bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship between thickness, chapping andStaphylococcus aureuscolonization of bovine teat tissue
Authors: Fox Lawrence K. , Cumming Melinda S. 
Published: June 2009

SummaryPost-milking measurements of teat skin chapping score, teat thickness and colonization byStaphylococcus aureuswere determined for 11·5 d. Three teats on each of twelve Holstein cows, free fromStaph, aureusintramammary infections, were immersed in 1 M-NaOH solution to induce teat chapping; the fourth teat served as a control. To achieve different degrees of chapping, one teat per cow received one immersion after each milking for three consecutive milking periods, a second teat received two immersions, and the third teat received one immersion which coincided with the last immersion of the other two teats. All teats were challenged twice with a skim milk broth culture ofStaph, aureus(5 × 106cfu) after the first and second milking following NaOH treatment. Measures were initiated with the milking following the lastStaph, aureuschallenges. Tissue thickness of the lateral side of the teat (barrel) and colonization byStaph, aureusdeclined with time. Thickness of the teat end varied more erratically. Teat skin chapping score was positively correlated (P< 0·001) with tissue thickness of the barrel andStaph, aureuscolonization. Thickness of the barrel was not significantly correlated withStaph, aureuscolonization. Barrel thickness as a covariate had a significant effect (P< 0·05) on teat skin colonization ofStaph, aureus, whereas teat skin score and teat end thickness had no significant effect. Thus, thickness of the lateral side of the teat explained the greatest variation inStaph, aureusteat skin colonization in the model tested.
317. The resazurin and methylene-blue tests as a measure of the keeping quality of milk
Authors: Anderson E. B. , Wilson G. S. 
Published: June 2009

1. During four periods equally spaced throughout the year raw milks coming from surrounding farms into the Buckingham receiving station were examined by (a) the 10 min. resazurin test, (b) the 1 hr. resazurin test, (c) the resazurin test in which the time to reach disk 1 was recorded, (d) the modified methylene-blue test, and (e) a keeping quality test based on taste and alcohol precipitation. Altogether, 2588 samples were examined.2. Table 2, in which the correlation coefficients are worked out between the results of the dye and the K.Q. tests, shows that there is little to choose between the methylene-blue test and the time to reach disk 1 in the resazurin test; but since an average of only 15 min. was saved by carrying out the resazurin test, there seems little advantage to be gained by the use of this test. Both of these tests are superior to the 10 min. and the 1 hr. resazurin tests.3. A comparison of Tables 5–7, in which the average K.Q. of the milks corresponding to different disk numbers or reduction times is recorded, shows that the methylene-blue test affords the best indication of the K.Q.4. A study of Table 3, setting out the relation between the 10 min. resazurin and the methylene-blue reduction tests, shows that 99% of milks giving a 0–½ reading in the resazurin test reduce methylene blue within 30 min. and 80 % of them within 10 min.; but that, of milks reducing methylene blue within 30 min., only 53% give a disk reading of 0–½ in the 10 min. resazurin test. If it is agreed that no raw milk on arrival at the creamery which reduces methylene blue within 30 min. and which has, according to Table 7, an average K.Q. of only about 5 hr. at the time of testing, is fit for human consumption, then it is clear that the present rejection standard in the 10 min. resazurin test passes nearly 50% of unsatisfactory milks.5. The data recorded in this paper all go to show that the best indirect index of the K.Q. of raw milk is afforded by the methylene-blue test as carried out by the method officially laid down by the Ministry of Health.6. On the other hand, if time is an overruling consideration, then a slightly less accurate estimate of the K.Q. of raw milk is afforded by the 1 hr. resazurin test. It must be pointed out, however, that the figures given in Table 6 suggest that below disk 2 there is some irregularity in the relation between the disk numbers and the K.Q. If the 1 hr. resazurin test should come into use for the routine grading of milk, a revision of the present tints at the lower end of the scale might prove desirable.
320. Comparison of the growth-promoting value for rats of butter fat, of margarine fat and of vegetable oils
Authors: Henry K. M. , Kon S. K. , Hilditch T. P. , Meara M. L. 
Published: June 2009

