bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanics of machine milking: II. The flow-rate pattern within single pulsation cycles
Authors: Thiel C. C. , Clough P. A. , Westgarth D. R. , Akam D. N. 
Published: June 2009

SummaryThe milk flowing during a single pulsation cycle was collected in a circle of contiguous cups which rotated in a chamber at 1 rev/pulsation cycle just below the end of the teatcup liner. The mean flow rate during the time taken for each collecting cup to pass under the milk stream was calculated and the flow-rate curve for the milkflow period of the pulsation cycle plotted. Flow rates were measured at 130, 97, 65, 32 and 16 c/min, and also after the pulsator had been stopped with the liner open for 0·5 min (0 pulsation).It was concluded from the series of flow-rate curves at the different pulsation rates that flow rate from the teat increased in about 0·05 sec to a steady value which continued for 0·5 sec or so, and then declined over a period of about 1·5 sec to a new constant value approximately equal to that shown after milk had flowed continuously from the teat for 0·5 min.These results suggest that once the pressure difference across the streak canal during milking forces the teat sphincter open a considerable time elapses before the muscle control system responds, and that a further much longer period elapses before the full closing force of the sphincter is exerted. Thus, it would appear that at pulsation rates of about 50 c/min and above, the streak canal is closed by pressure exerted on the teat by the closing liner, the sphincter muscle playing no active part because its response rate is slow compared with the pulsation rate. At lower pulsation rates the flow rate declines during each cycle because the sphincter muscle has time to exert a closing force to a greater or lesser extent depending on the duration of the milkflow period.
The variation in the cell count of cow's milk throughout lactation and from one lactation to the next
Authors: Blackburn P. S. 
Published: June 2009

SummaryTotal and differential cell counts were obtained for approximately 38000 fore-milk samples taken from cows of the Institute herd during a period of 12 years.For most of the period of the experiment the incidence of subclinical mastitis associated with coagulase-positive staphylococci was about 5% of all the quarters in milk, but for a period of about 12 months in the 7th and 8th year of the experiment the herd was free from infection with coagulase-positive staphylococci.The average cell count for cows in each lactation up to the 7th was calculated, and in addition each lactation was divided into 4 equal periods, and the average cell count for each period determined.It was found that the average total cell count increased from one lactation to the next, and that this rise was due mainly to an increase in the number of polymorphs in the samples, the counts of cells other than polymorphs remaining relatively constant.It was also found that the average total cell count rose during the course of any one lactation; but this was due to an increase in both the number of polymorphs and the number of cells other than polymorphs.During the period when the herd was free from infection with coagulase-positive staphylococci the average lactation age of the cows was 4·3 lactations, and the average total cell count was 0·30 million cells/ml, a figure which was the same as that obtained throughout the experiment for animals in their 1st lactation.Possible relationships between the rise in cell counts and the pathology of mastitis are discussed.
The effect of concentrating milk on the fat retention property of the cheese curd
Authors: Mabbitt L. A. , Cheeseman G. C. 
Published: June 2009

SummaryConcentration of milk results in a considerable increase in retention of fat by the rennet curd formed under conditions of disturbance. The fat retention property is not conferred by concentration per se but by some effect, probably involving surface phenomena, associated with the process.Changes in composition of the fat globule membrane due to incorporation of milk protein accompany the improvement in fat retention. It is suggested that casein bound firmly to the globule during the concentration process, forms strong links with the coagulated micelles of the curd.
The effect of equal and unequal intervals in twice-daily milking on the milk yield of ewes
Authors: Morag M. , Fox S. 
Published: June 2009

SummaryThe effect of equal and unequal milking intervals (12 + 12, 10 + 14 and 8 + 16h) was investigated in milch ewes. The treatments were applied to 9 ewes using a double 3 × 3 Latin square. The daily production of milk and fat was unaffected by the changes in milking interval.
A suggested correction to the British Standards hydrometric method for the estimation of total solids in milk
Authors: O'Keeffe M. G. 
Published: June 2009

