bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect on the amount of residual milk of the interval between milkings, duration of milking, and delay between udder stimulation and milking
Authors: Elliott Gillian M. 
Published: June 2009

SummaryUsing an experimental method of half-udder comparisons the effects on the amount of residual milk of varying milking intervals, the duration of milking, and the delay between the stimulation of milk ejection and the start of milking were measured. Yield of residual milk was not related to the length of milking intervals within the range of 4–16 h but the butterfat content was directly related to the length of the interval. Neither the yield nor the butterfat content of residual milk was affected by a change in the duration of milking of 1 min. A delay between the stimulation of ejection and the start of milking of 6–8 min resulted in increasing the yield of residual milk by about 1 lb.It is suggested that these results indicate that milk ejection is sufficiently persistent that residual milk is unlikely to be affected by delays between stimulation of milking and the start of milking until they exceed 4–6 min.
Application of the hydrometric method of analysis to the estimation of solids-not-fat production
Authors: Wallace G. M. 
Published: June 2009

SummaryThe effect of preservative tablets added to milk on its composition and density is discussed. A comparison between the S.N.F. content of 10-day composite samples of milk from individual herds after making due allowance for added preservative, and the weighted mean S.N.F. calculated on a daily basis, showed that the 10-day composite sample could be used successfully for estimating S.N.F. hydrometrically. A comparison of the weights of S.N.F. supplied when estimated by gravimetric and hydrometric methods was made for ten herds supplying a commercial plant over a period of 260 days. The mean difference was –0·14% of the gravimetrically estimated weight, S.D. 0·4, and the range was ±0·6%. The result is discussed and is considered of sufficient accuracy to justify, on a technical basis, using the hydrometric method of estimating S.N.F. for determining and, if necessary, paying for the S.N.F. supplied.
The action of rennin on casein The disruption of thek-casein complex
Authors: Beeby R. , Nitschmann Hs. 
Published: June 2009

SummaryApproximately 30% of the nitrogen of κ-casein was soluble at pH 4·7 after the protein had been treated with rennin at pH 7 while approximately 10% was soluble in 12% trichloroacetic acid (TCA). The material soluble in 12% TCA appeared at a slower rate initially than did the nitrogen soluble at pH 4·7 but as the reaction proceeded it was released more rapidly.Treating κ-casein with urea, or repeated precipitation of the protein at pH 4·7, caused the formation of material insoluble at pH 7, apparently para-κ-casein. Both treatments appeared to free the same soluble fraction as does rennin acting in low concentration or for a short time.Low concentrations of rennin (0·07 μg/ml) released only part of the available soluble nitrogen from 2% solutions of whole casein at pH 7. Heating the reaction mixture appeared to restore the casein complex, the restoration being less complete the longer the reaction had proceeded.It is suggested that κ-casein is not a single protein but a complex, and that the action of rennin is first to open the secondary bonds responsible for the stability of this complex.
Biological estimation of oestrogenic activity in red clover (Trifolium pratense): relative potencies of parts of plant and changes with storage
Authors: Flux D. S. , Munford R. E. , Wilson G. F. 
Published: June 2009

SummaryImmature ovariectomized mice were used to compare the oestrogenic activities of different parts of the same clover plants; to estimate the relative potencies of biochanin A, genistein and diethylstilboestrol; and to compare the effects of different methods of storage on the oestrogenic potency of red clover leaf and petiole. Test materials were incorporated in the diet fed to the mice and the uterine weight response was used to measure oestrogenic activity.With material harvested at four different times, the leaf or leaf and petiole had the highest activity; small and large stem fractions of the plant were both relatively less active, and blossom and seed head were inactive.Comparison of successive estimates of the relative potency of isoflavones and diethylstilboestrol indicated that the relative responsiveness to the two types of oestrogen did not remain constant. Thus comparisons of estimates of oestrogenic activity of plant material, obtained in terms of diethylstilboestrol in different experiments, could be invalid.The potencies of alcohol, acetone and freeze-dried preparations were compared after storage for 18, 115, 212 and 230 days. Of the procedures tested, the most satisfactory was that in which fresh material was placed in 95% alcohol and the liquor and residue dried and stored at room temperature over concentrated sulphuric acid at reduced pressure.
The oxidative stability of butterfat extracted from Cheddar cheese
Authors: McDowell A. K. R. 
Published: June 2009

