• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 37
  • 36
  • 24
  • 8
  • 7
  • 5
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 136
  • 58
  • 35
  • 32
  • 21
  • 20
  • 19
  • 18
  • 18
  • 17
  • 17
  • 17
  • 16
  • 15
  • 14
  • 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.
101

Untersuchungen zu Methoden der Milchleistungsprüfung bei dreimaligem Melken

Wangler, Anke 03 July 2003 (has links)
In der vorliegenden Arbeit wurden verschiedene Methoden der Milchleistungsprüfung (MLP) bei dreimaligem Melken getestet. Mit Hilfe von Modellentwicklungen und dem Test verschiedener Schätzverfahren wurde das Ziel verfolgt, den hohen Arbeitsaufwand zur MLP beim dreimal täglichen Melken zu reduzieren und trotzdem hinreichend genaue Prüfergebnisse zu garantieren. Dazu wurden Untersuchungen in zwei Milchviehbetrieben vorgenommen, die jeweils etwa 400 Kühe dreimal täglich in einem Intervall von 8:8:8 Stunden melkten. Es wurden am MLP-Tag zusätzlich zur obligatorischen Mischprobe aus allen drei Gemelken (Standardmethode) die Milchinhaltsstoffe jedes Einzelgemelkes analysiert und die Gemelksmengen erfasst. Die Untersuchungen ergaben, dass sich trotz gleicher Zwischenmelkzeiten die Mittelwerte sowohl der Milchmengen als auch der Inhaltsstoffe Fett und Eiweiß signifikant voneinander unterschieden. Dabei wiesen die Milchmengen und Inhaltsstoffe des Mittagsgemelkes die geringsten Unterschiede bzw. die höchsten Korrelationen zur Tagesgesamtleistung auf. Ein signifikanter Einfluss der Laktationsnummer und des Laktationsmonates auf die Schätzung der Tagesmilchmenge bzw. des Fett- und Eiweißgehaltes konnte nachgewiesen werden. Im Ergebnis des Vergleiches aller getesteten Schätzverfahren wurden für die Verwendung zweier Gemelke generell höhere Schätzgenauigkeiten erreicht als bei Einbeziehung lediglich eines Gemelkes in die Hochrechnung. Die alleinige Nutzung des Mittagsgemelkes ergab jedoch ähnlich hohe Schätzgenauigkeiten und erfordert einen deutlich geringeren Arbeitsaufwand. Die Methode der einfachen linearen Regression innerhalb von Klassen nach Laktation und Laktationsmonat führte zu den höchsten Übereinstimmungen in Bezug auf die wahren Tagesleistungen. Das Verfahren der MLP mit einem konstanten monatlichen Prüfgemelk (nur mittags) ergab höhere Genauigkeiten als ein monatlicher Wechsel der Probegemelke. Für die Praxis können folgende Empfehlungen gegeben werden: 1. Anhand der eigenen Ergebnisse ist ein Melkintervall von 8:8:8 Stunden anzustreben. 2. Unter den Bedingungen gleicher Zwischenmelkzeiten sollte die Probenahme aus dem Mittagsgemelk erfolgen, ohne das Prüfgemelk monatlich zu wechseln. 3. Die eigenen Auswertungen ergaben, dass sowohl der Eiweiß-, Laktose-, Zell- als auch der Harnstoffgehalt des Mittagsgemelkes hohe Übereinstimmungen zur Tagesgesamtleistung aufwiesen und demzufolge ohne Korrektur auf die Tagesleistung übertragen werden können. 4. Im Vergleich zu den anderen Inhaltsstoffen wurden für den Fettgehalt der Milch deutlich größere Variationen festgestellt. Der Fettgehalt des Mittagsgemelkes wies aber auch hier die höchsten Übereinstimmungen mit der Tagesgesamtleistung auf. Eine Korrektur zur Hochrechnung auf die Tagesleistung ist jedoch notwendig. 