| 1. |
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| 2. |
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| 3. |
- Agenäs, Sigrid, et al.
(författare)
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The effect of 17 beta-estradiol on lactose in plasma and urine in dairy cows in late lactation
- 2019
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 86, s. 188-192
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the effect of 17 beta-estradiol on mammary tight junctions in cows in late lactation. The experiment included five non-pregnant cows around day 290 in lactation. The cows received injections of 17 beta-estradiol for six days. The effect of exogenous 17 beta-estradiol on milk yield, milk composition and lactose in plasma and lactose in urine was investigated before, during and after the treatment. Milk yield decreased after 17 beta-estradiol injections and lactose in plasma and urine increased, showing an effect on the integrity of the mammary tight junctions. However, there was a delay between hormone injections and the decrease in milk yield and opening of tight junctions, indicating that other factors are involved. A high correlation between lactose in urine and blood plasma was found. More than 30% of the total lactose production was lost in urine after 17 beta-estradiol treatment.
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| 4. |
- Anglart, Dorota, et al.
(författare)
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Modeling cow somatic cell count using sensor data as input to generalized additive models
- 2020
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 87, s. 282-289
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Tidskriftsartikel (refereegranskat)abstract
- This research paper presents a study investigating if sensor data from an automatic milking rotary could be used to model cow somatic cell count (composite milk SCC: CMSCC). CMSCC is valuable for udder health monitoring and individual cow udder health surveillance could be improved by predicting CMSCC between routine samplings. Data regularly recorded in the automatic milking rotary, in one German dairy herd, were collected for analysis. The cows (Holstein-Friesian,n= 372) were milked twice daily and sampled once weekly in afternoon milkings for 8 weeks for CMSCC. From the potential independent variables, including quarter conductivity, milk flow, blood in milk, kick-offs, not milked quarters and incomplete milkings, new variables that combined quarter data were created. Past period records, i.e. lags, of up to seven days before the actual CMSCC sampling event were added in the dataset to investigate if they were of use in modeling the cell count. Univariable generalized additive models (GAM) were used to screen the data to select potential independent variables. Furthermore, several multivariable GAM were fitted in order to compare the importance of the potential independent variables and to explore how the model performance would be affected by using data from various number of days before the CMSCC sampling event. The result of the model selection showed that the best explanation of CMSCC was provided by the model incorporating all significant variables from the variable screening for the seven preceding days, including the day of the CMSCC sampling event. However, using data from only three days before the CMSCC sampling event is suggested to be sufficient to model CMSCC. Variables combining conductivity quarter data, together with quarter conductivity, are suggested to be important in describing CMSCC. We conclude that CMSCC can be modeled with a high degree of explanation using the information routinely recorded by the milking robot.
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| 5. |
- Boqvist, Sofia
(författare)
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Occurrence and aetiology of subclinical mastitis in water buffalo in Bangladesh
- 2021
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 88, s. 314-320
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Tidskriftsartikel (refereegranskat)abstract
- Subclinical mastitis (SCM) in water buffalo is a production disease associated with decreased milk yield and impaired milk quality and safety. Water buffalo is an important livestock species in Bangladesh, but information about the occurrence and aetiology of SCM in this species is scarce. A cross-sectional study was conducted as part of the Udder Health Bangladesh Programme to (i) determine the occurrence of SCM and bulk milk somatic cell count (SCC) in water buffalo in Bangladesh, (ii) identify pathogens causing SCM and (iii) evaluate penicillin resistance in isolated staphylococci strains. Sixteen buffalo farms in the Bagerhat and Noakhali regions of Bangladesh were selected for study and a bulk milk sample was collected from each farm. In addition, 299 udder quarter milk samples were collected from 76 animals. The bulk milk samples were assessed by direct SCC and the quarter milk samples by California mastitis test (CMT). The occurrence of SCM calculated at quarter and animal level was 42.5 and 81.6%, respectively. Milk samples from 108 CMT-positive quarters in 48 animals and 38 randomly selected CMT-negative quarters in 24 animals were investigated using bacteriological culture. Estimated mean bulk milk SCC was 195 000 cells/ml milk (range 47 000- 587 000 cells/ml milk). On culture, estimated quarter-level intramammary infection (IMI) was 40.4%. The identity of isolated bacteria was confirmed by MALDI-TOF mass spectrometry. Non-aureus staphylococci (NAS) were the most common pathogens (24.7%) and, among 36 NAS tested, 36.1% were resistant to penicillin. Thus there was high occurrence of SCM on the study farms, with relatively high penicillin resistance in NAS. Further studies are needed to identify underlying risk factors and develop an udder health control strategy for water buffalo in Bangladesh.
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| 6. |
- Camussone, C. M., et al.
(författare)
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Immune response of heifers against a Staphylococcus aureus CP5 whole cell vaccine formulated with ISCOMATRIX™ adjuvant
- 2013
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Ingår i: Journal of dairy research (Print). - 0022-0299 .- 1469-7629. ; 80:1, s. 72-80
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Tidskriftsartikel (refereegranskat)abstract
- The shortcomings of Staphylococcus aureus vaccines to control bovine mastitis have been attributed to insufficient capacity of the vaccines to induce opsonizing antibodies and to stimulate cellular immune responses. Types of antigen, administration route and adjuvant used in a vaccine formulation have been identified as critical factors for the development of opsonic antibodies. Current commercially available vaccines for Staph. aureus bovine mastitis control are formulated with Al(OH)3 and oil-based adjuvants. The aim of this study was to evaluate the immune response of heifers immunized with a Staph. aureus CP5 whole cell vaccine formulated either with Al(OH)3 or ISCOMATRIX ™. Twenty primigravid Holstein dairy heifers in the last trimester of gestation were immunized either with a vaccine formulated with ISCOMATRIX™ (n = 6), Al(OH)3 (n = 7), or saline solution (placebo) (n = 7). Immunization was carried out 38 and 10 d before calving. Heifers vaccinated with Staph. aureus adjuvanted with ISCOMATRIX™ responded with significantly higher levels of anti-bacterin and anti-CP5 IgG and IgG2 in sera than animals in the Al(OH)3 or control groups. Animals in the ISCOMATRIX™ group responded with significantly higher anti-bacterin specific IgG in whey than animals in the Al(OH)3 and control groups, detected from the first week post calving until 60 d of lactation. Sera from animals inoculated with Staph. aureus in ISCOMATRIX™, obtained 7 d post partum, significantly increased both the number of neutrophils ingesting bacteria and the number of bacteria being ingested by the neutrophils, compared with sera obtained from heifers vaccinated with Al(OH)3 or non-vaccinated controls. These features coupled to safety of the ISCOMATRIX™ formulation, warrant additional studies.
