A total of 24 lactating Holstein cows averaging 620 (se=29) kg of body weight were allotted at week 17 of lactation to eight groups of three cows blocked for similar days in milk to determine the effects of feeding two sources of the plant lignan precursor secoisolariciresinol diglucoside, whole flaxseed and flaxseed meal, on concentrations of the mammalian lignans (enterodiol and enterolactone) in milk. Feed intake, digestion, milk production and milk composition were also determined to compare the use of whole flaxseed and flaxseed meal for milk production. Cows within each block were assigned to one of the three isonitrogenous and isoenergetic total mixed diets: no flaxseed product; 10% flaxseed meal; or 10% whole flaxseed in the dry matter. The experiment was carried out from week 17 to week 21 of lactation and diets were fed at ad-libitum intake. The mammalian lignan, enterodiol, was not detected in the milk of cows. Cows fed whole flaxseed and flaxseed meal had greater concentrations of enterolactone in milk than those fed the control diet. Feed intake, milk production and milk composition were also similar for all diets, indicating that both flaxseed meal and whole flaxseed are suitable feed ingredients for milk production of cows in mid lactation. The results provide new information on the conversion of plant secoisolariciresinol diglucoside from two flaxseed products into mammalian lignans in dairy cows.

Enterococci represent an important part of bacterial microbiota in different types of artisanal cheeses, made from either raw or pasteurized milk. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) of ribosomal DNA is currently one of the most frequently used fingerprinting method to study diversity and dynamics of microbial communities and also a tool for microbial identification. Among several primer pairs for DGGE analysis published so far, six primer pairs amplifying different variable regions of 16S rDNA were selected and applied in our DGGE analysis of 12 species belonging to genus Enterococcus and eight other bacterial species often found in cheeses (seven lactobacilli and one Lactoccocus lactis). When DGGE procedures were optimized, the same set of primers was used for DGGE analysis of five cheese samples. Our study demonstrates that the use of different primer pairs generate significant differences in DGGE analysis of enterococcal population, consequently, appropriate primers regarding the purpose of analysis can be selected. For differentiation and identification of pure enterococcal isolates, primer pair P1V1/P2V1 showed the most promising results since all 12 enterococcal isolates gave distinctive DGGE fingerprints, but with multiple bands patterns; therefore, these primers do not seem to be appropriate for identification of enterococcal species in mixed cultures. Use of primer pairs HDA1/HDA2 and V3f/V3r amplifying V3 region showed better potential for detection and identification of enterococci in mixed communities, but since some bacterial species showed the same fingerprint, for clear identification combination of DGGE and some other method (e.g. species specific PCR) or combined DGGE analysis using two primer pairs generating distinctive results should be used.

To test a system with milk flow-controlled pulsation, milk flow was recorded in 29 Holstein cows during machine milking. The three different treatments were routine milking (including a pre-stimulation of 50–70 s), milking with a minimum of teat preparation and milking with milk flow-controlled b-phase, i.e. with a gradually elongated b-phase of the pulsation cycle with increasing milk flow rate and shortening again during decreasing milk flow. For data evaluation the herd was divided into three groups based on the peak flow rate at routine milking (group 1: <3·2 kg/min; group 2: 3·2–4·5 kg/min; group 3: >4·5 kg/min). Compared with routine milking, milking with milk flow-controlled b-phase caused a significant elevation of the peak flow rate and the duration of incline lasted longer especially in cows with a peak flow rate of >3·2 kg/min in routine milking. In milking with a minimum of teat preparation the duration of incline lasted longer compared with the two other treatments. Bimodality of milk flow, i.e. delayed milk ejection at the start of milking, was most frequent at milking with a minimum of teat preparation. No significant differences between routine milking and milking with milk flow-controlled b-phase were detected for all other milking characteristics. In summary, milking with milk flow-controlled b-phase changes the course of milk removal, however mainly in cows with high peak flow rates.