5. Obwohl zwischen der Milchmenge des Mittagsgemelkes und der Tagesgesamtleistung eine hohe Korrelation besteht, sollten bei vorhandener automatischer Milchmengenmessung alle Gemelke in die Prüfung einbezogen werden. Ist dies nicht möglich, bedarf auch die Milchmenge einer Korrektur zur Hochrechnung auf die Tagesleistung. Das aus dieser Arbeit abgeleitete alternative Verfahren der MLP bei dreimaligem Melken wurde indessen von der ADR anerkannt, vom ICAR genehmigt und ist offiziell zugelassen. / Various methods of milk recording for 3-times milking per day have been tested in this study. The aim of the work was to expand models for estimating daily yield from only one or two milkings per cow and day. Comparisons of different models were made to select the highest accuracy of prediction. But also practicability was taken into consideration. Investigations were made on two dairy farms each milking 400 cows 3-times daily with an milking interval of 8:8:8 hours. In addition to a mixture of all three milking samples (obligatory sample for the standard method) a separate sample from each of the three milkings was taken and analysed. Single milk yields were registered, too. The results documented significant differences between yields of milk and contents of fat and protein per milking despite equal milking intervals. Milk yields were highest at morning milking and lowest in the evening. The lowest differences in relation to the whole daily yield were found for the midday milking. This milking also had the highest correlation with daily yield. A significant influence of number and stage of lactation was established for the estimation of daily milk yield and fat and protein content, respectively. In the result of the comparison between all estimation methods generally better accuracies have been found for including two out of three milkings per day than including only one milking for estimating daily yield. But using only midday milking proved similar high precision and requires smaller expense of work and cost. Method of simple linear regression within classes of lactation number and lactation stage led to the highest correspondences in relation to the true daily yield. The testing method which included only midday samples each month (without changing) resulted in higher accuracies than a monthly change between all three milkings (morning/midday/evening). The following recommendations can be given for practice: 1. On the basis of results a milking interval of 8:8:8 hours is to prefer. 2. Under conditions of equal times between milkings samples should be taken from midday milking. 3. The corrected method with midday milking has to be used. Each month only midday milking has to be sampled and analysed, without an alternating sampling of milkings. 4. The results showed that under conditions of equal milking intervals there were high correspondences between contents of protein, lactose, somatic cell count, and urea of the midday sample and the mixed sample of all milkings per day. To estimate daily yields, here no correction is necessary. 5. The content of fat varied extremely within cow and day in comparison with other components. Midday milking showed highest correspondences with daily yield, too. But here a correction is necessary. 6. Even though there is a high correlation between milk yield of the midday milking and the whole yield of the day it is advisable to include all milking yields of the test day if automatic equipment for measuring milk yield is available. Otherwise a correction of milk yield of midday milkings is necessary, too. The in this study recommended alternative method of milk recording under conditions of 3-times daily milking is meanwhile accepted by ICAR as well as registered in Germany.
102

