The effect of stage of harvesting on dry-matter (D.M.) yield and chemical composition of barley, wheat and the legumes common vetch (F. sativa), woollypod vetch (F. dasycarpa) and fodder peas (P. sativum) were studied in Cyprus under low rainfall conditions in a series of trials sown in four successive years. Cereals were harvested at the beginning of heading, 50% heading and the milk stage of grain, and legumes at three stages from preflowering to full pod formation, D.M., protein and digestible D.M. yields and percentage D.M. content increased with age, whereas percentage protein content and D.M. digestibility declined. Under moisture stress conditions before and during the harvesting period D.M. yields did not increase significantly with age. Protein content of cereals under low rainfall conditions was higher than that of cereals grown in the U.K. under higher N fertilization levels. Rainfall conditions affected drastically the performance of both cereals and legumes. However, average yields were satisfactory; the barley variety 628 gave 8·98 t/ha, the highest D.M. yield among all cereal and legume varieties.

A microbial cell product was compared with fish meal at three levels of dietary inclusion, using barley as the basal diet. Digestibility coefficients for flash-dried microbial cells (DMC) were calculated to be 0·85 for gross energy and 0·91 for N. Digestible energy (DE) values were 18·8 MJ DE/kg D.M. for DMC and 16·5 MJ DE/kg D.M. for the fish meal. Digestible nitrogen (DN) values were 119 g DN/kg D.M. for the DMC protein and 108 g DN/kg D.M. for the fish meal. The metabolizable energy (ME) values for diets containing DMC were similar to those for diets containing fish meal; ME/DE for diets containing about 16·5% crude protein was 0·96. Microbial N was less efficiently utilized than fish meal N; this was largely attributed to the different contents of nucleic acid N.

Grains from ears of known anthesis time in seven spring barley cultivars were measured for dry weight and α-amylase activity at regular intervals during grain maturation. During the period 10–31 days after anthesis, dry weight increase of the grain was found to be substantially linear in all the cultivars. Comparisons between linear slopes fitted for this phase of growth were found to provide an objective means of comparing grain growth rates in different cultivars.

α-Amylase activity per grain reached a peak in all except one cultivar at between 10 and 16 days after anthesis but declined rapidly during the linear phase of grain growth. α-Amylase activity per gram grain dry weight decreased exponentially during this period and transformation of the data to logarithms allowed a substantially linear fit to be made. Slopes for each of the cultivars were compared.

Differences were found between cultivars in grain growth rates, total α-amylase activity and rates of fall of α-amylase activity per gram for the period 10–31 days after anthesis. No relationship could be found between grain growth rate and either the absolute level of α-amylase activity achieved in the grain or the rate of fall in activity during development.

The effect of a single injection of 100 μg prostaglandin analogue Cloprostenol, during the luteal phase of the oestrous cycle was examined for synchronization of oestrus, time of ovulation and embryonic viability in ewes.

Following injection of Cloprostenol alone, 84% of ewes were detected in oestrus 29–48 h later. Pretreatment with PMSG increased the proportion of ewes in oestrus within 36 h. In these ewes 38% had begun ovulating 30 h after the onset of oestrus and by 36 h 87% had begun ovulating. Normal embryos of 8-cells to blastocysts were obtained from ewes given PMSG and Cloprostenol, and on transfer to recipient ewes, treated with Cloprostenol, all recipient ewes produced lambs.

It is concluded that injection of 100 μg Cloprostenol is an efficient method of synchronizing oestrus in ewes and that normal embryonic development would be expected in mated ewes following this treatment.

About sixty male lambs were fed ad libitum from 6 weeks of age on low- or highprotein diets based on barley or barley and fishmeal and containing respectively 120 and 200 g crude protein/kg dry matter. Some lambs were changed from one diet to the other when they reached 28 kg live weight. All were slaughtered as they attained a predetermined series of live weights ranging from 20 to 75 kg.

Throughout the experiment, rates of live-weight gain were substantially higher with the high-protein (HP) than with the low-protein (LP) diet, but were highest after a change from low to high protein (LHP). The feed consumption of the LHP lambs did not exceed that of the HP lambs, but the former showed a substantial superiority in feed conversion ratio at the same live weight.

