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- Forsbäck, Linda, et al.
(author)
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Udder quarter milk composition at different levels of somatic cell count in cow composite milk
- 2009
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In: Animal. - 1751-7311 .- 1751-732X. ; 3, s. 710-717
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Journal article (peer-reviewed)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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- Lakic, Branislav, et al.
(author)
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Is there a special mechanism behind the changes in somatic cell and polymorphonuclear leukocyte counts, and composition of milk after a single prolonged milking interval in cows?
- 2009
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In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 51, s. 1-10
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Journal article (peer-reviewed)abstract
- Background: A single prolonged milking interval (PMI) e.g. after a technical stop in an automatedmilking system is of concern for the producer since it is associated with a short-lasting increase inmilk somatic cell count (SCC), which is a major quality criterion used at the dairy plants. Thecontent of polymorphonuclear leukocytes (PMN) and how the milk quality is influenced has notbeen much investigated. The SCC peak occurs without any obvious antigen challenge, possiblyindicating a different leukocyte attraction mechanism after a PMI than we see during mastitis.Methods: Composite cow milk samples were taken at the milkings twice daily during 7 days beforeand 5 days after a PMI of 24 h. Milk was analyzed for SCC, PMN, fat, protein and lactose, and atsome occasions also casein and free fatty acids (FFA).Results: During the PMI the proportion of milk PMN increased sharply in spite of marginallyincreased SCC. The peak SCC was not observed until the second milking after the PMI, in theafternoon day 1. However, the peak SCC value in morning milk did not occur until one day later,concomitantly with a decrease in the proportion of PMN. After declining, SCC still remainedelevated while PMN proportion was decreased throughout the study as was also the milk yield,after the first accumulation of milk during the PMI. Milk composition was changed the day after thePMI, (increased fat and protein content; decreased lactose, whey protein and FFA content) but thechanges in the following days were not consistent except for lactose that remained decreased therest of the study.Conclusion: The PMI resulted in increased SCC and proportion of PMN. Additionally, it gave riseto minor alterations in the milk composition in the following milkings but no adverse effect on milkquality was observed. The recruitment of PMN, which was further enhanced the first day after thePMI, appeared to be independent of milk volume or accumulation of milk per se. Hence, we suggestthat there is a special immunophysiological/chemoattractant background to the increased migrationof leukocytes into the milk compartment observed during and after the PMI.
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- Millogo, Vinsoun, et al.
(author)
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Day-to-day variation in yield, composition and somatic cell count of saleable milk in hand-milked zebu dairy cattle
- 2009
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In: African Journal of Agricultural Research. - 1991-637X. ; 4, s. 151-155
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Journal article (peer-reviewed)abstract
- The aim of the study was to determine the relative day-to-day variation in yield and composition of zebu cows. Ten multiparous zebu cows in day 41 +/- 1.6 of lactation were used in the study. After a 14 day adaptation period, milk production was recorded daily for four consecutive weeks. Cows had access to natural pasture for 6.5 h per day and were also supplemented with hay, cottonseed cake and molasses. The cows were hand-milked and calves were used to stimulate milk ejection before and during milking. Average yield of saleable milk was 2.08 +/- 0.23 l/day with a relative day-to-day variation of 18-21%. The variation of saleable milk was 23-25% for fat, 12-14% for protein, 6% for lactose and 8% for somatic cell count. The variation in fat content was higher in strip milk (19-46%) than in saleable milk. The results indicated a larger variation in composition of milk from hand-milked Bos indicus Zebu than from machine-milked Bos taurus cows. The most likely reasons for the difference in variation are the suckling by the calf and that hand-milking entails larger variation in the degree of emptying machine-milking does.
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