In present study, three strains of lactic acid bacteria (LAB) viz. Lactobacillus casei, Lactobacillus acidophilus and Lactococcus lactis and milk fermented with these strains have been studied for antioxidant and cholesterol assimilation activities in-vitro and in-vivo, in addition to the effect on total lactobacilli, lactococci and coliform counts into the gut of mice fed with diets supplemented by fermented milk. All three selected strains exhibited potent 2,2-diphenyl-1-picrylhydrazyl, malonaldialdehyde and hydrogen peroxide radical scavenging abilities as well as inhibition of linoleic acid peroxidation activity. These activities were highest in Lb. casei as followed by Lb. acidophilus and Lc. lactis. In addition, these bacterial cultures also exhibited good in-vitro cholesterol assimilation potential. Oral administration to mice of milk fermented with selected LAB strains, slightly decreased blood cholesterol, increased colonization of total lactobacilli and lactococci, and decreased coliforms in the intestinal tissues as well as faecal samples. These results indicate that, selected LAB strains have good antioxidant, hypocholesterolemic and coliform removal activities. It may suggest that, a novel functional food can be obtained by supplementation of selected LAB in milk, which may have various health beneficial properties such as antioxidant and hypocholesterolemic activities.

An experiment was conducted with 12 lactating dairy ewes and 12 goats with the objective to determine whether, under the same dietary treatments, the differences in their fatty acid (FA) profile with emphasis on cis-9 trans-11 CLA milk fat content, are reflected in the transcript levels of genes involved in FA and cis-9, trans-11 CLA biosynthesis. The animals were fed with two diets (A, B) in different days of milk (DIM) due to the different milk yield, body weight etc, in order to have the same food intake and to avoid dietary effects. Diet A was fed to the animals on a group basis as it is traditionally used in practice, while diet B was chosen to avoid individual feed intake variation which is usually observed in group feeding. The results showed that there are significantly lower mRNA levels of acetyl-CoA carboxylase (ACC) in sheep mammary gland compared with those of goats, independently from the diet fed. The same trend was observed with the mRNA level of FA synthase (FAS), but the results were significant only for diet A. The mRNA level of lipoprotein lipase (LPL) in the mammary gland did not differ between sheep and goats fed with diet A. In addition, the concentration of cis-9 trans-11 CLA content was significantly higher in sheep milk fat compared with those of goats. This is in accordance with the significant higher levels on mRNA of stearoyl-CoA desaturase (SCD) which were observed in their mammary adipocytes of sheep compared with those of goats, independently of the fed diet (A or B). In conclusion, these findings demonstrate that the differences between sheep and goats, concerning cis-9, trans-11 CLA and FA milk fat content, under the same dietary treatments could be explained in part by the differences in mRNA of SCD and lipogenic genes in their mammary gland.

Organic dairy farming is an expanding segment of the dairy sector where cow management differs from the conventional model in many respects. Thus, a comparative evaluation of disease and welfare status in organically and conventionally managed dairy cows is required. Assessment of milk yield, udder health and reproductive performance (RP) was done in 20 organically and 20 conventionally managed Swedish dairy herds. In accordance with earlier findings we confirmed lower milk yield in organic cows. Udder health and RP were chosen as indicators of animal health in view of their clinical relevance and the availability of appropriate data bases providing good background knowledge for further animal health assessment. No obvious differences were found in the investigations of somatic cell count (SCC) profiles or time to veterinary-treated cases of mastitis between organically and conventional managed cows. Pregnancy success at first insemination, an appropriate measurement of RP with biological interpretation and background, did not reveal any difference between management types, whereas the hazard rate-ratio (HR) of having a calving-interval was significantly lower (HR=0·71) in organically managed cows. The calving-interval is an important financial determinator in dairy production, but it is not considered an optimal indicator of biologic relevance as it partially reflects farmer decisions. In conclusion, the organically managed cows in this study did not differ from conventionally managed cows in udder health or RP, with the exception of calving interval.

