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- Forsbäck, Linda
(författare)
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Bovine udder quarter milk in relation to somatic cell count : focus on milk composition and processing properties
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The dairy industry requires raw milk of high quality in order to produce milk products of high quality and quantity. Mastitis is one of the most prevalent and economically important production diseases in dairy cattle. It causes increased somatic cell count (SCC), deteriorated milk composition and consequently altered processing properties of milk. Altered milk composition due to mastitis often occurs in only one of the four udder quarters of the cow. Milk with high SCC and deteriorated milk composition can be excluded at cow level. A future option will be to detect and exclude milk at udder quarter level, which can be achieved in automatic milking (AM) systems. This thesis examined alterations in milk composition in individual udder quarters in relation to elevated SCC. The studies were mainly carried out on Swedish Red Breed cows with low to moderate SCC, all supplying milk to a commercial dairy. It was found that around 30% of the cows with low cow composite SCC (below 100 000 cells/ml) had one or more udder quarters with elevated SCC and altered milk composition. Furthermore, individual udder quarters with deteriorated milk composition and signs of reduced blood-milk barrier were found in cows with low to moderate levels of composite SCC. In addition, cows with elevated SCC had one or more udder quarters with low SCC and unaffected milk composition. It was also observed that the relative day-to-day variation in milk components in the four udder quarters of a healthy cow is similar, which suggests that using repeated measurements of milk composition at udder quarter level could be a suitable tool for detecting alterations in milk composition and health. Milk composition was affected by duration of storage and content of bacteria, as well as SCC. Separating the milk from individual udder quarters was shown to affect the content of total protein, whey protein and lactose at cow level. The main conclusions from this thesis are that individual udder quarters with deteriorated milk composition can be found in cows with fairly low SCC, and that exclusion of the milk from these udder quarters can improve overall milk quality. These results are important when discussing whether exclusion of some milk at udder quarter level should be introduced to improve milk quality.
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| 2. |
- Forsbäck, Linda, et al.
(författare)
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Day-to-day variation in milk yield and milk composition at udder quarter level
- 2010
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 93, s. 3569-3577
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Tidskriftsartikel (refereegranskat)abstract
- Automatic in-line measurement of milk composition and milk yield could be a useful tool in management of the dairy herd. Data on milk components and milk yield provide information on milk quality alterations and cow health status but are also useful in planning feeding and breeding. In automatic milking systems, udder quarters are milked individually, enabling analysis and recording at the udder-quarter level. Frequent records of components require knowledge about day-today variations. A component with greater day-to-day variation needs more frequent sampling when used as a diagnostic tool and for management decisions. Earlier studies have described the day-to-day variations in milk components for cow composite milk, but with the quarter milking technique and the possible sampling at the udder-quarter level, knowledge about day-to-day variations at the udder-quarter level is needed. In this study, udder-quarter and cow composite milk samples were collected from 42 consecutive milkings of 10 cows during 21 d. Milk yield was recorded and the milk was analyzed for total protein, whey protein, casein, fat, lactose, and somatic cell count. The results showed that the day-to-day variations and mean values for 4 healthy udder quarters within a cow were similar. In addition, different milk components had different levels of day-to-day variation, the least variation being found in lactose (0.9%) and the greatest in fat (7.7%). This suggests that repeated milk sampling and analysis at the udder-quarter level can be used to detect alterations in composition and cow health and would, thus, be helpful in the management of the dairy herd.
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| 3. |
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| 4. |
- Forsbäck, Linda, et al.
(författare)
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Evaluation of quality changes in udder quarter milk from cows with low-to-moderate somatic cell counts
- 2010
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Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 4, s. 617-626
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Tidskriftsartikel (refereegranskat)abstract
- Much emphasis has been put on evaluating alterations in milk composition caused by clinical and subclinical mastitis. However, little is known about changes in milk composition during subclinical mastitis in individual udder quarters with a low-to-moderate increase in milk somatic cell count (SCC). This information is needed to decide whether milk from individual udder quarters with a moderate-to-high increase in milk SCC should be separated or not. The aim of this study was to determine how milk composition in separate udder quarters is affected when cow composite milk has low or moderately increased SCC levels. Udder quarter and cow composite milk samples were collected from 17 cows on one occasion. Milk yield was registered and samples were analyzed for SCC, fat, total protein, whey proteins, lactose, citric acid, non-protein nitrogen (NPN), lactoferrin, protein profile, free fatty acids (FFAs), lactate dehydrogenase (LDH), proteolysis, sodium and potassium. Bacteriological samples were collected twice from all four quarters of all cows. The cows were divided into three groups depending on their SCC at udder quarter level. The first group comprised healthy cows with four udder quarters with low SCC, < 50 000 cells/ml; composition was equal when opposite rear and front quarters were compared. In the second and the third groups, cows had one udder quarter with 101 000 cells/ml < SCC < 600 000 cells/ml and SCC > 700 000 cells/ml, respectively The remaining udder quarters of these cows had low SCC (<100 000 cells/ml). Despite the relatively low average cow composite SCC = 100 000 cells/ml of Group 2, milk from affected udder quarters exhibited lower casein number, content of lactose and beta-casein (beta-CN, while the content of whey protein, sodium, LDH and (alpha-lactoalbumin (alpha-la) were higher compared to healthy opposite quarters. In addition to these changes, milk from affected udder quarters in Group 3 also exhibited lower values of potassium and alpha(s1)-casein (alpha(s1)-CN) and higher values of lactoferrin when compared to milk from opposite healthy quarters. This indicates that even when the SCC in cow composite milk is low, there might exist individual quarters for which milk composition is changed and milk quality impaired.
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| 8. |
- Forsbäck, Linda, et al.
(författare)
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Udder quarter milk composition at different levels of somatic cell count in cow composite milk
- 2009
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Ingår i: Animal. - 1751-7311 .- 1751-732X. ; 3, s. 710-717
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Tidskriftsartikel (refereegranskat)abstract
- Automatic milking systems have made possible the separation of high- and low-quality milk at the udder quarter level during the milking process. The aim of this study was to investigate the composition and yield of milk from individual udder quarters to determine whether deteriorated milk composition occurs in udders that are assumed to be healthy and whether quarters with high-quality milk are found in udders with high milk somatic cell count (SCC). Milk samples were collected on one occasion from 90 cows at udder quarter level and cow composite level. The milk was analyzed for content of total protein, whey protein, casein, fat, lactose, citric acid and SCC; milk yield was registered. The cows were divided into three groups depending on the SCC of their composite milk. Cows in group 1, cow composite SCC<100 000 cells/ml were assumed to have healthy udders. However instances of increased SCC and decreased milk quality were discovered in one or more udder quarters of approximately 30% of the group. Cows in group 2, cow composite SCC of 100 000 to 300 000 cells/ml, and group 3, cow composite SCC>300 000 cells/ml, were assumed to have affected udders. However, the majority of these cows had one or more udder quarters in which increased SCC and deteriorated milk quality were not detected. Calculations of bulk-tank milk values, when separation of milk from affected udder quarters was performed, indicate that SCC changes to a much greater degree compared to the other milk components. These results show that milk from affected udder quarters suffers compositional changes, but calculations of simulated separation indicate that the compositional changes in bulk-tank milk are small. The effect of separation of milk from individual udder quarters on bulk-tank milk needs to be further studied.
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| 9. |
- Åkerstedt, Maria, et al.
(författare)
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Natural variation in biomarkers indicating mastitis in healthy cows
- 2011
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Ingår i: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 78, s. 88-96
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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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