Sensor-based detection of the teat load caused by a collapsing liner using a pressure-indicating film

Demba, Susanne 22 November 2017 (has links)
Ziel der Arbeit war es zum Einen die Eignung der Messung statischer Drücke in unterschiedlichen Größenordnungen mit Hilfe von roter Farbdichtevariation zur direkten Messung des Druckes zwischen Zitze und Zitzengummi beim Melken zu testen. Zum Anderen wurden verschiedene Einflussfaktoren auf diesen Druck analysiert. Dafür wurden Untersuchungen im Versuchsmelkstand unter der Verwendung verschiedener Zitzenmodelle durchgeführt. Der Einfluss verschiedener Anlagenvakua, Pulsationsraten, Pulsphasenverhältnisse und Zitzengummis auf die Zitzenbelastung wurde umfangreich analysiert. Es wurde festgestellt, dass sich die getestete Methode zur direkten Messung des Druckes zwischen Zitze und Zitzengummi eignet. Des Weiteren konnte ein signifikanter Einfluss aller getesteten Faktoren nachgewiesen werden. Die Zitzenbelastung beim Melken nimmt mit ansteigendem Anlagenvakuum, ansteigender Pulsationsrate und ansteigendem Phasenverhältnis zu. Die technischen Eigenschaften eines Zitzengummis, vor allem aber die Form des Zitzengummischaftes, unterscheiden sich signifikant hinsichtlich des von ihnen applizierten Druckes auf die Zitze. In allen Untersuchungen wurde der größte Druck auf das Zitzenende ausgeübt. / The aim of the present thesis was to test whether the measurement of static pressure distribution and magnitude with the aid of red color density variation is appropriate to directly measure the teat load caused by a collapsing liner and to identify different factors influencing this load. Therefore, investigations were carried out in a laboratory milking parlor using different artificial teats. The influence of the machine vacuum, the pulsation rate, the pulsation ratio, and the liner type were analyzed. The present investigations showed that the tested method is appropriate to directly measure the teat load due to liner collapse. A significant effect of all tested factors could be found as well. The higher the machine vacuum, pulsation rate, and pulsation ratio, the higher the teat load caused by a collapsing liner. The technical characteristics of a liner, especially the shape of the barrel, differ significantly with regard to the teat load. In all investigations more pressure was applied to the teat end.
103