Mastitis is the most frequent and costly disease in dairy herds, as it negatively affects yield and milk quality. The presence of clinical mastitis is quite easy to asses, whereas the diagnosis of the subclinical form can be more difficult and requires laboratory assays. Somatic cell count (SCC) is widely used as a rapid and low-cost indicator of mastitis, even if is not useful in discriminating between the clinical and subclinical form. As amyloid A has been investigated as a marker of mastitis, the aim of this study was to assess the potential value of measuring amyloid A in serum and milk and the correlation with SCC in the diagnosis of subclinical mastitis. The reliability of two different ELISA kits for the measurement of amyloid A in milk was also tested. During a 1-month trial period, 21 cows were assigned to three experimental groups according to their health status: 6 cows with clinical mastitis (CM), 10 cows with subclinical mastitis (SM) and 5 healthy cows (HE). Amyloid A was measured both in serum (SAA) and in quarter milk samples (mAA) with a serum ELISA kit, and in quarter milk samples (MAA) with a milk ELISA kit. SCC, total microbial count (TMC) and bacterial examination of the milk were also carried out. After a log transformation, the data were submitted to ANOVA and linear regression. TMC was significantly higher in cows with clinical mastitis, while no differences were observed between the other two experimental groups. SCC and MAA levels were significantly different among the three groups. mAA concentrations were similar between cows with subclinical and clinical mastitis, and SAA was not affected by mastitis. A significant correlation between SCC and MAA or mAA was detected, while no correlation was recorded between SAA and mAA. A close relationship between MAA and mAA was noticeable even at low concentrations, suggesting MAA as a potential physiological marker of subclinical mastitis.

Sow milk protects the piglet against infectious diseases through a variety of mechanisms. In this study, the presence of potentially probiotic lactic acid bacteria in this biological fluid was investigated. Milk samples were obtained from 8 sows and a total of 19 rod-shaped isolates were selected for identification and assessment of their probiotic potential. RAPD profiling revealed the existence of 8 different genetic profiles among them. One representative of each profile was selected for further characterization and they were identified as Lactobacillus reuteri, Lb. salivarius, Lb. plantarum, Lb. paraplantarum, Lb. brevis and Weissella paramesenteroides. Then, their probiotic potential was evaluated through different assays, including survival in conditions simulating those existing in the gastrointestinal tract, production of antimicrobial compounds, adherence to intestinal mucin, production of biogenic amines, degradation of mucin, and pattern of antibiotic sensitivity. Three strains, Lb. reuteri CR20 (a reuterin-producing strain), Lb. salivarius CELA2 (a bacteriocin-producing strain) and Lb. paraplantarum CLB7 displayed the highest probiotic potential.

Concentration of natural protective factors (NPFs) which have the ability to inhibit growth of mastitis-causing pathogens increase rapidly following the cessation of milking of dairy cows. One such NPF is lactoferrin, an iron-binding protein present in high concentrations in dry-cow secretions. Earlier studies have demonstrated that intermittent milking at the end of lactation increases levels of NPFs in milk and may decrease prevalence of intramammary infections at calving; however, most of these studies date back several decades and may not apply to current high-producing cows. The objective of this study was to assess whether an intermittent milking schedule prior to dry-off increases the concentration of lactoferrin in mammary secretions at the end of lactation and what other factors influence lactoferrin concentration at dry-off. One week prior to dry-off (pre-dry), cows were randomly assigned to an intermittent milking schedule or they continued to be milked twice daily. Duplicate quarter milk samples for microbiological culture were taken at pre-dry and at dry-off to determine infection status of quarters. Quarter somatic cell counts (SCC) were measured on the day of dry-off. Lactoferrin concentrations were quantified by ELISA. Intermittent milking, mean SCC for the last three months prior to dry-off, SCC at dry-off, lactoferrin concentration at pre-dry, quarter infection status at pre-dry and dry-off, days in milk at dry-off, breed, parity, cumulative milk yield for the final week of lactation and season were considered as potential explanatory variables. Their effect on lactoferrin concentration at dry-off was assessed using a mixed-effects linear regression model. Lactoferrin concentration increased significantly during the final week of lactation for cows on an intermittent milking schedule and was significantly associated with initial lactoferrin concentration and infection status at dry-off.

