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.

A comparison of leaf-area index (L) in the postflowering period was made between a single cross maize hybrid in Rhodesia and a winter and a spring wheat variety in England. At the beginning of the period L of the maize was lower than that of the wheat but it remained near its initial value for a relatively long time, whereas L of the wheat decreased rapidly. The proportion of L consisting of sheath was much lower in the maize than in wheat. Grain yield was higher in the maize largely because of its longer period of grain growth. In Rhodesia maize might benefit from a greater L than that recorded in this study. The high yields achieved by maize are partly due to the relatively long life of its leaves.

The development of a community may rightly be said to be reflected in its meat requirements. Primitive peoples are quite satisfied as long as their bulk needs are met, irrespective of quality. This condition may fairly be said to be representative of most of Africa today. A more developed community demands meat of high quality from young and properly finished animals, and this is the I'equirement of the European and emergent African communities, a steadily rising demand which must be met from within the Continent if possible.

An experiment is described in which the growth rate and conformation changes of cattle subjected to different levels of nutrition during their yearling winter, and then re-alimentated on grass, were studied.

For this purpose thirty-six Sussex x Shorthorn steers between 38 and 52 weeks of age were randomly distributed on the basis of live weight into three groups, each of twelve animals.

Part I described the growth of Angoni cattle as shown by changes in live weight. This Part deals with proportional growth as shown by linear growth and carcass characters.

LINEAR GROWTH

A virtually complete summary of the basic work on linear growth has been given by Brody (1945) and specific references will therefore be quoted only as required for discussion.

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.

The data on the conformation and age at slaughter, together with that on the slaughter and carcass work obtained from the thirty-six animals which had been subjected to differential winter feeding (see Part I), is presented and discussed.

1. Evidence is given of an association between the two loci governing inheritance of haemoglobin type and erythrocyte potassium concentration in Welsh Mountain sheep.

2. In the 1777 animals examined, there was an excess of high potassium types amongst carriers of the haemoglobin B gene.

3. At both high and low levels of potassium, sheep possessing haemoglobin A only had significantly more potassium in their blood than animals possessing haemoglobin B only. AB heterozygotes were intermediate in. value.

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.

A population of 1549 Welsh Mountain sheep, typed for haemoglobin and blood potassium concentration, were examined for correlations with production traits.

The statistical analysis was carried out within years, to avoid seasonal effects, and constants were fitted for sire, parity of birth and sex, as well as for haemoglobin and potassium type.

Few of the associations dependent on haemoglobin and potassium level reached significance at generally accepted levels of probability but an underlying consistency existed in mean values. Generally, animals of LK phenotypes showed marginally better neo-natal growth than HK phenotypes and animals possessing haemoglobin A had greater fleece-weights than those which did not.

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.

Seed production stands of S 48 timothy and S 215 meadow fescue were obtained with varying plant densities by utilizing two driE widths, removing sections of drill, or oversowing drilled material.

Annual tiller counts were made in preselected quadrats, and performances of tiller populations were assessed from these quadrats.

1.Two experiments were carried out to investigate the possibility of sustaining good growth rates and high feed conversion efficiency on restricted levels of feed under conditions of high temperature and humidity.

2. Large White pigs were used over the weight ranges 50-90 lb. and 90-160 lb. live weight.

3. In Exp. 1, three groups each of eight pigs were fed on three planes, high, medium and low, the aim being to restrict energy intake while providing adequate protein intake for good growth. In Exp. 2, two groups each of eight pigs were fed on the medium plane from 50-90 lb. live weight and thereafter one group remained on the medium plane, while the other was fed a very low plane. The very low plane consisted of a daily feed allowance of 31b. 4oz. from 90 to 1601b. live weight. All the pigs were individually fed.

1. A feeding trial has been carried out with sixty-four individually fed Large White pigs offered eight different diets prepared at four energy levels and two levels of crude protein. A record was maintained of the rate of live-weight gain and food was given at a defined restricted level. Carcass quality was assessed by a procedure of complete dissection into visible fat, lean, etc.

2. Though differences in the rates of live-weight gain and food conversion efficiency were not statistically significant, the best performance was recorded when the diets contained 16 % crude protein and yielded the equivalent of 2950 kcal. digestible energy per kg. upon oxidation. The energy: lysine ratio (kcal. digestible energy per kg. per unit percentage lysine in the ration) was approximately 3500.

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.

A randomized block experiment has been carried out with 42 Friesian heifers over a 2-year period to examine the protein and energy requirements in late pregnancy. Rations were based on good quality hay fed to appetite plus various quantities and combinations of oats and decorticated groundnut meal. Minerals were given daily.

1. The literature on the early weaning of lambs has been reviewed.

2. Four experiments were carried out at the Grassland Research Institute, Hurley, during 1959, 1960 and 1961 on the early weaning of Suffolk x Half-Bred lambs. The technique used involved weaning one of a pair of twin lambs at ages varying from 15 to 28 days.

3. In 1959 oneof each of apair of six twin lambs was weaned on to grass alone at 15–20 days. No losses occurred, but the weaned lambs grew very slowly. The unweaned twin lambs remaining with the ewes (i.e. reared as singles) grew at rates comparable to those of single lambs.

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. Sixty-four Dorset Horn ewes and sixty Half- Bred ewes were X-rayed in the pelvic region at stages of pregnancy between 51 and 110 days.

2. Diagnosis of pregnancy and estimates of the number of foetuses carried were made from the X-ray film.

3. Over the range of gestation stages examined, interpretation of the number of foetuses present was found to be most accurate at stages between 91 and 110 days.

4. An accurate estimation of whether the ewe is pregnant or barren can be made from 50 days onwards.