Interação animal-ambiente: efeito do ambiente climático sobre as respostas fisiológicas e produtivas de vacas Holandesas em free-stall / Animal-environment interaction: effects of climatic environment over physiologic and productive responses of Holstein cows in free-stall

Martello, Luciane Silva 09 June 2006 (has links)
As relações entre os fatores climáticos e as respostas fisiológicas de vacas lactantes são bastante conhecidas, porém sob condições de ambiente controlado. Este estudo teve como objetivo monitorar as respostas dos animais em instalações típicas para vacas leiteiras, para identificar o real impacto do ambiente climático sobre o animal. Foi proposto um método para avaliar o nível de estresse de vacas, que poderá servir como uma ferramenta simples, que traduza as sensações de conforto térmico dos animais. O experimento foi realizado em três fases, a saber: primavera (28 dias), verão (31 dias) e inverno (31 dias). Foram utilizados animais da raça Holandesa com produção média entre 20 a 25 kg leite/dia. Os animais foram alojados em instalação tipo free-stall com acesso livre a um piquete adjacente. Foram avaliadas a freqüência respiratória (FR), a temperatura retal (TR), a temperatura do pelame (TPE), a temperatura auricular (TAU), a temperatura da base da cauda (TCAU), a temperatura da vulva (TVU) e a produção de leite (PL). O ambiente foi monitorado 24 horas por dia, todos os dias, com registros da temperatura de bulbo seco (TBS), da umidade relativa (UR), da temperatura de ponto de orvalho e da temperatura de globo negro (TG). Posteriormente foram calculados os índices de temperatura e umidade (ITU) e o de temperatura de globo e umidade (ITGU). Todas as variáveis fisiológicas apresentaram padrão sazonal bem claro, com maiores valores durante as estações mais quentes (primavera e verão) e menores valores no inverno. A TAU, a TVU e a TCAU apresentaram correlações positivas com a TR, a FR e a TPE, o que indica uma associação entre estas variáveis. Porém estudos adicionais devem ser conduzidos para validar a aplicabilidade destas variáveis (TAU, TVU e TCAU) na caracterização do estresse térmico dos animais. A TPE e a FR foram as variáveis mais influenciadas pelo ambiente climático em todas as estações do ano. O ambiente noturno foi associado às variações da TR, da FR e da TPE, enquanto o ambiente do dia anterior não explicou a variação das respostas fisiológicas. Não houve evidência de efeitos de uma variável ambiental isolada sobre as variáveis fisiológicas, o que indicou a complexidade das relações entre o animal e o ambiente climático. Mesmo com ITU acima de 79, considerado estressante pela literatura estrangeira para vacas lactantes, não foram evidenciados valores estressantes para TR e FR e reduções na produção de leite. O modelo proposto neste trabalho para estimar presença ou ausência de estresse em vacas alojadas em free-stall, apresentou boa aderência ao conjunto de dados, com R² de 0,43. Dessa forma, disponibiliza uma ferramenta simples e rápida para produtores e técnicos, pela associação de duas medidas fisiológicas (FR e TPE) de fácil mensuração, ou então pela associação de duas variáveis ambientais (TBS e UR). Tal ferramenta diz respeito a uma amostra da população de vacas Holandesas alojadas em determinada instalação e região, o que condiciona o modelo proposto a outros estudos para sua validação em outros rebanhos e regiões. / It has been well known the relation between the environment and physiological answers of lactating dairy cows under controlled environmental conditions. The present study aimed to monitor the animal answers allocated at typical housing system to identify the real environmental impact over it. A method was proposed to evaluate the stress level of the animal, to be used as a tool to identify the sensations of thermal comfort. The experiment was conducted in three phases, in spring (28 days), summer (31 days) and winter (31 days) periods. Holstein dairy cows were used averaging milk yield around 20 to 25 kg/day. The animals were housed in a free stall shed with an open area. Respiratory rate (FR), rectal temperature (TR), surface skin temperature (TPE), internal ear temperature (TAU), tail temperature (TCAU), vulva temperature (TVU) and milk yield (PL) were evaluated. The environmental conditions were monitored during 24 hours every day, by recording the dry bulb temperature (TBS), relative humidity (UR), dew point temperature (Tpo) and black globe temperature (Tg). The calculation of temperature humidity index (ITU) and the black globe humidity index (ITGU) was based on these environmental variables. The physiological variables had a seasonal standard with higher values during hot periods (spring and summer) and lower values during the winter. The IET, VT and TT demonstrated positive correlations with RT, RR and SKT showing association between them. More studies are necessary to validate the applicability of these variables (IET, VT and TT) and to characterize heat stress in dairy cows. SKT and RR were the most influenced by the environment in all seasons. The night environment was associated to the RT, RR and SKT, while the day before environment did not explained the physiological variations. There was no evidence of isolated environmental variables over the physiological ones, showing the complexity between the animal and the environment. Even with the THI values above 79, what is considered stressful to dairy cows, there was no evidence of stressful values for RT and RR and of MY losses. The model proposed in this study to estimate presence or absence of heat stress in dairy cows avails a simple and fast tool to milk producers and technicians, where it could be associated two physiological variables (RR and SKT) of easy measurement or other two environment variables (DBT and RH). However, this result is related to the studied population at a specific housing system and situated at a specific region. Addiitonal studies must be conducted to validate the proposed model to others dairy herds and locations.
104

