1. Records are offered of year old cattle reared to adult weight on rations of varying content in respect to calcium, phosphorus, sodium, potassium and chlorine. Minimal requirements for growth are higher in the case of phosphorus than in the case of calcium, and a ratio of P2O5 to CaO so high as three to one is not necessarily disadvantageous. Sodium requirements for growth are very low, 2 gm. Na2O being more than sufficient. Chlorine requirements are below 5 gm. per day. A relatively high ratio of potassium to sodium is not productive of specific disease. There is no good reason to suppose that excess of basic over acidic constituents is necessary in a dietary, and cattle can grow normally to full adult weight when the usual alkaline reaction of the urine is shifted to the acid side.

2. Explanation of certain observed abnormalities in calving is left open, except in the case of phosphorus deficiency, in which definitely abnormal calves may be born.

3. “Aphosphorosis,” or clinically recognisable phosphorus deficiency disease, is experimentally produced, and shown to be identical with the naturally occurring South African disease Styfsiekte.

4. The chemical composition of the milk of animals suffering from aphosphorosis meed not mecessarily be abnormal, but the “inorganic” fraction of the blood may drop to a quarter of the normal value even before the disease can be diagnosed clinically. Other phosphorus compounds of the blood remain normally high. Blood calcium remains practically normal.

5. Vitamine deficiency of the diets had no adverse effect. Exogenous requirements of cattle for vitamines A, B, and C are so low that they are covered by a few pounds of poor quality roughage, and therefore do not enter into consideration under any natural system of cattle rearing.

During the carrying out of the series of researches which led to the formulation of the well-known expression for calculating the starch equivalent of a feeding stuff, Kellner(1) was led to investigate the value of crude fibre in the fattening ration of oxen. For this purpose he used material which had resulted from the boiling of rye straw with an alkaline solution under pressure, the object of this treatment being to free the cellulose of the straw from incrusting substances. This fibre-rich preparation was added to a basal ration which was slightly in excess of maintenance requirements. The result produced by the addition to the basal ration of the digestible matter derived from the fibre of the treated straw was found by Kellner to be equal to that produced by the addition of an equal weight of pure starch. The conclusion was therefore warranted that the digestion products of cellulose in the ruminant organism are equal, for purposes of fat formation in the body, to those derived from the digestion of starch. This finding is given practical expression in Kellner1s formula for calculating the starch value of a feeding stuff, an equal value being attached to digestible fibre and digestible carbohydrate.

It is clear that any theory which is put forward to explain the breakdown of cellulose in the ruminant tract must be compatible with the experimentally demonstrated fact that the products of such digestion of a given weight of digestible fibre are equal in nutritive value to the products derived from the digestion of the same weight of starch.

Although the primary object of recording cows' milk yields is to provide a means of comparing one individual with another, it is not satisfactorily achieved when the records have been obtained, since yields are influenced to a large extent by environmental factors which vary from cow to cow. The lactation record is the result of two sets of factors—genetic and environmental—and for purposes of selection and breeding it is important to be able to make accurate allowance for the one, so as to arrive at a good estimate of the other.

Leaving aside the variation due to feeding and management (which, whilst undoubtedly large, is minimised for the cows of the same herd, and which it is hardly possible to study statistically in the existing data) the chief factors operating on the lactation yield (i.e. the measurable environmental factors) are the following:

(1) Season of the year; the lactation yield is influenced to a certain extent by the month of the year in which the cow calves.

(2) Service; i.e. the stage of the lactation at which the cow again becomes pregnant. The interval between calving and the next fertile service is here termed the Service Period (S.P.); thus if a cow calves on June 1st, and becomes pregnant again on July 1st, her S.P. for that lactation is 30 days.

Dried spent hops possess a high absorptive capacity, and attention is drawn to its use as a “filler” to absorb such by-products as molasses and treacle.

The material possesses a high crude protein value and its ether extract is very high for a fibrous food, while the amount of crude fibre is the same as in good meadow hay. There is a high percentage of mineral matter present.

The digestibility of the material has been determined by feeding with hay chaff and linseed cake meal to three sheep. The spent hops were not readily eaten and could only be included in a ration in an amount equal to one-seventh of the dry weight of the total ration.

Its digestibility is low, a fifth of the crude protein and the nitrogenfree extractives, one-half of the ether extract, one-twentieth of the crude fibre and one-fifth of the total organic matter only being digestible. The production starch equivalent was 24.5.

During recent years a large number of samples of milk having a peculiar flavour have been sent to this Institute by farmers, retailers, and wholesalers of milk.

The flavour is marked and has almost invariably been described as “oily.” In many instances it has been referred to as the “castor oil flavour.”

Although, as would be expected, the opinions of individuals on the flavour of such samples were not unanimous the majority agreed that “oily” was an appropriate name and since this is the name by which this taint is known to the trade it is proposed to retain it.

1. As a result of soaking in water at body temperature (38° C), foods show variations in swelling ranging from approximately 10 per cent. to 260 per cent.

2. The volumes of equal weights of different foods after soaking also vary within wide limits. The percentages of moisture in the soaked foods show corresponding variations, being in some cases as high as those found in roots or green fodder.

3. These facts have led the authors to put forward a new conception of “bulk” in assessing the value of a ration.

4. Feeding experiments have been carried out to determine how far this factor of bulk is applicable in practice.

5. In the case of pigs of 40 to 80 lb. live weight, the bulk occupied by the foods did affect the quantity of food taken.

6. With calves, the swelling capacity of the concentrated food did not yield any definite results so far as food consumption was concerned.

Some of the factors affecting the rate of loss of water from a drying system are shortly reviewed. These factors fall into two groups: (1) the drying system itself, and (2) the environmental conditions. The second group may include (a) diffusion of water vapour through the air, (b) bulk air movements due to (i) temperature gradients between different parts of the drying vessel, (ii) temperature lowering of the drying mass itself due to evaporation, (iii) lower density of moist air, (iv) inevitable disturbances introduced by experimental conditions such as weighing or movement of apparatus, (v) the geometry of the system. It is shown that of the external factors the most important are (2 (a)), (2 (b) (i)) and (2 (b) (ii)); (2 (b) (iv)) may produce irregularities in the rate curves of airdry granular materials; (2 (b) (iii)) and (2 (b) (v)) appear to have little or no effect.

In a former communication (1) a study has been made of the influence of the stage of lactation on the yield and quality of the milk, and in the following paper a similar investigation has been made of the influence of the age of the cow on the same factors.

Mackintosh (2) finds a gradual increase in yield up to the 4th or 5th lactation period, and a decrease after the 7th or 8th; thus a heifer calving at 2¾ to 3 years gives 60–70 per cent. of the amount it will produce as a mature cow; after the second calf it gives 80 per cent. and after the third 90 per cent. Tocher's results (3) show an increase from 85 per cent, of the maximum yield at 3 years to a maximum at 7½ years, and a subsequent fall to 90 per cent. at 12 years of age.