bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of the replacement of concentrates by roots on the intake and production of dairy cows
Authors: Castle M. E. , Drysdale A. D , Waite R. , Watson J. N. 
Published: June 2009

SummaryTo investigate the effect of replacing part of the concentrates by roots, a 16-week winter-feeding experiment was made using twelve Ayrshire cows. All the cows received 8 lb of hay per day and enough grass silage for a measurable residue to be left at each feed. Two rations were supplemented with 45 lb of fodder-beet per day but the other two contained no roots. At each level of root feeding, concentrates were fed at either 3·50 or 1·75 lb per 10 lb of milk.All the fodder-beet was eaten (8·4 lb dry matter) and, as this caused a reduction in the intake of silage dry matter of only 3·4 lb per day, there was a net increase in drymatter intake. The level of concentrate feeding had little effect on the intake of the other feeds. Rations which included roots contained significantly less crude fibre than rations without roots.The mean daily milk yields for the treatments with the low and high concentrate levels were 29·5 and 33·9 lb, respectively, without roots and 31·8 and 35·8 lb with roots. The fat percentages of the milk were similar on all four treatments whereas the solids-not-fat (S.N.F.) increased significantly from 8·42% on the treatment without roots and low concentrates to 8·64% on the treatment with roots and high concentrates. The response per 1 lb of extra S.E. was 1·0 lb milk and 0·02% S.N.F. between the low and high concentrate treatments and 0·7 lb milk and 0·05% S.N.F. between the two root treatments. The analysis of milk from individual quarters of all the cows during each period showed the continuous presence of some subclinical mastitis. It was estimated that this lowered the general level of S.N.F. percentage by 0·2% but did not bias the results from any one feeding treatment. For milk from healthy quarters only, the response to 1 lb extra S.E. from concentrates was 0·03% S.N.F. and from beet it was 0·08% S.N.F.
Inherited casein variants in cow's milk: II. Breed differences in the occurrence of β-casein variants
Authors: Aschaffenburg R. 
Published: June 2009

SummaryA survey was made of the frequency of β-casein variants in the milk of cows of five major British breeds. Three variants A, B and C differing in electrophoretic mobility were found to occur either singly or in pairs, as expected if each were determined by a single allele. The A variant was the most common and found in all breeds. Ayrshires and Shorthorns produced no other variant, whilst the B variant occurred in Jerseys and, at low frequency, in Guernseys and Friesians. Production of the C variant was restricted to the Guernsey breed in which it occurred at low frequency. The technique of paper electrophoresis, used for β-casein ‘typing’ of some 600 cows, is described in detail.
Lactic casein whey powder in rations for pigs: I. The substitution of un-neutralized lactic casein whey powder for barley meal in an all-meal ration for growing pigs
Authors: Dunkin A. C. 
Published: June 2009

SummaryThe results of 2 experiments indicated that casein whey powder can successfully constitute a relatively high proportion of an all-meal diet for growing pigs. Pigs given a diet consisting of a basal meal allowance per day of ½ lb meat meal and 1½ lb barley meal plus increasing amounts of casein whey powder took significantly less time and required significantly less food to grow from 50 lb to 120—140 lb liveweight, than either the control pigs or those given diets containing smaller basal meal allowances but correspondingly more whey powder. In the best diet whey powder comprised approximately 40% of the total food consumed. In one experiment, diets containing more whey powder than this resulted in slower growth rates, relative to that of the controls, from 110 lb liveweight onwards.There was a little more scouring on the diets containing the greater amounts of whey powder; but even where whey powder formed approximately 83% of the total food consumed, the incidence of scouring was not of great practical importance. Moreover, there was considerable variation among animals within treatment groups in this respect.
Transduction inStreptococcus lactis
Authors: Allen Lois K. , Sandine W. E. , Elliker P. R. 
Published: June 2009