SummaryCheeses collected monthly for 6 months from 6 factories in the same district were stored for a period of 12 months. At intervals the cheeses were sampled and the fats extracted for oxidation tests. There was no increase in peroxide value, no decrease in induction period and only a slight increase in free fat acidity during storage of the cheeses.
Effects of dilution, freezing and thawing and drying on the dispersibility of isolated fat globule membrane
Authors: Chien H. C. , Richardson T. , Amundson C. H. 
Published: June 2009

SummaryThe effects of dilution, freezing and thawing, and drying on the dispersibility of fat-globule membrane (FGM) preparations were studied. Dilution of FGM favoured aggregation of the lipoprotein particles. Freezing and thawing of FGM had a similar effect. Drying FGM by roller-drying markedly decreased its dispersibility. Drying by low-temperature vacuum-drying only slightly increased the dispersibility of FGM, while freeze-drying and spray-drying gave larger increases in the dispersibility.
Phytanic acid and other branched-chain fatty acid constituents of bovine rumen bacteria
Authors: Hansen R. P. 
Published: June 2009

SummaryPhytanic acid, 3,7,11,15-tetramethylhexadecanoic acid, which hitherto had been isolated and identified from several natural sources including butterfat, ox perinephric fat and cow plasma, has now been found present in small amounts (2·9%) in the total fatty acids extracted from the rumen bacteria of a fistulated dairy cow fed a diet of clover-grass hay. This C20 multibranched fatty acid was not detected in the dietary clover-grass hay, and it is considered to have been derived from phytol by enzymic activity of the rumen bacteria.
The preparation of cheese curd by a continuous method: the effect of heating the curd in the absence of whey
Authors: Berridge N. J. , Scurlock P. G. , Aston R. 
Published: June 2009

SummaryCurd was made in a continuous curd-making apparatus (Berridge & Scurlock, 1969) and immediately separated from its whey. Its temperature was maintained at a high level (41–48 °C) as it was moved continuously in the form of a thin layer through a set of rollers. The curd then had a moisture content similar to that of normal curd at the end of scalding in the traditional process. After a suitable period of cheddaring the pH value and the moisture content of the continuously made curd were the same as those normally reached at the same stage in the traditional process.
Studies on the mechanism of gel formation in the California mastitis test reaction
Authors: Nageswararao G. , Derbyshire J. B. 
Published: June 2009

SummaryThe effects of various factors on gel formation in the California Mastitis Test (CMT) were studied to obtain information on the mechanism of the reaction. Death of the leucocytes in milk, produced either by storing the milk at 5°C or by freezing and thawing, markedly reduced the viscosity of the gel formed by the milk with CMT reagent. Samples of skim-milk to which leucocytes were added gave increasingly viscous gels with CMT reagent as the pH was increased to 10·0. Soluble casein increased the viscosity of the gel formed by leucocytes with CMT reagent. The viscosity of the gel was decreased by the addition of CaCl2 and NaCl. On microscopic examination the gel formed in the CMT appeared as an irregularly arranged fibrillar network containing DNA. Deoxyribonuclease I rapidly eliminated the gel-forming property of leucocyte nuclei with CMT reagent, and EDTA inhibited this enzyme activity. Crude protease, trypsin, papain and bacterial protease decreased the gelforming property to different degrees. The presence of EDTA with these enzymes resulted in the formation of a viscous, ropy gel before the addition of CMT reagent. It was concluded that at least a part of the protein of the DNA-protein complex of leucocyte nuclei, in addition to the native polymer of DNA, was necessary for gel formation in the CMT reaction.
Effects of ultra-high-temperature (UHT) processing and of subsequent storage on the vitamin content of milk
Authors: Ford J. E. , Porter J. W. G. , Thompson S. Y. , Toothill Joyce , Edwards-Webb J. 
Published: June 2009