At similar empty body weights, the LP lambs contained more fat and less water in the empty body than the HP lambs. Although the percentage differences decreased at higher weights, differences were still apparent at 70 kg live weight.

The LHP lambs showed dramatic and rapid changes in body composition, particularly in water and fat content. By 40 kg live weight, their composition approached that of the HP lambs.

The ratio of water to protein was consistently lower for the LP lambs. The ratio of protein to ash also differed between LP and HP lambs. It was initially highest for the HP lambs, at about 40 kg live weight it was the same, and at 70 kg live weight it was highest for the LP lambs.

The ash content of the LHP lambs remained virtually constant during the period of rapid growth and rapid deposition of water, protein and fat which took place immediately after the change of diet, and only showed compensatory increases after 35 kg live weight. This finding was supported by the pattern of changes in weight and specific gravity of the femur and tibia + fibula.

Use was made of separate relationships between live weight and body composition for the LP, HP and LHP lambs to estimate rates of accretion of crude protein, fat and water in the empty body. There was a particularly striking increase in the rate of accretion of water immediately following the change of diet. There was an increase in the water content of empty-body gain and a reduction in the ratio of gain in fat to gain in protein.

Derived estimates of the ratio of metabolizable energy intake above maintenance to the energy content of empty-body gain gave some suggestion of an improvement in efficiency of utilization of metabolizable energy for gain following the change from low to high protein. It is concluded however that the improvement in food conversion ratio following the change is attributable mostly to difference in the composition of gain.

Chopped barley straw was fed ad libitum to penned Romney wether sheep. Supplements of urea, ground wheat grain + urea, lucerne hay and autumn saved pasture (ASP) were given for five periods each of 3 weeks using a 5 × 5 Latin square design. The latter three supplements supplied similar amounts of nitrogen and approximately 20% of the energy required for maintenance.

The concentration of ammonia in the rumen fluid of sheep fed the basal straw diet was low and was increased by all the supplements. The concentration of total volatile fatty acids (VFA) in rumen fluid was unaffected by supplementation with urea, but was increased by the three supplements of nitrogen and energy. Differences in VFA molar proportions between treatments were small.

Sheep offered straw alone had a digestible energy (DE) intake of 69% of maintenance and showed a weight loss of 121 g/day. Supplementation with urea had no effect upon apparent energy digestibility (42%) or voluntary intake, but significantly reduced the rate of live-weight loss. The lucerne hay and ASP supplements also had no effect upon straw consumption, but increased total DE intake to 87% of maintenance due to the additional energy provided by the supplements, and reduced live-weight loss. Supplementation with wheat + urea increased the estimated amount of digestible organic matter derived from straw by 8·5%, increasing DE intake to 94% of maintenance and reducing live-weight loss to 18 g/day.

Averaged over all five groups of animals, straw intake increased by 9% in the second period of feeding and then gradually decreased with time, reaching a value in period 5 which was similar to period 1.

A linear relationship between the amount of allantoin excreted in the urine of cattle and the digestible dry-matter intake, has been found for cattle fed different roughage diets. The relation was also linear for buffalo although they excreted less urinary allantoin than cattle at the same level of digestible dry matter intake. It is postulated that the relationship arises because of the contribution that degraded microbial nucleic acids make to the excreted allantoin in the urine of cattle.

Results of experiments made on cultivators' fields under rainfed conditions show that response to P application decreased as available P status of soil increased. The response to N application was higher in low organic carbon soils than in medium organic carbon soils with all levels of application and the difference in response widened with increase in N level.

Blood samples were taken on six occasions from a herd of 172 Friesian, Ayrshire and Friesian × Ayrshire dairy cows, and analysed for packed cell volume, blood glucose, haemoglobin and serum albumin, total protein, urea nitrogen, inorganic phosphate, Ca, Mg, K and Na. Differences in blood composition among cows, adjusted for differences in stage of lactation, were demonstrated for all blood constituents (P < 0·001) with the variation among cows proportionally largest for globulin and total protein and smallest for Na. Correlations between blood constituents were for the most part small.