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| 7. |
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| 8. |
- De Oliveira, Daiana
(författare)
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Methodological terminology and definitions for research and discussion of cow-calf contact systems
- 2020
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 87, s. 108-114
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Tidskriftsartikel (refereegranskat)abstract
- Due to increasing public concern regarding separation of the dairy cow and calf within the first days after birth, alternative systems, where cows and calves stay in contact for an extended period, are receiving increasing interest from a broad array of researchers and other stakeholders. With more research in the area, there is a risk of inconsistencies emerging in the use of terminology. To create a better consensus in further discussions, the aim of this Research Reflection is to provide definitions and propose a common terminology for cow-calf contact in dairy production. We also suggest definitions for various systems allowing cow-calf contact and describe the distinct phases of cow-calf contact systems.
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| 9. |
- De Oliveira, Daiana
(författare)
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Methodology for experimental and observational animal studies in cow-calf contact systems
- 2020
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 87, s. 115-121
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Tidskriftsartikel (refereegranskat)abstract
- In this Research Reflection we describe a common standpoint on suitable methodology for controlled and observational studies in cow-calf contact systems in dairy production. Different methods to assess behaviour, health and production in cow-calf contact systems are outlined. Knowledge and experience from researchers working in this field supplement scientific literature whenever relevant. Specific methods including study design, early behaviour of cow and calf, social behaviour relevant to cow-calf contact systems, human-animal relationships and aspects related to management (milking, weaning and separation, health) are reviewed, and recommendations formed. We expect that this paper can contribute to a better understanding of the complexity of cow-calf contact systems and help to advance research in this area of dairy production.
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| 10. |
- De Oliveira, Daiana
(författare)
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Methodology for studying human attitudes and behaviour to cow-calf contact systems
- 2020
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 87, s. 122-127
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Tidskriftsartikel (refereegranskat)abstract
- This position paper describes a common stand on methodology of human attitudes and behaviour that is suitable to use in studies regarding cow-calf contact (CCC) in dairy production, in order to create a common knowledge base and foundation for future recommendations of CCC systems. We describe how different quantitative and qualitative methods can be used to study human attitudes to CCC as well as farmer or consumer behaviour. We aim to contribute to a better understanding of the available methods, and hope that this paper can be used as a guideline for future studies in this area.
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| 11. |
- Fall, Nils, et al.
(författare)
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Fatty acid content, vitamins and selenium in bulk tank milk from organic and conventional Swedish dairy herds during the indoor season
- 2011
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 78, s. 287-292
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Tidskriftsartikel (refereegranskat)abstract
- Fatty acids, vitamins and minerals in milk are important for the human consumer, the calf and the cow. Studies indicate that milk fromorganic and conventional dairy herds may differ in these aspects. The aim of this study was therefore to investigate whether there are differences in the fatty acid composition and concentration of vitamins and selenium in milk between organic and conventional herds in Sweden. Bulk tank milk was sampled in 18 organic and 19 conventional dairy herds on three occasions during the indoor season 2005–2006. Herd characteristics were collected by questionnaires and from the official milk recording scheme. Multivariable linear mixed models were used to evaluate the associations between milk composition and type of herd, while adjusting for potential confounders and the repeated observations within herd. In addition to management type, variables included in the initial models were housing type, milk fat content, herd size, average milk yield and time on pasture during summer. The median concentration of conjugated linoleic fatty acids (CLA) was 0·63% in organic compared with 0·48% in conventional herds, the content of total n-3 fatty acids was 1·44%and 1·04% in organic and conventional milk, respectively, and the content of total n-6 fatty acids was 2·72% and 2·20% in organic and conventional milk, respectively. The multivariable regression models indicated significantly higher concentrations of CLA, total n-3 and n-6 fatty acids in organic milk and a more desirable ratio of n-6 to n-3 fatty acids, for the human consumer, in organic milk. The multivariable models did not demonstrate any differences in retinol, α-tocopherol, β-carotene or selenium concentrations between systems. Median concentrations of α-tocopherol were 0·80 μg/ml in organic and 0·88 μg/ml in conventional milk, while for β-carotene the median concentrations were 0·19 and 0·18 μg/ml, respectively; for retinol, the median concentration was 0·32 μg/ml in both groups; the median concentrations of selenium were 13·0 and 13·5 μg/kg, respectively, for organic and conventional systems
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| 12. |
- Fall, Nils, et al.
(författare)
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Milk yield, udder health and reproductive performance in Swedish organic and conventional dairy herds
- 2009
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 76, s. 402-410
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Tidskriftsartikel (refereegranskat)abstract
- 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
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| 13. |
- Ferneborg, Sabine, et al.
(författare)
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Effect of increased milking frequency and residual milk removal on milk production and milk fatty acid composition in lactating cows
- 2017
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 84, s. 453-463
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Tidskriftsartikel (refereegranskat)abstract
- It has been well established that milk yield is affected both by milking frequency and due to the removal of residual milk, but the influence of a combination of these factors is unclear. In this study, four mid-lactation cows were used in a 4 x 4 Latin square design to test the hypothesis that the effects of more frequent milking and residual milk removal on milk yield and composition are additive and alter milk fatty acid composition. Treatments comprised two or four times daily milking in combination with (or without) residual milk removal over a 96 h interval preceded by a 2 d pretreatment period and followed by a 8 d washout in each 14 d experimental period. Milk was sampled at each milking for the analysis of gross composition and SCC. Samples of available and residual milk collected on the last milking during each treatment period were collected and submitted for fatty acid composition analysis. Increases in milking frequency and residual milk removal alone or in combination had no effect on milk yield or on the secretion of lactose and protein in milk. However, residual milk removal during more frequent milking increased milk fat yield. Milking treatments had no major influence on the fatty acid composition of available milk, but resulted in rather small changes in the relative abundance of specific fatty acids, with no evidence that the additive effects of treatments were due to higher utilisation of preformed fatty acids relative to fatty acid synthesis de novo. For all treatments, fat composition of available and residual milk was rather similar indicating a highly uniform fatty acid composition of milk fat within the mammary gland.
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| 14. |
- Ferneborg, Sabine, et al.
(författare)
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Effects of automatic cluster removal and feeding during milking on milking efficiency, milk yield and milk fat quality
- 2016
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 83, s. 180-187
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Tidskriftsartikel (refereegranskat)abstract
- In order to increase milking efficiency, the effects of two different cluster take-off levels (200 and 800 g/min) and feeding vs. not feeding during milking were tested in a Latin square design study including 32 cows. Milk yield, milking time, milk flow and milking interval were measured and milk samples were analysed for gross composition, sodium and potassium concentration, free fatty acid (FFA) content, milk fat globule (MFG) size, MFG membrane (MFGM) material and fatty acid composition. Residual milk was harvested to evaluate udder emptying. Increasing the take-off level from 200 to 800 g/min at the whole udder level decreased milking time and increased harvest flow. Udder emptying decreased slightly, but there were no effects on milk yield, FFA content or MFGM. There were interactive effects of take-off level and feeding during milking on content of fatty acids C4:0, C6:0, C16:0, C18:3(n-3) and C20:0. Feeding during milking increased milk yield per day and decreased milking interval. Sodium and potassium concentrations in milk were unaffected by treatments, indicating no loss of tight junction integrity. From these results, it is clear that feeding during milking should be used to increase milk yield and improve milking efficiency, regardless of take-off level used, and that the effect of feeding is more pronounced when a low take-off level is used. Feeding seemed to counteract the effects of the low take-off level on milking time and milking interval. Low take-off levels can therefore be used in combination with feeding.