1. A series of experiments with rats is described in which the growth-promoting properties of butter fat have been compared with those of the solid and liquid fractions of butter fat, with margarine and with certain vegetable oils.2. The separation of butter fat into fractions containing a preponderance of glycerides of saturated or unsaturated acids was effected by means of crystallization from acetone.3. The following results were obtained by incorporating fats in liquid skim milk:(a) No differences were detected between the growth-promoting properties of butter and margarine or of butter fat and deodorized arachis oil; in the latter comparison the arachis oil was more economically used than the butter fat.(b) No differences were found between butter fat and maize oil alone or containing the solid or liquid fractions of butter fat in the approximate proportions in which they occur in the original fat. The less saturated oils, i.e. maize oil and maize oil + the liquid butter fraction, were more economically used than butter fat and its solid fraction mixed with maize oil.(c) No differences were observed between the growth-promoting values of butter fat, arachis oil, cottonseed oil or soya-bean oil. The butter fat was rather less well utilized than the less saturated oils, but the differences were not significant.(d) Poorer growth was observed with the more saturated fraction of butter fat than with the original fat or the liquid fraction.4. When butter fat, margarine fat or arachis oil was incorporated in a dry basal diet, no differences were observed in the growth-promoting value of these fats, but the arachis oil was more economically used than the other fats. This finding was not con- firmed in a second experiment of longer duration in which poorer growth was observed with the arachis-oil diet, though the economy of gains was the same with all diets.5. It is concluded from these experiments that it is unlikely that butter fat possesses superior nutritive properties to those of other fats, and that the more saturated fraction of butter fat is certainly not superior in growth-promoting value to that of the more unsaturated fraction or to more unsaturated vegetable oils.
325. A study of the balance of certain milk nutrients in the making of Cheddar, Cheshire and Stilton cheeses, and of their fate during the ripening of the cheeses
Authors: Dearden D. V. , Henry K. M. , Houston J. , Kon S. K. , Thompson S. Y. 
Published: June 2009

1. Cheshire, Cheddar and Stilton cheeses were made on one occasion from winter, and on another from summer, milk.2. The distribution of vitamin A and carotenoids, vitamin B1, riboflavin and vitamin C between milk, whey and curd was measured during cheese-making.3. The fate of these vitamins during ripening was determined.4. Some 80% of vitamin A and carotene, 15% of vitamin B1and 25% of riboflavin originally present in milk were recovered in the green cheese and persisted throughout ripening.5. Vitamin C disappeared progressively during cheese-making and was absent from the cheeses.6. Vitamin B1and especially riboflavin were recovered in cheese in larger proportions than would be expected from the partition of water between curd and whey, indicating that they were partly present in milk in combination with the coagulable solids.
A quantitative analysis of mammary glands of dairy heifers reared at different rates of live weight gain
Authors: Harrison Roger D. , Reynolds Ian P. , Little William 
Published: June 2009

SUMMARYThe mammary glands of conventionally reared cows, never exceeding a live weight gain (LWG) of 0·74 kg/d, weighed 39% more and contained 68% more secretory tissue than glands of rapidly reared animals grown at 1·1 kg/d. In 11-month-old heifers reared at 3 rates of LWG (L, 0·57; M, 0·76 and H, 1·18 kg/d) gland weight was related to LWG, but dissected mammary parenchyma was heavier in animals on treatment L than on treatment H and followed a quadratic relationship. Parenchymal composition on treatment H was correlated to both age and body weight at puberty. No similar trend was observed in treatments L and M although group L animals had more ductal tissue and less fat than those of group M. Heifers from treatment L were reared during pregnancy at either 0·68 or 0·84 kg/d LWG (treatments LL and LH respectively) and heifers from treatment H at 0·58 kg/d (treatment HL). Total gland weight was unaffected by treatment, but the percentage by weight of secretory tissue in the gland in treatment HL was less than for treatments LL and LH. These experiments confirm that mammary development is permanently impaired by high rates of LWG in the first year of life. There was no impairment of mammary development in heifers reared moderately in the first year and more rapidly during pregnancy.
Preparation of dairy products for scanning electron microscopy: etching of epoxy resin-embedded material
Authors: Brooker Brian E. , Wells Karen 
Published: June 2009

