This work evaluated the effect of seed size and morphology on the development and biomass of durum wheat seedlings. Three different seed-grading sizes selected by sieving were used in glasshouse experiments, and a set of three developmental and 23 biomass-related indices were measured on eight genotypes, at two moisture levels. The influence of seed size on seedling development was studied at high and low temperatures (22/12 °C, and 15/5 °C day/night temperatures, respectively), in growth chambers.

The area of the seed and the area of the embryo were the seed morphological traits most affected by seed size. Seed size was strongly associated with seedling development and seedling biomass until the complete extension of the first two leaves, at the fourth leaf stage. The rate of first-leaf growth and the area of the first leaf were the developmental and biomass traits, respectively, most sensitive to seed-grading size.

Mean digestible energy (DE) intakes of 147 cows of three parities receiving three levels of DE including one ad libitum (about 2·2, 2·6 and 3·3 multiples of maintenance (MM)) drawn from three mixed diets containing hay and 60, 75 or 90% compound were calculated.

Rumen samples were taken from three-quarters of the cows at monthly intervals throughout the experiment. Molar proportions of volatile fatty acids (VFA) in the rumen were not affected by stage of lactation over the 36 weeks of the experiment. The proportion of acetic acid decreased and that of propionic acid increased with greater intakes and with higher proportions of compound in the diet. The proportion of n-butyric acid was little affected by level of intake but decreased with increasing proportions of compound. In young, non-lactating cattle given the same diets but at lower levels of intake, VFA proportions were unaffected by diet composition at intakes of about 0·7 MM but at intakes of about 1·3 MM the proportion of acetate decreased and that of propionate increased when the proportion of compound was increased from 75 to 90%.

The efficiency of milk energy production in relation to DE or metabolizable energy (ME) above maintenance decreased with increasing level of intake but was little affected by the proportion of compound. Partition towards live weight increased with level of intake in early lactation but not in late lactation. It also increased with higher proportions of compound in mid and late lactation but not in early lactation.

Estimates of the ME requirement for live-weight change (LWC) were in reasonable agreement with recently published standards in early lactation when live weight was decreasing, but later in lactation when live-weight gain was occurring, a much higher value was calculated which is difficult to reconcile with these standards.

Rumen VFA proportions were related to dietary fibre concentration and level of intake additively. The relationship to VFA proportions was close for milk fat concentration, but less so for energy partition towards live weight and none was apparent for the efficiency of ME utilization for milk energy production. It is suggested that both the reduction in milk fat concentration and the increase in milk yield in response to reductions in the fibre content of diets may be independently related to the increase in the proportion of propionate in the rumen VFA.

It is concluded that further progress in studies of the dietary factors affecting the efficiency of milk production will require measurements of nutrient uptake from the digestive tract and description of milk production and LWC in terms of their chemical composition rather than energy alone.

1. The use of a positive air pressure on closely packed soils decreases the time of recovery and increases the yield of solution obtained by water displacement.

2. Equipment and technique for the recovery of displaced solutions is described.

3. Data from three sandy loams and two silty clay loams are reported.

4. Successive displaced solutions of equal electrical conductivity were obtained from each soil. The concentration thus measured was in each case the same as that of the liquid obtained without the use of displacing water.

5. Concentrations of individual ions in successive portions of displaced solution are uniform in soils at optimum and this also appears to be true at half optimum.

6. There is an inverse proportion between total moisture content of soil and concentration of displaced solution as indicated by measurements of specific resistance.

7. When the solution displaced by water from a given mass of soil was used as displacing agent on another portion of the same soil, the newly displaced solution had the same concentration of electrolytes as the displacing solution. The opinion is expressed that this result indicates that the displaced solution has the same concentration as the solution with which it came in contact in the soil.

8. Typical differences in behaviour of the various solutes in displaced solutions are discussed.

9. The significance and limitations of water extractions of soils are discussed in the light of the results from displaced solutions.

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.