SummaryThe vitamin content of ultra-high-temperature (UHT) processed milk was compared with that of the original raw milk. Three processes were used. In the first, which caused no change in oxygen content, the milk was heated and cooled in a plate-type heat exchanger. In the second, the milk was again heated indirectly and then evaporatively cooled, leaving in the milk about one-third of the initial oxygen content. In the third process the milk was heated by direct steam injection and cooled by evaporation and contained little or no residual oxygen.On processing and during subsequent storage for 90 days there was no loss of vitamin A, carotene, vitamin E, thiamine, riboflavine, pantothenic acid, biotin or nicotinic acid. There was little or no loss of vitamin B6or vitamin B12on processing, but up to 50% of each of these vitamins was lost during 90 days' storage. All the dehydroascorbic acid (DHA) and about 20% of the ascorbic acid (AA) was lost on processing. There was no further loss of AA during 90 days’ storage when no residual oxygen was present, but in milks containing more than about 1 ppm oxygen all the AA was lost within 14 days. About 20% of the folic acid was lost on processing; thereafter, as with ascorbic acid, the extent of the loss on storage depended on the residual oxygen content of the milk: in the absence of oxygen the folic acid was stable.
The digestion of fatty acids in the stomach and intestines of sheep given widely different rations
Authors: Sutton J. D. , Storry J. E. , Nicholson J. W. G. 
Published: June 2009

SummaryThe amounts of total lipid and fatty acids consumed, leaving the stomach and excreted in the faeces were examined in 4 sheep fitted with rumen and re-entrant duodenal cannulas. Diets of high (HM1) and low (CM1) roughage content were given at 0·9 times maintenance and the low-roughage diet was also given at 1·7 and 2·3 times maintenance. With all the rations more fatty acid left the abomasum than was consumed in the food, the difference being greater on ration CM1 than on ration HM1 and increasing irregularly with the amount of the low-roughage ration fed. Of the fatty acid entering the duodenum in the chyme, 72–89% was digested in the intestine. About 80% of the increase in fatty acids in the stomach was stearic acid and most of the remainder was palmitic acid. Almost all the polyunsaturated C18acids ingested in the food were hydrogenated in the stomach, and the amounts of oleic acid were also greatly reduced, although more oleic acid entered the duodenum in the chyme with ration CM1 than with ration HM1. The possible origins of the increase in fatty acids in the stomach are discussed.
The effect of the periodic feeding of linseed oil on the production and iodine value of milk fat
Authors: Wadsworth J. C. 
Published: June 2009

SummaryA study was made of the changes in the iodine value of milk fat from cows following the feeding of linseed oil (450g) at intervals of 6 days. Three cows in midlactation and of differing age and breed were used. The experiment consisted of a series of 3 collection periods, each of 6 days' duration, with 12 days between periods. Three doses of oil were given (6 days apart) between periods 1 and 2, the last dose of oil being given immediately before the start of period 2. The mean iodine values for the 3 periods were 35·5, 40·5 and 34·7 respectively. There was a distinct pattern of change in iodine value with time after feeding the oil, a maximum of 45·5 being attained on the second day with a subsequent decline to 38·5 on the sixth day. Analysis of variance showed that these effects were significant and due to oil-feeding, whereas changes in yield and content of fat and production of milk could be accounted for by normal decline in lactation. It was concluded that the periodic feeding of a large dose of linseed oil produces a significant increase in the iodine value of milk fat and avoids the possible disadvantages of continuous fat supplementation.
Comparison of milks processed by the direct and indirect methods of ultra-high-temperature sterilization. II. The sporicidal efficiency of an experimental plant for direct and indirect processing
Authors: Franklin J. G. , Underwood H. M. , Perkin A. G. , Burton H. 
Published: June 2009

SummaryThe variation of sporicidal efficiency with processing temperature was determined for an experimental ultra-high-temperature (UHT) milk sterilizer operating alternatively as an indirect or as a direct heater. Whole milk was inoculated with large numbers of spores of Bacillus subtilis 786 and Bacillus stearothermophilus TH24, and the proportion of spores surviving the sterilizing process was calculated from dilution and colony counts on the untreated and treated milk. The results for B. subtilis spores were unreliable, and the dilution count results for B. stearothermophilus spores were influenced by the inhibitory effect of the UHT processed milk. The results for the colony counts of B. stearothermophilus spores were preferred as a basis for the comparison of the direct and indirect processes. Over the range of processing temperatures 137–145 °C it was found that the sterilizing temperature had to be 3–4 degC higher with direct heating than with indirect heating to give equal spore destructions.
Apparatus and milking techniques used in lactation studies with sheep
Authors: Treacher T. T. 
Published: June 2009