Summary1082 drip samples of fresh milk were taken at a creamery over a period of 3 years and tested for total solids by the current gravimetric method (British Standards Institution, 1963) and the hydrometric method with the fat in the liquid state (British Standards Institution, 1959). On average, the hydrometric method overestimated the total solids by 0·096. It is suggested that the formula which applied before 1 October 1957 is correct and should replace the present formula.
The effect of oxidation on the iodine values of phospholid in milk, butter and washed-cream serum
Authors: Pont E. G. , Holloway Gwenda L. 
Published: June 2009

SummaryPhospholipid was isolated from milk, butter, and washed-cream serum by solvent extraction followed by simple counter-current distribution and thin-layer chromatography. Iodine values from fresh samples, determined by a micro-Wijs technique, ranged, for the cephalin fraction, from 70 to 86, for the lecithin fraction from 44 to 55, and for the sphingomyelin fraction from 36 to 44. In washed-cream serum, oxidation with copper and ascorbic acid led to reduction in extractable phosphorus, decreased chromatographic mobility of phospholipid and significant falls in the iodine values of the 3 phospholipid fractions. In milk, slight reductions in phospholipid iodine values were observed following copper-catalysed oxidation but they were not consistently significant. Iodine values of butter phospholipids remained unchanged even after gross oxidative quality deterioration.
A technique for studying the build-up and prevention of milk film on hard surfaces
Authors: Clegg L. F. L. , Cousins Christina M. 
Published: June 2009

SummaryA laboratory technique using glass and stainless steel slides has been developed to study the build-up of milk film on hard surfaces and its removal with detergent-disinfectant mixtures. Soiling and cleansing treatments were of similar duration to those used in practice but were repeated 6 or 7 times a day for 4 days to simulate 12 or 14 days' milking and washing procedures in the farm dairy; no mechanical assistance was used with the cleaning solutions. Soiling was followed immediately by a pre-rinse, wash and final rinse, allowing a short period for drying before further re-soiling. The technique eventually developed involved treatments repeated 18 times, using solutions at 15·5 °C. The weight of milk film and its content of fat, mineral and ‘protein’ were determined.Under the conditions of the experiments the following were observed.(1) The deposit left by all treatments consisted mainly of fat with a smaller proportion of protein and still less of mineral matter.(2) Glass accumulated slightly less deposit than did stainless steel with an aquablast finish.(3) Removal of milk film was more complete when sodium hypochlorite was added to certain detergent solutions than when the materials were used separately.(4) With the treatments studied, the use of the detergent solution from a previous treatment as a pre-rinse did not result in a reduction in the residual film.(5) A final rinse with 0·1% phosphoric acid virtually eliminated the mineral matter from the residual film.(6) The substitution of a warm (46°C) for a cold (15·5°C) pre-rinse resulted in a reduction of 40% in residual film and the further use of a warm final rinse effected a reduction of 64%.(7) The addition of 0·05% wetting agent (Lissapol NDB, I.C.I. Ltd.) to the prerinse effected only marginal improvement in the treatments studied.(8) Omission of the pre-rinse and corresponding lengthening of the detergent treatment had no consistent effect.
Comparison of milks processed by the direct and indirect methods of ultra-high-temperature sterilization. I. An experimental ultra-high-temperature sterilizer and its characteristics
Authors: Burton H. , Perkin A. G. 
Published: June 2009

SummaryAn experimental ultra-high-temperature milk sterilizer, of 1140 1/h capacity and capable of operation as a plate-type indirect heating plant or as a steaminto-milk direct heating plant, has been installed for comparisons of the milk produced by the direct and indirect processes. The sterilizer and its ancillary equipment are described, together with methods of plant sterilization and milk processing. Time-temperature profiles of the plant are given for both modes of operation.
Nature of ceramide in bovine milk
Authors: Fujino Y. , Fujishima T. 
Published: June 2009

SummaryCeramide, an N-acyl derivative of sphingosine bases, has been isolated for the first time from bovine milk in the free form and its constitution studied. Sixteen component fatty acids were found, among which C23:0 (38·1%), C24:0 (29·5%), C22:0 (17·9%) and C16:0 (7·2%) were predominant. Seven component long-chain bases were detected. The principal bases were C18-sphingosine (35·0%) and C16-sphingosine (31·6%).
The role of the primary phase of rennin action in the coagulation of cow's milk
Authors: Wheelock J. V. , Penney J. P. 
Published: June 2009