SummaryTransduction experiments were carried out using recipient strainStreptococcus lactisC2Ss(streptomycin-sensitive) and virulent phages prepared on donor strainStr. lactisC2Sr(streptomycin-resistant). At a high multiplicity of infection of 10, transduction to streptomycin resistance occurred at a frequency approximately 1 in 30 surviving cells and the recombinant character exhibited a delayed expression. Transduction did not occur when phages propagated onStr. lactisC2Sswere used or when phage antiserum was added to the transducing phage suspension. The transducing phage manifested an altered lytic cycle following passage through theStr. lactisC2Srdonor which rendered it incapable of reinfecting the donor but did not alter its virulence for theStr. lactisC2Ssrecipient.
A comparison of hay and silage for milk production
Authors: Murdoch J. C. , Rook J. A. F. 
Published: June 2009

SummaryIn a series of 3 trials there was little or no difference in milk yield when cows were fed the same quantity of dry matter in the form of well-preserved hay or silage from the same sward.A higher milk yield was obtained from silage made from grass at an early stage of maturity than from silage or hay made from the same crop 5 weeks later.In 2 trials when hay or silage was fed ad lib. the dry-matter intakes of the cows were higher with hay than with silage, and there was a consequent increase in milk yield and S.N.F. content in favour of hay.Some of the results indicated that with certain silages a depression in the S.N.F. content of the milk, due to a decrease in the casein content, could occur, although this was not associated with an inadequate energy intake.
Greenish discoloration of butterfat during an extended period of cold storage
Authors: Lück H. 
Published: June 2009

SummaryDry butterfat occasionally develops a greenish colour when stored for at least 1½ years at −12°C whereas samples of the same fat kept for 2 years at +2 or +15°C do not show this colour defect. Spectrophotometrical measurements have shown that the defect is accompanied by a chemical change of the carotene. Its absorption maxima are shifted towards the shorter wavelengths, and a new absorption is observed at 400–410, 430–435 and 450–460 mm. The possible involvement of oxidation products of carotene, such as isomeric diepoxides or furanoid oxides is discussed. The colour defect can be observed before any change in flavour is noticed.
The para-caseinate-phosphate complex of washed rennet curd: its composition and its decomposition by water, sodium chloride solutions, and lactic acid solutions
Authors: Ling E. R. 
Published: June 2009

SummaryWashed rennet curd releases significant quantities of calcium phosphate and relatively small quantities of calcium para-caseinate when shaken with water. Treatment with small quantities of sodium chloride in aqueous solution similarly differentiates between these 2 components, but larger quantities attack both phosphate and para-caseinate with equal severity. A more extensive release of Ca and inorganic Poccurs when the curd is treated with lactic acid solutions; the comparative ease with which Mg is removed under these conditions suggests that Mg is present as magnesium citrate.
The effect of varying the interval between milkings on milk secretion
Authors: Wheelock J. V. , Rook J. A. F. , Dodd F. H. , Griffin T. K. 
Published: June 2009

SummaryThe effect of 6-, 12-, 18-, 24-, 30- and 36-h milking intervals on milk secretion has been investigated. The effect of the previous milking intervals was eliminated by interposing a recovery period consisting of 12-h milking intervals between the experimental intervals. Bias due to the carry-over of residual milk was reduced by removing the residual milk at the end of each milking, after an injection of oxytocin.The rate of secretion of milk and of the individual constituents decreased curvilinearly, with duration of the interval, but the degree of curvilinearity differed between constituents. The rates of decrease were in the following increasing order: sodium, chloride, fat, whey proteins, casein N, water, non-protein N, lactose and potassium. The effects of the treatments persisted for some time after the end of the experimental intervals, but the original rates of secretion were regained by the end of the recovery period. The differing effects on the secretion of individual constituents resulted in increases in the concentrations of sodium, chloride and whey proteins in the milk and decreases in those of lactose and potassium.
A comparison between a hot-wire laboratory apparatus and a plate heat exchanger for determining the sensitivity of milk to deposit formation
Authors: Burton H. 
Published: June 2009

SummaryUsing several milk supplies, a comparison has been made between the amount of deposit formed under standard conditions in a small plate type ultra-hightemperature heater, and the results from the hot-wire laboratory apparatus described previously. It is shown that the laboratory apparatus reproduces the variations in the sensitivity to deposit formation found using the plate heater. The relationship is linear if the criterion derived from the hot-wire results is taken as the square of that proposed previously. A decrease in the sensitivity to deposit formation during the ageing of fresh milk, and a seasonal variation, are indicated.
A method of detecting dissimilation of citrate by lactic acid bacteria usingStreptococcus lactisvar.diacetilactisNCDO 1007
Authors: Garvie Ellen I. 
Published: June 2009