SummarySections (1–5 μm thick) of epoxy resin-embedded cheese curd, yogurt, whipped cream and cream cheese were etched by treatment with warm alcoholic NaOH. Thin specimens were produced which could be metal coated and examined by scanning electron microscopy using accelerating voltages of at least 30 kV without producing charging problems. The images observed were easy to interpret and could be used to produce quantitative results. Although native milk fat globules did not survive the etching process, homogenized milk fat was not adversely affected. Critical point drying of etched sections produced results superior to those obtained by air drying.
Influence of the lactoperoxidase system on susceptibility of the udder toStreptococcus uberisinfection
Authors: Marshall Valerie M. E. , Cole Wendy M. , Bramley A. John 
Published: June 2009

SummaryLactoperoxidase (LP), thiocyanate (SCN-), pH and somatic cell counts (SCC) were measured in mammary secretions from 20 cows collected 14 d before drying-off, 7 and 21 d after drying-off, and 3–18 d postcalving. The inhibitory activity of the secretions onStreptococcus uberiswas determined and the susceptibility of the udder to infection by this organism was tested by intramammary infusion of 250 colony forming units at the above stages. LP, SCN-, pH and SCO increased during involution and fell postcalving. The secretions collected before drying-off, 7 d after drying-off and postcalving inhibited growth ofStr. uberis.; those collected 21 d after drying-off did not. Inhibitory activity in pre-drying-off secretions was destroyed by heating and restored by addition of LP, glucose and glucose oxidase, but addition of these substances to secretion 21 d after drying-off did not provide a full inhibitory system. The growth ofStr. uberisin the secretions was correlated with intramammary susceptibility, since challenges withStr. uberisat 14 d before drying-off, at 7 and 21 d after drying-off and postcalving led to 43·8, 25·0, 81·3 and 37·5% of quarters becoming infected. It is suggested that the LP/SCN-/H2O2system plays a role in protecting the lactating mammary gland from infection withStr. uberisbut becomes ineffective as involution progresses.
Oxygen concentration in milk of healthy and mastitic cows and implications of low oxygen tension for the killing ofStaphylococcus aureusby bovine neutrophils
Authors: Mayer Susan J. , Waterman Avril E. , Keen Peter M. , Craven Neil , Bourne F. John 
Published: June 2009

SummaryThe partial pressure of O2in milk from normal cows and from cows with mastitis was measured and the concentrations of O2calculated. Oxygen levels of milk from normal cows were similar to those in venous plasma, but inflammation of the mammary gland led to a dramatic drop in O2concentration to < 10% of control values. Intracellular survival ofStaphylococcus aureusstrain M60 in bovine neutrophils was greater under anaerobic than aerobic conditions. The implications of low O2concentrations in milk from infected mammary glands for the bactericidal activity of bovine neutrophils is discussed.
A simple procedure using trinitrobenzenesulphonic acid for monitoring proteolysis in cheese
Authors: Polychroniadou Anna 
Published: June 2009

SummaryA simple, rapid and sensitive spectrophotometric assay was developed and evaluated for monitoring proteolysis during cheese ripening, based on the fact that α-amino groups released by hydrolysis of cheese proteins react with trinitrobenzenesulphonic acid to form products that absorb strongly at 420 nm. A linear relationship was shown to exist between A420 and concentration of free α amino groups up to 0·5 HIM (r = 0·999, 38 df, P < 0·001). Repeatability of the method was satisfactory. The coefficient of variance was 0·53% for amino acid solutions and 1·19% for cheese extracts. Average recovery of glycine added to the cheese was 104 ± 2·9%. A comparison of the above method with that of determination of water-soluble N to total N ratio showed that there was good agreement between these two methods of assessment of proteolysis in cheese (r = 0·857, 32 df, P < 0·001). Mainly Feta and Teleme cheese were examined, but a similar correlation was obtained with hard Greek cheeses. Analytical conditions of the procedure are discussed.
Performances of falling film evaporators
Authors: Jebson R. Selwyn , Iyer Mani 
Published: June 2009

SummaryThe performances of falling film evaporators used in the New Zealand dairy industry for concentrating skim milk, whole milk and buttermilk were evaluated by determining (1) the kg steam used per kg water evaporated, and (2) the heat transfer coefficient of each pass in the evaporators. A computer program was used to calculate the results. The heat transfer coefficients varied from 0·3 to 3·2 kW/m2 per °C and the steam consumption from 0·4 to 0·09 kg steam/kg evaporation. The viscosity of the feed and the momentum of the vapours passing down the tubes were found to be the main factors controlling the heat transfer coefficient. A correlation between the heat transfer coefficient and these factors is presented. Other factors likely to have an influence on the performance are discussed.
Study of the fouling of inorganic membranes by acidified milks using scanning electron microscopy and electrophoresis. I. Membrane with pore diameter 0·2 μm
Authors: Attia Hamadi , Bennasar Michel , De La Fuente Blas Tarodo 
Published: June 2009