SummaryThe rennin coagulation time of cow's milk was inversely proportional to the amount of glycopeptides released by rennin action on the milk and to the initial velocity of the release of the glycopeptides. It was shown that the rennin coagulation of milk is largely determined by the primary phase of rennin action and, therefore, by the amount of κ-casein that is susceptible to attack by rennin.
Effect of 75% replacement of dietary N by urea and ammonium sulphate on the composition and properties of sheep's milk
Authors: Tanev G. 
Published: June 2009

SummaryA 23-week trial was conducted using 4 groups each of 6 ewes to study the effects on milk yield and composition of substituting non-protein nitrogen (NPN) for 75 % of the dietary nitrogen. The control group received a winter ration which included silage followed by a summer ration containing lucerne. The test groups received substitutes of urea, ammonium sulphate, or urea+(NH4)2SO4. The milk yield of the test groups was lower (P< 0·01) than that of the control group. Depression of the fat content of the milk reached statistical significance (P< 0·01) in the groups receiving (NH4)2SO4and urea+(NH4)2SO4. In comparison with the control group, the protein content of the milk was greater in the group receiving urea and smaller in the other 2 test groups. The milks of the test groups had lower amounts of essential amino acids in the free state and higher amounts of non-essential amino acids than did the control milk. Milk-clotting time was increased in the test groups; the increase was greatest (P< 0·01) for the group receiving (NH4)2SO4and least (P< 0·05) for that receiving urea.
The N-acetyl neuraminic-acid content of the milk of various species
Authors: Morrissey P. A. 
Published: June 2009

SummaryAverage N-acetyl neuraminic-acid (NANA) content of milk from cow, sheep, goat, mare, donkey and sow (about 10 samples from each species) was 17·7, 10·1, 6·4, 6·1, 12·0 and 64·0mg/100 ml, of which 14·2, 8·4, 3·2, 3·1, 5·0 and 53·7mg/100 ml respectively was in the casein fraction. The NANA content of casein showed marked species variation ranging from an average of 2·18 % for the sow to 0·09 % for the goat.About 28 % of the casein NANA of mare's milk was liberated in the fraction soluble in 12 % TCA by the action of rennin at pH 6·6 compared with 75 and around 100 % for donkey's and sow's milk respectively; about half the total NANA in the casein of cow's, sheep's and goat's milk was released under the same conditions.
The effect of reduction and alkylation on the primary phase of rennin action on unheated and heated milk
Authors: Wilson G. A. , Wheelock J. V. , Kirk A. 
Published: June 2009

SummaryThe effects of cystine-reducing and sulphydryl-alkylating agents on the extent of the primary phase of rennin action on unheated and heated milk samples were studied. Alkylating agents alone had a negligible effect, but heated samples, reduced with tri-n-butyl phosphine prior to alkylation with a mono-functional agent (sodium iodoacetate) did not show the usual inhibition of the primary phase. Heated samples, reduced and alkylated with a bi-functional agent (ethylene dibromide) which can re-cross-link the broken disulphide bonds, however, did give the normal inhibition. These results suggest that effects on the primary phase due to heat treatment of milk are determined to a large extent by rearrangement of the disulphide cross-links, and if these are permanently broken, heat appears to have little effect.The results differ in some important respects from those obtained on the complex formed between isolated β-lactoglobulin and isolated κ-casein, and therefore throw doubt on the generally held view that there is a similar type of interaction in whole milk.
Sulphur compounds in relation to Cheddar cheese flavour
Authors: Manning D. J. 
Published: June 2009

SummaryComparisons are made between the sulphur-containing volatiles of 4 Cheddar cheeses, using a gas chromatograph equipped with a flame photometric detector.Two of the cheeses were made aseptically from whole milk, with and without starter, the third was made from whole milk with starter in an open vat, and the fourth was made from skim-milk also in an open vat. Only the cheeses made from whole milk with a starter culture developed normal Cheddar flavour; the cheese made without starter and the skim-milk cheese had little or no flavour.Considerable differences were found in the chromatograms of the 4 distillates and in particular methanethiol was found only in the distillates from the cheeses having Cheddar flavour.
Fluoro-opto-electronic cell-counting on milk
Authors: Madsen P. Schmidt 
Published: June 2009

