|
|
Vlivy působící na kvalitu a složení bazénových vzorků mléka u dojnic českého strakatého skotu v konkrétním chovu
Strnadová, Jitka
The aim of the diploma thesis was to evaluate the influences on the quality and composition of bulk milk samples of dairy cows of Czech spotted cattle. The observation took place within one calendar year (January to December 2022) in the selected breeding of GenAgro Říčany a.s., when we took a total of 52 milk samples. The obtained samples were analyzed and, together with the data from the temperature-humidity sensors (HOBO), sorted in the Microsoft Excel program and subsequently evaluated in the STATISTICA 14.0 program. The highest number of somatic cells (SB) in milk was in the summer, while the lowest in the winter and spring (P < 0,05). The highest number of SB was in the temperature zone at 20.1 °C and the lowest at 0 °C (P < 0,05). The highest number of SB was found in the period with the highest average lactation order (P < 0,05). Regarding the influence of lactation phase, it was found that the highest number of SB was found in dairy cows in the period with the highest average lactation phase (P < 0,05). No significant differences (P > 0,05) were found for the other milk productivity parameters. Over the entire follow-up, the freezing point averaged -0,552°C in all cases.
|
|
|
Mléčný tuk a jeho využití v potravinářských technologiích
Nejedlíková, Martina
This bachelor thesis deals with milk fat and its use in dairy technology. The composition of milk is summarized and the knowledge regarding milk fat, its structure and properties is presented in details. Part of the thesis is devoted to methods of treatment and fractionation of milk fat. The findings regarding the studies of the antibacterial activity of lactose monolaurate ester (LML) and lactose monodecanoate (LMD) in milk at different temperatures and fat contents are summarized. Furthermore, the research trend of using milk fat in 3D food printing is presented, which offers new opportunities in the field of food design and customization. Overall, milk fat has significant applications in dairy technology and research trends in its use provide exciting opportunities for the development of the food industry.
|
|
|
Vliv úrovně metabolických procesů živočišného organismu na zastoupení lipidových složek mléka
Šulová, Marie
This bachelor thesis entitled ‘Influence of the level of metabolic processes of animal organism on the representation of lipid components in milk’ deals with physiological processes which influence synthesis, composition and release of lipids by secretory cells of the mammary gland through various metabolic ways. The introductory chapter focuses on the characteristics of the basic components in milk; individual fractions of milk fat are described in detail. The following chapters describe the synthesis of milk fat and lipid metabolism in the body of ruminants, namely cattle, and factors that influence the amount and composition of milk fat. A proposal of the methodology of experimental work describing division of animals into groups, feed diets and the overall progress of the experiment is a part of the thesis.
|
|
|
The effect of selected demographic factors on sensory evaluation and acceptability of commercial milks
TOMÁŠKOVÁ, Denisa
The diploma thesis was focused on a sensory evaluation of selected types of milk (pasteurized and UHT; both as 3.5% and 1.5% of fat content) and their acceptability depending on demographic factors. The next aim was to evaluate a questionnaire survey concerning this commodity. For sensory evaluation, the method of a paired preference test for a pasteurized milk and UHT milk of the same fat content was used. Furthermore, a ranking method for all samples was used. All the participants of the survey were university students. A total of 61 evaluators (average age 24.4 ? 6.7) participated in the sensory analysis and 106 respondents (35 ? 16.9) in the questionnaire survey. Research of the sensory evaluation revealed that evaluators preferred UHT milk and that they liked milks higher in fat more. Questionnaire survey showed that the taste of milk was the most important criterion for decision, followed by quality and the content of fat. Advertisement played the smallest part in a milk selection.
|
|
|
The effect of polymorphism of some enzymes on fatty acid composition in cow´s milk fat
SVOBODOVÁ, Martina
The aim of the diploma thesis was to determine the genotypes of polymorphic variants of some candidate loci in the AGPAT6 and LEP genes and to evaluate the influence of these polymorphic variants on milk yield and milk fatty acid proportions. Genotypic and allele frequencies of AGPAT6 and LEP were determined in dairy cows (n = 400) of the Czech Fleckvieh breed and its crossbreeds. The PCR / RFLP genotyping method was used. The results showed that the CT (AGPAT6) and MM (LEP) genotypes predominated in the population. The influence of AGPAT6 and LEP polymorphisms on milk yield indicators for the 1st and 2nd lactation could not be demonstrated. The influence of the AGPAT6 genotype on the representation of some short-chain fatty acids has been demonstrated. The effect of the LEP genotype on fatty acid proportions has not been demonstrated. The results of this work make it possible to obtain a more favorable composition of milk fat with respect to human health.
