The consumption of three different tropical pastures by the conventional clipping method and by the nitrogen–chromic oxide technique were assessed and compared over a 2-year period. The clipping method was found to give consistently higher estimates of consumption of herbage dry matter by grazing steers than the chromic oxide method by approximately 16, 14 and 25% respectively for treatments E (Gynodon + Centrosema), F (Mixture E + Stylosanthes) and G (Digitaria + two legumes), when data for the 2 years were pooled for each treatment.

The mean live-weight gain over the 2-year period was 0·19 kg per head per day. This figure is essentially in agreement with that obtained for the same group of animals in the previous 2 years. As would be expected the lowest gain was recorded during the dry season when there was little or nothing to graze. It was similarly observed that during a severe attack of trypanosomiasis the animals sustained some losses even though there was abundant pasture to graze.

A sodium hydroxide spray treatment of wheat straw was evaluated in experiments on twenty male calves. Sodium hydroxide solutions of 0, 3·3, 6·7 and 10% concentration were sprayed on ground wheat straw (Exp. 1) and chaffed wheat straw (Exp. 2) at the rate of 1000 litres per tonne. The straws were not washed. The treated straw was then fortified with groundnut cake, molasses and a mineral supplement. In Exp. 1 rations were prepared in bulk and dried and in Exp. 2 the rations were prepared daily and fed wet. A 1 kg green forage supplement was fed daily to all animals. The dry-matter intake (g/kg body weight0·75), and organic matter digestibility coefficients (%) for the four levels of alkali treatment were 86, 95, 78, 66 and 53, 63, 63 and 62 respectively in Exp. 1 and for Exp. 2 they were 95, 121, 105, 89 and 55, 70, 71 and 71. The intake of digestible organic matter thus increased by 25 and 63% in Exp. 1 and Exp. 2, respectively. Nitrogen, calcium and phosphorus retentions were not adversely affected up to 3·3% alkali treatment in Exp. 2. The effectiveness of this spray treatment in terms of increased nutritive value is compared with that of the older Beckmann method of alkali treatment. Treatment costs are also compared.

Several delignifying agents, used in various paper-making processes, have been compared for their ability to remove lignin and increase the digestibility of several roughages in laboratory experiments using a spray method of treatment recently suggested by Wilson & Pigden (1964). The chemicals were dissolved in small quantities of water which were then used to moisten the roughage. No washing was done after treatment. Sodium hydroxide was the most effective chemical; at a rate of 10 g per 100 g of roughage, the lignin content of ground maize cobs was reduced by 26% and rumen dry-matter digestibility increased by more than 100%. Bleaching powder was as effective as sodium hydroxide in removing lignin, but residual chlorine apparently inhibited rumen microbial digestion.

Maize cobs, wheat and paddy straws, sorghum stover and sugar cane tops, though of widely differing initial digestibility, were brought to an equal level of rumen digestibility if treated with 4% or more of sodium hydroxide. Drying the treated roughage at 100 degrees instead of at room temperature increased digestibility only in the case of maize cobs. The alkali spray treatment was as effective in increasing the digestibility of chaffed as of ground wheat straw. Data are presented which show the amounts of residual alkali in treated roughage as a function of time after treatment and of concentration of alkali used in the treatment. Further, data are presented which show the loss of nutrients from treated roughage if washed as in the traditional method.

Studies of leaf area estimate of some oil crops were made using planimeter measurement, punch borer and length × width × factor. The extent of sample variation depended on the variety in each of these methods; the last two methods were found to be simple, precise and less time consuming.

A protein index for animal feeds is suggested as a basis for the criteria relating nutritive value to chemical composition. The feeds were classified into four main groups: legumes, non-legumes, straws and concentrates. The regression equations for predicting the nutritive value gave a reasonable level of accuracy (0·18–14·74% error). Higher levels of accuracy were attained employing regression equations formulated for more homogenous feed subgroups classified according to their protein and fibre contents. The percentage error resulting from the use of the specific equations was found to range between zero and 9·88.

A study was carried out on the post-lambing normal and abnormal maternal behaviour of sheep using 237 Barki ewes of 2, 3, 4 and 5 years of age and their newborn single lambs.

Normal maternal behaviour was observed in 64·5% of the ewes as they immediately recognized their lambs after birth, readily accepted them and started grooming and helping them to suckle. The overall average time-interval from parturition until ewes stood, started cleaning and until lambs started suckling was 2·9 ± 0·5, 4·0 ± 0·8 and 20·5 ± 2·0 min respectively. The 2-year-old ewes and the ewes weighing 30 kg and less took longer to accept and nurse their new-born lambs than older and heavier ones.

