Studies on Milk Analyses of Individual Cow Milk Samples

Sjaunja, L.-O.; Philipsson, J.; Lundström, Kerstin; Swensson, Christian

doi:10.1080/00015128409435397

Cited by 14 publications

(8 citation statements)

References 6 publications

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“…The concentrations of fat, protein and lactose in the milk were measured by an infra-red technique (Milkosan 104, Shields Ltd.) described by Sjaunja (1982).…”

Section: Methodsmentioning

confidence: 99%

Fluid Balance During Heat Stress in Lactating Goats

Olsson

Dahlborn

1989

Exp Physiol

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SUMMARYFluid balance and thermoregulation were studied during an acute heat load (maximal daily temperature, 38 + 1°C; night temperature, 27 + 1°C) in six goats during lactation and nonlactation. The goats had free access to water for 1 day, followed by 29 5 h of water deprivation and then water was returned. With water available the goats increased water intake and urinary and milk water losses, while plasma and milk osmolality decreased. Water deprivation caused plasma osmolality and vasopressin concentration to increase most in lactating goats. Milk osmolality rose to values similar to plasma osmolality. Plasma cortisol increased in lactating goats at the end of dehydration. Renal Na+ excretion increased during dehydration in lactating goats. Evaporative heat loss was larger in lactating goats when hydrated, but became less than in non-lactating goats during dehydration. Lactating goats exhibited higher respiratory frequency and rectal temperature than non-lactating goats. In conclusion, our results show that goats increase the water turnover during heat stress if allowed to drink ad libitum, but when they are deprived of water lactating goats reduce water loss in urine, milk and by evaporation, and rectal temperature reaches higher levels than in non-lactating animals. This saving of water could allow milk production to be maintained for a longer time during heat stress.

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“…The concentrations of fat, protein and lactose in the milk were measured by an infra-red technique (Milkosan 104, Shields Ltd.) described by Sjaunja (1982).…”

Section: Methodsmentioning

confidence: 99%

Fluid Balance During Heat Stress in Lactating Goats

Olsson

Dahlborn

1989

Exp Physiol

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“…below and above 250000 cells/ml. The correction factors (6,) of the linear equations, used by the apparatus to correct for the interference of the secondary components, were estimated by multiple regression as described elsewhere (Sjaunja, 1982). The model used to describe the linear equations applied with MS-104 has a zcro intercept and the primary component (.rli) has a coefficient of regression equal to one, according to: =residual random term.…”

Section: Protein Analysesmentioning

confidence: 99%

“…As the uncorrected (XJ values are not displayed by MS-IM, they were first calculated as described by Sjaunja (1982).…”

Section: Protein Analysesmentioning

confidence: 99%

Studies on Milk Analyses of Individual Cow Milk Samples

Sjaunja

1984

Acta Agriculturae Scandinavica

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Studies on, milk analyses of individual cow milk samples. 11. Factors affecting milk analyses by infrared technique under laboratory conditions. Acta Agric Scand 34: [260][261][262][263][264][265][266][267][268][269][270][271][272] 1983.Differences between infrared (hlilko-Scan 103) and reference methods (Gerber and Kjeldahl) in fat and protein determinations were studied in. individual cows of four breeds over a 7-month period. The overall accuracy of fat and protein determinations, expressed as the standard deviation (coefficient of variation) of the difference between the methods, was 0.1 1 percentage units (C.V.=2.3 56) and 0.05 percentage units (C.V.= I .5 %), respectively. Fat analyses were significantly influenced by the biological factors breed, cow, stage of lactation and somatic cell count, and protein analyses by breed and COW. The factors studied accounted for about 50% of the total variation in analysis differences. The indirect 1R principle for fat determination and its sensitivity to variations in fat composition and fat ' globule size explained the influence on the IR method of the biological factors tested. The non-correspondence between the 1R method and the reference method as regards protein \ i t s not only an instrumental effect, but was largely explained by the indirect analysis principle of the Kjeldahl method. Stage of lactation had the most pronounced effect on fat analyses with the IR method. Analyses of Jersey milkfat had the lowest accuracy of the breeds studied. The accuracy achieved (inherent accuracy of the apparatus) \bas found to be sufiicient for milk recording of individual c o w , but the need to investigate all relevant factors in a routine analysis system is emphasized. Key uwrds: biologicnl factors. routitre otralysis.

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“…Gaudillere and Grappin (1982) and Sjaunja and Anderson (1985) have The formation of carboxylic acids by fermentation of lactose may also cause interference absorption at the protein wavelength (Goulden, 1964). Similarly, it has been demonstrated that lipolysis induces an increase of the protein signal by 0.01 percent unit per millimole of free fatty acid (Sjaunja, 1982). have c1earlydemonstrated that in fact most of the interfering compounds are present in the milk soluble phase (Fig.…”

Section: Instrumentationmentioning

confidence: 99%

“…which influence the proportion of NPN in milk, will have a significant influence on the accuracy of the method when the apparatus is calibrated for crude protein Sjaunja, 1982). Whenever possible, adjustment of the instrument calibration will therefore be necessary.…”

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confidence: 99%

Milk protein analysis

Ribadeau‐Dumas¹,

Grappin

1989

Lait

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Summary -After a short description of bovine milk proteins, the various methods of current or potential use for detecting and determining them in dairy products are reviewed. This includes, first, the determination of total protein from nitrogen analysis, dye-binding capacity, infra-red spectrometry and amino acid analysis. The methods that allow determination of sorne milk protein fractions of interest (whole casein, whey proteins,~-Iactoglobulin) are then given. They include the Aschaffenburg-Rowland procedure, dye-binding and infra-red methodologies. A description of the various methods (electrophoresis, column chromatography, immunochemical or enzymatic tests), that can be used for detecting and individually quantitating the various caseins and whey proteins is presented. Finally, sorne applications of various analytical procedures to the analysis of different classes of dairy products are given.

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Studies on Milk Analyses of Individual Cow Milk Samples

Cited by 14 publications

References 6 publications

Fluid Balance During Heat Stress in Lactating Goats

Fluid Balance During Heat Stress in Lactating Goats

Studies on Milk Analyses of Individual Cow Milk Samples

Milk protein analysis

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