bluuebunny/crossref_metadata_2025_split huggingface dataset:
651. The lactose-chloride contributions to the freezing-point depression of milk: II. Examination of partial contributions over the full lactation period of two cows
Authors: Cole E. R. , Douglas J. B. , Mead M. 
Published: June 2009

1. In testing the technique of using conversion factors (from determined concentration) for the calculation of the partial freezing-point depressions of lactose and chloride, regular weekly chemical analyses and freezing-point determinations have been made on the milk of one Jersey and one Friesian cow over a period of 7 months.2. Relative constancy of freezing-point has again been noted, but slight though consistent differences were present between the milks of the two cows. No seasonal variations were observed, but changes in the freezing-point depression for the milk of one were generally associated with corresponding changes for the milk of the other.3. Linear relationships were found and their adequacy tested between the partial depressions due to lactose and chloride for each animal. The relationships, though not statistically significantly different, differed considerably for each animal. It is suggested that formulae for the calculation of one of the constituents, lactose or chloride, from the determined amount of the other, need to be treated with caution in view of the results obtained for the two animals in this work.For the Jersey milk it was found that 80% of the total freezing-point depression was due to the lactose and chloride content (on a fat and protein-free basis). For the Friesian milk, indications were that the lactose-chloride contribution was of the order of 75% of the total depression, but the result of statistical analysis was less satisfactory for this milk.The co-operation of Mr J. McGibbon of the Hawkesbury Agricultural College is gratefully acknowledged. Thanks are due also to Mr J. V. Pascoe and the Dairy Farmers Co-operative Milk Co. Ltd. for their continued interest in the work.
659. Factors influencing the vitamin content of milk fat: V. Changes in vitamin A and carotenoid content of the blood plasma of cows and heifers near parturition in relation to secretion of these substances in the milk fat
Authors: Thompson S. Y. , McGillivray W. A. 
Published: June 2009

1. Plasma levels of vitamin A and carotenoids prior to and following parturition have been followed in groups of cows and heifers maintained under typical New Zealand farming conditions.2. Despite the high carotene intake prior to calving, the cows, and to a lesser extent the heifers, showed decreases in plasma vitamin A and carotenoid level at or near to parturition, the decreases in the levels for the cows being of the same order as those reported in Great Britain and the United States.3. Although the concentration of vitamin A and carotenoids was higher in the colostrum of heifers than of cows, the total daily secretion of these components by the cows was much greater over the first few days of lactation.4. Evidence is advanced to support the suggestion that the decrease in plasma components is related to the extra drain of colostrum synthesis rather than to any hormonal changes associated with parturition.We are indebted to the following: the Department of Scientific and Industrial Research for financial assistance towards the cost of this investigation; Mr R. M. Patchell and the farm staff of The Dairy Research Institute for the collection of milk samples; Miss Fay Frecklington for help with much of the analytical work; one of us (S.Y.T.) to the Royal Society, the Nuffield Foundation, and the Board of The Dairy Research Institute (N.Z.) for a travelling fellowship during the tenure of which the work reported here was carried out.
672. Variations in the solids-not-fat content of milk. Investigations into the nature of the solids-not-fat problems in the west Midlands
Authors: Griffiths T. W. , Featherstone J. 
Published: June 2009

1. During the period September 1954—August 1956 monthly samples of milk were obtained from individual cows in herds selected because of known history of low solids-not-fat. Records were kept of general feeding and management. Milk was analysed for total solids, butter fat and s.n.f. (by difference). Crude protein and lactose were also estimated at three-monthly intervals.2. Mean lactation averages were calculated for s.n.f. These showed a normal distribution around a mean of approximately 8·5%.3. Throughout the period a high proportion of samples failed to reach 8·5%. The seasonal effect is at its worst in March and April when 70% of the samples were below 8·5%.4. Effect of advancing lactation (uncorrected for the effect of season) agreed broadly with previously published work but marked differences in the shape of the lactation curve were found between different herds. Variations in s.n.f. are largely a reflexion of variations in crude protein.5. Age distribution of the cows agreed favourably with published figures for the national herd, and a mean regression of s.n.f. with age gave 0·11% per year.6. Supervision of the feeding of the herds in the investigation gave no measurable improvement in s.n.f. and no significant response was obtained from short-term trials where extra s.e. was fed.7. There was no undue incidence of disease of the udder, either clinical or subclinical.8. Little information could be obtained on breeding, but it is concluded that the major cause of the problem is the genetically poor potentialities of the cows as judged from the average composition of the milk they produce.
674. The lactic acid and volatile fatty acid contents of five locally made type cheeses
Authors: Barnett A. J. G. , Tawab G. A. 
Published: June 2009