Globulin and total protein concentrations increased with age (P < 0·001) and concentrations of inorganic phosphate, albumin, Mg, Na and urea decreased with increasing age (P < 0·001 for inorganic phosphate and Mg, P < 0·01 for albumin, Na and urea). Frequency distributions of the concentrations of the blood constituents adjusted for age and breed showed significant deviations from normality for globulin (P < 0·05) and Hb (P < 0·01).

There were significant relationships between the concentrations of globulin and total protein of 43 dams and their daughters (P < 0·01 for globulin, P < 0·05 for total protein). There were also significant differences in groups of daughters of different sires for concentrations of urea, globulin, total protein, albumin, Mg, Ca, K and PCV (P < 0·01 for urea and globulin, P < 0·05 for the other constituents).

Experiments made over a period of 3 years (1971–73) at Pantnagar, India, on the effect of plant density and spatial arrangement of a hybrid variety of maize (Ganga 2) and a local cultivar (Rudrapur) indicated that a density of (at least) 75000 plants/ha is necessary to obtain maximum grain yield. With increasing density from 25000 to 75000 plants/ha the date when 75 % of plants were silking was delayed 2–5 days and the percentage of barren plants increased from 1·7 to 28·7. In dense stands, grain yield of the hybrid variety was less affected by increasing row width from 60 to 90 cm than it was in the local cultivar.

The average increase in yield with narrow (60 cm) row width as compared with wider (75 cm) row width was 6.8 % and it is argued that, in the context of the national need for increased food production, this increase cannot be overlooked.

Twenty experiments between 1970 and 1974 tested the effect of five amounts of triple superphosphate (0–110 kg P/ha) on sugar-beet yield in fields where soil contained little sodium bicarbonate-soluble phosphorus. The average yield without phosphorus fertilizer was 6·69 t/ha sugar and the increase from the optimum dressing 0·46 t/ha; the average soil concentration was 12 mg P/l. The fertilizer increased yield by 0·77 t/ha sugar on fields with 0–9 mg/l soil phosphorus, by 0·31 t/ha when soil phosphorus was 10–15 mg/l and had little effect on soils containing larger amounts.

The concentration of phosphorus in plants harvested in mid-summer contained on average 0·29% P in dried tops and 0·13% in roots when given no phosphorus fertilizer, representing a total of 19·3 kg/ha P uptake. Giving superphosphate increased the phosphorus in both dried tops and roots by up to 0·03% and there was 3·7 and 1·7 kg/ha more phosphorus in tops and roots respectively. On the most responsive fields (0–9 mg/l soil P), the fertilizer increased the phosphorus in tops and roots by 0·05% and total uptake by 7 kg P/ha. The increase in uptake (or recovery) of fertilizer varied from 15% when 14 kg P/ha was given to less than 5% when 110 kg P/ha was used.

A dressing of 27 kg P/ha was adequate for maximum yield on 19 of the 20 fields. When fields were grouped, 0–9, 10–15, 16–25 and > 26 mg/l NaHCO3-soluble soil phosphorus, and taking into account the value of the increased sugar yield, the cost of the fertilizer and its residual value, 60, 30, 20 and 10 kg P/ha respectively were the most profitable dressings. These experiments provide evidence, however, that the fertilizer would be used more efficiently if fields containing 0–9 mg soil phosphorus were subdivided into those with 0–4·5 and those with 4·6–9·0 mg/l and the groups given 80 and 40 kg P/ha respectively. These recommendations are substantially less than those used at present; they are adequate for sugar beet but other crops in the rotation would need similar close examination to ensure maximum yield and maintain adequate soil reserves of phosphorus.