SummaryThe fouling of an inorganic microfiltration membrane with an average pore diameter of 0·2 μm obtained in static conditions with milk, acidified milk and acid coagulum was examined using scanning electron microscopy. The structure and porosity of external fouling related to the pH of the milk accounts for the performance and efficiency obtained in microfiltration. Electrophoretic analysis of permeate, characterized by lack of casein, shows that the deposit plays a fundamental role in mass transfer through filter layers. Variations in the physicochemical properties of casein as a function of pH at 50 °C were used to account for the development of the structure of fouling, which comprised three main states: (i) dense deposit of juxtaposed micelles, (ii) loose network formed by chains made up of bonded protein aggregate, (iii) irregular protein aggregate leading to high-porosity deposits. The presence of a protein film strongly adsorbed on the membrane layer of alumina particles is demonstrated.
Study of the fouling of inorganic membranes by acidified milks using scanning electron microscopy and electrophoresis. II. Membrane with pore diameter 0·8 μm
Authors: Attia Hamadi , Bennasar Michel , De la Fuente Blas Tarodo 
Published: June 2009

SummaryThe functioning of an inorganic microfiltration membrane (Membralox-SCT) with an average pore diameter of 0·8 μm, used for processing milk, acidified milk and lactic coagulum, was studied using dynamic and static conditions. Milk processing (pH 6·62) gave acceptable rates of protein retention but at low flow rates. Study of the effect of operating parameters during microfiltration of coagulum led to determination of optimal operating conditions leading to satisfactory performance and adequate retention rate. The results are explained using a model of the formation and development of internal and external fouling of a mineral membrane. Observations using scanning electron microscopy related to the pH of milk were used to verify the model by showing that internal fouling occurred only when the pH was higher than 5·50. This internal fouling was closely linked with the physicochemical state of milk proteins. Indeed, the fouling particles visualized at the alumina grains of the membrane support changed progressively from individual micelles (pH 6·62) to a chain or clustered structure (pH 5·60). Electrophoretic study confirmed this observation and showed that casein was present in milk permeates (pH 6·62) but not in coagulum permeates (pH 4·40).
Characterization of lactococci and lactobacilli isolated from semihard goats' cheese
Authors: Requena Teresa , Peláez Carmen , Desmazeaud Michel J. 
Published: June 2009

SummarySeveral strains ofLactococcus lactissubsp.lactis, Lactobacillus caseiandLactobacillus plantarumisolated from traditional goats' cheese have been studied for titratable acidity, proteolysis in milk and enzymic activities. Aminopeptidasc activities were measured with whole cells and cells permeabilized with Triton X-100. Caseinolytic activity was investigated using electrophoresis in polyacrylamide gel with sodium dodecyl sulphate.Lc. lactissubsp.lactishad a level of proteolytic activity in skim milk greater than that ofLb. casei, while this activity inLb. plantarumwas very low. Alanine aminopeptidase activity was almost non-existent for all strains tested, while lysine aminopeptidase activity appeared to be of fundamentally intracellular origin. Leucine aminopeptidase activity was also greater in cells that had been permeabilized than in whole cells forLb. caseiandLb. plantarum. Lc. lactissubsp.lactisleucine aminopeptidase activity was greater in whole cells. No significant hydrolysis of casein was found withLb. caseiI FPL 725 andLb. plantarumIFPL 722 permeabilized with Triton X-100 after 24 h incubation with whole bovine casein.
Dairy cow characteristics related to Staphylococcus aureus isolation from quarter samples
Authors: Enevoldsen Carsten , Gröhn Yrjö T. , Thysen Iver 
Published: June 2009