Pieno kokybės ir sudėties rodiklių palyginimas melžiant karves melžimo aparatais ir melžimo robotais X ūkyje / A Comparison of the milk quality and nutritional components using automatic and robotic milking systems on farm X

Ivanauskaitė, Laisvida 18 June 2013 (has links)
Pieno ūkis – viena svarbiausių žemės ūkio šakų pasaulyje. Pagal statistiką, Lietuvoje vienam gyventojui tenka 563kg pieno, kas yra vienas didžiausių rodiklių pasaulyje, tad pieno ūkis yra viena svarbiausių žemės ūkio, tuo pačiu ir ekonomikos sričių. Siekiant gerinti pieno kokybę bei mažinti kaštus vis daugiau pieno melžimo įmonių investuoja ir taiko naujas technologijas - melžimo aparatai į liniją ir robotai. Lietuvoje pirmoji robotizuota sistema įdiegta 2007 m. Tiriamajame ūkyje ši sistema įdiegta 2009 m. Tyrimo tikslas buvo palyginti pieno sudėties ir kokybės rodiklius X ūkyje, melžiant karves melžimo aparatais ir robotais. Svarbiausios pieno sudėtinės dalys yra – baltymai, riebalai ir angliavandeniai (laktozė, mineralinės ir biologiškai aktyvios medžiagos, vitaminai, fermentai ir kitos). Melžimas turi didelę reikšmę karvių produktyvumo bei pieno sudėtinių dalių rodikliams, todėl būtina parinkti teisingą melžimo būdą. Buvo ieškota būdų – kaip pilnai pakeisti žmogų melžimo aikštelėse. Siekiant pagerinti karvių pieno kokybę ir padidinti primilžį, modernizuojant pieno ūkius inovatyviomis technologijomis, rekomenduojama robotizuoti karvių melžimą. Nustatyta, kad robotais melžiamų karvių pieningumas padidėja vidutiniškai 15 proc. Pieno gamybą skatina dažnesnis karvių melžimas ir geresnė jų savijauta. Mažuose pieno ūkiuose, kur karvių yra mažai naudojamas įprastas melžimo būdas, t. y. melžimas rankomis. Melžiant karves rankomis yra didesnė tikimybė pieną užteršti bakterijomis... [toliau žr. visą tekstą] / Dairy farming is one of the most important branches in agriculture worldwide. According to statistics in Lithuania there's 563 kg of milk produced per capita. That is one of the highest production rates per capita in the world. Dairy farming is crucial to local economy. In order to achieve higher milk quality and minimize expenditures more dairy farms are investing and adapting new technologies: milking pipelines and fully automated robotic milking. The first fully automated robotic milking line in Lithuania was used implemented in 2007. In the researched farm the system was implemented in 2009. The main goal of research was to compare milk composition and quality in the research farm X by milking cows to pipelines and using fully automated robotic milking. The main nutrients that compose milk are: proteins, fats and carbohydrates(lactose, minerals and biologically active materials, vitamins, enzymes and others). The way that cows are milked has high impact on milk yields and nutrients, so the best milking technology is essential for optimal results. The research on how to eliminate human labor during milking process has been done. In order to increase the quality and yields of cow's milk by modernizing the dairy farms and using the fully automated robotic milking. It was concluded that by using fully automated robotic milking milk yield increases by 15% on average. The milk production is increased by more frequent milking and cattle welfare. In the small dairy farms with... [to full text]
105

Studies in anaerobic/aerobic treatment of dairy shed effluent : a thesis presented in partial fulfilment of the requirement for the degree of Doctor of Philosophy in Agricultural Engineering at Massey University, Palmerston North, New Zealand

Warburton, David John January 1977 (has links)
Increases in herd size and enforcement of water quality regulations have created an effluent disposal problem for the New Zealand dairy industry. Spray disposal to land and lagooning are commonly used but mechanical failures, management requirements and pressure on land have limited their suitability in many situations. This project was established to consider an alternative system. Initial studies revealed that anaerobic treatment in unmixed, non-insulated tanks, followed by trickling filter aeration, might be suitable. Two laboratory scale and one field treatment plant (1/15 - 1/20 full scale) were constructed to investigate the system. A factorial experimental design allowed investigation into three anaerobic treatment levels with a 3 x 3 aerobic treatment interaction nested within each anaerobic treatment. Anaerobic residence times of 5, 7.5 and 10 days provided loading rates of 1.35 - 0.63 kg COD/m3-day and 1.36 - 0.67 kg T S/m3-day. Removals between inlet and outlet averaged 71% and were insensitive to loading rate. Total solids accumulation rates of 40-50% TS input rate suggests that anaerobic tank design should be based on solids accumulation rate and cleaning frequency. The stone media trickling filter was loaded at approximately 0.61 kg COD/m3-day. Aeration periods of 1, 2 and 3 days and hydraulic loads of 2.8, 10.1 and 18.2 m3/m2-day were studied to determine their influence on treatment efficiency. Multiple regression analysis indicated that the longer residence times and higher recycle rates improved treatment efficiency. Removals varied with the measured parameters but ranged from 42-66% for COD. Design alterations to allow the final discharge to be taken from the bottom of the filter, after settling, would increase aerobic treatment efficiency above 75% COD removal. Prediction of treatment efficiencies beyond the monitored operating conditions suggested that only marginal improvements could be made. The TS accumulation rate in the aerobic phase was approximately 13% of the TS input rate or 56% of the BOD removal rate. Overall plant treatment efficiencies of 80-89% were obtained. Removals in excess of 92% could be achieved with minor design alterations. Maintenance and operational requirements were minimal. The only problem with the system was an average 15 fold increase in NO3-N and 4 fold increase in DIP under conditions for optimum removal of the other parameters. Intermittent land disposal could reduce this problem. Treatment comparison between similar laboratory plants, and between laboratory and field plants which varied by a scale factor of 56, suggests that identically designed plants would give a similar performance and that there is little scale effect. Increasing the scale only improved treatment efficiencies under unstable aerobic conditions, i.e., high recycle rates and low residence times. Increasing scale gave some decrease in maintenance and operational problems. Design of a full scale plant, based on daily pollution loads from a 250 cow dairy shed, suggests that the system is a viable proposition.
106