There is an increasing interest in the effect of dietary lipids on the fatty-acid composition of animal tissue lipids, and long-chain fatty acids may make a substantial contribution to the nutritive value of the diet. A cow at pasture may ingest as much as 450 g of lipid in a day (Garton, 1960a) and a recent study reported the influence of pasturefeeding on the body-fat composition of horses (Bowland & Newell, 1974). Most of the data on the fatty-acid composition of pasture lipids are for clover-rich pastures and mixed pasture grasses grown in temperate climates (e.g. Garton, 1960b). By contrast, the lipid composition of tropical pastures has been neglected. This paper reports the seasonal changes in the lipid content and fatty-acid composition of eight species of tropical pasture plants.

Weed control in irrigated peanuts was evaluated under arid conditions over an 8-year period. Weed competition during the first 8 weeks of the growing season, affected the yield in three out of eight experiments. Mechanical cultivation and herbicides alone or in combination did not control the weed population completely. The best weed control was accomplished by the combination of two herbicides, a system which allowed a complementary effect and long-term control of annual weeds.

The effect of six intervals between harvests and three levels of N application on the proportion and yield of green leaf, dead leaf, ‘stem’ and inflorescence was studied in four ryegrass (Lolium) varieties during a 30-week period in the first harvest year in a field experiment. In one variety, S.23, the ‘stem’ was divided into true stem, leaf sheath, unemerged leaf and unemerged inflorescence.

There was a bigger yield of ‘stem’ and a bigger total herbage yield response to doubling the interval between harvests in S.321 and S.22 than in S.23 and S.24.

In the absence, but not generally in the presence, of applied N, S.321 outyielded the other varieties. S.24 was particularly responsive to applied N, especially in terms of green leaf yield.

There was a large positive effect on yield of doubling the interval (from 3, 4 or 5 weeks to 6, 8 or 10 weeks respectively) during the main period of stem development. During the subsequent period, however, doubling the interval produced very little extra yield of total herbage and reduced green leaf yield substantially.

The percentage increase in yield due to the application of N progressively decreased as the interval was increased.

Maximum net production of green leaf was obtained by harvesting every 4 or 5 weeks for most of the season, extending to 6 weeks at the end. Harvesting every 3 weeks, by comparison, resulted in a slightly lower annual green leaf yield, but with a distinctly higher proportion of green leaf in the crop.

Applied N generally had little effect on the proportion of crop fractions, but reduced the proportion of green leaf and increased that of' stem' in S.23 and S.24 at the August and September harvests.

The problem of sheep grazing in the deserts of Rajasthan is that animals do not get drinking water for 2–3 days at a time. Studies carried out at this Institute, on water deprivation in sheep, have indicated that sheep deprived of water for 72 h did not show any adverse effect on wool yield, in spite of the fact that water deprivation reduced feed intake (More & Sahni, 1972). The present experiment is a part of extensive studies carried out on water deprivation with particular reference to sheep production. The paper describes the influence of water deprivation on nutrient digestibility and nitrogen retention in sheep.

The percentage of natural cross pollination was estimated in the Alexandria area (Egypt) in two sites near and far from an apiary. The Egyptian cotton variety Giza 45 and the glandless strain Bahtim 110, as a marker parent, were used during three growing seasons. The average natural crossing within the square of the marker parent were 3·54 and 0·34% near and far from the apiary respectively. For the plants around the square of pollen source, however, the average of natural crossing was 0·56% near the apiary, while it was 0·21% far from the apiary. The natural crossing steadily decreased as the distance from the marker variety increased.

Changes in the amounts of nitrogen, phosphorus, magnesium, calcium and sodium present in intact grain, endosperm, testa pericarp and embryo throughout the developmental period were recorded. While the overall pattern in intact grain was one of steady accumulation, considerable variation from this pattern was found within the different parts. The results are discussed in relation to the biochemical events accompanying maturation.

Application of B-9 shortened mainstem and branch internodes of several peanut cultivars at all times of application. The numbers of mainstem and branch nodes were little affected by B-9. Interactions between cultivars and B-9 treatments in these vegetative characters were small, inconsistent and generally non-significant. B-9 had inconsistent effects on plant dry weight and did not increase pod yields. In an upright bunch type, podding was more compact, but mean seed dry weight and number of seeds per pod were slightly reduced by B-9.