bluuebunny/crossref_metadata_2025_split huggingface dataset:
689. The effect of variations in nutrient intake upon the yield and composition of milk: III. A note on experimental methods
Authors: Burt A. W. A. 
Published: June 2009

1. Data from seven winter feeding experiments with dairy cows, using 3×3 latinsquare designs and from two randomized block experiments on the supplementation of summer grazing, were used in a study of some aspects of experimental technique.2. In the 3×3 trials the use of observations from 2 weeks instead of the last week of each period reduced minimum significant differences by 0·1 lb. milk/cow/day, and 0·06 and 0·02 mean percentage unit of fat and solids-not-fat, respectively.3. In three out of four experiments no advantage was obtained from recording live weights on more than 1 day at the end of each period.4. It was shown that the analysis of variance of milk yields expressed as individual differences between yield in the experimental period, and the mean of pre- and post- experimental control periods was considerably more efficient than that of yields in the experimental period, or covariance with yield in the initial control period.5. The results were discussed in relation to the sources of error involved, and the relative efficiency of various types of experimental design.
690. An investigation of fourteen herds producing substandard milks in the East of Scotland
Authors: Edwards R. A. 
Published: June 2009

1. Four hundred and sixteen individual cow samples of milk from fourteen herds were analysed for fat, total solids, crude protein, lactose and chloride.2. Wherever possible information concerning feeding, incidence of mastitis, age of cow, stage of lactation and successful service dates was collected.3. The milk samples were divided into normal (with 8·50% S.N.F. or over) and substandard (with less than 8·50% S.N.F.) groups.4. The difference in S.N.F. content between the normal and substandard groups was due almost equally to a drop in lactose and protein, but with the latter playing the major part. Thus, although inadequate feeding was probably a major factor in lowering the S.N.F. in this population the fact that the lactose content was so often low was taken as indicating that mastitis was also important.5. Breed, age of cow and stage of lactation all affected the incidence of low S.N.F. milks.6. On average the substandard milks showed a reduced fat content as well as a lowered S.N.F. level.
710. The determination of free fatty acids in milk
Authors: Perrin Dawn R. , Perrin D. D. 
Published: June 2009

An extraction-titration method is described for the determination of free fatty acids in small samples of fresh milk.Recoveries of fatty acids added to milk ranged from 63% for butyric acid to 97% for stearic acid. For a composite sample approximating milk fat in fatty acid composition the recovery was 83%.Interference from citric and lactic acids was not significant for reasonably fresh samples.The method gives a higher recovery of the lower molecular weight fatty acids than is possible by earlier methods.For titrating very dilute solutions of fatty acids α-naphtholphthalein was shown to be a more accurate indicator than phenolphthalein; it also provides a better defined endpoint.
714. The relation between the chemical composition of milk and the stability of the caseinate complex: III. Coagulation by rennet
Authors: White J. C. D. , Davies D. T. 
Published: June 2009

1. The variation in the time required for the coagulation of milk by rennet and the relationship between milk composition and renneting time were examined.2. The renneting times of herd bulk milks varied over the relatively narrow range of 3·2–5·4 min., whereas the renneting times of milks from individual cows varied from 1·4 to 12·9 min. and two did not coagulate.3. In general, milk quick to coagulate gave a firm curd (early lactation milk) and milk slow to coagulate gave a soft curd (late lactation and subclinical mastitis milk).4. The renneting time of milk was related to the stage of lactation of the cow. In early lactation, renneting times were short and as lactation advanced there was a progressive increase in renneting time; the increase became more pronounced towards the end of lactation.5. The property of milk most closely related to renneting time was acidity. As pH increased from 6·4 to 7·2, there was a curvilinear increase in renneting time from 1·5 to 13 min. Titratable acidity was related to renneting time in the opposite way to pH.6. Although milk containing a relatively high concentration of ionized calcium coagulated quickly with rennet, the renneting time of milks containing average, or less than average, amounts of ionized calcium was not related to their content of this constituent.7. Weak relationships between the concentrations of other milk constituents and renneting time could be attributed to the interrelations of the concentrations of these constituents and pH.
735. The B-vitamin content of milk in relation to breed of cow and stage of lactation
Authors: Gregory Margaret E. , Ford J. E. , Kon S. K. 
Published: June 2009