Six Romney Marsh ewes exposed daily in a hot-room to temperatures averaging 105° F. dry bulb and 87° F. wet bulb for 2 months prior to the start of the breeding season all experienced oestrus and, as a group, at the same time of year as non-heated controls.

However, when maintained under daily hot-room treatment throughout the pregnancy period only one ewe lambed, suggesting an adverse effect of high temperature on gestation.

In a further experiment to confirm this, eight control ewes all lambed, average birth weight of lambs being 9 lb. 5 oz. Of six experimental ewes exposed to temperatures of 107° F. (dry bulb) and 92° F. (wet bulb) for 7 hr. daily during the last third of pregnancy, one failed to lamb and the lambs averaged 7 lb. 15 oz. A further six experimental ewes exposed to similar room conditions for the last two-thirds of pregnancy produced still smaller lambs, averaging 6 lb. 11 oz. at birth, and three ewes failed to lamb.

The yield of lamb per ewe was 9 lb. 5 oz. for controls, 7 lb. 13 oz. and 4 lb. 1 oz. for ewes exposed to heat during the final third and two-thirds of pregnancy respectively and, in the previous year's experiment, 1 lb. 2 oz. for those exposed throughout the pre-mating, mating and post-mating period.

It is concluded that although high temperature is apparently without effect on the incidence of oestrus in sheep, it is inimical to satisfactory gestation.

1. The normal level of blood ammonia in the sheep seems to be somewhat higher than in nonruminants.

2. The toxicity of ammonium acetate, ammonium chloride or urea placed in the rumen follows different metabolic pathways. In the case of the chloride there is an uncomplicated metabolic acidosis which is not, however, adequate to account for the toxic symptoms. When the acetate is administered there is also a respiratory alkalosis and in the presence of urea the changes in the acid-base status, though interesting, do not account for the toxicity.

3. The toxicity is almost certainly due finally to a direct effect of the circulating ammonium ion level though in the case of urea, there is an earlier effect that may be of a pharmacological type and is less severe.

4. The organisms within the rumen rapidly reach a maximum level of adaptation (7 days) to handle large quantities of ammonia by a synthetic pathway.

5. The intravenous administration of L-arginine did not markedly ameliorate the ammonia toxicity.

The objective of the present study was to evaluate the effects of betaine supplementation on rumen fermentation, lactation performance and plasma characteristics in dairy cows. Twenty multiparous Holstein dairy cows (597±11·8 kg body weight (BW), 88±4·5 days in milk (DIM) and average daily milk production of 26·3±0·5 kg/cow) were used in a replicated 4×4 Latin square experiment. The treatments were: control (without betaine), low-betaine (LB), medium-betaine (MB) and high-betaine (HB) with 0, 50, 100 and 150 g supplemental anhydrous betaine/cow/day, respectively. Betaine was hand-mixed into the top one-third of the daily ration at feeding. Experimental periods were 30 days with 15 days of adaptation and 15 days of sampling. Dry matter (DM) intake was not affected with increasing the betaine supplementation. There were linear increases in milk yield and fat-corrected milk yield (corrected to 40 g fat/kg) and a linear and quadratic increase in milk fat concentration with increasing the betaine supplementation, whereas the proportion and yield of milk protein and lactose, and feed efficiency, were not affected. Ruminal pH and ammonia N linearly decreased, whereas total volatile fatty acid (VFA) concentration linearly and quadratically increased with increasing the betaine supplementation. The ratio of acetate to propionate (A:P) linearly increased from 3·06 to 3·53 as betaine supplementation increased. Digestibility of DM linearly increased, whereas digestibilities of organic matter (OM), crude protein (CP), neutral detergent fibre (NDF) and acid detergent fibre (ADF) in the total tract were quadratically increased with increasing the betaine supplementation. Plasma concentrations of non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHBA) were lower for betaine supplementation than for control, and were linearly decreased by betaine supplementation. The results indicate that supplementation of mid-lactation dairy cow diets with betaine increased milk yield through increased feed digestion. Betaine supplementation may benefit lactation performance when methionine supply is limiting.