Post-lambing abnormal maternal behaviour was observed in 30·4% of the ewes, among which 43·1, 45·8 and 11·1% were classed as fair, poor and very poor mothers respectively. Fair mothers failed to nurse their lambs, poor mothers deserted them and very poor mothers permanently deserted their lambs and were aggressive to them. The post-lambing abnormal maternal behaviour was more frequent among 2-year-old maiden ewes than older ewes.

Blood samples were obtained at monthly intervals for 12 months from 8 HK and 8 LK wethers of the Marwari breed maintained at Jodhpur (26° 05′ N, 73° 01′ E). The samples were analysed for packed cell volume (PCV), red blood cell count (RBC), haemoglobin concentration (Hb), mean cell volume (MCV), mean cell haemoglobin concentration (MCHC), plasma inorganic phosphorus and plasma specific conductance.

The HK animals, on average, had significantly higher PCV, RBC, Hb, MCHC and plasma inorganic phosphorus values than the LK animals but the MCV was significantly higher in the LK group. There was no difference in the plasma specific conductance.

PCV, RBC and Hb values differed considerably from animal to animal within each group. These individual variations could help the breed to survive in a desert environment.

No particular tendency or pattern in the effect of season on the blood characters studied has been observed. This indicates that the animals of both groups responded in a similar way to the environmental changes.

A technique is described for speeding germination of monogerm sugar-beet seed. The optimum treatment was four cycles of wetting seed with its own weight of water and storing it in a sealed container for 24 hours before drying for 48 hours. The number of cells per embryo was doubled, seedlings emerged approximately 2·5 days sooner and seedling shoot weight was increased by 31 to 53%.

The crude protein content and in vitro dry-matter digestibility (I.V.D.) of leaves and stems of Andropogon gayanus, grouped into four different age categories, were measured at weekly intervals during the secondhalf of the 1968 wet season. The crude protein content of all categories of leaf and stem rose to a maximumat ear emergence; significant reductions occurred thereafter, especiallyin the younger categories of leaf and stem. At any point in time the younger leaves and stems contained significantly more crude protein than the older leaves and stems.

Although the mean crude protein content of each stem category was significantly lower than the corresponding leaf category, the young, elongating stems had a significantly higher crude protein content than the older, mature leaves at the time of ear emergence.

The mean I.V.D. of all leaf and stem categories was highest at the start of the recording period. At ear emergence the I.V.D. of the young elongating stems was at least as high as the mature leaves. After ear emergence the I.V.D. of the stems fell more rapidly than the leaves.

The results support the principle of cutting at ear emergence to achieve maximum yields of digestible nutrients.

In field experiments carried out over a period of three years studies were made of the effects on soil moisture characteristics and crop yields of incorporating pulverized fuel ash into the surface 30 cm of a sandy loam and a coarse sand. Ash from two different sources was used at rates equivalent to 0, 125, 251, 502 and 753 t/ha and crops of carrots, lettuce, radish and red beet were grown.

On every occasion when determinations were made the available-water capacities of the soils treated with 251 t/ha or more of ash were greater than the untreated soils; the largest increase (93%) was obtained with the highest rate of ash. Moisture release characteristics indicated that the increased amount of available water was retained in the soils at matric suctions between 0·05 and 1·0 atmospheres.

Despite the increased amount of available water retained in these soils there was generally no beneficial effect on crop growth and yields.

Ten experiments (1967–9) on sandy soil in East Anglia measured the effect of magnesium fertilizer on yield and cations in sugar beet. Magnesium fertilizer increased sugar yield by up to 0·80 t/ha and on the three most responsive fields it consistently increased top and root dry·matter yields throughout the growing period.

On average, without magnesium fertilizer, the concentration of magnesium in tops progressively decreased from 0·33% at singling to 0·15% at harvest, and in roots from 0·39% to 0·09%. The corresponding decreases with magnesium fertilizer were (tops) from 0·68% to 0·20% and (roots) from 0·48% to 0·10%. Yield was increased by magnesium fertilizers when tops contained less than 0·35% Mg during May, 0·30% during June, 0·22% during July and 0·17% during August. Deficiency symptoms were not visible until the concentration in tops averaged less than 0·2% – the percentage of plants with symptoms increased rapidly at smaller concentrations. Magnesium fertilizer decreased the concentration of calcium in tops and roots but did not affect the concentration of potassium or sodium.

The maximum amount of magnesium, potassium, sodium and calcium in tops (August–September) was 11, 218, 75 and 62 kg/ha respectively; these decreased to 8, 168, 55 and 50 kg/ha at harvesting, showing that only about 75% of the largest amount in tops was present at harvest. The amounts removed in roots at harvest were 9 kg/ha Mg, 75 kg/ha K, 11 kg/ha Na and 26 kg/ha Ca. A dressing of 100 kg/ha magnesium increased the amount of magnesium in the crop at harvest by only 4·5 kg/ha.

