Joanna Barłowska

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).

Influence of Production Season and Lactation Stage on the Technological Suitability of Milk from Cows of Various Breeds Fed in the TMR System

Abstract The aim of the study was to evaluate selected indicators of the technological suitability of milk from four breeds of cow housed in free-stall barns and fed in a TMR system. A total of 1, 146 milk samples were analysed, collected from cows of the breeds Polish Holstein-Friesian (Black-and-White and Red-and-White populations), Jersey, and Simmental. The following were determined in the samples: content of solids non-fat and casein, protein-to-fat ratio, active and potential acidity, heat stability, rennet clotting time, and milk fat dispersion. Despite the use of a mono-diet (TMR) year round, somewhat higher daily milk yield was obtained in the spring/summer season, but the differences were statistically significant (P≤0.01) only in the case of PHF RW. The milk obtained in the autumn/winter season contained more solids-non-fat, including casein, and in the case of JE and PHF HO the differences were statistically significant (P≤0.01). It also had significantly higher heat stability and a longer rennet clotting time (P≤0.01), with the greatest differences noted in the case of the SM breed. Milk from this period also had a higher percentage of fat globules with a diameter. 6 ≥m. The concentration of solids-non-fat, including casein, increased significantly (P≤0.01) over the course of lactation in all of the breeds evaluated. The stage of lactation did not significantly affect clotting time, heat stability, or milk fat dispersion.

Nutritional value and technological suitability of milk from cows of three Polish breeds included in the genetic resources conservation programme

Nutritional Value and Technological Suitability of Milk from Cows of Three Polish Breeds Included in the Genetic Resources Conservation Programme The study included milk obtained from cows of three native cattle breeds, i.e. White-backed (BG), Polish Red (RP) and Polish Black-and-White (ZB) kept under conventional conditions. The reference group consisted of milk from Polish Holstein-Friesian cows (PHF) maintained in the intensive system and milk from Simmental cows (SM) kept under conventional conditions. The following parameters were determined in 976 samples of milk: content of fat, protein, casein, lactose and solids; acidity (pH value); heat stability; rennet coagulation time; content of α-lactalbumin, β-lactoglobulin, serum albumin, lactoferrin and lysozyme. Additionally, a certain proportion of samples was investigated for fatty acid profile and content of macro- and microelements. Cows of native breeds produced milk of higher nutritional value (higher content of whey proteins and polyunsaturated fatty acids, including CLA) and more suitable for processing as compared to PHF cows. Milk from cows of the Polish Red breed was the most valuable in terms of these parameters, which can be associated with a distinctive phylogenetic origin of this breed. The favourable parameters in regard to the nutritional value and technological suitability of milk obtained from analysed population of cows of 3 breeds included in the programme of genetic resources conservation are therefore an important reason of validity for subsequent implementation of this programme. Wartość odżywcza i przydatność technologiczna mleka krów trzech polskich ras objętych programem ochrony zasobów genetycznych Badaniami objęto mleko trzech rodzimych ras krów, tzn. białogrzbietej (BG), polskiej czerwonej (RP) i polskiej czarno-białej (ZB) użytkowanych w tradycyjnym systemie chowu. Jako grupę odniesienia wykorzystano mleko krów rasy polskiej holsztyńsko-fryzyjskiej (PHF) użytkowanych w systemie intensywnym i mleko krów rasy simentalskiej (SM) z chowu tradycyjnego. W 976 próbach mleka oznaczono: zawartość tłuszczu, białka, kazeiny, laktozy i suchej masy, kwasowość (pH), stabilność cieplną, czas krzepnięcia mleka pod wpływem podpuszczki, zawartość α-laktoalbuminy, β-laktoglobuliny, albuminy serum, laktoferyny i lizozymu. W pewnej części prób oznaczono także profil kwasów tłuszczowych oraz zawartość makro- i mikroelementów. Krowy ras rodzimych produkowały mleko o wyższej wartości odżywczej (więcej białek serwatkowych i wielonienasyconych kwasów tłuszczowych, w tym CLA) i lepszych parametrach do przetwórstwa w porównaniu do PHF. Najbardziej cenne pod tym względem było mleko krów rasy polskiej czerwonej, co można łączyć z innym pochodzeniem filogenetycznym tej rasy. Uzyskane korzystne parametry w zakresie wartości odżywczej i przydatności technologicznej mleka ocenianej populacji krów trzech ras objętych programem ochrony zasobów genetycznych są ważnym argumentem dla zasadności dalszej realizacji tych programów.

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.

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.

Changes in Milk Yield and Quality During Lactation in Polish Red and White-Backed Cows Included in the Genetic Resources Conservation Programme in Comparison with the Simmental Breed

Abstract Milk yield and quality was assessed in cows raised on low-input farms (traditional feeding), i.e. two breeds covered by genetic resources conservation (RP and BG) and the SM breed. The reference group was PHF HO cows from an intensive milk production system (PMR feeding). A total of 1,212 milk samples were collected from three periods of lactation: I (up to 120 days), II (121–200) and II (over 200). The milk was analysed for content of fat, protein, casein, lactose, dry matter, non-fat dry matter and the protein-to-fat ratio, coagulation time, heat stability and the percentage of fat globules in different size ranges. Fatty acid profile and cholesterol content were determined in a representative number of 180 milk samples. Daily yield in the native breeds in the third phase of lactation was 9.6 and 8.7 kg, which was slightly over 55% of their yield in phase I, compared to 66% in the SM and 73.4% in the reference group (PHF HO). The increase in fat and protein (including casein) in the milk during lactation was much higher in the native breeds, so its energy value in phase II of lactation was 11% higher in the BG cows and 9% higher in RP, but only 4% higher in the SM with regard to phase I of lactation. The milk fat from the Polish Red cows had the highest proportion of PUFA in each phase of lactation, including CLA, and the highest PUFA/SFA ratio. Over the course of lactation the percentage of large fat globules in the milk decreased, particularly in the native breeds (P≤0.01), while in the SM the differences were much smaller and statistically insignificant. Lactation persistency in both native breeds raised in a low-input system was worse than in the SM, but the increase in basic components during lactation was markedly higher, while that of cholesterol was lower.