiency. The results show the high selection of cows out of the herd. It result shows from a number of included heifers. Most frequent reasons of selection are health condition, low milk efficiency and fertility disorders. Average efficiency in control increases. On the other hand the protein contest in milk is weak. A breading aim 3,3% was achieved only in year 2003 (3,32%). Milk production increases from the first to the third lactation. Milk production is decreasing from the fourth lactation. Fat percentage content increases to the third lactation, then it stagnates. The protein content goes down with number of lactation. Required interval length to 400 days is exceed in all lactation. Service period is to high regardless of lactation number. Insemination interval increases to the third lactation, then it decreases, but it is nonconforming all the time. The results show that fat and protein content decreases with milk production. The high milk production was reached on cows calved in autumn (8920,77 kg) and in winter (9231,48 kg). Data of cows calved in spring and in summer are almost the same. The results evidence general rule, that fertility decreases with increasing milk production.
36

Sistema agroindustrial do leite: custos de transferência e preços locais. / Dairy value chain: transfer cost and local prices.

Gustavo Fischer Sbrissia 15 April 2005 (has links)
O presente trabalho estudou os sistemas de pagamento de leite no Brasil, nos seis principais estados produtores. Analisou e discutiu a diferenciação de preços do leite em decorrência do pagamento de bonificações por volume de 1666 produtores dentro de 62 diferentes linhas de coleta de 5 cooperativas. Cerca de 34% das cooperativas amostradas no Brasil pagam por volume e cerca de 55% das cooperativas utilizam os critérios de volume e qualidade na remuneração dos produtores. Para o pagamento do frete, 58% das cooperativas cobram o frete somente pelo volume entregue, enquanto 23% utilizam os critérios distância e volume no cálculo do frete e 19% das cooperativas cobram o frete dos produtores pela distância percorrida. Na segunda etapa foram selecionadas cinco cooperativas que utilizavam somente o critério volume no pagamento do leite. O volume total captado no mês pela amostra foi de 4.300.810 litros, em 62 linhas de coleta das cinco cooperativas. A média foi de 106 litros/dia por produtor, com um mínimo de 0,6 litros até um valor máximo de 3983 litros/dia para o maior produtor. O trabalho também analisou o frete pago por litro. A média da amostra foi de R$ 0,029/litro, com um pagamento variando desde nenhuma cobrança de frete até R$ 0,070 por litro. O valor líquido por litro apresentou uma média de R$ 0,373, com um mínimo de R$ 0,255 e um valor máximo de R$ 0,541, variações de 112%. Foi observado que o valor recebido pelo litro do leite aumenta significativamente com o aumento do volume. As constatações efetuadas permitem afirmar que o valor do frete cobrado aos produtores, como se poderia esperar, está vinculado positivamente ao tamanho da rota de coleta e ao número de produtores na rota e negativamente ao volume coletado de cada produtor. Essas mesmas variáveis influem também de acordo com a lógica econômica nos preços recebidos pelos produtores. Observou-se, todavia, que o volume produzido influenciava positivamente os preços recebidos também por outras vias que não seu impacto sobre o valor do frete. Essa é, fora de dúvida, uma forte evidência favorável à discriminação de preços contra os menores produtores, embora não seja uma prova cabal da ocorrência de tal fato. / This article aimed to study payment systems of milk in Brazil, in the six main producing states. It analyzed and discussed the different milk prices practiced due to the paying of bonus per volume, of 1,666 producers, among 62 different lines of collect of 5 cooperatives. Roughly 34% of the studied cooperatives in Brazil pay per volume and around 55% of the cooperatives use the criteria of volume and quality to pay producers´ income. For the freight payment, 58% of the cooperatives charge the freight only based on the volume delivered, whereas 23% use the criteria of distance and volume in the figures and 19% of the cooperatives charge producers the freight based on the distance run. On the second phase was chosen 5 cooperatives, which use only the criterion of volume to pay the milk. The amount of volume obtained in the month studied totaled 4,300,810 liters, in 63 lines of collect of 5 cooperatives. The average was 106 liters/day per producer, with the minimum of 0.6 liters up to a maximum value of 3,983 liters/day for the biggest producer. The study also analyzed the freight paid per liter. The average of the study was R$ 0.029/liter, with the payment ranging from no charge of freight up to R$ 0.070 per liter. The net value per liter showed an average of R$ 0.373, with the minimum of R$ 0.255 and a maximum price of R$ 0.541, variations of 112%. It was observed that the value received per liter of milk significantly increases with the raise of volume. The conclusions obtained alow to state that the price of the freight charged on the producers, as It was expected, is linked positively to the length of the route of collect and to the number of producers in the route and negatively to the volume collected from each producer. These very variables affect also according to the economic logic of the prices received by producers. It was noticed, however, that the volume produced affected positively the prices received also by other vias that did not have any impact on the freight price. This is, without doubt, one strong evidence favorable to the discrimination of prices against minor producers, even thought it is not a real proof of such fact.
37