SummaryIn suitable media the relationship between the citrate content and the acetoin formed by the growth ofStreptococcus lactisvar.diacetilactisNCDO 1007 is linear. An assay method for citrate is described which is based on this relationship. It has been used to assay the residual citrate in cultures of lactic acid bacteria and, therefore, to assess the ability of these bacteria to dissimilate citrate. Some suitable media for the test are described.
The persistence of cloxacillin in the mammary gland when infused immediately after the last milking of lactation
Authors: Smith A. , Neave F. K. , Dodd F. H. , Jones A. , Gore D. N. 
Published: June 2009

SummaryA series of experiments has been carried out in order to develop antibiotic preparations which, when infused into the udder at drying-off, eliminate established infection and prevent new infection from occurring in the dry period. It has been shown that the persistence of antibiotic in the dry udder is affected by the solubility of the antibiotic salt, the quantity of antibiotic infused and the base in which it is formulated. Whereas 0.2 g cloxacillin as the sodium salt infused in a 3% aluminium monostearate in mineral oil base after the last milking of lactation persisted for less than 1 week, 0.5 and 1.0 g cloxacillin in the form of the benzathine salt, in a similar base, usually persisted for 3 weeks.Secretions removed from the udders of dry cows inhibited the growth ofBacillus subtilisandSarcina luteabut not 2 strains of staphylococci.
n-Pent-l-en-3-ol and n-Pent-en-3-one in oxidized dairy products
Authors: Stark W. , Smith J. F. , Forss D. A. 
Published: June 2009

SummaryPent-1-en-3-ol and pent-l-en-3-one were isolated in approximately equal amounts from buttermilk obtained from oxidized cream. The two vinyl compounds were identified by combined gas chromatography and mass spectrometry. The flavour of pent-1-en-3-ol is comparatively mild being detectable in water, skim-milk, butter oil and butter at 3 pts in 106, 3 pts in 106, 1 pt in 105 and 1 pt in 105, respectively. The flavour of pent-1-en-3-one is approximately 1000 times stronger being detectable in water, skim-milk, butter oil and butter at 1 pt in 109, 3 pts in 109, 5 pts in 109 and 5 pts in 109, respectively: these concentrations are of the same order of magnitude as for the compound responsible for metallic flavour, oct-1-en-3-one.The formation of pent-1-en-3-ol and pent-1-en-3-one is discussed.
The effect of a temporary suspension of milking in mid-lactation on milk secretion after the resumption of milking and in the following lactation
Authors: Wheelock J. V. , Smith A. , Dodd F. H. 
Published: June 2009

SummaryAfter the suspension of milking for 2 weeks in 2 ‘experimental’ quarters of each of 4 Friesian cows, there was a reduction in the yield of milk from these quarters. Although subsequently there was a marked recovery, for the remainder of the lactation the yield was lower than that of the corresponding control quarters in which milking had not been suspended. Throughout the next lactation, in all 4 cows, the experimental quarters produced more milk than the corresponding control quarters. At the first milking after the suspension, there were marked increases in the concentrations of sodium and chloride and decreases in those of lactose and potassium in the milk obtained. Within 8 weeks, the composition recovered, and for the remainder of the experiment the composition of the milk from the control quarters was similar to that from the experimental quarters of each cow.
The interrelationship of the viscosity, fat content and temperature of cream between 40° and 80°C
Authors: Phipps L. W. 
Published: June 2009

SummaryThe dynamic viscosity coefficients η of creams containing up to 50% fat have been determined at temperatures of approximately 40, 50, 60, 70 and 80°C. All the creams behaved as Newtonian liquids, the shear stress being proportional to rate of shear up to the maximum rate used of 100 sec−1. At a given temperature a linear dependence of log η on (φ+φ5/3) was obtained for φ < 0·4, where φ is the concentration (w/w) of fat. Interpolation formulae have been derived to enable η to be calculated at any temperature between 40 and 80°C and for any fat content up to 40%. Formulae for the density ρ of cream have also been deduced to permit kinematic viscosities η/ρ to be computed. Nomograms have been constructed to enable η and ρ to be readily determined without the use of the interpolation formulae and when slight loss in accuracy is unimportant.
Determination of moisture in dairy products by near infra-red absorption of methanol extracts
Authors: Goulden J. D. S. , Manning D. J. 
Published: June 2009

