Six field experiments made between 1960 and 1968 determined the effect of previo cropping and manuring on the nitrogen requirement of sugar beet. Three were at Silsoe in Bedfordshire on soils developed over Lower Greensand and Gault Clay and three were at Broom's Barn (Suffolk) on Calcareous Drift soils over chalk. Each experiment lasted 2 years, a preparatory crop followed by sugar beet.

Spring barley and potatoes were treatment crops in all the experiments and winter wheat, a ryegrass ley and barley undersown with trefoil were included in the Suffolk experiments. Nil, 0·6 or 1·2 cwt N/acre was tested on the sugar beet in the first three experiments and 0, 0·5, 1·0 or 1·5 cwt N/acre in later ones.

All the experiments showed that previous cropping influenced the nitrogen requirement of the sugar beet. There was a linear relationship (r = – 0·86) between the amount of fertilizer nitrogen given minus that removed by the preparatory crop, and the quantity of nitrogen fertilizer needed by the sugar beet for maximum sugar yield. Sugar beet grown after barley or potatoes (each given 0·5 cwt N/acre) needed on average 1·0 cwt N/acre at both Broom's Barn and Silsoe for maximum sugar yield. Sugar beet after winter wheat or a ryegrass ley also needed 1·0 cwt N/acre at Broom's Barn. When the previous potato crop was given 1·5 cwt N/acre, 0·5 cwt/acre sufficed for maximum yield of sugar at both centres; also after ploughed-in trefoil, sugar beet needed only 0·5 cwt N/acre.

Phosphate uptake and dry-matter yield from unfertilized pots and relative yield (ratio of unfertilized to fertilized yield) of Rhodes grass were used as plant indices of P supply from twenty-four soil samples from long-term manurial trials in Nigeria. Although measurements of the soil P quantity factor were generally the more important, intensity measurements also made a highly significant independent contribution to the P supply. Inorganic P (a quantity measure) combined with the log of P concentration in a saturation water extract (an intensity measure) gave a multiple correlation coefficient of R = 0·954*** with relative yield, accounting for 91% of its variation. The best single measure was resin-extractable P, which gave r =0·930*** for correlation with relative yield. Organic P did not appear to contribute to plant growth.

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.

This paper reviews extensive work at Jealott's Hill and elsewhere in England and Wales on the agronomic effects of including various levels of urea in 2:1:1 NPK fertilizers combine-drilled with spring cereals.

Little evidence of phytotoxicity was found with fertilizers containing up to 12% urea and providing about 0·6 cwt N/acre. The inclusion of 20% urea reduced braird more frequently on soils of high pH than did lower proportions although grain yields were seldom affected adversely. Such soils are not uncommon, especially in the barleygrowing areas of Southern and Eastern England, where perhaps a quarter of the cereal acreage may be located on soils of pH 7·7 and above.

Seven commercial barley varieties were inoculated with mycelial suspensions of different isolates of Gescosporella herpotrichoides. There were significant varietal differences in eyespot susceptibility. There were significant differences between isolates which originated from both wheat and barley. The yield of the varieties was reduced between 30 and 50% depending upon the isolate used. Significant interactions between isolates and varieties were found for the incidence of disease, its effect on tiller number and upon total yield.

An experiment was carried out over a 5-year period on a grass/clover sward at North Wyke to compare three methods of experimental management—individually grazed plots, communally grazed plots and cutting with removal of herbage. Responses to phosphate and potash fertilizers under each management were measured.

P fertilizer increased grass yields in the first 4 years and decreased clover yields in the last 2. In almost all respects cut and grazed sward responded similarly to P. Fertilizer K had no effect on grass yield but markedly increased clover yield and raised herbage K content. Grazed swards developed a higher herbage K content than cut swards, and K fertilizer increased it more in the fourth and fifth years on the individually grazed than on the communally grazed plots. Thus communal grazing resulted in appreciable transfer of K from plot to plot in animal returns.

It is concluded that whilst cutting management may be used for short-term experiments, its use in long-term experiments gives different results from grazing. Communal grazing can lead to the transfer of N and K effects from plot to plot, so that plots must be grazed individually except perhaps where P is the only variable nutrient.

Analyses of cow urine showed that about 10% of housed cows excreted phosphate greatly in excess of ‘normal’. The phosphaturia only occurred when the cows were permanently housed. No high phosphate concentrations were found in. urines from grazing cows although a significant increase in phosphate concentrations occurred when these cows were temporarily transferred to housed conditions.

No significant differences were detected between the high and low phosphate excreting cows with respect of urinary concentrations of creatinine, calcium, or chloride, urine specific gravity or pH, or plasma concentrations of calcium, inorganic phosphate, magnesium, sodium, potassium, alkaline phosphatase, chloride or bicarbonate.