Ninety 4-month-old wether lambs were allocated to an initial slaughter group (n =10) or to one cell (n= 5) of a 4 × 4 factorial treatment design involving four levels of infection with Ostertagia circumcincta (0, 1000, 2000 and 4000 larvae/day) and Trichostrongyluscolubriformis (0, 1000, 2000 and 3000 larvae/day). They were maintained indoors in individual pens and offered freshly cut ryegrass-white clover herbage during an 84-day period of infection after which they were slaughtered. Body protein, fat, water, Ca and P contents were determined. Feed digestibility was determined in all sheep during 5-day periods during weeks 2, 5, 8 and 11. Faecal egg counts were determined and blood samples obtained at intervals and total worm counts done at slaughter.

The effects of mixed infection on feed intake and body-weight gain were multiplicative. Mean D.M. intake of sheep infected simply with 3000 larvae of T. colubriformis or with 4000 larvae of O. circtimcincta was reduced by 10 and 8% respectively, but in those infected simultaneously intake was reduced by 30%. Energy retention was depressed mainly by reduction in gross efficiency of use of metabolizable energy in infections with T. colubriformisand by reduction in feed intake in infections with O. circumcincta. The additional effect of mixed infection occurred mainly through further depression in feed intake.

There was no interaction between infections in effect on deposition of Ca or P in the body, both species having significant effect. Infection with T. colubriformis caused hypophosphataemia and hypocalcaemia, but infection with O. circumcincta had no effect.

The number of worms established by the infections was generally low compared with previous studies with conserved and concentrate feeds. This was associated with relatively low pathogenicity in infection with O. circumcincta and normal pathogenicity with T. colubriformis.

Infection with T. colubriformis reduced the number of adult worms of O. circumcincta present at slaughter.

Inadequate soil moisture is one of the main constraints on the productivity of chickpea in the rainfed farming systems of the dry areas in West Asia and North Africa. The response to irrigation at flowering and pod filling of winter- and spring-sown kabuli chickpea was studied in 1983–86 at ICARDA's main research station at Tel Hadya in northern Syria. In 1983/84 when the cultivar ILC3279 was sown in winter, irrigation increased yield by 105% over a crop receiving 229 mm of precipitation. In 1984/85, ILC3279 was sown in winter and spring. Advancing the date of sowing to winter increased yield by 65% and irrigation increased seed yield by 73% in winter and 143% in spring sowings compared with crops grown receiving 373 mm rainfall.

In 1985/86, six cultivars (ILC482, ILC3279, FLIP81–57W, FLIP81–293C, FLIP84–19C and FLIP84–80C) were compared, but differences in their response to irrigation were negligible. Advancing sowing from spring to winter increased seed yield by an average of 66%. Irrigation increased seed yield in winter and spring sowings by 56% and 72%, respectively, over those receiving 316 mm annual precipitation. Irrigation is, therefore, a way of increasing the productivity and yield stability of chickpea in northern Syria but the improvement in yield depends on the total rainfall and its distribution over the growing season.