Two perennial ryegrass swards – one consisting of S. 24, a diploid variety, and the other of Reveille, a tetraploid variety – were compared in a 20-week grazing experiment with 16 Ayrshire cows in 1968 and again with 12 cows in 1969. Each grass sward was grazed at either a high or a low rate of stoeldng and no other feeds were offered to the cows. On average, the amount of herbage dry matter on offer to the cows was slightly greater on the S. 24 than on the Reveille sward but the contents of total soluble sugars and digestible organic matter were significantly higher in the dry matter of the Reveille than in that of the S. 24. The crude protein contents of the herbage dry matter were similar on the two swards. The mean daily milk yields from cows grazing at the high and the low rates of stocking in 1968 were 14·0 and 15·7 kg/cow respectively on the S. 24 sward and 14·7 and 16·1 kg on the Reveille sward. In 1969 the milk yields from these same treatments were 15·4 and 17·2 kg on the S. 24, and 16·5 and 17·7 kg on the Reveille. The fat content of the milk was not significantly affected by the treatments. In both years the solids-not-fat and the crude protein contents of the milk were higher on the Reveille than on the S. 24 sward, but these differences were significant at the low rate of stocking only. The live weight of the cows did not differ significantly between the two swards. The average output of milk per hectare was approximately 4% higher from the Reveille than from the S. 24 sward but the major factor influencing milk production per hectare was the stocking-rate. On average over the 2 years the output of milk per hectare was 36% higher on the high than on the low rate of stocking. It is suggested that in selecting herbage for milk-production purposes attention should be paid to material with a high digestible organic-matter content and a high content of soluble sugars.

The absorption and translocation of phosphate by roots of intact seedlings of rape, oats, flax and buckwheat were studied. Two hydroponic experiments were conducted in the greenhouse. A split-root technique was used in which a single root of the culture plants was grown in one solution and the rest of the roots in another solution in a twocompartmented glass jar.

The presence of other nutrients had a favourable effect on root growth and was essential for efficient phosphate absorption. There was a positive relation between the extent of root growth and phosphorus uptake. On the basis of unit weights of a single root, rape was not any better than oats and buckwheat. A single root of rape, in the presence of other nutrients, absorbed two-thirds of the phosphorus absorbed by all the other roots, whereas single roots of buckwheat, oats, and flax were much less efficient than the rest of the roots. In the absence of other nutrients, single roots of buckwheat, rape and oats absorbed 4·61, 0·18 and 3·49%, respectively, of the phosphorus supplied. However, in the presence of other nutrients, the corresponding values were 21·68, 43·86, and 7·62%, respectively. Both in the presence and absence of other nutrients the single root of flax did not absorb phosphorus from solutions high in phosphate. The results indicate that the age of the plant has an important bearing on the uptake and translocation of phosphorus.

The effects of crop density and fertilizer application on three varieties of marrowstem kale were investigated. The yield of stem, yield of leaf, components of leaf yield and plant height were studied separately. Varietal differences and effects of density and fertilizer application were significant for all characters, except for the effect of crop density on leaf and stem yield per ha.

Significant variety x treatment interactions occurred for a number of the characters measured. The possible importance of these is discussed.

1. In a series of experiments with cannulated lambs the amounts of 2, 6-diaminopimelic acid (DAPA) and a-amino nitrogen passing daily through the abomasum, terminal ileum and rectum were measured. While there was a very significant net absorption of α-amino nitrogen between the abomasum and terminal ileum, there was no net absorption of DAPA between these points. Indeed, there was a tendency for more DAPA to leave the terminal ileum than entered the abomasum, though this was only significant at the 10% level. In all cases significantly less DAPA passed out of the rectum than passed through the terminal ileum, indicating extensive degradation of this amino acid in the hind-gut, probably as a result of microbial activity.

2. In adult sheep given control rations no DAPA could be detected in the blood, even when 643 ml plasma were analysed. These sheep usually excreted less than 5 mg DAPA daily in the urine.

3. When synthetic DAPA was introduced into the peritoneum, blood, abomasum, rumen or caecum of cannulated adult sheep in physiological amounts, approximately 80, 83, 53, 5 and 0 % of the administered dose was recovered in the urine. Furthermore, when introduced into the abomasum, DAPA could be measured in plasma from the anterior mesenteric and jugular veins.

4. It was concluded that in the normal sheep the DAPA-containing fraction of the bacterial cell-wall material synthesized in the rumen is not digested in the small intestine. In the caecum and colon, however, this fraction is extensively degraded by hindgut bacteria.

1. In experiments with four lambs cannulated in the abomasum and terminal ileum the amounts of muramic acid, diaminopimelic acid and α-amino nitrogen passing through the abomasum, terminal ileum and rectum were compared. While the concentration of muramic acid and diaminopimelic acid was higher in the ileal than in the duodenal dry matter, the ratio of muramic acid to diaminopimelic acid remained fairly constant at about 1·00:0·86 on a molar basis.

