Effect of Breed and Feeding System on Content of Selected Whey Proteins in Cow's Milk in Spring-Summer and Autumn-Winter Seasons
The objective of the present study was to evaluate the effect of breed and feeding system on the content of selected whey proteins in cow's milk collected in the spring-summer and autumn-winter periods. A total of 2,278 milk samples from Black- and Red-and-White variety of Polish Holstein-Friesian cows and Simmental and Jersey cows were examined. In each sample the content of selected whey proteins, i.e. alpha-LA, beta-LG, lactoferrin, BSA and lysozyme, was analysed by RP-HPLC method. Evaluation of the simultaneous effect of breed and production season on whey protein content showed significant interactions (P≤0.05 and P≤0.01) for all analysed whey proteins. The milk of Simmental cows kept in the conventional system was characterized by a higher content of whey proteins (with the exception of BSA), in comparison to the cows managed under TMR system. Furthermore, for most of the evaluated components, except the content of BSA and lysozyme and the alpha-LA/beta-LG ratio, the simultaneous effect of feeding system and production season was also found.
The aim of the study was to compare the content of selected bioactive whey proteins and lipophilic vitamins, which largely determine the bioactive status of milk, in milk obtained from local breeds of cows raised in Poland (Polish Red, White-Backed and Simmental) and Polish Holstein-Friesian cows. Basic chemical composition and content of selected bioactive compounds (β-lactoglobulin, α-lactalbumin, lactoferrin, bovine serum albumin, and vitamins: E, A, D3 and β-carotene) in 550 milk samples were analysed. The milk produced by local breeds proved to be a more valuable source of whey proteins and lipophilic vitamins than that of the Polish Holstein-Friesians. It was distinguished by its content of all bioactive compounds, including those with antioxidant properties, i.e. vitamins E, A and D3 and β-lactoglobulin, and antimicrobial properties, mainly lactoferrin. Therefore, the milk of cows of local breeds should be considered a valuable material for processing, especially at the level of the farm or small local processing plant, to produce products that are richer in health-promoting compounds. The promotion of milk from local breeds can therefore be an opportunity for the farms that raise them.
The aim of the paper was to discuss the factors determining the susceptibility of cows to mastitis, the most important for breeders, including losses incurred by milk producers due to the disease. Inflammations of mammary gland are common and the most awkward problem which dairy farmers face around the world. In the case of clinical udder inflammation, it is estimated that the cost of mastitis is about 200 € per cow with fluctuations from 100 even up to 1000 €. Resistance, i.e. the susceptibility of cows to mastitis, is conditioned genetically. The possibility of BoLA and lactoferrin gene polymorphism, using in the selection cows resistant to mastitis, is indicated. Bacteria inhabiting the mammary gland, and the living environment of animals are primarily the main etiological factor. Moreover, many authors indicate the differences between breeds of cows in resistance to mastitis. High-productive breeds are generally more susceptible to the udder inflammation, in comparison to the local breeds. The greatest reduction in milk yield is observed in the case of these breeds, and especially in Holstein-Friesian breed, in which the decline of daily yield at somatic cell count (SCC) amounting above 500,000 per ml of milk can reach 25%. The probability of mastitis occurrence increases with an age of cows and following lactation, and dry period is a time of increased risk. Higher incidence of inflammation is also associated with abnormalities in the construction of the udder (unevenly developed quarters, too long or too short teats). In recent years, a possible relationship between feeding system of cows with their resistance to udder infections has been reported. It is emphasized that a deficiency of selenium and vitamins A and E in the ration may contribute to the increase in the number of mastitis incidences. There are, however, unclear opinions of various authors on the effect of automatic milking system on udder health.
Enlargement of the left atrium is perceived as a part of athlete’s heart syndrome, despite the lack of evidence. So far, left atrial size has not been assessed in the context of exercise capacity. The hypothesis of the present study was that LA enlargement in athletes was physiological and fitness-related condition. In addition, we tried to assess the feasibility and normal values of left atrial strain parameters and their relationship with other signs of athlete’s heart. The study group consisted of 114 international-level rowers (17.5 ± 1.5 years old; 46.5% women). All participants underwent a cardio-pulmonary exercise test and resting transthoracic echocardiography. Beside standard echocardiographic measurements, two dimensional speckle tracking echocardiography was used to assess average peak atrial longitudinal strain, peak atrial contraction strain and early left atrial diastolic longitudinal strain. Mild, moderate and severe left atrial enlargement was present in 27.2°%, 11.4% and 4.4% athletes, respectively. There were no significant differences between subgroups with different range of left atrial enlargement in any of echocardiographic parameters of the left ventricle diastolic function, filling pressure or hypertrophy. A significant correlation was found between the left atrial volume index and maximal aerobic capacity (R > 0.3; p < 0.001). Left atrial strain parameters were independent of atrial size, left ventricle hypertrophy and left ventricle filling pressure. Decreased peak atrial longitudinal strain was observed in 4 individuals (3.5%). We concluded that LA enlargement was common in healthy, young athletes participating in endurance sport disciplines with a high level of static exertion and was strictly correlated with exercise capacity, therefore, could be perceived as another sign of athlete’s heart.