Milk fat globule stability : lipolysis with special reference to automatic milking systems /

Wiking, Lars, January 2005 (has links) (PDF)
Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
107

Indicadores de balanço energético negativo em vacas leiteiras no início de lactação / Negative energy balance indexes in dairy cows in the beginning of lactation

Capelesso, Alsiane 26 February 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Early lactation in dairy cows involves metabolic changes, being mobilization of corporal reserves very common. So the objective of this work is to study indexes of negative energetic balance in dairy cows on early lactation, in two different energy levels. For this, 20 cows were distributed in a randomized complete block design, resulting in 2 treatments: T1 one milking per day for 8 weeks on the beginning of lactation and T2 two milkings for the same period of time. In animals, it was measured live weight, body condition scoring, skinfold thickness, being also collected blood samples for non-esterified fatty acids, urea, glucose, acetoacetate and Dβ-Hydroxybutirate analyses. It was also realized urea dilution measurements. As a result dry matter intake wasn´t different between treatments, milk production and milk solids in kg were lower for T1. For differences analyses T1 resulted in a better energy balance for the treatment period (P = 0.0002), obtaining the opposite result for residual period (P = 0.0423). Talking about corporal characteristics, corporal protein was statistically different between the treatments only for residual period, being higher for T1 (P = 0.0463), meanwhile in blood measures, non-esterified fatty acids (P = 0.0352) and Dβ-Hydroxybutirate (P = 0.0004), were lower for T1, for treatment period. Dβ-Hydroxybutirate didn´t show relation with energy balance, so more studies must be done. / Período inicial da lactação em vacas leiteiras envolve várias modulações a nível metabólico, sendo mobilização de reservas corporais característico neste momento. Portanto, o objetivo com este trabalho é estudar indicadores de balanço energético negativo em vacas leiteiras em período inicial de lactação, mantidas sob dois níveis de balanço energético. Para isso, 20 vacas foram arranjadas em um delineamento blocos ao acaso, sendo aplicados dois tratamentos: T1 uma ordenha diária durante oito semanas iniciais de lactação; T2 duas ordenhas diárias durante oito semanas iniciais de lactação. Nos animais foi determinado peso vivo, escore de condição corporal, espessura de gordura subcutânea; sendo ainda coletadas amostras de sangue, para análise de ácidos graxos não esterificados, ureia, glicose, acetoacetato e Dβ-Hidroxibutirato. Técnica de diluição de ureia também foi realizada. Consumo de matéria seca não diferiu entre os grupos. Produção de leite e kilogramas de sólidos foram menores para T1. Pelas análises das diferenças T1 apresentou melhor balanço energético em período de tratamento (P = 0,0002), invertendo a relação para o período residual (P = 0,0423). Para as características corporais, proteína corporal diferiu no período residual sendo maior para T1 (P = 0,0463), já das mensurações sanguíneas, ácidos graxos não esterificados (P = 0,0352) e Dβ-Hidroxibutirato (P = 0,0004) foram menores no período de tratamento em T1. Dβ-Hidroxibutirato não apresentou relação com balanço energético, assim mais estudos deverão ser realizados.
108

Psychrotrofní lipolytické bakterie a obsah volných mastných kyselin v bazénových vzorcích syrového kravského mléka / Psychrotrophic lipolytic bacteria and content of free fatty acids in bulk samples of cow?s raw milk