SummaryA comprehensive description of the health status of 2406 cows in 28 herds was used to study complex interrelationships between Staphylococcus aureus occurrence and potential risk factors at the cow level over a broad spectrum of production conditions. The objective of the study was to characterize those cows shedding Staph, aureus in milk and to provide indications of possible causal relations that should be further explored. The estimates are expected to aid in providing valid and precise evaluations of results from cross sectional microbiological examination of bovine (quarter) milk samples. Staph, aureus were isolated at microbiological examination of quarter milk from 5·2, 13·5, 17·9 and 22·0% of 1552, 490, 296 and 277 cows in lactations 1, 2, 3 and 4–9 respectively. Simultaneous isolation of other mastitis pathogens was not significantly associated with occurrence of Staph, aureus. Of the positive samples, 95% had a positive California mastitis test reaction. Among the clinical measures of udder health, only visibly abnormal milk combined with normal udder tissue was associated with increased occurrence of Staph, aureus, although not consistently. Prior antibiotic treatment for udder disorders was not significantly associated with Staph, aureus isolation. The occurrence of sole ulcers in multiple digits was consistently associated with Staph, aureus in the first lactation. Milk yield was involved in interactions with other pathogens isolated, prior veterinary disease treatment, body weight and season of calving. Strong herd-year effects were revealed. This, combined with the interactions, indicated that some herd-specific factors were major determinants of Staph, aureus occurrence. The study indicated which cow characteristics should be taken into account in epidemiological analyses and causal interpretations of data from cross sectional microbiological examinations of dairy herds.
Intraspecific variation inSchistosoma haematobiumfrom Algeria
Authors: Kechemir N. , Théron A. 
Published: June 2009

AbstractA comparative analysis has been carried out between two populations ofSchistosoma haematobiumusing the same intermediate snail host,Bulinus truncatus, but originating from two distinct ecological areas of Algeria: Khemis-El-Khechna in a sub-humid mediterranean zone and Djanet in a saharan bioclimatic zone. Four parameters have been studied: the growth rate of adult worms, size and shape of the eggs, chronobiology of cercarial emergence and the compatibility with the intermediate host. Results showing divergences for all the characters studied are discussed for the origin of this intraspecific polymorphism ofS. haematobiumin Algeria.
Scanning electron microscopy and intraspecific variation in Euchordodes nigromaculatus from New Zealand
Authors: Schmidt-Rhaesa A. , Thomas F. , Poulin R. 
Published: June 2009

AbstractTaxonomic characters of the male posterior end and the body cuticle of Euchordodes nigromaculatus (Nematomorpha) were described by scanning electron microscopy (SEM) and compared with the original description by Poinar (1991a) and with other Euchordodes species. Intraspecific variation was found in the body length, the distance between the cloacal opening and the posterior end and especially in the form of the male posterior end. The latter either possesses two short lobelike structures and a ventral groove or lacks these structures. The importance of SEM investigations and observations of intraspecific variation is stressed for the taxonomy of nematomorph species.
Larval trematode infections in freshwater gastropods from the Albufera Natural Park in Spain
Authors: Toledo R. , Muñoz-Antolí C. , Pérez M. , Esteban J.G. 
Published: June 2009

AbstractMalacological samplings were made from January 1994 to December 1996 in the Albufera Natural Park (Valencia, Spain) to trace the dynamics of molluscan populations and the prevalence and intensity of infection by larval trematodes. A total of 10,533 freshwater gastropods belonging to seven species (Lymnaea auricularia, L. truncatula, L. palustris, L. peregra, Bithynia tentaculata, Physa acuta and Gyraulus chinensis) was examined, and 110 (1.04%) were found to harbour some of the nine distinguishable types of cercariae, namely four echinostome cercariae (Hypoderaeum conoideum, Echinoparyphium recurvatum, Euparyphium albuferensis, and Echinostoma sp.), four furcocercous cercariae, and one xiphidiocercous cercaria. This study shows that the composition of the snail and trematode communities may be determined by the particular environmental conditions present and the human intervention in the area.
OnSyngamus iereisp. nov. from Domestic Cats, with some Observations on its Life-cycle
Authors: Buckley J. J. C. 
Published: June 2009

1. A new species ofSyngamusfrom the pharynx and nares of domestic cats in Trinidad is described.2. The larval development from egg to 3rd stage larva is described with particular reference to the anatomy of the 3rd stage larva.3. An attempt to trace the life cycle of the worm by direct infection of cats with the 3rd stage larvae was unsuccessful. It is suggested that an intermediate host is essential in the life cycle of this species.