SummaryAbsorbance measurements at the 1·93 μm water band on methanol extracts from butter, cheese and dried milk enabled moisture contents to be determined with coefficients of variation of 1·0, 1·1 and 2·0%, respectively. Butter, cheese and cheese curd analyses could be completed within a few minutes, but a 2-h standing period was required for dried milk to overcome difficulties associated with lactose precipitation.
The effects of intravenous infusions of insulin and of sodium succinate on milk secretion in the goat
Authors: Rook J. A. F. , Hopwood J. B. 
Published: June 2009

SummaryThe effects of intravenous infusion of insulin and of sodium succinate on milk yield and composition and on the yields of milk constituents was investigated in the goat. Depression of plasma glucose concentration to less than 40 mg/100 ml in response to infusion of insulin was associated with a decrease in milk volume and lactose yield, and increases in the contents of fat and casein and in the yield of fat. The increase in fat yield was the result of an increased output of C12–C18 fatty acids; the output of C4–C10 acids was slightly reduced. Infusion of succinate caused a reduction in the yields of milk and of lactose, protein and fat. There was no consistent change in milk composition.The origin of the effects is discussed.
Measurement of the quantity of lactose passing into mammary venous plasma and lymph in goats and in a cow
Authors: Kuhn N. J. , Linzell J. L. 
Published: June 2009

SummaryLactose in the plasma of 12 lactating goats and one cow with healthy udders has been measured by a sensitive and specific enzymic assay. Mean values (±S.E.) for arterial and venous concentrations were 52±11 µM and 70±11 µM respectively. Simultaneous measurement of mammary blood flow, milk yield and milk lactose concentration showed that 2·70±0·25% (mean±S.E.) of the total lactose production passed into the plasma. This rose to 42·7% in a goat when milking was suspended for 46 h. No lactose was found in the plasma of male and non-lactating female goats, but it was detected 4 days before parturition in a nulliparous goat.
The effect of fatty acids on the metabolism of pyruvate in lactic acid streptococci
Authors: Anders R. F. , Jago G. R. 
Published: June 2009

SummaryThe metabolism, of pyruvate by resting whole-cell suspensions of Group N streptococci was studied over the pH range 4·0–7·0, in the presence and absence of oleic acid. In the absence of oleic acid pyruvate was utilized maximally at pH 4·5 with the formation of acetate (volatile acid), acetoin + diacetyl and carbon dioxide. The formation of acetate took precedence over the formation of acetoin + diacetyl. In the presenoe of oleic acid the utilization of pyruvate was maximal at pH 6·5 and completely inhibited at pH 4·5. The only products detected at pH 6·5 were acetoin + diacetyl and carbon dioxide. This effect of oleic acid on the metabolism of pyruvate was also obtained after treating the cells with acetone. The mechanism of action of oleic acid on cells of Group N streptococci and its possible influence on the formation of flavour compounds in cultured dairy products is discussed.
Effect of varying enzyme concentration on the action of rennin on whole milk
Authors: Castle A. V. , Wheelock J. V. 
Published: June 2009

SummaryThe kinetics of the release of glycopeptides by the action of rennin on bovine whole milk have been studied. The initial rate of release of glycopeptides was proportional to the concentration of rennin. Using the integrated form of the Michaelis–Menten equation, values have been obtained forKmandV. These values varied between milk samples from individual cows, and for a single milk sample the value forKmincreased with increasing rennin concentration. It is suggested that theKmvalue is partly dependent on the carbohydrate composition of individual κ-casein molecules.
The status of casein micelles in chilled milk from the buffalo and the cow
Authors: Sabarwal Pershotam Kumar , Ganguli N. C. 
Published: June 2009