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| 15. |
- Ferneborg, Sabine, et al.
(författare)
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The effect of pulsation ratio on teat condition, milk somatic cell count and productivity in dairy cows in automatic milking
- 2015
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 82, s. 453-459
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Tidskriftsartikel (refereegranskat)abstract
- The pulsation ratio of a milking machine affects milk flow and milking time, and has also been reported to influence teat condition and milk somatic cell count (SCC). However, most studies comparing pulsation ratios have been performed on conventional cluster milking (whole-udder level), where effects such as deteriorated teat end condition and increased milk SCC are likely to be caused by over-milking on teats that are emptied faster than the other teats. When the teat cups are detached from each udder quarter separately which can be done in automatic milking systems (AMS), the risk of over-milking, especially in front teats, may be significantly reduced. This study investigated the effects of pulsation ratio on teat end condition, milk SCC, milk yield, milking time and milk flow in an automatic milking system where each udder quarter is milked separately. In total, 356 cows on five commercial farms were included in a split-udder design experiment comparing three pulsation ratios (60:40, 70:30 and 75:25) with the standard pulsation ratio (65:35) during 6 weeks. Pulsation rate was 60 cycles/min and vacuum level 46 kPa. The 70:30 and 75:25 ratios increased peak and average milk flow and the machine-on time was shorter with 75:25, while both peak and average milk flows were lower and machine-on time was longer with the 60:40 ratio. No negative effects on teat condition or milk SCC were observed with any of the pulsation ratios applied during the study. Thus it is possible that increased pulsation ratio can be used to increase milking efficiency in AMS where quarter milking is applied.
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| 16. |
- Hallén, Elin, et al.
(författare)
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Casein retention in curd and loss of casein into whey at chymosin-induced coagulation of milk
- 2010
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 77, s. 71-76
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Tidskriftsartikel (refereegranskat)abstract
- Impact of milk protein composition on casein (CN) retention in curd during the milk coagulation process was studied using a model cheese making system. Individual milk samples from 110 cows in mid lactation of the Swedish Red and Swedish Holstein breeds with known genotypes of beta-casein, kappa-casein and beta-lactoglobulin were defatted, coagulated with chymosin, subjected to syneresis and subsequent pressing simulated by centrifugation. The results indicated that)c-casein concentration of milk plays an important role in the curd formation process and initial syneresis (whey after cutting), whereas an increased CN ratio was associated with less casein in whey after simulated pressing. Increased kappa-casein concentration of milk also characterized the milk samples with no measurable loss of casein in whey, compared with milk samples with casein lost in whey, both after cutting and after simulated pressing. Concentrations of alpha(s)1-casein, beta-casein, and total casein in milk were positively associated with fresh curd yield, which showed a strong correlation with amount of casein retained in curd. No effect of protein genotype on fresh curd yield or casein in whey was found. The beta-lactoglobulin BB genotype was associated with increased casein retention in curd, most likely due to the association of this genotype with CN ratio.
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| 17. |
- Hallén, Elin, et al.
(författare)
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Composition of poorly and non-coagulating bovine milk and effect of calcium addition
- 2010
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 77, s. 398-403
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Tidskriftsartikel (refereegranskat)abstract
- Ninety-nine individual milk samples from 37 cows in lactation week 10-35, selected for producing well or poorly/non-coagulating milk, were compared regarding protein composition, total calcium content, casein micelle size, pH, and coagulating properties after addition of 0.05% CaCl(2). The results showed that a low kappa-casein concentration in milk was a risk factor for non-coagulation. CaCl(2) addition improved coagulating properties (coagulation time, curd firmness) of nearly all samples and eliminated differences between poorly/non-coagulating and well-coagulating milk, particularly regarding curd firmness. A second, independent data set with 18 non-coagulating or well-coagulating milk samples were analysed for protein composition, where indications of a similar association with kappa-casein was observed.
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| 18. |
- Högberg, Madeleine, et al.
(författare)
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Growth rate and behaviour in separated, partially separated or non-separated kids and the corresponding milk production of their mothers
- 2021
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 88, s. 381-387
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Tidskriftsartikel (refereegranskat)abstract
- We address the hypothesis that keeping kids and mothers together would have positive effects on the milk composition of the mother and the behaviour of the kids. Kids were either permanently separated (SEP), daily separated between 7.30 and 15 h (DAY-SEP) or kept with mothers 24 h/d (NON-SEP). The NON-SEP kids were only allowed to suckle one teat. All kids had similar growth rate throughout the study (lactation days 5–70). DAY-SEP kids spent 24% of their time with their mother at both ages. NON-SEP spent only 15% of the time with their mothers at 2 weeks of age and this increased to 28% at 2 months of age. NON-SEP kids showed more hiding behaviour at 2 weeks and SEP were more active alone, at both 2 weeks and 2 months, compared to the other treatments. The mean available milk yield and fat concentration were higher in DAY-SEP goats (2420 g ± 119 g and 4.9 ± 0.1%) compared with NON-SEP goats (2149 ± 79 g and 4.4 ± 0.1%). There were no differences between DAY-SEP and NON-SEP goats in total protein, lactose, or casein concentrations. Based on these data it was estimated that 7.1 kg milk was needed to produce 1 kg semi-hard cheese in DAY-SEP goats and 7.5 kg in NON-SEP goats, respectively. When comparing milk yield and composition between udder halves, the milk yield was, as expected, higher from the machine milked teat than from the suckled one in the NON-SEP goats but there was no difference between right and left udder halves in DAY-SEP goats. Milk fat concentration varied between teats at morning and afternoon milkings in NON-SEP goats, but there was no difference in milk fat between udder-halves in DAY-SEP goats. In conclusion, the kid growth rate was similar in all treatments, however, an altered behaviour was seen in permanently separated kids (SEP). The results show that it is possible to have a high milk yield and fat concentration with one kid together with the dam.
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| 19. |
- Högberg, Madeleine, et al.