SummaryThe equipment tested (Fossomatic) is a fully automatic electronic instrument for counting the somatic cells in milk samples. The results are printed on a paper strip and displayed on a digital counter. The capacity is 180 samples/h.Counting results obtained with the instrument have been compared with direct microscopic cell counts and particle counts by Coulter counter. The correlation coefficient with microscopic cell counts was 0·922–0·988, and with counts by the Coulter counter it was 0·916–0·992.Reproducibility showed a coefficient of variation of 2–5 %. The carry-over between the samples was 2·0 %. Preserving milk samples with 0·05 % potassium dichromate did not influence cell counts, whereas freezing the samples reduced the counts 30 %.
Carnitine secretion into milk of ruminants
Authors: Snoswell A. M. , Linzell J. L. 
Published: June 2009

SummaryTotal acid-soluble carnitine concentration in cow's, goat's and ewe's milk was 117, 101 and 872 nmol/ml respectively, of which acetylcarnitine made up 30% in goats, 10% in cows and 11% in ewes. The concentration of carnitine in the arterial blood of goats decreased significantly (P< 0·01) with the onset of lactation from 18·1 to 8·4nmol/ml and during lactation in goats and cows there was a significant arterio-venous difference of carnitine across the udder, with mean extractions of 14 and 5% respectively. Calculation of the udder uptake of carnitine, from these figures and from udder blood-flows, showed that in goats the amount lost in the milk was much less than that taken from the blood, but in cows about the same. Two groups of lactating ewes on low and high nutritional planes were sampled at 2-weekly intervals from 2 to 8 weeks of lactation. The concentrations of total acid-soluble carnitine and acetylcarnitine in the milk were similar in the 2 groups and remained relatively constant over this period, but the total acid-soluble carnitine concentration in jugular blood from the ewes on the low nutritional plane was significantly (P< 0·01) higher than from the ewes on the higher nutritional plane from the fourth week of lactation. The total acid-soluble carnitine concentration in liver of goats was 290 nmol/g wet wt; mammary gland, 324; kidney-cortex, 692; heart, 2030 and skeletal muscle, 14300. Carnitine acetyltransferase (E.C. 2.3.1.7) activity of mammary tissue from lactating ewes was 0·6 μmol per min per g wet wt of which approximately half appeared to be ‘latent’ or membrane bound. Acetate thiokinase (E.C. 6.2.1.1) activity in this tissue was found to be 1·5 μmol per min per g wet wt and was predominantly localized in the cytoplasm. Carnitine palmitoyltransferase (E.C. 2.3.1.21) activity in the same tissue was 0·8 μmol per min per g wet wt while no acetylcarnitine hydrolase activity could be detected. The results suggest that carnitine in mammary tissue is extracted from the blood for the oxidation of both acetate and long-chain fatty acids and that some is lost in the milk.
High-melting-point triglycerides and the milk-fat globule membrane
Authors: Wooding F. B. P. , Kemp P. 
Published: June 2009

SummaryThe initial milk-fat globule membrane (MFGM) consists of a unit membrane with a layer of dense material 10–20 nm thick on one side. Extraction of isolated initial MFGM preparations 3 times with chloroform: methanol removes 90% of the triglycerides and most of the phospholipids. This extraction has no significant effect on the width or morphology of the dense material examined subsequently in the electron microscope, although all trace of the unit membrane disappears. This indicates that the dense material is more likely to be derived from protein from the secretory cell cytoplasm than from high-melting-point triglycerides from the milk-fat globule as has previously been asserted.
Effect of feeding fat to dairy cows receiving a fat-deficient basal diet: II. Fatty acid composition of the milk fat
Authors: Banks W. , Clapperton J. L. , Ferrie Morag E. 
Published: June 2009

SummaryThe effects on the fatty acid composition of milk fat of feeding various oil-enriched diets (soya oil, red palm oil/palmitic acid and tallow) to dairy cows receiving a fat-deficient basal diet are reported. It was found that a linear relation was obtained between the dietary intake of C18fatty acids and their output in milk fat. A similar relation, applicable only to the oil-rich diets, was found for the C16acids. The significance of these relations is discussed. Fatty acid compositions and yields are discussed and compared with literature examples in which similar oil-rich diets were fed, but in which the low amount of fat in the basal diet did not markedly depress milk yield. The proportion oftrans-isomer in the octadecenoic acid was found to increase appreciably on feeding soya oil, and to a lesser extent with dietary tallow. A linear relation between the 18:0 and 18:1 contents of milk fat was found, and its significance is discussed.
Lactostrepcins - acid bacteriocins produced by lactic streptococci
Authors: Kozak Witold , Bardowski Jacek , Dobrzański Władysław T. 
Published: June 2009