1. A study has been made of the development of titratable acidity, lactic acid and volatile fatty acids in five locally made type cheeses. The study of the changes involved has been made over the period of ripening up to the stage at which each type would normally be marketed. All the cheeses were made from the same batch of milk at the same time.2. Slight modifications to the micro-column devised by James & Martin (13), and its use, have been suggested which have resulted in improved recovery of volatile fatty acids.3. The volatile fatty acids have been determinedin totoand also as separate constituents. Formic acid has been noticed as a common constituent of the acid mixture in all the cheeses, while, over the ripening period involved and apart from unidentified acids higher than caproic, the only other volatile acids encountered have been acetic and butyric, and on one occasion iso-butyric.4. Over the short ripening period studied, the lactic acid content of the soft cheeses rose, but after the initial rise in Pont l'Évêque and in Dutch cheese the results showed a downward trend. Fluctuations in the lactic acid content of the Smallholder cheese have been noted which compare with the corresponding findings of other workers.5. All the results presented have been calculated on the basis of fresh cheese because this is the customary practice and comparisons with other work would be difficult if this had not been adhered to.
677. The effect of variations in nutrient intake upon the yield and composition of milk: I. Variations in the amount and type of concentrates fed in winter rations
Authors: Burt A. W. A. 
Published: June 2009

1. A series of five experiments on the effects of variation in the concentrate ration of cows receiving normal diets of hay and grass silage are described.2. Responses in milk yield to the feeding of additional concentrates occurred in all five experiments and were statistically significant in three of them.3. Mean responses in four experiments with adequate statistical control ranged from 0·7 to 1·0 lb. milk/lb. additional S.E. at levels of feeding from 90 to 120% of the Woodman standard, and were not economic at prices ruling during the winter of 1955–56.4. There were indications that the responses varied with the yield of the cow, and in two experiments there was clear evidence that the response to a second addition of 20% in the production ration was approximately half of that to the first.5. The response to additional S.E. was appreciably reduced when normal protein standards were not maintained in the additional concentrates.6. A limited substitution of hay for concentrates, which did not alter S.E. intakes appreciably, had no appreciable effect on milk yield.7. Significant responses of solids-not-fat percentage to the feeding of concentrates above the normal standards occurred in two experiments, but not in two others where the control percentages were lower. The importance of factors other than energy intake in influencing this quantity was emphasized.
679. The relationship between milking rate and milk yield
Authors: Sandvik Öystein 
Published: June 2009

This paper deals with an investigation on the influence of milking characteristics on lactation yield, maximum daily yield, and persistency carried out at the Institute of Animal Breeding and Genetics at the Agricultural College of Norway.Data used for the analyses were collected from 57 heifers of Norwegian Red Poll and 111 heifers of Norwegian Red and White Cattle. The Red Polls were recorded at the Hafslund Progeny Testing Station, while the recording of the Reds and Whites were carried out by field control.When the effect of the milk yield at the recorded milkings on the observed milking characteristics was eliminated, the milking character had no significant effect on the lactation yield, the maximum daily yield, or the persistency. This was the case when the effect of the milk yield at the recorded milkings was eliminated by correction as well as by using only those observations of milking characteristics that were taken when the milk yield was between 6·1 and 7·0 kg. Slow-milking cows are not, therefore, necessarily poor milk producers.
686. The fatty acids of butterfat and the volatile acids formed on oxidation
Authors: Hawke J. C. 
Published: June 2009