(författare)
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Milk processing quality of suckled/milked goats: effects of milk accumulation interval and milking regime
- 2016
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 83, s. 173-179
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Tidskriftsartikel (refereegranskat)abstract
- Milk with a high concentration of fat and casein is required for cheese production, and these components have a major impact for both quality and yield of the curd. Recent observations have shown that suckling can elevate milk fat concentration in goats and our aim was therefore to check the hypothesis that animal welfare and cheese-processing properties of goat milk could be optimised by appropriate management of suckled/milked goats. Twelve Swedish dairy goats were kept together with one kid each in 4 different mixed management-systems (milking combined with partial suckling) in a cross-over design. Two milk accumulation intervals were tested; Short = dams and kids were together for 16 h (T16) and Long =; dams and kids were together for 8 h (T8 h). In addition, two milking regimes were used; Suckled Before Milking = S and Milked Before Suckling = M. Milk accumulation interval referred to how long dams and kids were separated. The milk yield available for processing (milk offtake), was weighed and analysed from each milking occasion and the suckled milk yield was estimated by a weigh-suckle-weigh method (WSW) in combination with observing the suckling behaviour during the free suckling periods. Milking managements, such as 'suckling before milking (S)', increased milk fat concentration compared to milking before suckling (M) and 'Short accumulation treatments (T16)' gave higher milk fat, casein concentration and individual curd yield (%) compared to the 'Long accumulation treatment (T8)'. The total individual curd yield (g) was the same despite treatment, but the animal welfare was most likely higher in T16 where dams and kids spent more time together.
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| 20. |
- Höjer, Annika, et al.
(författare)
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Proliferative effect of whey from cows' milk varying in phyto-oestrogens in human breast and prostate cancer cells
- 2012
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 79, s. 143-149
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Tidskriftsartikel (refereegranskat)abstract
- Intake of dietary phyto-oestrogens has received a great deal of attention owing to their potential influence on hormone-sensitive cancers such as breast and prostate cancer. Cows' milk contains phyto-oestrogens and the content varies according to the composition of the feed and the type and amount of legumes used. In this study we evaluated the proliferative effect of milk (whey) with different phyto-oestrogen content in human breast (MCF-7) and prostate cancer cells (PC-3). Milk was obtained from cows fed either a birdsfoot trefoil-timothy silage based ration (B1) or two different red clover silage based diets (R1 and R2) resulting in total phyto-oestrogen contents of 403, 1659 and 1434 ng/ml for the B1, R1 and R2 diets, respectively. Whey was produced from the milk and added to cell culture medium in concentrations up to 10% for MCF-7 cells and 5% for PC-3 cells. Cell proliferation was measured fluorometrically after 7 d for MCF-7 cells and 5 d for PC-3 cells. There was no significant difference in the proliferative effect of whey from the different dietary treatments at any of the whey concentrations tested. An anti-proliferative effect (P<0.01) of 5 and 10% whey was seen when tested in the presence of 10 pM oestradiol in the medium. This effect was independent of dietary treatment of cows. Whey induced a significant (P<0.01) proliferative response in PC-3 cells independent of dietary treatment. Purified equol in concentrations similar to equol concentrations in milk decreased PC-3 cell proliferation, and therefore the stimulatory effect of whey in PC-3 cells is believed to be mediated by other bioactives than equol. In conclusion, our results suggest that using whey in these proliferation assays, it was not possible to discriminate between milk with high or low levels of phyto-oestrogens.
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| 21. |
- Johansson, Monika, et al.
(författare)
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Composition and enzymatic activity in bulk milk from dairy farms with conventional or robotic milking systems
- 2017
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 84, s. 154-158
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Tidskriftsartikel (refereegranskat)abstract
- The objective of the studies reported in this research communication was to investigate differences in composition and enzymatic activities in bulk milk samples provided from Swedish dairy farms with different management systems, i.e. automated (AMS) and conventional milking systems (CMS). A bulk milk sample was collected from each of 104 dairy farms, 51 using AMS and 53 using CMS, located in the same geographical region. Sampling took place within two consecutive days during the indoor period (October). Milk samples were analysed for contents of total fat and protein, free fatty acids (FFA), caseins and whey proteins, somatic cell count (SCC), pH, plasmin and plasminogen derived activities, and total proteolysis. Our results showed a lower protein content and higher SCC in bulk milk from AMS herds compared with milk from CMS herds. Plasmin, plasminogen and total plasmin/plasminogen derived activities were lower in milk from AMS herds but despite this, total casein and the beta-casein fraction as % of total protein were lower in milk from AMS herds than in milk from herds using CMS. Total proteolysis was higher in milk from AMS herds, suggesting that other proteases than plasmin, e.g. cellular and bacterial proteases, contributed to the degradation of casein. This was supported by a positive correlation between SCC and total proteolysis (P < 0.01), as well as a negative correlation between total proteolysis and beta-casein fraction (P < 0.05). In conclusion, comparing the quality of bulk milk from commercial dairy herds using AMS and CMS, respectively, several differences were observed, suggesting a significant effect from management system.
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| 22. |
- Juhlin, Jessica, et al.
(författare)
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Relative impact of alpha-tocopherol, copper and fatty acid composition on the occurrence of oxidized milk flavour
- 2010
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 77, s. 302-309
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Tidskriftsartikel (refereegranskat)abstract
- The oxidative process in milk fat, resulting in spontaneous oxidized off-flavour (SOF), is commonly assumed to depend on contents of pro- and antioxidants in milk and availability of fatty acids acting as their substrate. An important antioxidant in milk is alpha-tocopherol whereas the most potent prooxidant is the metal ion copper. The separate effects of alpha-tocopherol, copper, and milk fatty acid profile, and their combined effect on SOF development were examined in milk from 44 multiparous cows fed different roughage types and different amounts of dietary, unsaturated fat. A clear association between concentrations of copper and poly-unsaturated fatty acids in milk and the risk for developing SOF was found. Heritability estimates suggest that occurrence of SOF is partly under genetic control which indicates that milk quality may be compromised if breeding bulls are selected that carry genotypes predisposing for milk prone to develop SOF.
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| 23. |
- Lindqvist, Hanna, et al.
(författare)
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Supplementing dairy steers and organically managed dairy cows with synthetic vitamin D-3 is unnecessary at pasture during exposure to summer sunlight
- 2009
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 76, s. 372-378
-
Tidskriftsartikel (refereegranskat)abstract
- Use of synthetic feed additives, including synthetic vitamin D-3 (D-3) 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 enclogenous production of D-3 from summer sunlight as a source of D-3. To examine the impact of supplemental synthetic D-3 from the feed on the D-3 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 D-3 in the feed and one not supplemented with synthetic D-3. Vitamin D-3 status of the animals was assessed by measuring the concentration of the liver-derived 25-hydroxyvitamin D-3 (25OHD(3)) in plasma. Results showed that 25OHD(3) 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 25OHD(3) 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 D-3 since unsupplemented and supplemented animals had the same D-3 status at this time of year. In all cows summer concentrations of 25OHD(3) were 20-25 ng/ml and in all steers 40-50 ng/ml plasma. The decrease in vitamin D-3 status during winter indicates that cows and steers are able to store D-3 only to a limited extent. The results also show that cows or steers fed supplemental D-3 according to Swedish recommendation throughout the year are not able to maintain their summer value of 25OHD(3) during winter.