Wheat grain yield is often associated with grain number/m2. Spike fertility (SF), i.e. the quotient between grain number and spike chaff dry weight, is a major component of grain number/m2 determination. Several methodologies have been proposed in the literature for field determination of SF, but they are tedious and expensive. Also, no comparison between methodologies has been done. The feasibility of using wheat SF as a selection criterion in a breeding programme or as a variable of interest in crop physiology studies depends largely upon the availability of a simpler and faster method for collecting and processing samples. Thus, the objective of the present study was to determine: (1) the association between SF calculated with the non-grain spike dry weight at anthesis (reference method) or at crop maturity, (2) the association between SF evaluated at the plot level (i.e. both non-grain spike dry weight and grain number determined as per area unit) and at the individual spike level and (3) the minimum number of individual spikes that should be sampled for the development of a screening method that can be applied in wheat breeding programmes or in crop physiology studies. Associations between variables were determined by correlation analysis of treatment means, and by a test of agreement for categorical rating (low, medium and high SF) between individual data of each variable. Four experiments (BY95, BC96, BC97 and ML07) were performed with five, ten, eight and eight wheat cultivars, respectively, under no environmental limitations, except for experiment ML07 which was not irrigated. In the first three experiments, SF was determined both at the beginning of grain filling and at maturity, in plot-size samples (0·8 m2/plot). In experiments BC96 and BC97, SF was determined both in plot-size samples and in individual spikes (five spikes per plot), at the beginning of grain filling. In experiment ML07, increasing numbers of individual spikes were sampled at maturity to assess SF. As a result: (1) a significant association (R2=0·78; P<0·001; d.f.=20) was detected between SF determined at the beginning of grain filling and at maturity, and the test of agreement for categorical rating showed that the classification of data into categories of SF was equivalent between methods (P>0·05); (2) when comparing SF determined in large plot-size samples v. in small samples of individual spikes, a good adjustment (R2=0·77; P<0·001; d.f.=6) was also observed, with no significant cultivar×experiment interaction and a good agreement between methods in the classification of data into categories of SF (P>0·05); and (3) increasing sample size from 5 to 40 spikes gradually decreased the average relative standard error of the mean (from 0·034 to 0·012, respectively). In conclusion, wheat SF can be determined in a fairly accurate way by sampling a small group of individual spikes at crop maturity, thereby allowing the evaluation of a large number of treatments in a timely fashion and the screening of breeding material from early generations.

Grain yields of 14 spring oat varieties grown at two levels of nitrogen in three seasons at two locations were compared. A genotype × environment analysis demonstrated that the more recent varieties not only had higher yields but also were better adapted to high-yielding environments. Modern varieties demonstrated a yield improvement of 30% over the older varieties. Examination of components of yield by a series of simple correlations indicated that improvement in varieties by breeding has been associated with shortened straw and higher harvest indices. Within varieties, 1000-grain weight was the most stable character and harvest index the character which varied most consistently with variations in grain yield.

Experiments were carried out to study the effects of dietary P depletion on plasma concentrations of inorganic P (P1), calcium, 1,25-(OH)2-Vit.D3 and alkaline phosphatase, and to investigate the effects of P depletion, in comparison with P repletion, on intestinal flow and net disappearance of Ca and P in sheep. The animals were adapted to an experimental diet of pellets and chopped straw providing between 0·91 and 1·04 g P/day for depletion. They were repleted by single infusions of phosphate into the duodenum raising total P supply to about 4·1 g/day. During P depletion plasma P1, concentrations decreased significantly whereas those of Ca increased. The development of hypercalcaemia is discussed with respect to intestinal absorption and bone accretion and resorption. Plasma 1,25-(OH)2-Vit.D3 and alkaline phosphatase were not affected by P depletion.

In P depletion the flow through the gastrointestinal tract of total P contained in the digesta and faecal P excretion were significantly reduced and the P balance was slightly negative. Calcium net absorption from the gut was also reduced. Daily flow of total P and P1, contained in the particle-free intestinal fluid was markedly lower in P depletion as compared with P repletion. The percentage of net disappearance from the small intestines of total P and P1, in the particle-free fluid was 57 and 70 % in the depleted state and 79 and 93% in the repleted state.

Flowers were present over a period of approximately 6 weeks in 12 varieties of oil-seed rape. A linear relationship was found between flower cover (maximum 74%) and photon reflectivity (400–700 nm) which increased from around 0·047 during vegetative growth to 0·195 for a canopy in full flower. Reflexion and absorption of photons by flowers reduced light available to the leaf canopy and immature pods. Spectral measurements indicate that flowering canopies reflect substantially more radiation and absorb less than vegetative canopies between 500 and 700 nm but reflect less and absorb slightly more between 400 and 500 nm.