SummaryAll 47 non-nisin producing strains ofStreptococcus lactisand 12/13 strains ofStr. lactissubsp.diacetylactisexamined produced bacteriocins, for which the term lactostrepcins is suggested. Seven strains ofStr. cremorisexamined produced no bacteriocins active against 3 lactic streptococci strains used as indicators. The strains examined were divided into 3 groups: I, those producing lactostrepcins active against only one streptomycin resistant mutant ofStr. lactis60 indicator strain; II, those producing lactostrepcins active against all 3 indicator strains; III, those not producing lactostrepcins active against the indicator strains employed. The lactostrepcins were sensitive to various proteolytic enzymes and to phospholipase D, but retained full or partial activity after dialysis. Most of the bacteriocins studied were fully active only within the pH range 4·2–5·0 and were reversibly inactivated at pH 7·0 or 8·0. Results suggested occurrence of 4 different lactostrepcins. The lactostrepcins produced by all group I strains were the same, but there were differences among the lactostrepcins produced by group II strains. Lactostrepcins killed some β-haemolytic streptococci and some strains ofLactobacillus helveticus. One of the lactostrepcins was also active against certainLeuconostocstrains, but not against otherLeuconostocstrains, nor againstL. helveticusor other Gram-positive bacteria.
Effect of lipases on the ripening of Egyptian Ras cheese
Authors: El-Salam Mohamed H. Abd , El-Shibiny Safinaz , El-Bagoury Ekram , Ayad Elyen , Fahmy Nadia 
Published: June 2009

SummaryThe effect of added gastric lipases on the ripening and flavour development in Ras cheese was studied. Ras cheese was made from pasteurized milk with the addition of Italase, Capalase K or Capalase KL at the rate of 12 g/100 kg milk before renneting and analysed at different intervals for fat, moisture, salt, pH, soluble tyrosine and tryptophan and Shilovich ripening index. The organoleptic properties of the cheeses were also assessed. The addition of lipases was found to accelerate the development of flavour, particularly when Capalase K was used. These lipases had no effect on the gross composition of cheese during ripening.
Developments in column chromatography for the separation and characterization of casein micelles
Authors: McGann Thomas C. A. , Kearney Robert D. , Donnelly William J. 
Published: June 2009

SUMMARYSkim-milk was fractionated by permeation chromatography on CPG-10 (300 nm) at 20 °C with synthetic milk serum. The elution profile, which was highly reproducible, showed 3 partly resolved peaks. On treatment with 0.1% glutaralde-hyde before chromatography, a similar profile was obtained indicating no appreciable micellar dissociation during chromatography of the milk. The casein composition of the eluent fractions, determined by quantitative chromatography on hydroxyapatite, showed that 12.1% of total casein was associated with the low molecular weight peak. The micelle content of ²- and κ-casein increased with increasing elution volume, and the ±s/κ ratio showed a progressive diminution from 4·3 to 2·3. Large differences were found in the colloidal phosphate contents and the weight average diameters of the micelle fractions which clearly show that CPG-10 fractionates on the basis of molecular size.
Factors affecting the concerntration of vitamins in milk: II. Effect of breed, season and geographical location on riboflavin
Authors: Thompson S. Y. , Kon S. K. 
Published: June 2009

SummaryIn a survey done in 1943–44 there was no seasonal difference in the riboflavin content of milk from 10 different areas in England and Wales that could have been associated with the change from stall to pasture feeding, and mean values were about 160 μg/100 ml for both the periods November-April and May-October. However, values for the 6 months August-January were higher (about 175 μg) than for the 6 months February-July (about 150 μg). Over a 12 months' period the mean riboflavin contents of Shorthorn and Guernsey milk from the Institute's farm were 142 and 191 μg/100 ml, respectively.