1.The breakdown of urea, soluble starch and glucose was followed in the rumen of fistulatedsheep and in artificial rumens containing rumen ingesta or strained rumen fluid.

2. Carbohydrate remained in the rumen two to three times as long when starch was dosed in vivo as when glucose was given.

3. The relative rates of breakdown of urea and carbohydrate by strained rumen fluid in vitro differed markedly from those in vivo. This was due to the fact that straining removed large numbers of starch- and glucose-utilizing micro-organisms which were attached to the larger food particles, while the concentration of the urea-splitting organisms which were freely suspended in the strained liquor was apparently the same as that obtained in the strained material. Strained rumen fluid should therefore not be used for studies of the utilization of urea in vitro.

1.Fixed ammonium could be completely recovered from clay minerals by leaching small amounts of clay with large volumes of salt solutions (containing the cations but not K+, Rb+, or Cs+), but no clay fixed ammonium could be found in soils when analysed by this technique.

2. It is suggested that ammonium fixation is largely a laboratory phenomenon caused by the use of extractants containing potassium ions which trap exchangeable ammonium, or the use of reagents which decompose organic nitrogen compounds.

1. Samples of faeces obtained from eleven continuous digestibility trials in which sheep, steers or cows were given fresh herbages grown in different seasons in 2 years were analysed for the ‘dissolved faeces fraction’ (D.I-.F.).

2. Dry-matter intake by sheep was linearly related to the weight of D.F.F. excreted and the equation predicted intakes that were 20 %higher at the mean intake than those estimated from a similar type of relationship obtained by Owen (1961). A logarithmic relationship was derived when the observations for all species were combined.

1. The object of the experiment was to investigate the detailed carcass composition, and the fatty acid composition of the depot fat, of pigs fed from 10 Ib. to almost 200 lb. live weight on semi-synthetic isocaloric diets containing no fat, saturated fat (beef tallow) and unsaturated fat (maize oil).

2. The carcasses of seven litter-mate Large White x Essex hogs, two from each semi-syntheticdiet and one from a natural diet were dissected into their individual muscles, bones, fat depots and remainder.

1. The content of gross and digestible energy of twenty-four forages grown in Trinidad was determined using samples of food and faeces from previously described digestibility trials.

2. The content of gross energy of the forages ranged from 4-13 to 5-02 kcal./g. and that of digestible energy, from 2-23 to 3-20 kcal./g. The corresponding regression equations could be used for the prediction of digestible energy.

4. The calorific equivalent of TDN was calculated in each case and the mean value was found to be 2114 kcal./lb. Highly significant differences in this parameter existed among diets.

1. An examination was made of four chemical components of herbage—nitrogen, crude fibre, acid-soluble ash and acid-insoluble fraction—from different genetic populations of Lolium perenne, grown in two trials at various related densities, some plots being irrigated. Dates of the frequent harvests were determined by the growth stage of the herbage.

1. A simple inexpensive anemometer is described; the instrument is intended for general husbandry use.

2. The essential part of the apparatus is a 1 in. diameter electrically heated duralumin spherecapping a mercury-in-glass thermometer.

3. Charts are given relating wind-speed to sphere temperature, ambient temperature and heat input to the sphere. No further calibration is required.

1. The influence of castration on meat production has been studied in three experiments involving cattle, sheep and pigs. The results are presented to indicate the changes which might be expected in more extensive experiments, and give an indication of the parameters likely to be important.

1. The mean concentrations of sodium, potassium, phosphorus, calcium and magnesium were determined in the dry matter of the gut contents of European and Zebu steers which were allowed water ad lib. or in restricted quantities. Except for K concentrations in the colon and rectum, which were significantly higher in the Zebus, there were no breed differences.

1. Sodium, potassium, calcium, and magnesium balances in seven Hereford and seven Zebu steers have been determined during two 10-day trials. Values for phosphorus, omitting urine excretion, were also determined.

2. No breed differences were found apart from a tendency for Zebu steers to excrete less potassium in their faeces and more in their urine than Herefords.

1. Ten-day balances of sodium and potassium were recorded for Shorthorn and Zebu steers fed poor quality chaffed hay with and without sodium supplements.