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| 24. |
- Mohamad Salleh, Suraya Binti, et al.
(författare)
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Using machine learning methods to predict dry matter intake from milk mid-infrared spectroscopy data on Swedish dairy cattle
- 2023
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 90, s. 5-8
-
Tidskriftsartikel (refereegranskat)abstract
- In this research communication we compare three different approaches for developing dry matter intake (DMI) prediction models based on milk mid-infrared spectra (MIRS), using data collected from a research herd over five years. In dairy production, knowledge of individual DMI could be important and useful, but DMI can be difficult and expensive to measure on most commercial farms as cows are commonly group-fed. Instead, this parameter is often estimated based on the age, body weight, stage of lactation and body condition score of the cow. Recently, milk MIRS have also been used as a tool to estimate DMI. There are different methods available to create prediction models from large datasets. The main data used were total DMI calculated as a 3-d average, coupled with milk MIRS data available fortnightly. Data on milk yield and lactation stage parameters were also available for each animal. We compared the performance of three prediction approaches: partial least-squares regression, support vector machine regression and random forest regression. The full milk MIRS alone gave low to moderate prediction accuracy (R-2 = 0.07-0.40), regardless of prediction modelling approach. Adding more variables to the model improved R-2 and decreased the prediction error. Overall, partial least-squares regression proved to be the best method for predicting DMI from milk MIRS data, while MIRS data together with milk yield and concentrate DMI at 3-30 d in milk provided good prediction accuracy (R-2 = 0.52-0.65) regardless of the prediction tool used.
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| 25. |
- Olsson, Kerstin, et al.
(författare)
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Plasma vasopressin and oxytocin concentrations increase simultaneously during suckling in goats
- 2009
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 76, s. 15-19
-
Tidskriftsartikel (refereegranskat)abstract
- Goats are often kept on small farms where they suckle kids and are hand milked for human consumption. Our first objective was to investigate whether vasopressin secretion increases together with oxytocin during hand milking and suckling in seven goats 6-8 weeks after parturition. Four goats suckled and three were hand milked on the first day and the treatments were reversed on the next day. Blood samples were taken via a semi-permanent catheter. Plasma concentrations of vasopressin and oxytocin increased during suckling, but not during hand milking. Plasma cortisol concentration was elevated for 10 min after both treatments. These results initiated a second series in which the objectives were to measure vasopressin and oxytocin concentrations during hand milking in a larger number of goats and to investigate whether the rise in cortisol concentration was due to the experimental conditions or to milking, by adding a no-milking treatment. Nine goats in lactation weeks 4-10 were studied. Heart rate and arterial blood pressure were registered in eight of the goats. Oxytocin concentration did not change during hand milking and the vasopressin concentration was below the detection limit. Heart rate and blood pressure were elevated during milking and for about 10 min thereafter. Cortisol concentration increased after milking, as above. None of the variables changed in the no-milking treatment. This suggests that the rise in cortisol concentration was due to milk excretion and was not a stress reaction. In conclusion, suckling increased plasma concentrations of vasopressin and oxytocin, but hand milking did not. In a mixed system, presence of the kids may be necessary to stimulate release of the peptides and thereby contraction of the myoepithelial cells. However, milk stored in the udder cisterns can be obtained by hand milking without presence of oxytocin or vasopressin.
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| 26. |
- Pettersson, Gunnar, et al.
(författare)
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Relationships between milking frequency, lactation persistency and milk yield in Swedish Red heifers and cows milked in a voluntary attendance automatic milking system
- 2011
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 78, s. 379-384
-
Tidskriftsartikel (refereegranskat)abstract
- A large dataset comprising output from an automatic milking (AM) system between 1999 and 2006 was examined and a total of 172 cow lactation curves and 68 heifer lactation curves were identified for further analysis. Relationships between milking frequency at different stages of lactation and lactation persistency and total lactation yield were determined. Cows had higher peak and total milk yields than heifers, but heifers had higher persistency (defined as the rate of decline in milk yield between days 100 and 300 post calving). Milking frequency did not differ significantly between cows and heifers in early lactation, but thereafter decreased significantly more in cows than in heifers. The effect of milking frequency on yield characteristics was analysed by comparing the highest and lowest quartiles for milking frequency. High milking frequency in early lactation was consistently associated with increased peak yield. High milking frequency averaged across the whole lactation was associated with increased peak yield in both cows and heifers, and with improved lactation persistency in cows only. This resulted in total lactation yield that was 21% greater in the high quartile cows compared with the low.
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| 27. |
- Priyashantha, Hasitha
(författare)
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Harnessing the untapped potential of indigenous cow milk in producing set-type yoghurts: case of Thamankaduwa White and Lankan cattle
- 2022
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 89, s. 419-426
-
Tidskriftsartikel (refereegranskat)abstract
- This research paper assessed textural, microstructural, sensory and colour properties of set-yoghurts produced using milk from two indigenous cattle types, Thamankaduwa White (TW) and Lankan cattle (LC) compared to two generic cattle breeds, Friesian and Jersey. Instrumental texture profile (firmness, adhesiveness, cohesiveness and springiness), colour space (L* a* b*) and scanning electron micrographs of set-yoghurts during 21 d of storage (4 +/- 1 degrees C) were evaluated. Sensory quality attributes were evaluated with 40 untrained panellists using a five-point hedonic scale. Set-yoghurts prepared using indigenous cow milk showed higher (P < 0.05) firmness, cohesiveness and apparent viscosity values compared to those prepared using generic cow milk. As revealed by micrographs, set-yoghurts made from TW milk had lesser and smaller void spaces and a dense protein gel network than gels made from LC and the two generic breeds. The gel network made from Friesian milk showed a comparatively larger porous gel structure and thinner protein strands resulting in a weaker gel than other milk gels. The highest lightness (L*) and yellowness (b*) were observed from set-yoghurt produced from Friesian and LC milk, respectively. Set-yoghurts from TW milk had the highest (P < 0.05) sensory scores for all sensory attributes. The lowest sensory acceptance was recorded in set-yoghurt made from Friesian milk. Thus, milk from TW and LC is likely to be suitable in producing set-yoghurts with superior textural, microstructural and sensory properties, compared to milk from Jersey and Friesian. Our results suggest the merits of using indigenous cow milk in producing set-yoghurts and, thereby, prioritizing the preservation of the genetic pool of these indigenous breeds.
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| 28. |
- Sundberg, Martin, et al.