CLA levels and fatty acid composition were measured to compare the fat composition in organic bulk milk, destined to the production of Grana Padano cheese, with those produced by conventional system. The curds and Grana Padano cheeses were also analysed to evaluate the effects of the production technology on the CLA content. All analysed organic samples were characterized by higher annual means of CLA, vaccenic acid (TVA) and linolenic acid (LNA) in comparison with conventional samples (with P<0·05). Nevertheless, no particular effect of the production technology was seen on the CLA content. The animal diet appears to be the factor which has the highest effect on the CLA concentration in milk and milk products and an organic diet based on fresh or dried forage, that is rich in CLA precursory fatty acids, may improve the yield of fatty acids with beneficial effects on health.

The aim of the present work was to perform a physico-chemical, descriptive quantitative and consumer-preference analysis of hard ewes'-milk cheeses that had been matured for one year and to determine the correlations between the variables studied. The cheeses were elaborated with milk from three breeds of sheep (Castellana, Churra and Assaf) with different somatic cell counts (lower than 500 000 cells ml−1; between 1 000 000 and 1 500 000 cells ml−1, and more than 2 500 000 cells ml−1). The results show that the cheeses elaborated with milk with high SCC had lower values of dry extract and fat and high values of pH and fat acidity and were described as pungent, granulose and less creamy. Regarding the effect of breed, the cheeses made with milk from the Churra breed had lower values for fat and those made with Assaf breed milk were significantly more rancid. The study of correlations showed that creaminess was positively correlated with the dry extract and total fat content and negatively correlated with ash and fat acidity, indeed grainy texture and pungency had the opposite sign in their correlation with these latter variables. The yellow colour was positively correlated with ash and negatively with protein. Finally, the consumer preferences reveals that the less accepted cheeses showed the higher values for rancidness and pungency and they were less likely to accept the cheeses made with Assaf breed milk.

The coagulant retained in cheese curd is a major contributor to proteolysis during ripening. The objective of this study was to quantify residual coagulant in 9 cheese varieties by measuring its activity on a synthetic heptapeptide (Pro-Thr-Glu-Phe-[NO2-Phe]-Arg-Leu) assayed using reversed-phase HPLC. The level of residual coagulant activity was highest in Camembert cheese, probably due to its low pH at whey drainage and the high moisture content of the cheese, followed in order by Feta=Port du Salut=Cheddar>Gouda>Emmental=Parmigiano Reggiano=low-moisture part-skim Mozzarella=Mozzarella di Bufala Campana. The high cooking temperature (50–54°C) used during the manufacture of Emmental and Parmigiano Reggiano cheeses and the cooking and stretching step in hot water during the manufacture of Mozzarella cheese may be the reasons for the lowest residual coagulant activity in these cheeses. The level of residual coagulant activity was higher in Feta cheese made from milk concentrated by ultrafiltration than in conventional Feta.

The effects of high-pressure homogenisation (HPH) in the pressure range 100–300 MPa on the gel formation and rheological properties of rennet-induced skim milk (0·08%, fat, w/w) and standardised milk (3·60% fat, w/w) gels at pH 6·60 were studied. The average casein micelle size in skim milk was significantly reduced and the gel formation time decreased when skim milk was subjected to the pressures of 200 and 300 MPa. The storage modulus of rennet-induced skim milk gels at 2700 s after rennet addition was higher for samples homogenised at higher pressures, which contained smaller casein particles. HPH had little effect on the large deformation properties of rennet-induced skim milk gels. The gel formation time of renneted standardised milk was significantly reduced as a result of HPH, while the storage modulus of rennet-induced milk gels 2700 s after rennet addition increased with increasing homogenising pressure. The apparent fracture stress was slightly higher for standardised milk gels formed from HPH-treated milk, whereas the apparent strain at fracture was lower, than that of unhomogenised milk. In conclusion, HPH treatment influenced gel formation processes of skim milk and its small-deformation rheological properties, mainly through modification of casein micelles. HPH also significantly affected the gel formation process of standardised milk gels and its rheological properties as a result of an increase in volume fraction of aggregating particles, while the particle size was of lesser importance.