1. Despite the presence of appreciable quantities of steam volatile fatty acids as glycerides in butterfat, no short-chain fatty acids with odd carbon number have been detected by gas-liquid chromatography of the acids.2. Mild oxidation of butterfat for short periods of time produces steam volatile fatty acids with odd carbon number. A large proportion of these acids was formic, with smaller proportions of propionic, valeric and nonanoic acids.3. The relative ease with which short-chain fatty acids are produced on oxidation of fats, points to the danger of contaminating naturally occurring fatty acids with extraneous acids.4. A total analysis of the fatty acids of New Zealand butterfat by gas-liquid chromatography compared well with similar analyses carried out by previous workers by means of esterfractionation analysis.
737. The heat coagulation of milk: II. variations in sensitivity of casein to calcium ions
Authors: Pyne G. T. 
Published: June 2009

1. The sensitivity to calcium of the caseinate-phosphate complex of milk heated at 120°C., increases to an early maximum and thereafter steadily declines, apparently in consequence of parallel changes in the sensitivity of its caseinate constituent.2. A simultaneously developed capacity of the heated complex to bind additional colloidal phosphate appears to be unrelated to these changes in casein sensitivity.3. Colloidal phosphate content is confirmed as a factor in the heat coagulation of milk.4. Heat-developed acidity contributes to the heat coagulation of milk primarily by increasing hydrogen-ion concentration and only slightly, if at all, through release of calcium ions from insoluble combinations.5. Neither serum proteins nor protein-lactose combinations play any significant part in the heat coagulation of milk.6. The bearing of these results on the heat coagulation of milk in general and on the operation of certain high-temperature stabilization treatments is discussed.
739. The effect of heat treatment and temperature of storage on the yield, quality and chemical composition of karish cheese
Authors: El-Sadek G. M. , Motteleb L. Abd El 
Published: June 2009

1. Four batches of soft (Karish) cheese were made from raw and from heat-treated milk containing 1·5% fat and 7% added salt. The cheeses were sealed in tins in contact with their own whey and examined after storage for 1 month and 2 months at room temperature and at 4—6°C.2. Cheese stored at room temperature lost weight throughout the 2 months, but cheese stored at the low temperature gained weight after 1 month and lost weight after 2 months. Parallel changes occurred in the moisture content and salt content of the cheese.3. The fat-in-dry-matter content of the cheese increased with room temperature storage, but at 4—6°C. it decreased after 1 month and increased after 2 months.4. Pasteurization of the milk increased the yield of cheese and the flavour, body and texture were better than that of raw milk cheese stored at the same temperature. The effect of low-temperature storage was, however, greater than that of pasteurization.5. The total nitrogen content of the cheese decreased throughout storage, particularly at room temperature. The decrease was smaller with pasteurized milk cheese which ripened more slowly. The total nitrogen content of the whey increased throughout storage at room temperature, but at 4—6°C. it increased after one month and decreased slightly after 2 months. The increases were greatest at room temperature and in wheys from raw milk cheese.6. The initial acidities and also the subsequent rates of increase were higher in wheys from raw milk cheese.7. The results are discussed in detail.
Microscopical observations on Cheddar cheese and curd
Authors: Dean Marion R. , Berridge N. J. , Mabbitt L. A. 
Published: June 2009

1. It is possible to study the structure of cheese curd and the disposition of microorganisms therein by microscopical observation of sections cut on the freezing microtome after fixation in formalin.2. In the small number of cheese examined bacterial colonies were found only in crevices.3. As ripening proceeded the finer protein structures tended to disappear.4. The distribution of bacteria in cheese curd is markedly uneven.
Some observations on slow and fast acid-producing variants of strains of Streptococcus cremoris and Str. lactis used as cheese starters
Authors: Garvie Ellen I. 
Published: June 2009