The bacteriophages Cb1/204 and Cb1/342 were obtained by induction from the commercial strain Lactobacillus delbrueckii subsp. lactis Cb1, and propagated on Lactobacillus delbrueckii subsp. lactis 204 (Lb.l 204) and Lactobacillus delbrueckii subsp. bulgaricus 342 (Lb.b 342), respectively. By cross sensitivity, it was possible to detect a delay in the lysis of Lb.l 204 with Cb1/342 phage, while the adsorption rate was high (99·5%). Modified and unmodified phages were isolated using phage Cb1/342 and strain Lb.l 204. The EOP (Efficiency of Plaquing) values for the four phages (Cb1/204, Cb1/342, Cb1/342modified and Cb1/342unmodified) suggested that an R/M system modified the original temperate phage, and the BglII-DNA restriction patterns of these phages might point out the presence of a Type II R/M system. Also, the existence of a Type I R/M system was demonstrated by PCR and nucleotide sequence, being the percentages of alignment homology with Type I R/M systems reported previously higher than 95%. In this study it was possible to demonstrate that the native phage resistant mechanisms and the occurrence of prophages in commercial host strains, contribute strongly to diversify the phage population in a factory environment.

STATs are a group of transcription factors that mediate actions of a variety of peptide hormones and cytokines within target cells (for example, prolactin and growth hormone). Therefore, STAT5A gene is a candidate marker for quantitative traits in farm animals with respect to milk production traits. In this study the STAT5A/AvaI polymorphism was investigated with PCR-RFLP in a sample of 233 Italian Brown cattle. This polymorphism is localized in the coding region of the bovine STAT5A gene. It is a substitution C→T at position 6853 within exon 7. All three possible genotypes for the C/T polymorphism were identified. The overall frequencies of alleles C and T were 0·83 and 0·17 respectively; the Hardy-Weinberg equilibrium was verified. In order to study the relationship between STAT5A/AvaI polymorphism and milk performance traits, the data for a 305-d milk production that included milk yield, protein and fat yield, fat and protein percentage were used. Significant differences between the two genotypes were found in yields of milk, fat and protein and protein percentage (P<0·01). CC cows produced more milk than CT (5418·68 v. 5149·54 kg). Protein content was higher in milk from CC compared with CT genotypes (3·40 v. 3·21%). No significant difference was found in fat content. Owing to the low number of TT cows in the studied population, this genotype was not included in the statistical analysis; in fact the number of TT cows was not enough to provide an accurate statistical analysis. Although more studies are needed to better clarify the role of this SNP on production traits, STAT5A/AvaI polymorphism appears to be a promising indirect marker to improve milk production traits in cattle.

The intestinal ecosystem contains a normal microbiota, non-immune cells and immune cells associated with the intestinal mucosa. The mechanisms involved in the modulation of the gut immune system by probiotics are not yet completely understood. The present work studies the effect of a fermented milk containing probiotic bacterium Lactobacillus (Lb.) casei DN114001 on different parameters of the gut immune system involved with the nonspecific, innate and adaptive response. BALB/c mice received the probiotic bacterium Lb. casei DN114001 or the probiotic fermented milk (PFM). The interaction of the probiotic bacteria with the intestine was studied by electron and fluorescence microscopy. The immunological parameters were studied in the intestinal tissue and in the supernatant of intestinal cells (IC). Results showed that the probiotic bacterium interact with the IC. The whole bacterium or its fragments make contact with the gut associated immune cells. The PFM stimulated the IC with IL-6 release, as well as cells related to the nonspecific barrier and with the immune cells associated with the gut. This last activity was observed through the increase in the population of different immune cells: T lymphocytes and IgA+ B lymphocytes, and by the expression of cell markers related to both innate and adaptive response (macrophages). PFM was also able to activate the enzyme calcineurine responsible for the activation of the transcriptional factor NFAT. PFM induced mucosal immune stimulation reinforcing the non-specific barrier and modulating the innate immune response in the gut, maintaining the intestinal homeostasis.

Flaxseed meal (FM) is rich in the plant lignan secoisolariciresinol diglucoside (SDG) which is converted to the mammalian lignans enterodiol and enterolactone (EL) by ruminal microbiota. Feeding FM to dairy cows increases linearly EL concentration in milk but enterodiol is not detected. The objectives of the study were to determine the length of time to obtain peak EL concentration in the milk of dairy cows fed 20% FM and the length of time to return to EL baseline level in milk when cows are switched from high to low intake of flax SDG. A total of 12 multiparous lactating Holstein cows were assigned randomly to one of two feeding regimens: the control (CO) diet was fed for 6 weeks or the FM diet was fed from week 0 to 3 inclusive and then cows were switched to the control diet from week 3 to 6 inclusive. Milk samples were taken weekly for EL analysis. There was a significant interaction between feeding regimen and week for milk concentration of EL as a result of higher concentration of EL from week 1 to 3 for cows on the FM regimen compared with those on the CO regimen. Concentrations of milk EL on the FM regimen maintained uniform high levels from week 1 to 3 and they decreased significantly from week 3 to 4 when the CO diet was reintroduced in week 3. This study suggests that the conversion of SDG to the mammalian lignan EL and the transfer of EL to the mammary gland are well established after one week of feeding 20% FM in the diet of dairy cows and that milk concentration of EL returns to baseline level after one week of FM deprivation.