Rennet coagulation parameters, curd texture and gross compositional variables were studied in ewes' raw milk samples from nine commercial flocks using different concentrate:forage ratios and grazing times. From early lactation to March flocks were fed concentrate pellets and hay whereas from April to the end of lactation flocks were allowed to graze from 6 to 19 h/day receiving concentrate supplementation in the morning and evening. Milk from late-lactation flocks, when allowed to graze, showed higher content of fat, dry matter, protein, casein, soluble protein, total calcium, curd firmness and curd resistance to compression than the milk from early lactation flocks. Higher total calcium content and lower fat content were found when the early lactation flocks were fed high concentrate:forage ratio than when the flocks were fed low ratio. Curd firmness were lower for milk from flocks fed high concentrate:forage ratio, and the curd resistance to compression was greater, than for milk from flocks fed low ratio. At late lactation, when flocks grazed for a long time per day the total calcium content was higher than when the flocks grazed for a short time per day. Principal component analysis showed that protein and fat content were highly correlated with coagulum and curd firmness, whereas total calcium content was highly correlated with curd resistance to compression, and milk pH with rennet coagulation time.

The activity of human milk on cell growth has been evaluated on two cell lines, MDCK and Caco-2. The proportion of human milk samples that reduced by half the growth of MDCK cells was of 36%. This inhibitory activity was associated with casein and not the whey fraction. Great variability was found in the degree of inhibitory activity depending on the milk sample. The susceptibility of Caco-2 cells to milk inhibitory activity was lower than that of MDCK. Bovine milk did not have any effect on cell growth, either as skimmed milk or as whey or casein. Morphology of cells incubated with active human casein showed abnormal features, such as chromatin condensation, reduced cellular volume and apoptotic bodies, and also fragmented DNA, which are all features of apoptosis.

Bifidogenic effect and stimulation of short chain fatty acid (SCFA) production by fractions of oligosaccharides with a DP⩾3 and Gal β(1-6) linkages synthesised from lactose or lactulose by Pectinex Ultra SP-L and Lactozym 3000 L HP G were evaluated in human faecal slurries. Results were compared with those obtained for the commercial oligosaccharide mixture Vivinal®-GOS. Quantitative real-time PCR showed that all galacto-oligosaccharide (GOS) fractions stimulated slightly higher bifidobacteria growth than lactose, lactulose and Vivinal®-GOS. GOS fractions promoted the production of total SCFA and acetic acid in a similar way to Vivinal®-GOS and more than glucose, lactose and lactulose. In conclusion, oligosaccharides derived from lactose and lactulose may represent a suitable alternative to lactulose for the design of new functional food ingredients.

Determination of somatic cell count (SCC) is used worldwide in dairy practice to describe the hygienic status of the milk and the udder health of cows. When SCC is tested on a quarter level to detect single quarters with high SCC levels of cows for practical reasons, mostly foremilk samples after prestimulation (i.e. cleaning of the udder) are used. However, SCC is usually different in different milk fractions. Therefore, the goal of this study was the investigation of the use of foremilk samples for the estimation of total quarter SCC. A total of 378 milkings in 19 dairy cows were performed with a special milking device to drain quarter milk separately. Foremilk samples were taken after udder stimulation and before cluster attachment. SCC was measured in foremilk samples and in total quarter milk. Total quarter milk SCC could not be predicted precisely from foremilk SCC measurements. At relatively high foremilk SCC levels (>300×103 cells/ml) foremilk SCC were higher than total quarter milk. At around (50–300)×103 cells/ml foremilk and total quarter SCC did not differ considerably. Most interestingly, if foremilk SCC was lower than 50×103 cells/ml the total quarter SCC was higher than foremilk SCC. In addition, individual cows showed dramatic variations in foremilk SCC that were not very well related to total quarter milk SCC. In conclusion, foremilk samples are useful to detect high quarter milk SCC to recognize possibly infected quarters, only if precise cell counts are not required. However, foremilk samples can be deceptive if very low cell numbers are to be detected.