Improved growth of Streptococcus cremoris 924 was obtained in the presence of CO2.When fast and slow acid-producing variants of Str. cremoris 924 were mixed and the mixture subcultured daily the resulting cultures were all active acid producers, irrespective of the initial ratio of fast to slow cells. A balance is established between the two types of cell; probably this will vary with the cultural conditions and vary between strains of Str. cremoris and Str. lactis for any particular conditions of maintenance.Providing the strains are correctly selected, single-strain starter cultures can be maintained by daily subculture in litmus milk, apparently indefinitely. Activity varies with the present method within wide limits and this variation seems to be a function of the culture.Freeze drying is a satisfactory method of maintaining active single-strain starters.The author wishes to thank Miss Shelagh Gibbs for technical assistance, Miss H. R. Chapman for making the cheese, and Messrs. Cow and Gate, Ltd., for supplying the dried milk powder for these experiments.
A quantitative evaluation of some factors affecting the non-fatty solids of cow's milk
Authors: Alexander W. H. , Leech F. B. 
Published: June 2009

SummaryTen farms in the county of Durham took part in a field study of the effects of feeding and of udder disease on the level of non-fatty solids (s.n.f.) in milk. Statistical analysis of the resulting data showed that age, pregnancy, season of the year, and total cell count affected the percentage of s.n.f. and that these effects were additive and independent of each other. No effect associated with nutritional changes could be demonstrated.The principal effects of the factors, each one freed from effects of other factors, were as follows:Herds in which s.n.f. had been consistently low over a period of years were compared with herds in which s.n.f. had been satisfactory. Analysis of the data showed that about 70% of the difference in s.n.f. between these groups could be accounted for by differences in age of cow, stage of lactation, cell count and breed.There was some evidence of a residual effect following clinical mastitis that could not be accounted for by residual high cell counts.The within-cow regression of s.n.f. on log cell count calculated from the Durham data and from van Rensburg's data was on both occasions negative.The implications of these findings are discussed, particularly in relation to advisory work.
Incorporation of [1-14C] and [3-14C] butyrate into milk constituents by the perfused cow's udder
Authors: Lauryssens Monique , Verbeke R. , Peeters G. , Reinards M.-Thérèse 
Published: June 2009

SummaryOne half-udder from a lactating cow was perfused for 110 min with blood containing 1 mc of [1-14C]butyrate. Inactive sodium butyrate was added at the eightieth minute. The volume of milk collected was 320 ml. One half-udder from another cow was perfused for 120 min in the presence of 0·5 mc [3-14C]butyrate, inactive sodium acetate being added at the sixtieth minute. The volume of milk collected was 150 ml.The total amount of14CO2recovered was 5·7% of the [1-14C]butyrate given and 7·6% of the [3-14C]butyrate given. In both instances casein, followed by the volatile fatty acids, showed the highest specific activity of the constituents isolated from the milk. The glyceride fatty acids in the udder were fifty times as active as those in the milk. With [3-14C]butyrate the activity of the total fatty acids amounted to 24% and that of total lactose to 0·38% of the added14C. Butyrate did not appear to be used for glycogenesis in the perfused gland. The specific activity of the lower fatty acids of both the udder and the milk increased stepwise with increasing chain length to reach a maximum at C10. A satisfactory explanation for this peculiar14C distribution cannot be given at the present time. There was no evidence of direct esterification of butyrate. Most of the activity of casein was due to labelled glutamic and aspartic acids, the activity of the former being four times as high as that of the latter. The acids of the Krebs cycle isolated from the udder tissue when [3-14C]butyrate was given showed very high activity. No striking differences were observed between the results of the two experiments. It is concluded that butyrate is split into two C2components which behave identically. These are utilized for fatty acid synthesis and take part in the Krebs cycle. The relative14C distribution between the components isolated from milk and those from tissue may be a reflexion of the secretory processes in the udder cells, synthesized fat tending to be secreted in the alveoli after the other constituents.
The effect of various sampling intervals on the estimation of lactation milk yield and composition
Authors: O'Connor L. K. , Lipton S. 
Published: June 2009