(författare)
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Cleaning effectiveness of chlorine-free detergents for use on dairy farms
- 2011
-
Ingår i: Journal of dairy research (Print). - 0022-0299 .- 1469-7629. ; 78:1, s. 105-110
-
Tidskriftsartikel (refereegranskat)abstract
- A method for evaluating cleaning effect based on Bacillus cereus spores was developed and tested in a model system designed to resemble actual farm conditions. A test rig with four removable sampling plates was mounted in a milk line. The plates were attached at the end of T-junctions protruding either 15 or 3-times the milk pipe diameter from the main loop to reflect different levels of cleaning difficulty. In each cleaning test, B. cereus spores were applied to the four sampling plates to simulate soil. A series of cleaning tests was conducted at 35, 45, 55 and 65C with six commercial chlorine-free, alkaline detergents; three liquid and three powder-based products. A commercial alkaline detergent with chlorine, a sodium hydroxide solution, a sodium hydroxider/hypochlorite solution and pure water were also tested. Triplicate tests were performed with each cleaning solution, giving a total of 120 cleaning tests. The cleaning effect was evaluated by comparing the number of spores before and after cleaning. At all temperatures, the two chlorine-based cleaning solutions gave significantly greater reductions in B. cereus spores than the chlorine-free products. All six commercial chlorine-free, alkaline detergents generally gave similar cleaning effects, with no differences in the performance of powder-based and liquid forms. The mechanical spore reduction effect with water alone was greater (15-18 log-units) than the additional chemical effect of sodium hydroxide or chlorine-free detergents (05-12 log-units). The chlorine-based solutions had a considerably more powerful chemical effect (2-4 log-units depending on temperature). In general, an increase in cleaning solution temperature up to 55C gave a greater reduction in spores. A further increase to 65C did not improve cleaning effectiveness. © 2010 Proprietors of Journal of Dairy Research.
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| 29. |
- Thulin, Måns, et al.
(författare)
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Increased take-off level in automatic milking systems - effects on milk flow, milk yield and milking efficiency at the quarter level
- 2019
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 86, s. 85-87
-
Tidskriftsartikel (refereegranskat)abstract
- This research communication describes how different detachment levels (0.48, 0.3 and 0.06 kg milk/min) at the quarter-level affect milk flow profiles and overall milking efficiency in automatic milking systems. We hypothesized a higher detachment level would result in greater mean flow rates without affecting the volume of harvested milk per cow during 24 h compared to lower detachment levels. The data suggest milk flow decreased to a rate below the overmilking limit within the 6-s delay time required for termination in all treatments, but the duration of overmilking was shorter for the greatest detachment level compared to the other treatments. We conclude that setting a detachment level at a greater milk flow rate reduces the duration of overmilking without affecting the amount of milk harvested when applied to cows in mid-lactation during quarter-level milking. We also suggest that the steepness of the decline phase of the milk flow curve might have a larger effect than the actual detachment level on the duration of overmilking.
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| 30. |
- Wickström, Erik, et al.
(författare)
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Relationship between somatic cell count, polymorphonuclear leucocyte count and quality parameters in bovine bulk tank milk
- 2009
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 76, s. 195-201
-
Tidskriftsartikel (refereegranskat)abstract
- The somatic cell count (SCC) in bovine bulk tank milk is presently used as an indicator of raw milk quality, reflecting the udder health status of the herd. During mastitis, SCC increases, mostly owing to an influx of polymorphonuclear leucocytes (PMN) from blood into milk, with a concomitant change in milk composition. Bulk tank milk samples were categorized according to their SCC, as well as polymorphonuclear leucocyte count (PMNC), to study relationships between SCC, PMNC and various raw milk quality traits, i.e. contents of total protein, whey protein, casein, fat and lactose, casein number, proteolysis and rheological properties. The proportion of PMN, obtained by direct microscopy, was significantly higher in samples with high SCC compared with low SCC samples. SCC and PMNC were strongly correlated, yielding a correlation coefficient of 0.85. High SCC samples had lower lactose and casein contents, lower casein number and more proteolysis than low SCC samples. Samples with high PMNC had a lower casein number than low PMNC samples. Samples with high and low SCC or PMNC did not differ in respect to rheological properties. Our results do not indicate that PMNC is a better biomarker than SCC for raw bulk tank milk quality, as previously proposed.
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| 31. |
- Åkerstedt, Maria, et al.
(författare)
-
Haptoglobin and serum amyloid A in bulk tank milk in relation to raw milk quality
- 2009
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 76, s. 483-489
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 32. |
- Åkerstedt, Maria, et al.
(författare)
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Natural variation in biomarkers indicating mastitis in healthy cows
- 2011
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 78, s. 88-96
-
Tidskriftsartikel (refereegranskat)abstract
- Dairy herds are expanding and, with increasing numbers of animals in each herd, there is a need for automatic recording of indicators in milk in order to detect mastitis, inflammation of the udder. A number of biomarkers for mastitis have been suggested over the years. Mastitis usually occurs in one of the four udder quarters and since it is now possible to milk each udder quarter separately in automated milking systems, it is important to evaluate the normal variation in the biomarkers at udder quarter level. This study evaluated the normal variations between milkings for some biomarkers in clinically healthy cows, determined by repeated somatic cell count and bacteriological analysis. The biomarkers studied were serum amyloid A (SAA), haptoglobin (Hp), lactate dehydrogenase (LDH), N-acetyl-beta-D-glucosaminidase (NAGase) and alkaline phosphatase (AP), parameters that have been suggested as markers for mastitis. Ten cows were monitored on 42 consecutive milking occasions through collection of udder quarter milk samples and representative cow composite milk samples, giving a total of 2100 individual milk samples. Each cow had its individual profile for the concentrations and variations in the parameters analysed. Although there was relatively large variation between cows for the biomarkers analysed, the variation between milkings in clinically healthy quarters within cows was often below 10%. The biomarker with the lowest variation in this study was LDH. The results suggest that comparing quarters within an individual cow can identify deviations from the natural variations between milkings. This could be a valuable tool instead of, or in combination with, a cut-off value for each parameter in order to detect changes in the milk indicating mastitis.
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| 33. |
- Åkerstedt, Maria, et al.
(författare)
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Protein degradation in bovine milk caused by Streptococcus agalactiae
- 2012
-
Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 79, s. 297-303
-
Tidskriftsartikel (refereegranskat)abstract
- Streptococcus (Str.) agalactiae is a contagious mastitis bacterium, often associated with cases of subclinical mastitis. Different mastitis bacteria have been evaluated previously from a diagnostic point of view, but there is a lack of knowledge concerning their effect on milk composition. Protein composition is important in achieving optimal yield and texture when milk is processed to fermented products, such as cheese and yoghurt, and is thus of great economic value. The aim of this in vitro study was to evaluate protein degradation mainly caused by exogenous proteases originating from naturally occurring Str. agalactiae. The samples were incubated at 37 degrees C to imitate degradation caused by the bacteria in the udder. Protein degradation caused by different strains of Str. agalactiae was also investigated. Protein degradation was observed to occur when Str. agalactiae was added to milk, but there were variations between strains of the bacteria. Caseins, the most economically important proteins in milk, were degraded up to 75% in milk inoculated with Str. agalactiae in relation to sterile ultra-high temperature (UHT) milk, used as control milk. The major whey proteins, a-lactalbumin and beta-lactoglobulin, were degraded up to 21% in relation to the sterile control milk. These results suggest that different mastitis bacteria but also different strains of mastitis bacteria should be evaluated from a milk quality perspective to gain knowledge about their ability to degrade the economically important proteins in milk.