Complete phosphorus balance measurements on four cows during the last six weeks of pregnancy showed that an increase in urinary phosphate excretion occurred in both high- and low-phosphate excreting cows when a dietary 'steaming-up' schedule was employed, and that the phosphaturia was accompanied by an increase in absorption of dietary phosphorus.

The cause of the phosphaturia does not appear to be acidosis. Little change in urinary phosphorus excretion occurred after oral doses of ammonium chloride but some increase occurred after equivalent doses of sodium and potassium carbonates. It is concluded that a small proportion of cows have a tendency to excrete relatively large amounts of phosphorus in the urine but that this only occurs under housed conditions.

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.

A study was made of the effects of supplementing low-protein teff (Eragrostis tef) hay with (a) protein (egg albumin), (b) urea and (c) urea plus C4 and C5 branched-chain volatile fatty acids (VFA) on the cellulolytic flora in the rumen of sheep conditioned to these diets and on the digestibility of cellulose and hemicellulose. Addition of urea, as opposed to no supplementation, increased voluntary hay intake and the percentage digestibility of cellulose and hemicellulose, while counts of cellulolytic bacteria were not greatly affected. The proportion of ruminococci amongst the cellulolytic bacteria increased somewhat and that of the butyrivibrios decreased. When branched-chain VFA were added to the hay together with urea the numbers of cellulolytic bacteria per g rumen ingesta and the proportion of ruminococci increased over those for urea alone. This was accompanied by a further increase in voluntary hay intake. Percentage digestibilities of cellulose and hemicellulose were similar to those for the urea/hay diet. Supplementation with protein resulted in lower digestibility of α-cellulose and hemicellulose when compared with the urea-supplemented diets. The cellulolytic bacteria formed a lower percentage of the ‘total culturable’ counts than was the case for the other diets.

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.

Of 120 mature Merino ewes, balanced groups received the following treatments from days 8 to 15 after fertile mating: 1, submaintenance nutrition plus 10 mg/day progesterone; 2, submaintenance without progesterone; 3, maintenance nutrition plus progesterone as above; 4, maintenance nutrition without progesterone.

The ewes were in light condition, they lost some weight before mating, they had an ovulation rate of 108·3% and they barely maintained their mating weight during the first 3 months of pregnancy. The percentages of ova shed not represented by lambs at term were 60·6, 58·1, 48·5 and 62·5 for groups 1–4 respectively. There were no significant treatment differences or interactions.

The high overall loss of ova could have been due in part to depressed fertilization rate: however, the general environmental conditions and low body weight of the ewes seems likely to have made an important contribution to the high basal loss. There was a significant regression of prenatal mortality on body weight at mating, but no detectable relationship between prenatal mortality and condition score.

Sixteen oestrous cycles of over 21 days were distributed through all groups, indicating that considerable mortality occurred after day 13.

Mature Merino ewes (108) which had been hand-mated to fertile rams received the following treatments: 1, submaintenance nutrition days 7–14 (34 ewes); 2, submaintenance nutrition days 20–27 (40 ewes); 3, control (34 ewes).

The ewes were in fat condition, and gained weight before mating and throughout pregnancy except when on the submaintenance treatment. Their overall ovulation rate was 180·6%. The percentages of ova not represented by lambs at term were 30·6, 37·5 and 41·0 for groups 1–3 respectively, the differences being non-significant.

Loss of ova in multiple ovulators was not significantly different from that in single ovulators and there was no relationship between body weight and prenatal loss. Nine post-mating oestrous cycles longer than 21 days were distributed through all groups in a pattern which bore no apparent relationship to nutritionally-induced embryo mortality. A higher proportion of ewes remained barren when re-mated after long than after normal-length oestrous cycles.

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.

Three groups of mature Merino ewes, balanced for body weight and number of ovulations, and totalling 122 animals, received the following treatments subsequent to mating to fertile rams: 1. approximately half maintenance requirements from day 7 to 37; 2. approximately half maintenance requirements from day 7 to 37, plus 10 mg progesterone daily from day 20 to 37; 3. control.

The ewes, which were in fat condition, had a mean ovulation rate of 121·3 %; except during the submaintenance period, they gained weight throughout pregnancy.

The percentages of ova not represented by lambs at term were 34·7, 46·0 and 42·6 in groups 1 to 3 respectively, the differences being non-significant. Detailed examination of the cycle length data of ewes returning to service suggests that some embryos may have been killed by the submaintenance treatment. Progesterone treatment was not beneficial, nor did its sudden withdrawal on day 37 appear to be detrimental to foetal survival. In a sample of ewes slaughtered on day 37, adrenal gland weights were significantly lower in the two treated groups.

Significantly higher losses of ova occurred among twin than among single ovulators and there was some evidence that this was non-random. There was no significant relationship between prenatal mortality and body weight at mating.

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.