MIKULOVÁ, Magda January 2012 (has links)
The objective of the study was to analyze the relationship of psychrotrophic lipolytic bacteria in bulk samples of cow?s raw milk and their metabolic activity based on the content of free fatty acids and identifying the factors that may influence their levels. The contents of free fatty acids (FFA) and counts of total bacteria, psychrotrophic lipolytic bacteria (PLiBC) and somatic cells were determined in 150 samples of cow?s bulk raw milk on 20 farms with three different milking technologies in South Bohemia during 2008?10. FFA were determined using an extraction-titration method. Within the compared technologies, the highest mean values of FFA (38,8 mmol?kg-1; P<0,001) and PLiBC (696 CFU?ml?1) were observed on farms with pipeline milking in stalls. The lowest mean FFA level (15,4 mmol?kg-1) was determined on farms with an automatic milking system. Medium values were determined on farms with parlour milking. From the aspect of the inhibition of an increase in psychrotrophic bacteria, and mainly in psychrotrophic lipolytic bacteria in conditions of cold storage of raw milk the temperature of 4°C seems optimum as it markedly inhibits the growth of mesophilic and psychrotrophic bacteria and at the same time the increase in the values of free fatty acids is slower at this temperature compared to the temperatures of 6,5 and 10°C.
109

Zjišťování kvality a standardnosti mléka u automatických systémů dojení / Quality assurance and its standardization of milk in automatic milking systems

HRŮŠA, Jan January 2013 (has links)
Thesis deals with the finding reliable measurement of the quality of milk by automatic milking system. The observed reliability of the system to measure the quality of milk is a significant parameter for herd management and also an effective tool for farmers. Thanks notice on udder health in the program T4C farmer is able to detect a number of health problems or deficiencies in the herd before they break out in full force. This gives the farmer more options to treat dairy cows, such as inflammation, at the very beginning and as such can successfully use homeopathic treatment.
110

Perfil das propriedades leiteiras em Santa Catarina e sua relação com a adequação às normas brasileiras de qualidade do leite Lages SC / Adaptation on dairy farms of Santa Catarina to the brazilian norms of milk quality

