Fatty acids (FAs) of milk fat are considered to be important nutritional components of the diets of a significant portion of the human population and substantially affect human health. With regard to dairy farming, the FA profile is also seen as an important factor in the technological quality of raw milk. In this sense, making targeted modifications to the FA profile has the potential to significantly contribute to the production of dairy products with higher added value. Thus, FAs also have economic importance. Current developments in analytical methods and their increasing efficiency enable the study of FA profiles not only for scientific purposes but also in terms of practical technological applications. It is important to study the sources of variability of FAs in milk, which include population genetics, type of farming, and targeted animal nutrition. It is equally important to study the health and technological impacts of FAs. This review summarizes current knowledge in the field regarding sources of FA variability, including the impact of factors such as: animal nutrition, seasonal feed changes, type of animal farming (conventional and organic), genetic parameters (influence of breed), animal individuality, lactation, and milk yield. Potential practical applications (to improve food technology and consumer health) of FA profile information are also reviewed.

Milk protein content is an important component of milk, especially from a nutritional point of view and also for payment purposes. The aim of work was to draw up an overview on reference and routine methods for protein determination. Reference methods perform accurate analyses comply according to the International Standard ISO whereas routine methods perform analyses using routine instrumental techniques for faster and cheaper results with acceptable accuracy and a large number of processed samples. In most of cases, using of routine indirect methods for milk protein analysis requires their specific calibrations according to biological kind of measured milk (cow’s, goat’s or sheep’s milk) or specific conditions of milk technology treatment. Also, the quality control measures have a significant role for result determination reliability.

Milk fat content is an important indicator of milk quality because of nutritional and technological aspects of dairying. In this sense the milk fat determination is important practice procedure. The work goal was to do an effective overview and comparison of reference and routine methods of fat determination during their development. Nowadays, there exist a number of methods for determining milk fat content. Reference methods require accurate analysis in compliance with the International Standard ISO, whereas routine methods perform analysis using routine instrumental techniques for faster and cheaper results with acceptable accuracy. Quality control measures have a significant role for result determination reliability and they include internal quality controls, external quality controls, precision of evaluation, and blank samples. In conclusion, due to continuous development and improvement, routine methods will be used more often.

This study evaluated the effects of four factors (breed, parity, month of lactation and feeding ration) on the total explained variation (R 2 ) determining composition of nutritionally important fatty acids. Individual milk samples were collected four times over an entire year (March, June, September, and December, respectively) on a conventional farm from two breeds: Czech Fleckvieh (dual-purpose, local) and Holstein (dairy, worldwide). In total, 145 samples (36; 38; 35 and 36, respectively) were analysed. Within the R 2 , feeding ration and month of lactation were the main factors affecting milk fatty acids composition, whereas breed and parity showed a low effect. A high percentage of the R 2 was observed in rumenic acid (52 %), for example, whereas a low percentage was observed in both palmitic acid (30 %) and oleic acid (30 %). This may be due to intra-breed variability affected by different genetic predisposition of each cows, their performance or individual response to changes in feeding ration.

Cow´s milk consisted of relatively high quantity of saturated fatty acids (about 70 %), which are considered less beneficial health. The content of more desirable fatty acids is about 25 % (monounsaturated) and 5 % (polyunsaturated). The aim of this research was to find ways how to increase the content of mono-and polyunsaturated fatty acids in milk fat. One of the ways how to alter the content of fatty acids is the monitoring of candidate genes and their polymorphism. Therefore, the manuscript deals with selected candidate genes, particularly DGAT1, SCD1 and FASN, which are associated with fatty acid biosynthesis. The results suggest that observing of this issue could be helpful for improving the quality of milk fat.