Seed yield was not strongly correlated with estimates of the radiation absorbed by the leaf canopy under the flower layer. It appears that whilst increased flower density in a canopy might be expected to contribute to increased seed yield, increased reflectivity by petals may have a negative effect on yield. Breeding for reduced petal size or for apetalous lines may result in improved yields by producing more efficient light distribution within the canopy.

The crude-fibre determination is misleading, because the fraction obtained does not bear any definite relationship to the structural constituents of the material. The cellulose is partially attacked, and lignin extensively removed. Considerable variation is found in the lignin content of crude-fibre fractions. Highly lignified materials do not necessarily yield a crude fibre high in lignin.

Since the presence of lignin exercises a direct effect on the digestibility of the material, any empirical method should include all the lignin, and alkaline treatment must be avoided. Acid hydrolysis may be a possible alternative method, if a correction for protein be made in the case of materials high in nitrogen, and a determination of the lignin content made.

Two field experiments have been conducted to investigate the pattern of tillering, ear emergence and survival of the component tillers of three barley varieties, representing old and new varieties. The varieties were grown under contrasting nitrogen fertilizer levels and plant spacings. The results reported are for the variety means and variety x nitrogen and variety x spacing interactions. After the main stem (M) the most frequently occurring tiller was the tiller appearing in the axil of the first true leaf (T2), followed by the coleoptile node tiller (T1) and the tiller in the axil of the second true leaf (T3). The T1 tiller occurred most frequently in the newest variety, Deba Abed, and least in the oldest one, Spratt Archer. Survival rates of the shoots were highest in M, followed by T2, T1 and T3. Higher-order tillers occurred relatively infrequently and had low survival rates. M contributed the largest percentage of the grain yield, followed by T2, T1 and T3. The 13% grain yield advantage of Deba Abed over Spratt Archer was mainly accounted for by the difference in production by the T1 tiller. The results are discussed in. relation to the only other known paper on component tillers in barley.

The amino acid, mineral and collagen composition of certain different components of the bodies of preruminant calves was determined. The amino acid composition (g/kg crude protein) of the empty bodies of preruminant calves was: hydroxyproline, 40; aspartic acid, 81; threonine, 40; serine, 44; glutamic acid, 129; proline, 81; glycine, 113; alanine, 71; cystine, 13; valine, 39; methionine, 17; isoleucine, 28; leucine, 69; tyrosine, 25; phenylalanine, 36; lysine, 64; histidine, 25; arginine, 70; tryptophan, 8. The hydroxyproline, proline and glycine contents were much higher than in bovine muscle because about one-third of the total protein of the calves was collagen, a protein particularly rich in these amino acids. The collagen content of the individual body components varied considerably as did their amino acid contents. There were also some marked differences in the contents of some of the major constituents and minerals in the individual components. In particular the internal organs and blood (component (6)) contained significantly lower concentrations of crude protein, ash, Ca, Mg and P but significantly higher concentrations of Cu and Fe.

Forty pregnant sheep were allocated to four groups and maintained indoors in individual pens on a pelleted diet. During the last 6 weeks of pregnancy and the first 6 weeks of lactation groups were infected daily with 4000 larvae of Ostertagia circumcincta or remained as controls in a cross-over design. Thus groups were either not infected (CC), infected only during pregnancy (IC), during lactation (CI) or during both pregnancy and lactation (II). Food was offered on the basis of body weight at the beginning of pregnancy and lactation. Food intake, body-weight change, faecal egg counts, plasma pepsinogen and milk production were measured weekly, wool growth and fibre diameter during 21-day periods and tensile strength of wool over the whole experimental period.

Eggs were seen in faeces of only three sheep infected during pregnancy, but in all sheep infected during lactation; maximum mean values were 467 ± 144 and 222 ± 58 eggs/g fresh faeces in CI and II sheep, respectively. Pepsinogen concentrations rose after 1 week of infection during pregnancy and lactation; peak values were 868 + 57 and 1104 ± 146 m-u/l, respectively.

