Evaluation of quality changes in udder quarter milk from cows with low-to-moderate somatic cell counts

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-tomoderate 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 5 100 000 cells/ml of Group 2, milk from affected udder quarters exhibited lower casein number, content of lactose and b-casein (b-CN), while the content of whey protein, sodium, LDH and a-lactoalbumin (a-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 a s1 -casein (a 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.

Phenotypic, antimicrobial susceptibility profile and virulence factors ofKlebsiella pneumoniaeisolated from buffalo and cow mastitic milk

“…After gently suspending each sample, the milk was poured into a separate, unused container. As previously indicated, 16 a composite milk sample representing one udder was created; this sample was comprised of all four quarters in one collection vial. A subsample of 15 ml of milk, taken from the composite milk sample, was transferred to sterile universal bottles.…”

Effect of somatic cell count on composition and hygiene indicators of bulk tank milk

“…In order to characterize milk quality, the most commonly used criteria are hygiene milk composition, and sensory characteristics of consumer interest (BRANDT et al, 2010). The main factors that affect raw milk quality are the prevalence of subclinical mastitis, hygiene conditions, and storage during milk production and processing (FORSBÄCK et al, 2010b).…”

Effect of somatic cell count on milk fat and protein in different parities and stages of lactation in Holstein cows

“…It has been observed that milk samples collected from infected quarters contain more total protein and whey protein and less casein and lactose in comparison to healthy quarters (Kitchen, 1981;Cinar et al, 2015;Neitzel et al, 2015). During mastitis, increase in permeability of the blood-milk barrier also results in *0: 0-17,000 (cell/ml), 1: 18,000-34,000, 2: 35,000-70,000, 3: 71,000-140,000, 4: 141,000-282,000, 5: 283,000-565,000, 6: 566,000-1,130,000, 7: 1,131,000-2,262,000, 8: 2,263,000-4,525,000, 9: 4,526,000-and above; All the differences were significant at p < 0.0001; a, b an influx of serum proteins and enzymes from the blood, which may lead to increased proteolysis (Forsbäck et al, 2010). Reports on aforementioned research (Bansal et al, 2005;Forsbäck et al, 2010;Malek dos Reis et al, 2013) showed change in milk composition of infected quarters (including change in level of casein, decrease in α-casein and β-casein due to either proteolytic activity of enzymes or decreased casein synthesis in affected udder quarters, and increase in whey proteins) in comparison to milk produced by healthy quarters.…”

“…During mastitis, increase in permeability of the blood-milk barrier also results in *0: 0-17,000 (cell/ml), 1: 18,000-34,000, 2: 35,000-70,000, 3: 71,000-140,000, 4: 141,000-282,000, 5: 283,000-565,000, 6: 566,000-1,130,000, 7: 1,131,000-2,262,000, 8: 2,263,000-4,525,000, 9: 4,526,000-and above; All the differences were significant at p < 0.0001; a, b an influx of serum proteins and enzymes from the blood, which may lead to increased proteolysis (Forsbäck et al, 2010). Reports on aforementioned research (Bansal et al, 2005;Forsbäck et al, 2010;Malek dos Reis et al, 2013) showed change in milk composition of infected quarters (including change in level of casein, decrease in α-casein and β-casein due to either proteolytic activity of enzymes or decreased casein synthesis in affected udder quarters, and increase in whey proteins) in comparison to milk produced by healthy quarters. Regarding to the previous reports and results of this study, it can be concluded that permeability of basal lamina is higher either in young animals or in early stages of lactation because of higher milk protein percentage and SCS in both lower lactations and early stages of lactation.…”