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| 34. |
- Antonsson, Martin, et al.
(författare)
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Screening and selection of Lactobacillus strains for use as adjunct cultures in production of semi-hard cheese
- 2002
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Ingår i: Journal of Dairy Research. - 0022-0299. ; 69:3, s. 457-472
-
Tidskriftsartikel (refereegranskat)abstract
- Thirty-three Lactobacillus strains were tested as adjuncts in a cheese model system. Eighteen strains originated from cheese (nine Lactobacillus spp. and nine Lb. paracasei/casei) and 15 from human intestinal mucosa (11 Lb. rhamnosus; three Lb. paracasei; one Lb. plantarum). Model cheeses weighing 120 g were made of cheese grains from full-scale production of washed curd semi-hard cheese (Herrgard). The model system was reproducible and similar to full-scale production with respect to moisture, salt content, pH and microbial flora. The model cheeses were sampled for aerobic and anaerobic plate count and viable counts of Lactobacillus and Lactococcus. The presence of adjuncts in the model cheeses was confirmed by typing isolates with Randomly Amplified Polymorphic DNA (RAPD). The sensory properties of model cheeses were described. In a first trial 23 of the 33 adjuncts were re-isolated from the corresponding model cheeses after 9 or 13 weeks. Adjuncts of Lb. paracasei were re-isolated more frequently than adjuncts of Lb. rhamnosus. Nine strains were selected, on the basis of their ability to grow and be a dominating part of the microflora of model cheese with interesting sensory properties. These strains were further studied together with two commercial cultures. The sensory influences on model cheeses of six of the adjuncts were confirmed, and flavour scores were in the range of 2(.)9-7(.)1 for model cheeses with different adjuncts while the control had a flavour score of 5(.)6 (0-10 scale). Survival and growth of seven out of the nine strains correlated with the results of the first trial. Growth and influence on flavour of four adjunct cultures were confirmed in experimental cheese manufactured in a 400-1 open vat.
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| 35. |
- Eneroth, Åsa, et al.
(författare)
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Contamination of pasteurised milk by Bacillus cereus in the filling machine
- 2001
-
Ingår i: Journal of Dairy Research. - 0022-0299. ; 68:2, s. 189-196
-
Tidskriftsartikel (refereegranskat)abstract
- The contamination of pasteurized milk by Bacillus cereus during the ®lling process was studied in two dairy plants. Samples of pasteurized milk were taken at four different sites along the production line. The samples were stored at 7 °C for 7 d, or at 10 °C for 5 d, before plate counting and random selection of B. cereus isolates. Isolates of B. cereus were typed by the polymerase chain reaction (PCR)-based method randomly ampli®ed polymorphic DNA (RAPD). Samples taken at three different sites between the pasteurizer and the ®lling machine were all holding similar low concentrations of B. cereus, while an increase of the B. cereus count was seen in the consumer packages. More B. cereus of different RAPD types was growing in the consumer packages than in samples taken just before the ®lling machine. Several RAPD types found in the consumer packages were not detected in the samples taken just before the ®lling machine.
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| 36. |
- Folkenberg, Ditte M., et al.
(författare)
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Interactions between EPS-producing Streptococcus thermophilus strains in mixed yoghurt cultures
- 2006
-
Ingår i: Journal of Dairy Research. - 0022-0299. ; 73:4, s. 385-393
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Tidskriftsartikel (refereegranskat)abstract
- Mixed cultures of different EPS-producing Streptococcus thermophilus strains in combination with a Lactobacillus delbrueckii subsp. bulgaricus strain with negligible EPS-production were used for yoghurt production. The yoghurt texture was characterised with respect to sensory, rheological and microstructural properties and the EPS-concentrations were determined. The cultures resulted in yoghurts with highly different texture properties, and positive interactions between certain Streptococcus thermophilus strains were observed. The underlying properties of yoghurt texture are multidimensional, but a number of microstructural characteristics were apparent in the yoghurts with the highest mouth thickness, creaminess and viscosity. A strong protein network, not too dense and with medium size pores containing EPS, seems associated with these properties. The presence of capsular polysaccharides (CPS) also appeared to be beneficial as did a combination of FPS types, which were distributed differently in the protein network (in serum pores, respectively in association with protein). Obviously, a certain concentration of FPS must be present to provide for these effects on yoghurt texture, but other factors than concentration per se seem more important.
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| 37. |
- Glantz, Maria, et al.
(författare)
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Effect of polymorphisms in the leptin, leptin receptor and acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) genes and genetic polymorphism of milk proteins on bovine milk composition.
- 2012
-
Ingår i: Journal of Dairy Research. - 0022-0299. ; 79:1, s. 110-118
-
Tidskriftsartikel (refereegranskat)abstract
- The relations between cow genetics and milk composition have gained a lot of attention during the past years, however, generally only a few compositional traits have been examined. The aim of this study was to determine if polymorphisms in the leptin (LEP), leptin receptor (LEPR) and acyl-CoA:diacylglycerol acyltransferase 1 (DGAT1) genes as well as genetic polymorphism of β-casein (β-CN), κ-CN and β-lactoglobulin (β-LG) impact several bovine milk composition traits. Individual milk samples from the Swedish Red and Swedish Holstein breeds were analyzed for components in the protein, lipid, carbohydrate and mineral profiles. Cow alleles were determined on the following SNP: A1457G, A252T, A59V and C963T on the LEP gene, T945M on the LEPR gene and Nt984+8(A-G) on the DGAT1 gene. Additionally, genetic variants of β-CN, κ-CN and β-LG were determined. For both the breeds, the same tendency of minor allele frequency was found for all SNPs and protein genes, except on LEPA1457G and LEPC963T. This study indicated significant (P<0·05) associations between the studied SNPs and several compositional parameters. Protein content was influenced by LEPA1457G (G>A) and LEPC963T (T>C), whereas total Ca, ionic Ca concentration and milk pH were affected by LEPA1457G, LEPA59V, LEPC963T and LEPRT945M. However, yields of milk, protein, CN, lactose, total Ca and P were mainly affected by β-CN (A2>A1) and κ-CN (A>B>E). β-LG was mainly associated with whey protein yield and ionic Ca concentration (A>B). Thus, this study shows possibilities of using these polymorphisms as markers within genetic selection programs to improve and adjust several compositional parameters.