2. There was a very significant net absorption of α-amino nitrogen between the abomasum and terminal ileum, but no net absorption of muramic acid between these points. However, less muramic acid passed out of the rectum than passed through the terminal ileum.

3. It was concluded that in the normal sheep bacterial mucopeptide synthesized in the rumen is not digested in the small intestine, but is extensively degraded by bacteria in the caecum and colon.

When incoming radiation was reduced artificially to 50% daylight during the postflowering period in peas, the rate of abscission of flowers and pods increased in the same way as when the density of planting is raised. Shading from flowering onwards reduced yield almost to the level of peas that were shaded throughout the growing season, even though peas that received full daylight until flowering had many fertile tillers and a greater reproductive potential in terms of the total number of flowers produced. Conversely, when shades were removed at flowering time the crop was able to compensate and yields approached those of peas grown entirely in full daylight, this was mainly due to a reduction in absoission losses of flowers and pods so that the majority of pods formed on the main stem contributed to final yield.

It is suggested from these results that the major source of dry matter for pea yield is the photosynthate produced during the post-flowering period rather than that translocated from roots or stems following storage during the vegetative period.

Two attempts were made to increase the number of lamb crops in intensively managed dairy sheep flocks. Rams were introduced into the flocks for the first 100 days after lambing. The ewes were milked twice daily from parturition. In the first flock of 188 ewes, the lambs were weaned at birth. Half the ewes received a course of progesterone and PMS in the third week post partum. 49% of the treated ewes conceived at average of 49 days post partum, and 59% of the non-treated ewes at an average of 53 days post partum. The hormone treatment reduced milk yield by 17% in the ewes which conceived and by 26% in those which did not conceive. Milk yield was 7% lower in those ewes which conceived a second time. Yield in the subsequent lactation was very low. In the second flock, the lambs of 83 ewes were weaned 40 days after lambing. 89% of the sheep conceived at an average of 64 days after lambing. The pregnant ewes yielded 6% less milk than those ewes which did not conceive. Yield in the following lactation was satisfactory. The practical implications of the results in terms of the possibilities of future production in dairy flocks are discussed.

Results of two groups of experiments testing phosphate fertilizer for sugar beet were re-examined; there were 53 experiments made between 1957 and 1960 in group 1 and 25 experiments between 1957 and 1959 in group 2. The mean response of total sugar to 126 kg/ha P2O5 was only 160 kg/ha but on a few fields response exceeded 1000 kg/ha. Response seemed to be greater in 1958 than in the other years, but between-site variance accounted for most of the difference from year to year.

Stored soil samples were analysed for phosphorus by four methods; the results were compared and related to the yield response to phosphate fertilizer. After allowing for experimental error, the percentages of the between-sites variance of the responses accounted for by log (soil P) were (group 1 first): sodium bicarbonate, 60 and 62%; anion resin, 52 and 30%; ammonium acetate/acetic acid, 52 and 0%; and calcium chloride, 42 and 2%. When soil pH was included in the regression equation, prediction of response by anion resin much improved and equalled that of sodium bicarbonate. Ammonium acetate/acetic acid was ineffective on soils with much free calcium carbonate.

As two-thirds of the soils had sodium bicarbonate-soluble phosphorus concentrations between 15 and 45 ppm P with mean response 65 kg/ha sugar, there is only limited scope for increasing the profitability of the crop by improving P manuring. However, more P fertilizer can be recommended for the few soils with ≤ 10 ppm P and P fertilizer can be withheld from fields with more than 45 ppm. The dressings we recommend are 180, 120, 60, 30 and 0 kg/ha P2O5 (approximately 1·5, 1·0, 0·5, 0·25 and 0 cwt/acr P2O5) on soils with ≤ 10, 11·15, 16·25, 26·45 and ≥45 ppm sodium bicarbonatesoluble P respectively.

The nitrogen requirements for maximum production of perennial ryegrass swards in August/September were shown to be of the order of 4 kg N/ha/day. Further increases above this level had no appreciable effect on dry-matter production, leaf area or light intercepted, but maximum tiller numbers were considerably enhanced. Shortage of nitrogenous fertilizer had comparatively little effect on crop growth rate in the early stages of regrowth, but thereafter caused the rate to fall increasingly short of potential. At high fertilizer levels crop growth rate based on total above-ground parts was linearly related to percentage light intercepted in the first month after defoliation, but values subsequently became erratic and at times negative. This change in crop growth rate and the resulting halt in effective net dry-matter production could be associated with the overall pattern of leaf and tiller formation and death, maximum net yield being achieved at the point in time when three new leaves had been produced on each tiller since cutting. It is concluded that in August and September worth-while increases in harvestable net dry matter are unlikely to occur after this stage has been reached, and that managements based on the maintenance of a complete crop cover are not likely to be successful at this time of year.