|
|
|
The level of energy metabolism of dairy cows and the composition of milk fat
KAUTSKÁ, Jitka
The aim of this study was to evaluate the relationship between the levels of energy metabolizm of high-yielding dairy cows and the amount of milk fat. Furthermore, the proportion and content of fatty acids in milk fat. The effect of antiketogenic prophylaxis of the monenzin-containing preparation was also evaluated, and the metabolic parameters were evaluated at the same time. The experiment took place in the breeding of high-yield dairy cows of the Holstein breed in the company Agropodnik Košetice a.s. s The average milk yield in breeding was 11,553 kg of milk in the observed period. The highest acid content was recorded in the first month of lactation and their content gradually decreased. Likewise, they had the highest proportion of short-chain saturated fatty acids (SAFA). The application of monenzin has a proven incidence of subclinical ketoses, both in first-calves and in cows for second and subsequent lactation. The reduction of ß- hydroxybutyric acid in blood and milk confirms the importance of the antiketogenic prophylaxis used.
|
|
|
Individual dynamic of urea in milk during lactation
BOUBLÍK, Tomáš
Experimental groups of 20 Holstein cows were observed in the course of 10 consecutive calendar months in order to describe the relationship between urea concentration in milk and milk production and milk production parameters. The calculated coefficients of the correlation showed that urea concentration in milk tended to have neutral relationship with milk fat content, milk yield and lactose content and negative relationship with milk protein content.
|
|
|
Polymorphism of some enzymes as factor affecting milk fat composition
KLOJDA, Martin
The aim of this diploma thesis was to determine allele and genotype frequencies for g.10329C>T (A293V) polymorphism in the SCD1 gene in dairy cow populations, establish effects of this locus on milk production traits and fatty acids composition. At first, allele and genotype frequencies were determined. Subsequently the effect of this polymorphism on milk production traits was proved and effects of this polymorphism were demonstrated as well. For the determination allele and genotype frequencies the PCR/RFLP technique was applied. In this diploma thesis the effect of polymorphism g.10329C>T (A293V) on milk production traits was demonstrated as well as the effects of this polymorphism on fatty acids composition. The findings following from this diploma thesis show economical and health benefits of this SCD1 locus.
|
|
|
Fatty acid composition of bovine milk and milk products
MAŠKOVÁ, Gabriela
The thesis deals with changes in proportion of fatty acids in bovine milk. The aim of this study was to assess the profile of fatty acids in milk and subsequently in yoghurt produced from it. The thesis also evaluates the influence of breeding management, breed as well as region. The results of the thesis confirmed that processing of milk into yoghurt has little to no effect on fatty acids profile and proportion of fatty acids is stable. Processing milk into yoghurt alters nutritional value of the product only minimally and the changes in fatty acids profile are not statistically relevant. Profile of fatty acids in the end product was mostly influenced by breeding management, where nutritionally most valuable milk and therefore yoghurt comes from grazing dairy cows. Breed itself has influence more over content of main elements, such as fat or protein content, in milk rather than over fatty acids profile. Influence of region tightly relates to breeding management where in highlands pasturing is more common and in lowlands it is more common to have dairy cows in stables.
|
|
|
Vliv polymorfních variant kandidátního lokusu na spektrum mastných kyselin kravského mléka
ZÁHORKOVÁ, Jana
Global studies show the effect of polymorphism of selected genes on dairy production and fatty acid spectrum. The aim of the diploma thesis was genotyping of candidate FASN locus with a focus on milk yield and fatty acid spectrum depending on genotype. The thesis describes the characteristics of cow's milk, milk fat and fatty acids in milk fat. Furthermore, the thesis deals with the genome of cattle and the potential influence of polymorphism of candidate genes affecting fatty acids of milk fat. Genotypes for FASN were determined by the PCR-RFLP method, the milk yield of selected dairy cattle was statistically evaluated according to the milk production indices for 1st lactation in individual breeds, and the determination of fatty acids was performed by spectrophotometry followed by statistical evaluation. The resulting genotypes in selected breeds were only two, the GG genotype with a higher relative frequency than the genotype AG. There is no statistically significant difference between FASN genotypes depending on the milk yield and the fatty acids spectrum.
|
guest ::