1. Microbiological methods were used to measure biotin, nicotinic acid, pantothenic acid, riboflavin, ‘vitamin B6’ and vitamin B12 in milk from Guernsey, Friesian and Shorthorn cows.2. A study was made of day-to-day variations and breed differences in the B-vitamin content of such milk. Fluctuations in each vitamin were observed from one day to the next in milk from individual cows, these variations being especially marked with biotin and vitamin B12. In addition, the variations in the mean vitamin levels of milk from cows of the same breed were generally greater than any breed difference.3. Samples of milk from ten Friesian and ten Shorthorn cows were taken at intervals throughout one complete lactation and analysed for each of the vitamins mentioned above. The results of this study of lactational trends are presented in detail.
Autogenous toxoid vaccine in the prophylaxis of staphylococcal mastitis in cattle
Authors: Pearson J. K. L. 
Published: June 2009

The use of an autogenous vaccine/toxoid in the prophylaxis of clinical and subclinical staphylococcal udder infections in a dairy herd is described. Mainly first calving cows were included in the trial, and the results are given on 25 vaccinated and 18 uninoculated control animals. Four injections of vaccine at weekly intervals were given and every 6 months a further inoculation was given with a view to reinforcing immunity.Observations were made over a period of 2½ years and there was a significant difference in the number of heavy staphylococcal infections and clinical cases in treated and control groups during the first 18 months, only one clinical case occurring in the treated group compared with 9 in the controls. Major infections totalled 8·1% during this period compared with 1·9% in the treated cattle, total staphylococcal infections being 16·2% compared with 7% in the respective groups.In the last 12 months of the experiment eight clinical cases occurred in the treated group compared with five in the controls. It is clear from these results compared with those for the first 18 months that the reinforcing doses of vaccine/toxoid every 6 months were insufficient to maintain immunity. Subclinical infections, however, remained at a lower level in the treated group than in the control animals.The significance of subclinical staphylococcal infections in relation to Whiteside tests is discussed, also the possible relationship of toxoid and bacterial vaccination to actual immunity produced. Some evidence is given that the presence of blood serum antitoxin is not necessarily associated with immunity.
Further studies on unrestricted whey for fattening pigs including the effect of omitting antibiotic from the diet during the later stages of fattening
Authors: Braude R. , Mitchell K. G. , Cray A. S. , Franke A. , Sedgwick P. H. 
Published: June 2009

1. Results are reported of an experiment with fattening pigs carried out under commercial conditions, to obtain further information on the comparison of all-meal feeding with meal plus unrestricted amounts of whey. In addition, the effect of omitting the antibiotic, oxytetracycline, from the diet during the latter half of the fattening period was investigated.2. There were four treatments. (i) Meal only ad lib. up to a daily maximum of 6 lb./pig, with oxytetracycline included in the diet for the whole fattening period. (ii) As (i) but oxytetracycline included in the diet only up to an average pen live weight of 130 lb. (iii) 3 lb. meal reduced to 2 lb./pig/day by 13 weeks of age plus unrestricted amounts of whey with oxytetracycline included in the basal meal for the whole fattening period. (iv) As (iii) but oxytetracycline included in the diet only up to an average pen live weight of 130 lb.There were five pens of nine group-fed pigs on each treatment, involving a total of 180 pigs. The pigs were on experiment from approximately 8 weeks of age to bacon weight. Comprehensive carcass measurements were made on all pigs.3. The meal plus whey-fed pigs grew significantly slower and utilized their food significantly less efficiently than those fed meal only. They also had a significantly lower dressing percentage, but longer and less fat carcasses than the all-meal fed animals. The results are discussed in relation to those obtained in earlier experiments completed under similar conditions at the Cow and Gate farm.4. Comparison of the efficiency of food utilization results of the all-meal and meal plus whey-fed pigs showed that 1 gal. of whey replaced approximately 0·7 lb. of meal.5. The results showed that omission of antibiotic from the diet of either the all-meal or meal plus whey-fed pigs after they reached 130 lb. live weight, had no significant effect on growth rate, efficiency of food utilization or any carcass measurements of the pigs.We wish to thank the Director of Messrs C. and G. Prideaux, Ltd., Bacon Curers, Motcombe, Shaftesbury, Dorset, for permission to take carcass measurements of the experimental pigs, and we are greatly indebted to Messrs K. Lawrence and P. Prideaux who most conscientiously took these measurements.
Heat resistance of lactobacilli from English Cheddar cheese
Authors: Perry K. D. , Sharpe M. Elisabeth 
Published: June 2009