Interactions between inflammatory cytokines and plasminogen (Pg) activation system on immune cells are yet to be established. In previous studies we reported a somatic cell-associated elevation of proteolytic activity in mammary secretion of drying-off goats and cows. The purposes of the present study were to examine the role of TNF-α in polymorphonuclear neutrophil (PMN)-associated Pg activation, and the significance of this activation pathway for overall plasmin (Pm) activity in mammary secretion of drying-off cows. Results of experiments in vitro showed that the spontaneous Pg activation observed on fresh preparations of bovine blood PMN was completely blocked by anti bovine TNF-α antibody, and was further up-regulated by exogenous bovine TNF-α. Monitoring the parameters of mammary secretion of drying-off cows revealed that both somatic cell counts and differential PMN ratio was significantly elevated at weeks 1, 2 and 3 of milk stasis. Nevertheless, specific activity of soluble Pm in mammary secretion increased and the level of 17-kDa TNF-α decreased immediately following milk stasis. Iimmunoblotting revealed that although both 26-kDa pro-TNF-α and 17-kDa TNF-α were consistently present in somatic cells of mammary secretion collected at weeks 0, 1, 2 and 3 of milk stasis, only 26-kDa pro-TNF-α was present in somatic cells of milk during lactation. In-vitro assay indicated that cell-free mammary secretion of drying-off cows exerted no Pg activation bioactivity towards bovine blood PMN. Altogether, the current study suggests the existence of an active TNF-α-Pg-Pm autocrine/paracrine loop on the massively infiltrated PMN inside udders of drying-off cows, which involves extensive binding and internalization of 17-kDa TNF-α on PMN and consequently activation of Pg, resulting in high Pm activity and low 17-kDa TNF-α level in mammary secretion. These coordinated mechanisms may play a role in the defence of drying-off mammary gland.

This study aimed to evaluate the effect of milk fermented with Lactobacillus acidophilus 145 and Bifidobacterium longum BB536 on plasma lipids in a sample of adult women. A double-blind, placebo controlled, cross-over study (two periods of four weeks each separated by a 1-week washout period) was performed in 34 women, aged between 18 and 65 years. Group A consumed 125 g fermented milk three times a day for the first 4 weeks while group B consumed regular yoghurt under the same conditions. (Groups A and B switched products for the second treatment period). Women taking the test product with a baseline total cholesterol above 190 mg/dl showed a significant reduction in LDL cholesterol. HDL cholesterol was also reduced by the test product. We conclude that the fermented milk may help to reduce LDL levels in hypercholesterolemic adult women.

Four ruminally fistulated multiparous Holstein cows were assigned to a 4×4 Latin square design with a 2×2 factorial arrangement of treatments to study the effects of dietary supplementation of monensin and flaxseed hulls on ruminal and milk concentration of the mammalian lignan enterolactone (EL) and ruminal and faecal activity of β-glucuronidase. The hypothesis was that monensin supplementation has no effect on the incorporation of EL into milk when cows are fed flaxseed hulls. Treatments were: 1) control, neither flaxseed hulls nor monensin (CO); 2) diet containing (dry matter basis) 20% flaxseed hulls (FH); 3) diet with monensin (16 mg/kg of dry matter; MO); 4) diet containing 20% (dry matter basis) flaxseed hulls and 16 mg/kg monensin (HM). Intake of dry matter was higher for CO and MO than for FH and HM and monensin had no effect. Milk production decreased in cows fed flaxseed hulls while monensin had no effect. Production of 4% fat-corrected milk and concentrations of milk fat, lactose, urea N, and total solids were similar among treatments. Although there was a decrease in ruminal activity of β-glucuronidase when feeding flaxseed hulls, the metabolism of plant into mammalian lignans may be increased as shown by enhanced concentration of EL in the rumen and milk. Supplementation with flaxseed hulls then may contribute to favourably change milk composition for better human health by enhancing mammalian lignan EL concentration.

