Two pairs of rams with different degrees of scrotal cover were subjected to hot room temperatures ranging from 26.7 to 4.5 °C to study the effect of elevated ambient temperatures on rectal temperature, respiration rate, scrotal length, flank temperature, scrotal temperature and intra-scrotal temperature.

Increase in room temperature caused increase in intra-scrotal temperature, but there was no significant difference between the two pairs.

The live-weight gain, efficiency of food conversion, energy and nitrogen accretion as edible carcass, and the forestomaeh development were measured in three groups of calves fed for 10 weeks (days 19–89 of life) either a diet of 4·5 1 of milk daily, or a concentrate meal containing 4% sodium propionate ad libitum, or a concentrate meal ad libitum. All groups had access to lucerne chaff and water ad libitum.

The mean live-weight gains of the three groups of calves were 47·5, 36·6 and 37·1 kg respectively even though their total energy and nitrogen intakes were not significantly different. The provision of dietary propionate did not improve the efficiency of food conversion or of energy or nitrogen accretion as the calves ate less of the meal containing propionate and more lucerne chaff. The differences in live-weight gain could be accounted for by the differences in carcass weight. Associated with the higher live-weight gain was a much higher efficiency of food utilization and of edible carcass energy and nitrogen accretion. The superior efficiency of the unweaned calves was concluded to be due to the liquid portion of the diet by-passing the rumeno-reticulum into the abomasum where the efficiency of utilization of highly digestible protein and carbohydrate is greater. The concentrate plus propionate fed calves ate less concentrate but more chaff and had a lower efficiency of food utilization and edible carcass energy accretion than the other weaned group of calves.

The weight of rumeno-reticular tissues was greater in the weaned than in the unweaned calves, although the meal plus propionate group ate similar quantities of chaff to the unweaned group. In all groups, the degree of papillary development was related to the intake of concentrates plus roughage. The most appropriate manner to describe ruminal tissue weight is discussed.

Three field experiments with sugar beet grown on a light calcareous soil tested a wide range of amounts of sodium and potassium fertilizer with either magnesium or nitrogen. Both sodium and potassium increased sugar yield and there was a large negative interaction between them. Magnesium also increased sugar yield, but the larger dressing of nitrogen decreased it. Sodium, potassium and nitrogen fertilizers also affected the concentration of impurities in the root juice at harvest.

Plant samples were also analysed in August when the crop usually contains most sodium. Sodium fertilizer greatly increased the sodium and decreased the potassium concentration in the dry matter of the tops but the composition of the roots changed little. Potassium dressings slightly increased potassium in the tops but did not affect the root composition.

Exchangeable sodium in the top soil of plots given sodium fertilizer decreased rapidly early in the season, but increased again from August, probably because sodium was taken up rapidly early in the summer and returned later in dead leaves. Soil potassium decreased throughout the season on plots where potassium was applied, but did not change on plots without potassium fertilizer; this is explained by fixation and release from non-exchangeable forms.

On this soil there was no reason to regard sodium in its effect on yield, other than as a replacement for potassium, but its behaviour in the soil and effect on the composition of the plant was quite different.

A co-ordinated trial has been carried out at twenty-one centres to obtain information on the following problems: does the addition of synthetic lysine to a ‘standard’ ration, widely recommended and used in this country, beneficially influence the performance of growing pigs, and is the effect influenced by whether the source of supplementary protein is white fish meal or soya bean meal ?

In comparison with a ration providing levels of crude protein and lysine recommended in the A.R.C. ‘Nutrient Requirements of Pigs’, the ‘standard’ ration which contained less crude protein and total lysine, produced slightly lower performance, but about the same profit. The performance on the ‘standard’ ration could be improved by the addition of synthetic lysine, but such supplementation would not be profitable unless the cost of synthetic lysine was less than 21s./kg.

The response to added synthetic lysine was similar on rations in which the source of supplementary protein was either white fish meal or soya bean meal.

The comparative effects of very heavy dressings of ammonium sulphate and urea on the growth of established plants of white clover (S100) have been studied in pot culture. Five applications each of 263 kg N/ha were applied over 9 months in 3 different ways (i) direct contact of the fertilizers with the leaves, (ii) only with the stolons or surface roots or (iii) applied 12·5 cm below the soil surface.

The ammonium sulphate broadcast over the leaves reduced the growth of the clover whilst urea under the same conditions caused temporary damage with very little reduction in dry weight compared with the control. When the ammonium sulphate was applied to the soil surface or 12·5 cm below, there was appreciable reduction in dry weight but less than when the fertilizer was in contact with the leaves. Under the same conditions, urea did not reduce growth.

The pH of the soil fell to about 4·6 with ammonium sulphate (control 6·1) but only slightly with urea.

Root development was not affected by urea but greatly reduced with ammonium sulphate. With both fertilizers the root nodules were very pale in colour and few in number compared with the control.

The source, control and function of serum citrate is not at present well understood. In human beings, however, a relationship between raised serum citrate levels and periodontal disease has been reported (Tsunemitsu, 1963; Simon et al. 1968). Two forms of periodontal disease have been described in sheep (Duckworth et al. 1962; Salisbury, Armstrong & Gray, 1953; Cutress & Ludwig, 1969), and are at present being studied by this organization. As part of the investigation into these conditions in sheep in New Zealand, serum citrate levels of animals from affected and unaffected flocks were determined during a period of 1 year. The results obtained showed considerable variations in serum citrate levels of the animals tested but a periodontal disease–serum citrate correlation was not found.

We have obtained evidence of normal development of cattle ova following storage at 10 °C. Of thirty-two treated ova transferred to the oviducts of pseudo-pregnant rabbits, twenty-three were recovered and ten of these had undergone further cleavage.

The distribution of red cell potassium concentrations in ninety–one Jersey cows was examined, and shown to be consistent with two populations, a high (HK) and low (LK) type. In tracer potassium uptake experiments the HK type cells were shown to have a higher active K+ uptake, and lower passive K+ leak than LK type cells. Tests with the sheep anti–L antibody showed that the L–antigen system, which controls active potassium transport in sheep red cells does not appear to act in cattle red cells.