Sixty female dairy calves (body weight, BW, 43·2±0·58 kg and age 9·8±0·61 d) were arranged in two groups to compare the short-term and long-term effects of an enhanced-growth feeding programme (EF) with those of a conventional-growth feeding programme (CF). After 1 week of adaptation to a milk replacer (MR), CF calves were fed 4 l/d of MR (25% crude protein, CP; 19·2% ether extract) at 12% dry matter (DM) from days 1 to 27 and 2 l/d at 12% DM from days 28 to 34, and the EF calves were offered the same MR at 18% DM: 4 l/d from days 1 to 6, 6 l/d from days 7 to 13, 7 l/d from days 14 to 20, 6 l/d from days 21 to 27 and 3 l/d from day 28 to weaning at day 34 of the study (50 d of age). Individual calf starter (20·7% CP) intake was recorded daily from the beginning until day 41 of study (57 d of age). Then, calves were placed in groups of six and they received a total mixed ration (TMR) containing 18·5% CP until day 56 d of study (72 d of age). Then, heifers were moved to larger pens and were fed the same TMR in both treatments at each subsequent stage of growth throughout the study. Calves were weighed weekly until day 56 of study and before every pen change (days 94, 149, 200, 387 of study). When heifers were 400 d old and weighed >380 kg, they were moved to a breeding pen where oestruses were checked three times a day. Heifers were inseminated 12 h after the detection of oestrus. One month before calving, heifers were returned to their original farm and milk yield at 305 days in milk was recorded from 28 cows. Starter intake was greater (P<0·001) in CF than in EF calves (0·79 v. 0·29±0·043 kg/d, respectively) during the preweaning period, but TMR consumption was similar in both treatments from days 42 to 56 of study. BW of EF calves was greater (P<0·01) than that of CF calves at weaning (76·4 v. 71·6±1·10 kg, respectively), but BW was not different at day 387 of study (405 d of age) (406·3 v. 401·3±4·05 kg, respectively). There were numerical differences in age at first breeding, fertility at first artificial insemination, age at pregnancy, and milk yield but some of these differences might have reached statistical significance with more replication.

Mastitis is one of the most costly diseases to the dairy farming industry. Conventional antibiotic therapy is often unsatisfactory for successful treatment of mastitis and alternative treatments are continually under investigation. We have previously demonstrated, in two separate field trials, that a probiotic culture, Lactococcus lactis DPC 3147, was comparable to antibiotic therapy to treat bovine mastitis. To understand the mode of action of this therapeutic, we looked at the detailed immune response of the host to delivery of this live strain directly into the mammary gland of six healthy dairy cows. All animals elicited signs of udder inflammation 7 h post infusion. At this time, clots were visible in the milk of all animals in the investigation. The most pronounced increase in immune gene expression was observed in Interleukin (IL)-1β and IL-8, with highest expression corresponding to peaks in somatic cell count. Infusion with a live culture of a Lc. lactis leads to a rapid and considerable innate immune response.

Rheological and microstructural properties of rennet-induced milk gels containing different fat globules were studied. Recombined milks were prepared by mixing reconstituted low-heat skim milk powder and anhydrous milk fat emulsified with reconstituted skim milk powder (SMP), sodium caseinate (NaCas), whey protein isolate (WPI) or Tween 20. Final elastic modulus of the rennet gels containing WPI- or Tween 20-stabilized fat globules showed significantly lower values compared with those prepared with SMP-emulsified fat globules. SMP-stabilized fat globules interacted with the continuous casein network reinforcing the gel structure. Confocal micrographs supported the rheological data revealing that gels containing SMP-stabilized fat globules formed a tighter network relative to other treatments. Microscopy images also showed some degree of droplet flocculation in the case of gels containing WPI- or Tween 20-stabilized fat globules, and this was most likely the cause of the increase of elastic modulus of these systems. Contrary to reports for acid-induced casein gels, NaCas-stabilized fat globules hindered the formation of rennet gels. These results illustrate that rennet gel structure is affected by droplet-droplet and droplet-casein interactions, which in turn are determined by the composition of the oil-water interface as well as the ionic equilibrium in the reconstituted milk gels.