Reestruturação do sistema lacteo mundial : uma analise da inserção brasileira / Restructuring of the global dairy production : an analysis of brazilian integration

Carvalho, Vera Regina Ferreira 25 July 2008 (has links)
Orientador: Celio Hiratuka / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Economia / Made available in DSpace on 2018-08-11T16:34:53Z (GMT). No. of bitstreams: 1 Carvalho_VeraReginaFerreira_D.pdf: 3152086 bytes, checksum: 4fda28fba678141d84f5aa299cbf4130 (MD5) Previous issue date: 2008 / Resumo: Essa tese tem como objetivo analisar a inserção brasileira na reestruturação do sistema lácteo global a partir das mudanças produtivas do final do século XX. Diversas evidências apontam para uma redistribuição da produção mundial de leite, a matéria-prima básica. Além disso, tem ocorrido um aumento do consumo mundial per capita de lácteos e derivados e também um aumento no número dos consumidores, expandindo-se por duas vias a demanda mundial. Na medida que a produção de lácteos alcançou um nível técnico de produtos e processos que permitiu superar a estreiteza territorial dos vínculos entre o mercado consumidor e uma base produtora local da matéria-prima, novas possibilidades estão colocadas. O mapa global da produção se altera e os interesses das grandes empresas nas regiões onde é possível expandir a produção condiciona novas estratégias de atuação. As transformações setoriais que encaminham a formação de uma nova cadeia produtiva global são o objeto de investigação do presente trabalho. Segundo este, a produção realizada no Brasil tende a estar inserida em uma cadeia mais integrada globalmente e, portanto, conforme uma nova divisão internacional do trabalho / Abstract: This thesis aims to analyze the Brazilian insertion in the restructuring of the global dairy production changes from the end of the XX century. Various evidences point to a redistribution of world production of milk, the raw material base. Moreover, there has been an increase in world per capita consumption of milk and derivatives and also an increase in the number of consumers, is expanding in two ways world demand. To the extent that the production of milk reached a level of technical products and processes that allow overcome the narrow territorial ties between the consumer market and a local production base of raw materials, new possibilities are raised. The global map of production changes and the interests of large companies in regions where it is possible to expand the production determine new strategies of action. The processing sectors that forward the formation of a new global production chain are the subject of this research work. According to this, the production in Brazil tends to be inserted into a chain more integrated globally and, therefore, as a new international division of labor / Doutorado / Teoria Economica / Doutor em Ciências Econômicas
38

Resistance of acid-adapted Escherichia coli O157:H7 to lactoperoxidase and heat in goat milk