The heat resistance of strains of lactobacilli previously isolated from Cheddar cheese was determined using a laboratory pasteurization test and a commercial pasteurizer.The laboratory tests showed variations in heat resistance at 140° F. for 10 sec. which were not correlated with species, but at 150° F. for 10 sec., an average of 99·55% destruction occurred with all strains.With the commercial pasteurizer, heating at 155° F. for 17 sec. caused a 99·99999–100% destruction, whilst heating at 160° F. for 17 sec. destroyed 100% of all strains of lactobacilli tested in every case.We wish to thank Miss H. R. Chapman and Miss A. J. W. Harrison for operating the pasteurizer.
Oestrogens in British pasture plants
Authors: Pope G. S. , McNaughton Mary J. , Jones H. E. H. 
Published: June 2009

1. Four species of Medicago, six species of Trifolium and fourteen grass species, all frequently found in British dairy pastures, have been tested for oestrogenic activity by the mouse uterine weight method. Activity was detected in four, four and six species respectively.2. It is probable that the quantity of oestrogen present in British pasture plants is insufficient to affect milk composition in cows at pasture. Some further experiments with cows are, however, suggested which might elucidate this.
Some volatile compounds in New Zealand Cheddar cheese and their possible significance in flavour formation: I. Identification of the volatile carbonyl fraction
Authors: Walker J. R. L. , Harvey R. J. 
Published: June 2009

Flavour concentrates from mature New Zealand Cheddar cheese were prepared by steam distillation methods. Using 2:4-dinitrophenylhydrazine reagent the presence of carbonyl compounds in the distillate was established. By means of paper chromatography, and other methods, the following compounds were identified in the distillate: acetoin, diacetyl, acetaldehyde, acetone, 2-butanone, 2-pentanone, 2-heptanone, 2-nonanone and 2-undecanone, and their approximate concentrations in New Zealand Cheddar cheese were determined. The possible role of these compounds in the formation of Cheddar cheese flavour is discussed.The authors gratefully acknowledge the helpful advice and criticism of Dr H. R. Whitehead and Dr W. A. McGillivray, and the technical assistance of Mr P. L. McLaughlin.
Restricted and ad lib. feeding of liquid skim-milk, with and without the addition of formalin, to fattening pigs
Authors: Mitchell K. G. , Sedgwick P. H. 
Published: June 2009

SummaryResults are reported of an experiment with fattening pigs, made under commercial conditions, on the effect of adding formalin to liquid skim-milk, to delay souring, on the nutritive value of the milk given either in restricted or in unrestricted quantities.There were four treatments: (i) Meal, fed to a scale based on live weight, plus sour skim-milk restricted to a maximum of 5¼ pints per pig per day. (ii) As (i) except that milk kept sweet by the addition of 0·15% formalin shortly after separation, was fed. (iii) Daily allowance of 2 lb meal/pig fed throughout the fattening period plus an unrestricted supply of sour skim-milk. (iv) As (iii) except that milk kept sweet by the addition of 0·15% formalin shortly after separation, was fed.There were five pens of nine group-fed pigs on each treatment, involving a total of 180 pigs. The pigs were on experiment from about 9 weeks of age to bacon weight. Comprehensive carcass measurements were made on all the pigs, and bacon-tasting tests were made on samples of both green and smoked bacon from a number of the carcasses.There were no significant differences between any of the four treatments in rate of growth or overall efficiency of food utilization.Pigs given formalin-treated milk had a significantly thinner layer of back fat over the loin than those given sour milk. Although the difference was relatively small, it was apparent whether the milk was fed in restricted amounts or ad lib. and was reflected in the commercial grading results. There were no significant differences between treatments in dressing percentage, carcass length, shoulder back fat thickness, belly thickness or size of eye muscle.No taint or off-flavour was detected in samples of green or smoked bacon from pigs fed milk to which 0·15% formalin had been added.The feeding of liquid skim-milk in unrestricted quantities is discussed in relation to the comparative prices of meal and skim-milk.The importance of adding the formalin to the skim-milk as soon as possible after separation, particularly during warm weather, is stressed in order that souring might be delayed for at least 1 week.
The effect of udder infections on the lactation yield of milk and milk solids
Authors: O'Donovan J. , Dodd F. H. , Neave F. K. 
Published: June 2009