Winck, César Augustus 18 October 2007 (has links)
Made available in DSpace on 2016-12-08T16:24:03Z (GMT). No. of bitstreams: 1 PGCV07MA023.pdf: 744484 bytes, checksum: 772fd248a65a313f8aa4d81844397124 (MD5) Previous issue date: 2007-10-18 / The Normative Instruction 51/2002 of MAPA (NI 51) defined technical regulations forthe production, identity and quality of the several types of milk. Total Bacterial Count (TBC) and Somatic Cell Count (SCC) are important parameters to evaluate the microbiological quality of the milk and the health of the mammary gland, respectively, being part of a group of quality attributes that include composition, sensorial aspects and absence of drugs and chemical residues. The aim of this work was to evaluate the adaptation of dairy farms to the limits established for TBC and SCC and the influence of the socioeconomics and cultural conditions of the dairy farmers on it, their perception about the NI 51 and the use of milking techniques. A diagnosis research throughout the application of a structured questionnaire for 166 dairy farmers of Meio-oeste and Alto Vale do Itajaí regions, State of Santa Catarina, from April to September of 2006, was performed. The results, of the percentage of months that TBC and SCC surpassed the limit of NI 51were analyzed by logistic regression. The farmers are, in their majority, small producers, with 97,6 liters of milk/day on the average, and 70% of the farms up to 30 hectares. On the average, tank TBC for producer surpassed 1.000.000 of UFC/ml in 70,3% of the months and SCC was higher than 1.000.000/ml in 14,8% of the months. The size of the farm and milk yield had no effect on the adaptation to NI 51 for SCC (P > 0,05). However, farms with more than 200 litres/day presented smaller percentage of months out of the patterns for TBC (P < 0,05). The degree of satisfaction of farmers with the activity as well as the fact of the milk being or not the main economic activity had no effect on the adaptation to the legislation (P > 0,05). Farmers with higher level of scholarity had better results for SCC and TBC. Farms with manual milking (33,5% of the farms) had better results for TBC and worse for SCC. Udder preparation before milking did not affect the results for SCC, but farmers that use pre-dipping had better results for TBC (P < 0,01). Milk cooling in bulk tanks or in milk cans had no effect on milk quality, even so both were better than freezer or refrigerator (P < 0,01). The majority of the farmers had little knowledge about the norms of milk quality and they did not have a clear perception of their consequences. It was concluded that most of the dairy farms of the researched areas, are adapted to the established by NI 51 for SCC, but not for TBC, and the socioeconomics and cultural conditions had a minor effect. The use of correct hygiene techniques improves the adaptation to the legislation, what does not happen with the simple acquisition of equipments (Milking equipment and bulk tank). The current level of information of the farmers about milk quality is not enough to guarantee product with quality according the limits established by the present normative / A Instrução Normativa 51/2002 do MAPA (IN 51) definiu regulamentos técnicos para a produção, identidade e qualidade dos diversos tipos de leite. A Contagem Bacteriana Total (CBT) e a Contagem de Células Somáticas são importantes parâmetros para avaliar a qualidade microbiológica do leite, sendo parte do conjunto de atributos de qualidade que incluem também composição, aspectos sensoriais e ausência de drogas e resíduos químicos. O objetivo da pesquisa foi avaliar a adequação das propriedades ao limite máximo para CBT e CCS e a influência da condição sócio-econômico-cultural do produtor, da sua percepção sobre a IN 51, e do emprego de técnicas de manejo de sobre a mesma. Realizouse uma pesquisa diagnóstica através da aplicação de questionário estruturado a 166 produtores de leite das regiões Meio-oeste e Alto Vale do Itajaí do Estado de Santa Catarina, no período de abril a setembro de 2006. Os resultados dos questionários sobre a percentagem de meses em que a CBT e a CCS ultrapassavam o limite da IN 51, foram analisados por regressão logística. Os produtores entrevistados caracterizam-se, em sua maioria, como pequenos produtores, comercializando em média 97,6 litros de leite/dia, sendo que 70% das propriedades tinham até 30 hectares. Em média, a CBT de tanque por produtor ultrapassou 1.000.000 de UFC/ml em 70,3% dos meses e a CCS foi maior que 1.000.000 em 14,8% dos meses. O tamanho da propriedade e o volume de leite comercializado não influenciaram a adequação da mesma ao estabelecido na IN 51 para CCS (P > 0,05). Porém, produtores com mais de 200 litros/dia apresentaram menor percentagem de meses fora dos padrões estabelecidos para CBT (P < 0,05). O grau de satisfação do produtor com a atividade leite bem como o fato do leite ser ou não a principal atividade econômica da propriedade não influenciaram a adequação à legislação (P > 0,05). Porém, produtores com maior nível de instrução escolar tiveram melhores resultados para CCS e CBT. As propriedades com ordenha manual (33,5% dos produtores) tiveram resultados melhores para CBT e piores para CCS. Preparação do úbere antes da ordenha não afetou os resultados de CCS, mas os produtores que utilizam pré-imersão das tetas em desinfetantes tiveram resultados melhores para CBT (P < 0,01). O resfriamento do leite em resfriadores de imersão ou expansão não afetou a qualidade do leite, porém ambas foram melhores do que o resfriamento com freezer ou refrigerador (P < 0,01). Os produtores, em sua maioria, possuem pouco conhecimento sobre a normatização de qualidade do leite e não apresentam uma percepção clara sobre as conseqüências da mesma em suas propriedades. Conclui-se que a maioria das propriedades leiteiras das regiões pesquisadas se adequam ao estabelecido pela IN 51 para CCS, mas não para CBT, sendo pequena a influência das condições sócio-econômico-culturais dos produtores. A utilização de técnicas corretas de higiene de ordenha e dos equipamentos melhora a adequação dos produtores à legislação, o que não ocorre com a simples aquisição de equipamentos (ordenhadeira mecânica e resfriador por expansão direta). O nível atual de informação dos produtores sobre as exigências de qualidade do leite não é suficiente para garantir a obtenção de um produto dentro dos limites estabelecidos pela normatização

Page generated in 0.0807 seconds