SummaryA study was made of the effect of various sampling intervals on the accuracy of estimating lactation milk yield, fat yield, solids-not-fat (S.N.F) yield, fat percentage and S.N.F. percentage. The basic data consisited of daily milk, fat and S.N.F. yields for eighteen lactations made by twelve Dairy Shorthorn cows. Estimates of the lactation yields and quality were obtained using sampling intervals of 7, 14, 28, 42, 56 and 63 days, and were expressed as differences from the actual values. Only in the case of milk yield was there any effective bias in the estimates. This bias increased with increasing sampling interval.The distributions of differences between estimated and actual values are presented. The error of estimation increased with increasing sampling interval. Keeping in mind the comparatively small-sized sample used in the investigation, the results are discussed in the light of the purposes for which records are kept.
Haematin compounds and tallowy discoloration in Cheddar cheese
Authors: Rammell C. G. 
Published: June 2009

SummaryEvidence linking a Cheddar cheese defect, known as ‘tallowy discoloration’, with a haematin-catalysed oxidation of the fat is presented. The defect has been produced experimentally by incorporating blood in the cheese-milk. The possibility that excessive amounts of blood in the cheese-milk may be a prime cause of tallowy discoloration is discussed.
The effect of root feeding on the intake and production of dairy cows
Authors: Castle M. E. , Drysdale A. D. , Waite R. 
Published: June 2009

SummarySince grassland conservation crops are normally bulky fibrous feeds and often limit the appetite and nutrient intake of dairy cows, a feeding trial was made in which a basal ration of hay and grass silage was compared with similar rations containing roots. Three rations were compared in a 12–week winter feeding trial using twelve Ayrshire cows. Ration A consisted of 8 lb of hay and 65 lb of grass silage daily, whilst rations B and C contained 30 and 60 lb of fodder-beet, respectively, in addition. With all three rations concentrates were given at 3½ lb per 10 lb of milk. The total weights of dry matter consumed per day were 29·1, 32·5 and 35·4 lb, respectively, for rations A, B and C and were significantly different. For every 1 lb of additional fodder-beet dry matter eaten the decline in the amount of basal feeds consumed was 0·45 lb. The largest effect was on the silage which fell from 10·8 lb of silage dry matter per day for ration A to 8·8 lb for ration B and 6·8 lb for ration C.The weight of starch equivalent (S.E.) given per day increased significantly from 18·1 lb for treatment A to 22·2 lb for treatment C, whilst at the same time the total weight of crude fibre and lignin eaten decreased significantly in the rations containing fodder-beet.The mean daily milk yields for rations A, B and C were 37·4, 39·2 and 38·5 lb, respectively, with a response of 0·9 lb milk per 1 lb of extra S.E. given between rations A and B but no further response between rations B and C. The fat percentages of the milk were not significantly different for the three rations whereas the solidsnot-fat (S.N.F.) varied significantly from 8·58% for ration A to 8·77% for ration C— a response of 0·05% S.N.F. for each additional 1 lb of S.E. The change in the S.N.F. was mainly in the protein fraction of the milk. The cows were significantly heavier when on ration C than when on ration A.The effect of feeding roots on the appetite of the cow and on the resulting milk quality, and the problems of growing roots on intensively managed grassland farms are briefly discussed.
A comparison of the hydrometric and gravimetric methods for the determination of solids-not-fat when applied to the milk of individual cows in a single herd
Authors: Edwards R. A. 
Published: June 2009

SummaryFive hundred and sixty-nine individual cow milk samples from forty-five cows in a single herd were analyzed for fat by the Gerber method, and solids-not-fat by a standard gravimetric method and by the two commonly used British hydrometric techniques. Three hundred and four of the samples were analyzed also for lactose, protein and ash. Large differences between the total solids values obtained by the hydrometric and gravimetric methods were recorded. The magnitude of the differences from the gravimetric values varied with the season of the year and the stage of lactation. The main factor affecting the differences was the protein content of the milk, and equations for the calculation of total solids content incorporating a protein correction factor are given for use if the protein content be known. The hydrometric methods are considered to be of limited use when applied to milks of individual cows.