SummaryA description is given of a simple milking apparatus for collecting the yields of individual ewes, and of the milking procedure used in studies of lactation in ewes of ‘mutton’ breeds. The incidence of mastitis, level of milk yield, some of the non-nutritional factors affecting the milk yield and the coefficients of variation of milk yield and composition are discussed in relation to data from 6 experiments in which ewes of mutton breeds were machine-milked twice daily for 6–9 weeks of lactation.
The composition of ewe's milk fat during early and late lactation
Authors: Noble R. C. , Steele W. , Moore J. H. 
Published: June 2009

SummaryThe composition of ewe's milk during the first 4 days of lactation and on the 100th day of lactation was investigated. The total fat content was highest (17· 9%) on the day of parturition but decreased rapidly to reach a level on the 2nd day after parturition that was similar to that observed on the 100th day of lactation (9·9 %).The concentration of octadecenoic acid, which was the major fatty acid of ewe's milk, was very much higher in early lactation than in late lactation. As the concentration of octadecenoic acid decreased the concentration of the shorter chain fatty acids (6:0−14:0) increased. The major octadecenoic acid was the cis-9 isomer. However, the proportion of the trans-11 isomer increased from 5·5 % of the total octadecenoic acid concentration in early lactation to 11·9 % in late lactation. Although linoleic acid remained a minor component of the fatty acids of the milk during lactation, its concentration increased from less than 1 % during early lactation to 1·4 % by the 100th day of lactation.
The temperature-dependent dissociation of β-casein from bovine casein micelles and complexes
Authors: Downey W. K. , Murphy R. F. 
Published: June 2009

SummaryThe temperature-dependent dissociation of β-casein from the casein micelles of milk and from the soluble casein complexes of colloidal phosphate-free (CPF) milk was investigated by high-speed centrifugation and gel-filtration. The percentage of the total casein in supernatants prepared by high-speed centrifugation of mid-lactation milks increased from approximately 6 to 15% on cooling the milks from 30 to 5 °C; β-casein accounted for about 46% of this increase, while αs-and κ-casein constituted 30 and 23%, respectively. On gel-filtration both of skim-milk and CPF milk on Sepharose 2B at 0, 2, 5, 10 and 25 °C, maximum amounts of free β-casein (c. 60% of total) were obtained at 5 °C. The remainder of the β-casein appeared to be more strongly bound to the αs- and κ-casein and may be involved in the internal cohesion of casein micelles. The free β-casein of both milk preparations appeared to be in equilibrium with the bound β-casein. On Sephadex G-200 columns at 5 °C, approximately 5 and 60% of the β-casein of skim-milk and CPF milk, respectively, was eluted in the free form in the expected position for a globular protein of molecular weight about 200000. At low temperatures, particularly at 5 °C, colloidal phosphate appeared to play an integrating role in the association of over half the total β-casein with the other casein components of native micelles. However, when the equilibrium between micellar and free β-casein was disturbed by gel-filtration on Sepharose 2B, the presence of colloidal phosphate did not prevent the release of most of the β-casein from casein micelles. Some problems encountered in the use of densitometry for the estimation of individual caseins on electropherograms are described.
Low resolution nuclear magnetic resonance in the determination of moisture in cheese curd
Authors: Berridge N. J. , Crean Elizabeth , Mansfield P. B. 
Published: June 2009

SummaryNuclear magnetic resonance was used to follow the decrease in moisture in curd cooled to solidify the fat as whey was exuded. The results did not correlate closely with those of moisture determinations by drying at 98 °C partly because of the relaxing effect of the solid curd structure when in close proximity to the whey. This effect was diminished as the whey left the curd, so that whey out of the curd was more readily saturated with radio-frequency energy and therefore absorbed less energy than whey in the curd when high intensity fields were used. The saturation effect could also be used to follow approximately the exudation of the whey.
Nutritional deficiencies of co-precipitate for the growth of a strain of Lactobacillus acidophilus
Authors: Keogh Barbara P. 
Published: June 2009