Parry-Hanson, Angela Araba Bondzewaa 04 June 2010 (has links)
Survival of Escherichia coli O157:H7 in fermented dairy products has been attributed to acid-adaptation. Acid-adaptation enhances resistance to extreme acid pH and confers cross-protection to heterologous stresses. This study sought to investigate whether acid-adaptation confers cross-protection to lactoperoxidase (LP) system and lactic acid in Tryptone Soy Broth (TSB), and to determine the mechanism of cross-protection. Subsequently, cross-protection of acid-adapted E. coli O157:H7 to the combination of LP activation, heat and lactic acid treatments was determined in fresh goat milk. Finally, the effect of LP activation and E. coli O157:H7 survival on acid production during fermentation of traditional and commercial goat milk was investigated with indigenous cultures and single strain lactic acid bacteria (LAB) respectively. Acid-adapted E. coli O157:H7 strain UP10 showed high acid-resistance at pH levels 4.0 and 5.0 for up to 24 h in TSB at 25°C compared to non-adapted E. coli O157:H7. Acid-adaptation also conferred cross-protection against activated LP system and lactic acid challenge at pH 4.0 and 5.0. Results from fatty acid analysis and quantitative real time Polymerase Chain Reaction (RT-PCR) indicated that sigma S (RpoS)-independent systems were responsible for acid-resistance and cross-protection in TSB. Increase in the saturation of fatty acids, increased expression of outer membrane porin, OmpC, and activation of the glutamate decarboxylase system contributed to acid-resistance and cross-protection. Growth of acid-adapted E. coli O157:H7 strains UP10 and 1062 were inhibited in fresh goat milk compared to the non-adapted cells. Nonetheless, strain 1062 showed better growth and resistance to activated LP in fresh goat milk compared to strain UP10. LP activation alone did not significantly inhibit either acid-adapted or non-adapted E. coli O157:H7, but it sensitized E. coli O157:H7 cells to sub-lethal heat treatment at 55 and 60°C. The combination of heat treatment at 60°C, LP activation and lactic acid at pH 5.0 had a greater inhibitory effect on both acid-adapted and non-adapted E. coli O157:H7, but the acid-adapted strains displayed cross-protection against combined treatments. This indicates that non-adapted E. coli O157:H7 can survive a certain threshold of stresses unscathed. Below that threshold, acid-adaptation may be detrimental to survival. LP activation did not inhibit growth and acid production by single strain and indigenous LAB in the processing of commercial and traditional fermented goat milk products. LP activation however inhibited E. coli O157:H7 in both the commercial and traditional goat milk products although E. coli O157:H7 had become acid-adapted during the fermentation process. E. coli O157:H7 inhibition could be due to the combination of LP activation, low pH, fermentation time and antimicrobial compounds present in the milk or produced by the LAB during milk fermentation. Results from this study suggest that while acid-adaptation protects E. coli O157:H7 under harsh conditions, it can sensitize E. coli O157:H7 to sub-lethal stresses that does not require acid-adaptation for survival. On the other hand, non-adapted E. coli O157:H7 could become acid-adapted in food at mild acid pH which may enhance prolonged survival in such foods. / Thesis (PhD)--University of Pretoria, 2010. / Food Science / unrestricted
39

Influence of Age on Milk Production of Holstein Cows in Utah

Green, Marvin R. 01 May 1962 (has links)
Production of dairy cows is influenced by many factors, among which are: genetics, nutrition, management, disease and age. Most of these factors can be modified to maintain a high level of production. Age, however, is beyond the influence of mankind; therefore, it is important to understand the effect of age on milk and butter-fat production.
40

Evaluation of Milk Production in Western Whiteface and Navajo-Churro Ewes

Brindley, Marla Faye 01 May 1995 (has links)
Western Whiteface and Navajo-Churro Ewes, two types of sheep present in the Intermountain West, were compared for their milk production ability. Amount of milk produced per individual and the group milk composition were analyzed for butterfat, lactose, somatic cell count, protein, calcium, and phosphorous. Ewes were fed ad libitum alfalfa hay and had access to free-choice grain while in the milking parlor. Lambs were weaned at 35 d of age and removed to another holding area and placed on creep feed . Ewes were milked for 90 d following the weaning of the lambs. Western Whiteface ewes had a much higher milk production level than the Navajo- Churro ewes (P < 0.05). Western Whiteface ewes were almost double in their overall level of production versus the Navajo-Churro ewes. Half of the Western Whiteface ewes completed the 90-d lactation period, producing an average of . 83 kg of milk per day. Navajo-Churro ewes did not complete the full lactation period, with I 000/o of them ceasing milk production before completion of the 90-d milking period. The criterion for being considered dry consisted of completing six consecutive milkings while producing 50 ml or less of milk. Overall production for the two groups of ewes was .83 kg/day of milk for the Western Whiteface ewes and .52 kg/day for the Navajo-Churro. The average number of days in production for the Western Whiteface ewes was 69.5 d and 50 d for the Navajo-Churro. Western Whiteface ewes consistently exhibited higher milk production levels than the Navajo- Churro ewes and they adapted well to the milking barn. Navajo-Churro ewes did not produce an adequate quantity of milk for a dairy setting.

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