Immune cells in the milk are most important in combating pathogens that invade the mammary gland. This study investigated the immune competence and viability of somatic milk cells that are already resident in milk and udders free of infection. Cells were studied in freshly removed milk to simulate conditions in the udder. Effects of incubation, cell preparation, and immunological stimulation with 0·5 μg/ml lipopolysaccharide (LPS) from Escherichia coli were analysed. Viability and differential counts of milk cells between high and low somatic cell count (SCC) quarters, and cisternal and alveolar milk with and without LPS stimulation were compared. Incubation and preparation of cells caused a cell loss which further increased with time independently of SCC and milk fraction. The viability of these cells was stable until 3 h post incubation and decreased until 6 h. Cell populations differed between both investigations, but did not change during the course of the experiment. mRNA expression of immune and apoptosis factors of the cells, measured by qPCR, did not change substantially: mRNA expression of caspase 3, Toll like receptor 4, and GM-CSF did not change, whereas the expression of the death receptor Fas/APO-1 (CD95), lactoferrin and lysozyme was decreased at 6 h. Cyclooxygenase-2 and TNF-α mRNA expression were decreased after 6 h of LPS treatment. In comparison with other studies in vivo or in vitro (in cell culture), in this study where cells are studied ex vivo (removed from the udder but kept in their natural environment, the milk) resident milk cells seem to be more vulnerable, less viable, less able to respond to stimulation, and thus less immune competent compared with cells that have freshly migrated from blood into milk after pathogen stimulation. The cell viability and differential cell count differed between high- and low-SCC milk and between cisternal and alveolar milk depending on the individual cow. In conclusion, the results support the view that for a most effective defence against invading pathogens the mammary gland is reliant on the recruitment of fresh immune cells from the blood.

The nutritional distinctiveness of pasture-fed dairy products is mainly influenced by the transfer of specific chemical compounds from the grass to the milk and by their effect on rumen microflora and animal metabolism. Thus, the pasture-fed origin has to be objectively proven, using fast and reproducible analytical methods applied to finished products, in order to protect consumers against potential frauds. In this work, Electronic Nose patterns of Alpine milks produced by cows grazing Trifolium alpinum and Festuca nigrescens pasture types have been examined, in order to test the potential use of this device for routine control analyses of the botanical origin of milk and dairy products. The data have been treated with different multivariate analyses (MANOVA, LDA) and chemometrics (MPLS). The results allow a very good classification of the milks, according to the two treatments. Such results demonstrate that this device could be successfully applied to PDO dairy products food chain as a tool for the determination of their dietary origin.

Use of synthetic feed additives, including synthetic vitamin D3 (D3) in the feed for cows and other ruminants, is not consistent with the international principles of organic farming. If dairy farmers wish to produce in accordance with the organic principles, production animals would be left with only their endogenous production of D3 from summer sunlight as a source of D3. To examine the impact of supplemental synthetic D3 from the feed on the D3 status of dairy cattle in organic production in Nordic countries, 20 high-yielding dairy cows and 30 dairy steers were divided into two groups: one supplemented with synthetic D3 in the feed and one not supplemented with synthetic D3. Vitamin D3 status of the animals was assessed by measuring the concentration of the liver-derived 25-hydroxyvitamin D3 (25OHD3) in plasma. Results showed that 25OHD3 concentration in plasma from dairy cattle as well as from steers decreased during winter for both supplemented and unsupplemented groups. Unsupplemented cows and steers had approximately 2 ng 25OHD3 per ml plasma during winter, whereas supplemented animals had between 10 (cows) and 30 (steers) ng/ml. During summer and autumn there was no additive effect of supplementing with synthetic D3 since unsupplemented and supplemented animals had the same D3 status at this time of year. In all cows summer concentrations of 25OHD3 were 20–25 ng/ml and in all steers 40–50 ng/ml plasma. The decrease in vitamin D3 status during winter indicates that cows and steers are able to store D3 only to a limited extent. The results also show that cows or steers fed supplemental D3 according to Swedish recommendation throughout the year are not able to maintain their summer value of 25OHD3 during winter.

Angiotensin-I-Converting Enzyme (ACE) inhibitors peptides were produced from unsupplemented acid goat whey fermented aerobically for 168 h by Kluyveromyces marxianus and Lactobacillus rhamnosus. This yeast-lactobacillus association is GRAS. Two novel lactokinins were identified: NYW and W with IC50 of 20 and 0·86 μm respectively. They both were resistant toward simulated gastrointestinal digestion. In addition, WLAHK was found in the hydrolysate. These three sequences belong to f(99–110) of α-la which seems to be a lactokinin cryptic zone. W was the major molecule released by the fermentation process. Considering that W is the precursor of serotonin, the hydrolysate produced could be of interest for the generation of functional health ingredient involved in regulation of affective disorders and hypertension.