SummaryData available for fifty cows mainly infected with Staphylococcus pyogenes have been analysed to determine the effects of udder infections and mastitis on milk, fat and solids-not-fat yield and on fat and solids-not-fat percentages over full lactations.It was found that lactation yields of milk, solids-not-fat and fat were depressed by 10, 11 and 12% respectively in the presence of infection. These depressions were significant (P < 0·05). The composition of the milk averaged over whole lactations was not significantly affected (P > 0·05), although the mean solids-not-fat percentage of the milk was significantly depressed by 0·196±0·092 during the period of infection.It is suggested that the depressions in lactation yield and changes in milk composition would have been greater in the absence of antibiotic therapy for mastitis.
Bulk feeds for milk Production: I. The influence of level of concentrate feeding in addition to silage and hay on milk yield and milk composition
Authors: Holmes W. , Arnold G. W. , Provan A. L. 
Published: June 2009

SummaryTwo experiments were carried out, Expt. 1 with twelve cows in a 4×4 Latin square and Expt. 2 with twenty-six cows in two groups which spent 11 weeks on the experimental rations. In both experiments hay and silage were fed ad lib. In Expt. 1 four levels of concentrate feeding were offered, 1¼, 2½, 3¾ and 5 lb/gal, and in Expt. 2 two levels, 1¼and 5 lb/gal. The levels of feeding as a percentage of Woodman's standards for starch equivalent (S.E.) ranged from 82 to 125% in Expt. 1 and from 83 to 116% in Expt. 2; for digestible crude protein (D.C.P.) the corresponding figures were 70–100% and 105–107%. When concentrate consumption increased by 1 lb dry matter the consumption of bulk feeds was reduced by 0·18–0·22 lb dry matter but the total fibre intake remained constant. Milk yield showed small but significant responses to level of feeding. Average responses per 1 lb S.E. were 0·77 lb milk in Expt. 1 and 0·61 lb milk in Expt. 2. Total lactation yields of the cows in Expt. 2 were unaffected by the experimental treatments. The production S.E. fed per gallon of milk ranged from 1·71 to 3·72 lb in Expt. 1 and from 1·92 to 3·27 lb in Expt 2. Production D.C.P. ranged from 0·37 to 0·63 lb and from 0·67 to 0·70 lb, respectively.High levels of feeding increased the S.N.F. and protein contents of the milk but did not affect other constituents. The responses in S.N.F. were lower than in some other experiments and some cows showed no response. The results are discussed with reference to the experimental methods and also with reference to the yield responses compared with published data, and to the practical importance of the high production obtained with low usage of concentrate feeds.
Fishy flavour in dairy products: I. General studies on fishy butterfat
Authors: Pont E. G. , Forss D. A. , Dunstone E. A. , Gunnis L. F. 
Published: June 2009

SummaryA distinct fish-oil or cod-liver-oil flavour appeared after storage in commercial butterfat containing, as an antioxidant, nordihydroguaiaretic acid (NDGA) and citric acid dissolved in propylene glycol. The fishy condition was reproducible in the laboratory by the combined effect of NDGA with either citric or lactic acids. The acids alone in butterfat gave oily and rather less clearly defined fishy flavours after storage.
Measurements of non-ionic iodine in the milk of dairy cows following oral administration of labelled sodium iodide
Authors: Morgan A. 
Published: June 2009