2. Sodium supplementation had no appreciable effect on growth, all animals being close to amaintenance regime.

1. Sodium and potassium balances and the growth rate of steers have been recorded for animalsreceiving a protein supplement on a high and low salt regime.

2. Zebu steers receiving less than an average of 0-2 g. sodium per day were able to grow at 82 % of the rate of Zebu steers receiving salt supplement. Shorthorn steers under the same conditions grew at 72 % of the rate of Shorthorns receiving the supplement.

1. The increase in soil carbon has been assessed in arable land sown to different leys variously managed.

2. Under swards cut for herbage conservation, carbon in the top 15 cm. of soil increased by about 0-05 % each year. Although an increase of 0-3 % was found immediately under drills of cocksfoot grown for seed production, there was no increase midway between the drills and, for a given area of land, the carbon increment under such row-crops is probably similar to that under cut swards.

1. The contents of moisture, intramuscular fat and total nitrogen in various muscles of boars at 200 and 260 lb. live weight have been compared with corresponding data from hogs.

2. Although total nitrogen was higher and moisture and fat lower in the muscles of boars than those of hogs at 200 lb. live weight the converse tended to apply when comparisons were made at 260 lb.

1. After synchronization of oestrus by treatment with progesterone before tupping small groups of ewes were slaughtered at approximately monthly intervals from 5 weeks post-conception to around 3 months post-weaning on two widely differing Scottish hill farms. A few barren ewes were also slaughtered.

2. Ash analysis of the 3rd, 4th and 5th cervical vertebrae of the breeding ewes indicated that there was a striking similarity between the flocks in the mean percentage ash values of these bones and also in the decline in these values which occurred between early gestation and 12 weeks after lambing.

In East Anglia Piesma quadratum is rare on wild beet and absent from sugar beet; it lives on wild plants and is confined to the coast. Larvae of P. quadratum which hatched from eggs laid on sugar beet in the laboratory died in an early instar, but older larvae and adults survived on the plants. There is little prospect that crinkle disease will become established in England.

1. Floret samples of S321 perennial rye-grass (Lolium perenne L.), S215 meadow fescue (Festuca pratensis L.) and S352 timothy (Phleum pratense L.) were taken at 3-day intervals from inflorescence emergence to seed harvest. These were analysed for total chlorophyll content, chlorophyll a: chlorophyll b ratio and total anthocyanin content.

2. All varieties showed qualitatively similar patterns of total chlorophyll content. At emergence chlorophyll first increased on exposure to light and then fell as anther formation progressed. After fertilization a rapid increase in floret chlorophyll content coincided with early seed formation due to pigmentation of the expanding seed epidermis. Polymerization of carbohydrates to form endosperm starch resulting in increasing dry-matter content caused a concomitant fall in total chlorophyll when assessed on this basis. The final stages of seed maturation were accompanied by a further gradual decline to a very low level.

Thirty-two ewes (of which 22 were P.M.S.- treated) were individually mated, each one eitherto two different rams or to four different rams successively, at predetermined intervals of time during a single oestrus period. The onset of heat was determined by a raddled vasectomized ram with free access to the ewe flock. Since each ram used was of a different breed the genotypes of the resulting lambs denoted which of the matings on each ewe had been effective.

1. A feeding trial involving sixty-four individually fed pigs was carried out to assess the effect of reducing the protein content of the diet at different live weights. The effect was examined at two planes of protein intake, 19 % falling to 14 % in the finishing stages, and 16 % falling to 12 %.

2. High protein levels improved growth rate and food conversion efficiency during the growing phase, and also improved carcass quality in terms of the lean content of the carcass, eye muscle area and length.

An objective appraisal system for intact lamb and mutton carcasses utilizing a fleshing index to relate carcass weight and length is presented. Gross fleshing index is defined as the number of pounds by which any carcass is heavier or lighter than the average carcass of its particular length. Penalty for overfatness is made when necessary by an estimation technique involving measurement of fat status at the level of the first lumbar vertebra on the intact carcass with the aid of a steel probe. The net fleshing index, a simple numerical expression of carcass fleshing, is arrived at by deducting the penalty for overfatness (when necessary) from the gross fleshing index. The greater the net fleshing index the greater the relative merit of the carcass.