SummaryWhen milk was chilled for 12 and 24 h at 0 °C, a decrease in the calcium and phosphorus contents of the casein micelle of both buffalo and cow's milk was observed. This decrease was directly proportional to the cooling period. A proportionate increase with cooling in the sialic-acid content of the casein micelle of chilled milk was noticed. Casein micelle isolated from chilled milk exhibited low opacity compared with the normal counterpart.A decrease in micellar casein and an increase in soluble casein were observed in both buffalo and cow's milk, in proportion to the cooling period. Similar results were obtained when casein micelles were resuspended in milk dialysate and centrifuged.Casein micelles from chilled milk showed different patterns on starch-gel electrophoresis compared with normal micelles. The intensity of the κ-casein band was relatively higher in the chilled samples. Gel-filtration studies suggest that some molecular rearrangement occurs in the casein micelle when milk is chilled.The release of sialopeptide from micellar casein by rennet was not influenced by chilling. However, a decrease in the rate of turbidity development in renneted suspensions of casein micelles was noted in chilled milk, which suggests a change in the structure of the casein micelle.No difference was noticed between buffalo and cow's milk in these respects.
Adsorption of casein components by halloysite and kaolinite
Authors: Mills O. E. , Creamer L. K. 
Published: June 2009

SummaryThe adsorption of whole casein and some of its constituent caseins by halloysite and kaolinite in the presence and absence of urea and 2-mercaptoethanol has been studied. The order of adsorption generally observed for both clays in the absence of urea and 2-mercaptoethanol was temperature sensitive casein component (TS) > αs1-casein B > αs1-casein A > β-casein in the pH range 7·5–9·5, confirming that these two clays have structurally similar surfaces. In the presence of urea and 2-mercaptoethanol the rate of adsorption on to halloysite increased, although the quantity adsorbed decreased and the relative affinities of the major casein components at pH 8 were altered. However, urea and 2-mercaptoethanol did not alter the relative affinities of the caseins to kaolinite, although the quantity adsorbed did decrease. The casein components are probably adsorbed as monomers, and it may be the superior dispersing properties of the urea solution that decrease the amount adsorbed. The halloysite structure was altered by absorption of urea and the altered relative affinities of the various casein components in the presence of urea can be ascribed to that effect.The results support the hypothesis that adsorption occurs because the energy of the system is lowered due to changes in protein-solvent, clay-solvent and solvent-solvent (solvent structuring), as well as to electrostatic interactions.
Flavour defects in edible casein and skim-milk powder: II. The role of aliphatic monocarbonyl compounds
Authors: Walker N. J. 
Published: June 2009

SummaryAliphatic monocarbonyls have been quantitatively estimated in casein and skim-milk powder during storage. Concurrently these products have been evaluated organoleptically. A close relationship was evident between monocarbonyl level and the flavour or age of the lactic casein. Furthermore, the greater flavour stability of rennet casein and skim-milk powder was coupled with reduced monocarbonyl content. Fractionation of monocarbonyls into classes and individual compounds has shown that the higher levels in lactic casein compared with other low-fat products can be accounted for by a high level of acetone. The absence of appreciable quantities of other odd-numbered methyl ketones suggests that either acetone is derived from a non-lipid constituent of acid casein or decarboxylation of acetoacetate is specifically catalysed at acid pH. All methyl ketones identified in these low-fat dairy products were present in subthreshold concentrations. Saturated and unsaturated aldehydes were present at similar levels in stored lactic casein, rennet casein and skim-milk powder samples irrespective of their degree of musty or stale flavour.
Basal levels of prolactin in goat blood measured throughout a 24-h period by a rapid double antibody–solid phase radioimmunoassay
Authors: Hart I. C. 
Published: June 2009

SummaryThe development of a rapid, highly sensitive double antibody–solid phase (DASP) radioimmunoassay for ovine/caprine prolactin is described. The assay was applied to the measurement of basal levels of prolactin in the blood of 4 anoestrous lactating female, 4 anoestrous virgin female and 4 castrated male goats. For several hours after milking there was a chronic gradually decreasing release of prolactin in the lactating goats, such that the circulating levels of prolactin were, for 14–16 h of the day, at a much higher level than those in the virgin female or castrated male goats. The basal levels of prolactin in the castrated male goats (87–200ng/ml) were somewhat higher than those in the virgin females (47–77ng/ml). The effects of feeding and stress on prolactin levels are discussed.