1. The body size and grading of the wastage cattle have been described. It was found that the average wastage cow is relatively small in size with an average live weight of 1100 lb. or 9¾ cwt. The condition was also disappointingly poor since over one-half of the total wastage cows are in grade C or are ungraded.

2. The seasonality of the sales shows an autumn glut, which appears to increase as the grade or condition deteriorates.

3. The annual variations in body size during the 4 years are very slight, which seems to indicate that under present circumstances the region can only maintain cows of this size.

4. It was shown that the region can be subdivided into four parts in which the average body size for each section falls into one of four well-defined ranges of weight.

In the course of an investigation on the yield and composition of sows' milk, we have experienced difficulties in obtaining representative samples of milk for analysis.

The technique adopted was that described by Braude et al. (1) in which 5 units of pitocin were injected into the ear vein of the sow and the milk withdrawn by hand. Since the yield of these sows was being measured over a 24 hr. period each week, it was possible to compare the quantities obtained, following injection, with the average amount suckled by the litters during natural sucklings. The comparison was never particularly accurate as we found that two operators, each milking one teat, were all that could be conveniently accommodated on each side of the sow. This meant that only four glands could be milked properly. We found, too, that variations in teat size and mammary gland size affected the speed of withdrawal and the final amount obtained.

This paper presents in statistical form the results of the bacteriological examination of over 1200 samples of National Dried Milk during the period 1944–9. Factors which may affect the results are discussed. The general level of bacterial quality disclosed is high, but appreciable differences are shown in the standards reached at different factories and repacking depots. No general trend with time was observed in the figures throughout the period of 6 years considered, and no correlation was observed between the counts obtained and the time which had elapsed since packing into 20 oz. tins. Between counts at 37 and at 55° C. some correlation was noted in the products of most factories and depots, and the significance of this observation is discussed. The counts obtained are compared with various standards which have been put forward or are now in operation, and ways are suggested in which the figures might be used to set up standards of bacterial quality for roller-dried milk powder in this country.

1. The experiments described in this part of the report were designed to obtain information about the effect of time and temperature of pre-test storage on test results and, in particular, about the possibility of a practical method of compensating test results to eliminate or minimize their dependence on the time and temperature of pre-test storage.

2. Four separate experiments were planned and carried out in three widely separated areas in England and Wales. Samples of morning milk, brought to the laboratory with the minimum of delay, were divided into a series of subsamples which were subsequently stored at controlled temperatures ranging from 3 to 24°C, and at shade atmospheric temperature, for periods ranging from 7 to 30 hr. before examination by one or more of the following tests: keeping quality at 18, 22 and 24° C. using clot-on-boiling (C.O.B.), and precipitation with 68% alcohol (A.P.T.) or 50% alcohol; methylene-blue test at 37–5° C. and at 18, 22 or 24° C. The results for the different tests were the times to end-point after transfer from the storage to the incubation baths.

A rapid method for the colorimetric analysis of micro quantities, of citric acid beginning at concentrations of 0·01% of citric acid in milk and in dairy products has been described. The analysis is based on the yellow colour which develops upon reacting citric acid with pyridine in a solution of acetic anhydride, as applied by Saffran & Denstedt for the estimation of citric acid in blood. The accuracy of the method in the ranges normally used in the estimation of citric acid in milk is approximately ±3%. Examples of determinations in milk and dairy products are given.

1. Improvements are described in the methods for the extraction and colorimetric estimation of metals in dairy produce, using the carbamate reagent for copper and thiocyanate for iron.

2. A combined filtration procedure has been developed to enable both metals to be determined on the same sample, and with slight modifications this procedure has been applied to the analysis of samples of butter, cream, buttermilk and whey.

3. The wet-ashing technique has also been improved to enable it to be used for the estimation of both metals on the same digest.

4. Comparisons show that the combined filtration method is capable of giving results which agree very well with those yielded by wet-ashing.

5. The results of many analyses show that the majority of creamery butter samples have a satisfactorily low content of both copper and iron.

6. Many whey butter samples have a rather high metallic content.

7. Notes are given on the results obtained when the methods described are applied to other dairy produce.

1. The viscosity temperature coefficient of homogenized milk has been determined with an estimated accuracy of 1%.

2. The effect of temperature on the viscosity has been investigated in some greater detail.

A preliminary investigation was carried out on the effects of two ranges of temperature (room and refrigerator) on the creaming properties of cows' and buffaloes' milk. The results reported show that:

(1) While refrigerator temperature favoured the creaming of cows' milk, it greatly retarded the creaming of buffaloes' milk. This retarding effect was associated with a smaller cream-layer volume and a greater percentage of fat in the skim milk.

(2) At room temperature, the creaming of buffaloes' milk proceeded much more rapidly, suggesting that fat clumping was probably being induced.

(3) For both kinds of milk, when creamed at room temperature, the maximum values of the cream-layer volume and the specific cream-volume were found to be less than when creaming occurred in the refrigerator: reverse temperature relationships were observed in connexion with the maximum fat content of the skim milks.

In conclusion, it may be added that the observed variations in the cream-layer volume, and the fat content of the skim milks resulting from creaming at the two different temperature levels and for the varying lengths of time, would clearly result in some variability in any cheese made from such milk. This would particularly affect the yield, quality, composition and nutritive value of the cheese.