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| 38. |
- Glantz, Maria, et al.
(författare)
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Genomic selection in relation to bovine milk composition and processability.
- 2012
-
Ingår i: Journal of Dairy Research. - 0022-0299. ; 79:1, s. 53-59
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Tidskriftsartikel (refereegranskat)abstract
- Genomic selection is a new technology in which selection decisions are based on direct genomic values (DGVs) or genomic enhanced breeding values (GEBVs). The objective of this study was to evaluate the relations between DGVs and several milk traits important for both the nutritional value and processability of milk. This is a new approach and can be used to increase the knowledge on how genomic selection can be used in practice. Morning milk samples from Swedish Holstein cows were analyzed for milk composition and technological properties. DGVs were received for each cow for milk, protein and fat yield, milk index, udder health, Nordic total merit and a quota was calculated between fat and milk yield as well as protein and milk yield. The results show that linear correlations exist (P<0·10) between the studied DGVs and contents and yields of parameters in the protein (P=0·002-0·097), fat (P=0·024-0·055) and mineral profiles (P=0·001-0·099) as well as for cheese characteristics (P=0·004-0·065), thus making it possible to obtain detailed information on milk traits that are not registered in the milk recording scheme. Hence, genomic selection will be an efficient tool for breeding and dairy industry to select cows early in life for targeted milk production.
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| 39. |
- Hoac, Tien, et al.
(författare)
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Short-term effects of selenium supplementation of cows' feed on the content and distribution of selenium, copper and zinc in bovine milk, whey and blood plasma.
- 2008
-
Ingår i: Journal of Dairy Research. - 0022-0299. ; 75:3, s. 326-334
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of selenium supplementation of feed on the Se content in bovine milk, whey and plasma, and on the distribution of Se, Zn and Cu in whey and plasma was investigated. In a cross-over study two groups of cows were given a basal feed with 0.16 ppm selenite (approx. 3 mg Se/d) with or without 25 mg yeast Se/d for 2 weeks. In the supplemented group the Se content increased 10-fold in milk, 10-fold in whey and 2-fold in plasma, and after the cessation of the supplementation, selenium in milk decreased with a calculated half-life of 3.5 d. In another experiment, two groups of cows were given either 100 mg yeast Se/d for 1 week or only the basal feed. The increase in Se content in both whole and defatted milk was 40-50-fold, and in whey it was approx. 20-fold. Size-exclusion chromatography of whey using inductively coupled plasma mass spectrometry for detection showed that supplementation increased the proportion of Se in the beta-lactoglobulin-alpha-lactalbumin fraction. Distribution of Cu and Zn was essentially unaffected. In plasma, supplementation increased the Se content in all major Se fractions like selenoprotein P, albumin and low-molecular-weight compounds, but the distribution profiles of Zn and Cu underwent no major changes. The study showed for the first time the rapid kinetics of the Se increase and decrease in milk after the initiation and cessation of supplementation, respectively, and the preferential appearance of Se in the beta-lactoglobulin-alpha-lactalbumin fraction of whey. Milk highly enriched in selenium will be a useful tool for different research purposes.
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| 40. |
- Torres, Isabel Celigueta, et al.
(författare)
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Effect of homogenisation in formation of thermally induced aggregates in a non- and low- fat milk model system with microparticulated whey proteins
- 2017
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Ingår i: Journal of Dairy Research. - 0022-0299. ; 84:2, s. 229-238
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of the research presented in this paper was to investigate how different characteristics of whey protein microparticles (MWP) added to milk as fat replacers influence intermolecular interactions occurring with other milk proteins during homogenisation and heating. These interactions are responsible for the formation of heat-induced aggregates that influence the texture and sensory characteristics of the final product. The formation of heat-induced complexes was studied in non- and low-fat milk model systems, where microparticulated whey protein (MWP) was used as fat replacer. Five MWP types with different particle characteristics were utilised and three heat treatments used: 85 °C for 15 min, 90 °C for 5 min and 95 °C for 2 min. Surface characteristics of the protein aggregates were expressed as the number of available thiol groups and the surface net charge. Intermolecular interactions involved in the formation of protein aggregates were studied by polyacrylamide gel electrophoresis and the final complexes visualised by darkfield microscopy. Homogenisation of non-fat milk systems led to partial adsorption of caseins onto microparticles, independently of the type of microparticle. On the contrary, homogenisation of low-fat milk resulted in preferential adsorption of caseins onto fat globules, rather than onto microparticles. Further heating of the milk, led to the formation of heat induced complexes with different sizes and characteristics depending on the type of MWP and the presence or not of fat. The results highlight the importance of controlling homogenisation and heat processing in yoghurt manufacture in order to induce desired changes in the surface reactivity of the microparticles and thereby promote effective protein interactions.
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| 41. |
- Muvva, Jagadeeswara Rao, et al.
(författare)
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Immunomodulatory Agents Combat Multidrug-Resistant Tuberculosis by Improving Antimicrobial Immunity
- 2021
-
Ingår i: Journal of Infectious Diseases. - : Oxford University Press. - 0022-1899 .- 1537-6613. ; 224:2, s. 332-344
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Tidskriftsartikel (refereegranskat)abstract
- Background. Multidrug-resistant (MDR) tuberculosis has low treatment success rates, and new treatment strategies are needed. We explored whether treatment with active vitamin D-3 (vitD) and phenylbutyrate (PBA) could improve conventional chemotherapy by enhancing immune-mediated eradication of Mycobacterium tuberculosis. Methods. A clinically relevant model was used consisting of human macrophages infected with M. tuberculosis isolates (n = 15) with different antibiotic resistance profiles. The antimicrobial effect of vitD+PBA, was tested together with rifampicin or isoniazid. Methods included colony-forming units (intracellular bacterial growth), messenger RNA expression analyses (LL-37, beta-defensin, nitric oxide synthase, and dual oxidase 2), RNA interference (LL-37-silencing in primary macrophages), and Western blot analysis and confocal microscopy (LL-37 and LC3 protein expression). Results. VitD+PBA inhibited growth of clinical MDR tuberculosis strains in human macrophages and strengthened intracellular growth inhibition of rifampicin and isoniazid via induction of the antimicrobial peptide LL-37 and I,C3-dependent autophagy. Gene silencing of LL-37 expression enhanced MDR tuberculosis growth in vitD+PBA-treated macrophages. Me combination of vitD+PBA and isoniazid were as effective in reducing intracellular MDR tuberculosis growth as a >125-fold higher dose of isoniazid alone, suggesting potent additive effects of vitD+PBA with isoniazid. Conclusions. Immunomodulatory agents that trigger multiple immune pathways can strengthen standard MDR tuberculosis treatment and contribute to next-generation individualized treatment options for patients with difficult-to-treat pulmonary tuberculosis.
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