SummaryIt has been shown that iodine present as iodide in milk can be quantitatively removed by passing the milk through a column of an anion-exchange resin in the chloride form. Any residual iodine is present as non-ionic species which are not removed by the resin.This technique was used to determine the non-ionic iodine in milk at various times after the oral administration of a single dose of 131I to dairy cows and also during a multiple-dose experiment. Non-ionic131I was present in milk 6 h after its administration and the fraction in this form varied considerably in milk from different cows, ranging from 1·2 to 14·5% of the total 131I content. The chemical form of the nonionic iodine was not investigated.
The colloidal phosphate of milk: III. Nature of its association with casein
Authors: McGann T. C. A. , Pyne G. T. 
Published: June 2009

SummaryRemoval of colloidal phosphate leads to changes in the propertics of milk of which the increased viscosity and greatly increased sensitivity to calcium salts, and the apparently diminished degree of mutual integration of the various casein fractions are the most striking. Re-introduction of colloidal phosphate restores incompletely and only in certain instances the original properties of the milk.These observations are interpreted as favouring the conception of chemical links between colloidal phosphate and casein in milk.
The effect of feed supplements on the yield and composition of milk from cows grazing good pasture
Authors: Castle M. E. , Drysdale A. D. , Watson J. N. 
Published: June 2009

SummaryTwo experiments are described in which spring-calved Ayrshire cows were fed supplementary food when grazing good, leafy pasture.In the first experiment 6 lb of a mixture of three parts bruised oats and one part flaked maize was fed daily to three groups of five cows. One group received the supplement from 1 July until 30 October, and the other two groups from 1 August and 1 September respectively. A control group received no supplement.In no month was there any statistical difference in daily milk yield between supplemented and unsupplemented groups of cows. The group fed from 1 July gave the highest total milk yield in the period June to October, but with a return of only 1 gal of milk from 34 lb of meal.The length of the lactation was not significantly affected by the treatment.In the second experiment, three groups of four cows on a 9-week change-over trial (4 May-5 July) grazed herbage containing an average of only 17·6% dry matter and 3·8% crude fibre. On the three treatments the cows ate pasture only, pasture plus 1·6 lb hay/day and pasture plus 5·7 lb of meal/day. The meal consisted of four parts by weight of undecorticated cotton cake, four of bruised oats and three of locust beans.Milk yield was significantly increased from 41·8 lb on the all-grass ration to 43·2 lb/day on the meal treatment but the hay did not affect milk yield.The fat content of the milk was significantly increased from 3·77 to 3·91% on the hay treatment, whereas the solids-not-fat content of the milk was not significantly affected by any of the treatments.At the present-day prices of the feeds and with cows on good leafy pasture it was clearly uneconomic to feed the meal supplements.
The effect of the plane of energy nutrition of the cow during the late winter-feeding period on the changes in the solids-not-fat content of milk during the spring-grazing period
Authors: Rook J. A. F. , Line C. , Rowland S. J. 
Published: June 2009

SummaryThree groups of eight Friesian cows, four of high and four of low milk yield, were given during the last month of the winter-feeding period rations that provided respectively low, normal and high planes of energy nutrition, at approximately 75,100 and 130% of the Woodman standards for starch equivalent (S.E.). They were then all changed to the grazing of good, spring pasture, without supplementary food. The changes with grazing in solids-not-fat (S.N.F.) content and yield of milk were markedly influenced by the previous level of winter feeding. After 15–18 days of grazing the mean changes in S.N.F. percentage were +0·33, +0·11 and –0·12 for the low, normal and high energy groups, and the corresponding changes in milk yield were +7·70, +2·13 and –0·68 lb per cow per day. The changes in S.N.F. reflected mainly changes in protein content, and to these casein, β-lacto-globulin and α-lactalbumin all contributed. Small, differential changes were found in the fat and lactose contents of the milk. The effects of the level of initial milk yield of the cow on the various responses to grazing are recorded.These observations support the view that when a rise in S.N.F. with spring grazing occurs it probably results from an improvement in the plane of energy nutrition. There appears to be no need to postulate a special effect of any specific herbage constituent.