Infection reduced food intake by 16% during lactation but had no effect during pregnancy. There were significant interactions between pregnancy and lactational treatments on intake during lactation. Infection during lactation increased bodyweight loss; mean values were 57, 40, 114 and 78 g/day for groups CC, IC, CI and II respectively. Milk production was decreased during weeks 4–6 of lactation, mean values being 1·59 and 1·32 kg/day in control and infected groups, respectively.

Infection reduced wool growth and wool fibre diameter by 20 and 7%, respectively, during the final 3 weeks of infection during lactation. The staple strength of wool grown during the experiment was reduced by 14, 45 and 23% in IC, CI and II groups, respectively. Infection moved the point of greatest wool tenderness from parturition in control sheep to a time during the period of infection, particularly when infection occurred during lactation.

At the time of the commencement of the Rothamsted experiments very little was known as to the amounts of combined nitrogen and other substances present in rain-water.

Marggraf (74) found nitric acid, chlorine and lime in rain-water collected during the winter of 1749–50, and, subsequently, in snow. These analyses, which are probably the earliest, were followed by those of Bergman (15) who detected the same substances both in rain and snow; whilst somewhat later de Saussure (99) noticed the presence of ammonia in the atmosphere. Between 1820 and 1825 several analyses of rain-water were made.

1. Some observations on the serum phosphatase of the domestic fowl are described. Laying hens, held to be normal birds, had higher and more variable serum phosphatase than cocks. No great difference in serum phosphatase could be found between laying hens and hens in a period of suspended egg production. Pullets from another source and which had never laid gave values comparable with the value for cocks.

2. The serum phosphatase of chicks shows a rapid increase to a maximum at about 10–12 days after hatching, followed by an equally sharp fall to a lower level at 3 weeks. Thereafter, the values for male birds fall regularly until maturity. The values for female birds correspond closely with the values for male birds until the onset of laying, when they increase again, but to a varying degree in different individuals.

3. An attempt to reduce the range of variation of serum phosphatase in laying birds by administration of 1 ml. per bird per diem radiostol B.D.H. (3000 international units vitamin D per ml.) was not successful.

4. Serum phosphatase showed a much greater increase during laying in pullets receiving a low calcium ration (0·37 per cent. CaO) than in pullets receiving the same ration supplemented with calcium carbonate (3·10 per cent. CaO).

5. Serum phosphatase is greatly increased in chicks suffering from rickets.

Four repletion experiments were carried out to clarify the roles of molybdenum, sulphur and iron in the inhibition of copper absorption by ingested soils. In each experiment, groups of four to six hypocupraemic Scottish Blackface ewes were repleted for 21 days with diets containing CuSO4 and/or soil Cu and the responses in plasma Cu used to assess the availability of the Cu supplied.

In Expts 1 and 2, three soils varying in Mo but high in Fe content and derived from Lower Lias Clay, Namurian Shale and Weald loam were added at 100 g/kg D.M. to diets of low (1·0) and high (4·1 g/kg D.M.) S contents: they provided 3·1, 2·8 and 0·1 mg Mo/kg D.M. respectively. When compared with groups given no soil, each soil increased plasma Cu repletion in the low S experiment and decreased it in the high S experiment. Inhibition was thus not completely dependent on soil Mo but dependent upon dietary S.

Soils varying in Fe content were compared in the manner of the above experiments in Expts 3 and 4. Two Fe-rich soils, developed from the Upper Chalk and a Barton Clay and providing 2·8 and 1·5 g Fe/kg D.M., impaired Cu repletion on the high S diet but not on the low S diet. A soil, developed on a sand from the Bagshot Beds and providing only 0·15 g Fe/kg D.M., did not impair repletion but FeSO4, providing 0·8 g Fe/kg D.M. did so, irrespective of dietary S content. Ingestion of Fe-rich soils in a high S diet caused three-fold increases in rumen sulphide concentrations 5 and 24 h after feeding. It is suggested that soil ingestion impairs Cu absorption in sheep by trapping S as heavy metal sulphides such as FeS and releasing sulphide in the acid abomasum.