The aim of the present study was to evaluate relationships between the presence of the two major bovine acute phase proteins haptoglobin (Hp) and serum amyloid A (SAA) and raw milk quality parameters in bulk tank milk samples. Hp and SAA have been suggested as specific markers of mastitis but recently also as markers for raw milk quality. Since mastitis has detrimental effects on milk quality, it is important to investigate whether the presence of Hp or SAA indicates such changes in the composition and properties of the milk. Bulk tank milk samples (n=91) were analysed for Hp, SAA, total protein, casein, whey protein, proteolysis, fat, lactose, somatic cell count and coagulating properties. Samples with detectable levels of Hp had lower casein content, casein number and lactose content, but higher proteolysis than samples without Hp. Samples with detectable levels of SAA had lower casein number and lactose content, but higher whey protein content than samples without SAA. The presence of acute phase proteins in bulk tank milk is suggested as an indicator for unfavourable changes in the milk composition, e.g. protein quality, due to udder health disturbances, with economical implications for the dairy industry.

Bulk milk somatic cell count (BMSCC) is a frequently used parameter to estimate the subclinical mastitis prevalence in a dairy herd, but it often differs considerably from the average SCC of all individual cows in milk. In this study, first the sampling variation was determined on 53 dairy farms with a BMSCC ranging from 56 000 to 441 000 cells/ml by collecting five samples on each farm of the same bulk tank. The average absolute sampling variation ranged from 1800 to 19 800 cells/ml. To what extent BMSCC represents all lactating cows was evaluated in another 246 farms by comparing BMSCC to the average herd SCC corrected for milk yield (CHSCC), after the difference was corrected for the sampling variation of BMSCC. On average BMSCC was 49 000 cells/ml lower than CHSCC, ranging from −10 000 cells/ml to 182 000 cells/ml, while the difference increased with an increasing BMSCC. Subsequently, management practices associated with existing differences were identified. Farms with a small (<20%) difference between BMSCC and CHSCC administered intramuscular antibiotics for the treatment of clinical mastitis more often, used the high SCC history when cows were dried off more frequently and had a higher number of treatments per clinical mastitis case compared with farms with a large (⩾20%) difference. Farms feeding high-SCC milk or milk with antibiotic residues to calves were 2·4-times more likely to have a large difference. Although sampling variation influences the differences between BMSCC and CHSCC, the remaining difference is still important and should be considered when BMSCC is used to review the average herd SCC and the subclinical mastitis prevalence.

Consumption of whole milk and related dairy products has decreased considerably as a result of negative aspects associated with the consumption of saturated fats. The main difference between the composition of goat milk and cow milk concerns the composition of the fat, that of goat milk containing a larger proportion of medium-chain triglycerides. The metabolic utilization of these compounds is fundamentally oriented towards their use as sources of energy, and they may even contribute to the synthesis of proteins. This study was carried out, using 40 rats at weaning, in order to determine whether, on the basis of their fat and protein composition, there is any difference between the nutritional utilization of the N and the energy from goat and cow milk. Eight animals were killed on arrival at the laboratory, and the rest were divided into four groups of eight animals and killed at the end of the experiment. Each group was given a different diet: diet 1 contained fat and protein from goat milk; diet 2 had fat from cow milk and protein from goat milk; diet 3 had fat from goat milk and protein from cow milk; diet 4 had fat and protein from cow milk. The animals were allowed to feed ad libitum for 30 d and a balance assay was performed during the final 7 d to determine N and energy utilization. At the same time and by the comparative slaughter method, the protein and fat deposition for each group was established. It was concluded that goat milk protein is more digestible than that of cow milk. Moreover, the metabolic utilization of digestible N was found to be dependent on the sources of both the protein and the fat in the diet; a higher degree of utilization was recorded for the digestible N obtained using diets with protein or fat from goat milk. Consumption of diets with goat milk fat led to a lower level of thermogenesis associated with protein oxidation and a higher one for that associated with fat oxidation, which in turn implied a protein-sparing effect of the goat milk fat. These results should be taken into account when deciding upon the type of goat milk to be used (whole, skim or semi-skim), in accordance with the dairy product to be produced from this milk.