SummaryThe nutritional deficiencies of co-precipitate as a growth medium for a strain of Lactobacillus acidophilus have been studied. Acid production by this organism was insignificant in a medium composed of 4% low-calcium co-precipitate and 5% lactose.Additions of the amino acids phenylalanine, tyrosine, valine, cysteine and threonine as well as of nicotinic acid, manganese, magnesium and citric acid all increased acid production.When only half the milk solids of skim-milk powder was replaced by the coprecipitate, fortification with manganese only was required.
A study of methods for estimating the cell content of bulk milk
Authors: Pearson J. K. L. , Wright C. L. , Greer D. O. 
Published: June 2009

SummaryFour methods of estimating the cell content of bulk milk were studied, correlated statistically and their degree of reproducibility estimated. The relative merits of the 4 methods are discussed, and the need for defining the object of testing before selecting a test is stressed. If designed for use in a programme for mastitis control, or the control of milk quality based on cell content, each country must choose a screening test or a precise cell-counting technique, depending on the availability of laboratory resources, extension advisory services and other economic factors.Screening tests studied were the California Mastitis Test (CMT) and the Brabant Mastitis Test (BMR), the former showing a correlation coefficient of 0·817 against the Electronic Cell Count (ECC) method in 320 samples. The more objective BMR correlated well with the ECC method, showing a correlation coefficient of 0·987 for 406 samples. Direct microscopic counts (DMC) were correlated with a centrifugal method and with a chemical method of preparing samples for electronic cell counting. For 430 samples in each case the correlation coefficients obtained were 0·930 and 0·966 respectively. The 2 ECC techniques were compared using 430 samples, and a very close relationship was found (r=0·988).For regular examination of large numbers of milk samples using the electronic cell counter we consider the chemical method of sample preparation more suitable than the centrifugal method. Differences in the reproducibility and accuracy of both tests are negligible, but the former procedure is quicker, more economical in terms of cost, and more adaptable to a national testing programme.
The specificity for κ-casein as the stabilizer of αs-casein and β-casein II. Replacement of κ-casein by detergents and water-soluble polymers
Authors: Green Margaret L. 
Published: June 2009

SummaryThe cationic detergent cetyltrimethylammonium bromide (CTAB), the anionic detergents sodium lauryl sulphate and sodium deoxycholate, and the nonionic detergents Tween 20, Tween 80 and Brij 35, and lecithin, starch, glycogen, chondroitin sulphate and polyethylene glycol, were tested for their ability to replace κ-casein in stabilizing αs- and β-caseins against precipitation by Ca2+. Of the materials tested, CTAB and Tween 20 stabilized both caseins and Brij 35 stabilized only αs-casein. Analytical ultracentrifugation of mixtures of CTAB with each casein and of Brij 35 with αs-casein indicated that both detergents acted by disrupting the casein aggregates and complexing with the monomers. Addition of CaCl2 did not aggregate the Brij 35–αs-casein complex. It is concluded that the basis of the stabilization phenomenon involves specific interactions between κ-casein and αs-casein or β-casein at mainly hydrophobic sites.
Efficiency of utilization of energy and nitrogen for milk secretion by buffaloes fed various levels of concentrates
Authors: Shukla K. S. , Ranjhan S. K. , Netke S. P. 
Published: June 2009

SummaryTwenty-four Murrah buffalo cows were divided into 4 groups and were fed 0·3, 0·4, 0·5 or 0·6 kg of concentrate mixture per litre of milk produced. Energy and N balance studies were conducted on 2 animals from each group in the sixteenth and seventeenth weeks of the study. The efficiency of conversion of gross energy into milk energy ranged from 10·9 to 12·7%. The efficiency of conversion of metabolizable energy (ME) and ME above maintenance into milk energy ranged from 25·0 to 32·2% and from 51·7 to 78·6% respectively. Differences amongst groups were not significant for all the 3 parameters.The conversion of digestible N into milk N varied between 23·6 and 27·3% in different groups. The efficiency of utilization of metabolizable N for milk production ranged between 47·6 and 56·4%. Various groups however did not differ significantly from each other in these respects.