Jolanta Król

Changes of protein content and its fractions in bovine milk from different breeds subject to somatic cell count.

Global milk production is undeniably dominated by 2 dairy breeds recognized worldwide: Holstein-Friesian and Jersey. A third breed, Simmental, serves as a dual-purpose breed. The objective of the present research was to establish potential changes in the fractional components of bovine milk protein (mainly whey) in relation to the health status of a dairy cows mammary glands, which is closely determined by somatic cell count (SCC). The milk of 3 breeds was studied: Polish Holstein-Friesian (Black and Red-White varieties), Simmental, and Jersey. The cows were housed in freestall barns and fed according to the total mixed ration feeding system for both winter and summer periods. Milk samples were collected individually from each cow twice a year, in the winter and summer seasons. A total of 1,822 milk samples were evaluated (946 in winter and 876 in summer). The milk was examined for SCC, crude protein, casein, and whey fraction proteins (α-lactalbumin, β-lactoglobulin, lactoferrin, BSA, and lysozyme). The research material for each breed was split into 4 groups based on SCC (group I: ≤100,000 cells/mL; group II: 101,000 to 400,000 cells/mL; group III: 401,000 to 500,000 cells/mL; and group IV: 501,000 to 1,000,000 cells/mL). It was found that an increase of SCC promulgated a progressive decline in the daily yield of milk, which was significantly true for the Polish Holstein-Friesian. The level of crude protein decreased slightly as SCC increased, and casein concentration (r=-0.591) also followed this trend of decline. Elevation of SCC produced a decrease of major albumins (i.e., α-lactalbumin and β-lactoglobulin). However, SCC increase induced an increase in the immunoactive proteins (lactoferrin and lysozyme) as well as BSA. The interactions of a breed with increased SCC, which can be measured based on the BSA content of the milk, has indicated various levels of susceptibility to the increase in different breeds. This is confirmed by different values of correlation coefficients for these relationships: 0.71 in the Holstein-Friesian, 0.58 in Simmental, and 0.47 in the Jersey cows. Holstein-Friesian cows are more sensitive to mammary gland infections causing a greater decline of their daily milk yields, which, in turn, is reflected in an increase of the negative value of the correlation coefficients between SCC and milk efficiency (-0.24). In the other 2 breeds, the correlations were also negative, but substantially lower (-0.12 and -0.15).

Effect of breed and feeding system on content of selected whey proteins in cow's milk in spring-summer and autumn-winter seasons.

Effect of Breed and Feeding System on Content of Selected Whey Proteins in Cows 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 cows 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. Wpływ rasy i systemu żywienia krów na zawartość wybranych białek serwatkowych mleka w okresie wiosenno-letnim i jesienno-zimowym Celem pracy było określenie wpływu rasy i systemu żywienia krów na stężenie wybranych białek serwatkowych w mleku pozyskiwanym w okresie wiosenno-letnim i jesienno-zimowym. Badaniami objęto 2278 próbek mleka pobranych od krów rasy polskiej holsztyńsko-fryzyjskiej odmiany czarnoi czerwono-białej, Jersey oraz simentalskiej. W każdej próbce oznaczono zawartość alfa-laktoalbuminy, beta-laktoglobuliny, laktoferyny, krowiej albuminy serum i lizozymu, metodą RP-HPLC. Oceniając równoczesny wpływ rasy i sezonu produkcji na zawartość białek serwatkowych wykazano istotne interakcje dla wszystkich analizowanych białek serwatkowych. Mleko krów simentalskich utrzymy-wanych systemem tradycyjnym wyróżniało się wyższą zawartością białek serwatkowych (oprócz BSA) w porównaniu do żywionych systemem TMR. Dla większości analizowanych składników, z wyjątkiem zawartości BSA, lizozymu oraz stosunku alfa-laktoalbuminy do beta-laktoglobuliny, zanotowano również jednoczesny wpływ systemu żywienia i sezonu produkcji.

Factors determining the susceptibility of cows to mastitis and losses incurred by producers due to the disease – a review

Abstract 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.

Effect of production season on protein fraction content in milk of various breeds of goats in Poland

Milk of various goat breeds was analysed to assess the effect of production season on content of basic chemical components, with regard to whey proteins. Milk of goats in the productive herds (white and coloured coat) contained significantly (P < 0.01) more total protein, casein, fat, dry matter and functional whey proteins. The production season significantly determined the content of total protein (P < 0.01), casein (P < 0.01) and whey proteins (P < 0.05), including a-lactalbumin (P < 0.01) and lactoferrin (P < 0.01). A higher content of total protein and casein was found in the autumn–winter season and the content of whey proteins was higher in the spring–summer period.