The effects of salt stress on the growth, nodulation and N accumulation during the vegetative phase was studied in chickpea (Cicer arietinum). Growth and N accumulation were adversely affected by salinity. The larger control plants produced new nodules but the existing nodules on stressed plants grew larger than those of control plants. All plants had similar %N contents but the total plant N was less in stressed plants due to the reduced growth of these plants. Reduced plant vigour was the primary effect of salt stress and was mediated through processes other than symbiotic N fixation.

The absorption and movement of 14C-labelled maleic hydrazide (2000 mg/1) and 2,4-D (250 mg/1) were studied in seedlings and mature plants of a local strain of onion (Allium cepa L.) from Kano, Nigeria, in the presence and absence of N (20 mg/1).

Plants absorbed and accumulated considerable amounts of both the chemicals. Addition of N to the treatment solution reduced the absorption of 2,4-D. Also, N reduced the mobility of the chemicals from the roots to the tops which resulted in accumulation of the chemicals in the bulbs.

Fourteen Friesian and 13 Angus steers, grown at pasture, were selected so that their carcass weights fell evenly throughout the range 200–300 kg. The right half of each carcass was dissected into muscle, fat, bone and fascia and tendon, and the left half boned-out and fat trimmed into retail cuts. A step-wise multiple regression procedure, including a pseudovariable for breeds, was used to compare compositional components on a common weight basis.

Angus, at the lower end of the live-weight range, had heavier empty bodies than Friesians; at the heavier end of the live-weight range, this was reversed. This relationship between live weight and empty body weight was due to variation between breeds in the weight of contents in the fore stomachs but not the intestines.

When compared at either the same live weight or the same empty body weight, Angus had more hot carcass than the Friesians (8·0 and 8·4 kg, respectively). There was no difference between breeds in loss of carcass weight in the 24 h post-slaughter.

There was no breed difference in weight of blood, head, kidney and channel fat, kidneys, liver, diaphragm, heart, lungs, tail or fore-stomachs, when compared at the same offal weight. The feet and intestines were, respectively, 0·55 and 2·43 kg heavier for Friesians than for Angus at the same offal weight, but the pizzle was 0·11 kg lighter. Hide weight was greater in the Angus at all offal weights, with the difference between breeds being 0·016% of (offal weight).

There was no difference between breeds in the weight of muscle or the weight of fascia and tendon when compared at the same dissected side weight; however, the Angus had 4·8 kg more fat and 3·0 kg less bone than the Friesians at the same dissected side weight.

When compared at the same muscle weight the Friesians had 1·04 kg more proximal hind-limb muscles, 0·30 kg more proximal fore limb muscles, but 0·74 kg less abdominal muscles than the Angus. At all dissected muscle weights the Angus had a greater weight of muscles of the neck and thorax, and this difference increased with increasing weight of dissected muscle. The Friesians also had 1·52% more of their muscle as ‘expensive muscle’. There were no breed differences in the distribution of any other muscle groups.

There was no breed difference in the distribution of dissected fat between subcutaneous and intermuscular depots when these were the only fat depots considered. However, when kidney and channel fat was included in the total dissectable fat of the carcass, Friesians had 22·4 % more kidney and channel fat, the same weight of intermuscular fat and less subcutaneous fat than the Angus at the same total dissected fat weight.

Friesians tended to have more of their bone weight in their legs (humerus, femur, tibiar–tarsus, radius–ulnar–carpus) and Angus more in their thoracic region (thoracic vertebrae and ribs, scapular and sternum-costal cartilages).

At the same retail side weights there was no difference between breeds in the weight of fat-trimmed, boned-out, retail cuts; however, the Friesians had 3·3 kg more retail bone than Angus, but 2·3 kg less fat trim and 0·46 kg less sausage mince.

There was no difference between breeds in the distribution of retail bone or of fattrimmed, boned-out cuts between the forequarter and hindquarter. However, the Friesians had 13·2 % more fat trim in the hindquarter. Friesians had 0·27 kg more retail cuts located in the rump but 0·80 kg less in the loin, when compared at the same weight of retail cuts. Also, the Friesians had more of their retail cuts as topside, thick flank and foreshin. There were no other differences between breeds in the distribution of retail cuts.

The oestrogenic isoflavones genistein, biochanin-A and formononetin, as well as the coumestan derivative coumestrol, were identified by thin-layer, paper and gas chromatography in berseem clover (Trifolium alexandrinum) grown in Israel. Under the conditions studied, the concentration of these oestrogens in the berseem clover (total < 0·01% in the dry matter) was considerably lower than those found in clover species known to be associated with infertility in ruminants.

The effects of six amounts (0, 17, 34, 51, 68, 85 kg N/ha) of fertilizer N, applied at sowing time, on the crude protein (N × 6·25) content of barley grain sown as the first, second and fourth or later tillage crop after grazed pasture were studied over three seasons at a total of 126 sites. In addition, non-protein N in the grain was measured at 24 sites.

The overall crude protein content was 11·3% without N, increasing to 13·4% with 85 kg N/ha. The first increment of 17 kg N/ha gave the least increase in grain protein content. The year which gave the largest yields gave the lowest grain protein contents and vice versa. The mean grain protein contents without N for 1971–3 inclusive were 10·8, 11·5 and 11·8% respectively.

The mean grain protein contents without N when barley was sown as the first, second and fourth or later tillage crop after pasture were 12·6, 11·5 and 10·0% respectively; the corresponding values with 85 kg N/ha were 14·4, 13·9 and 11·8%. There was a positive relationship between grain protein content and lodging, especially in barley sown as the first tillage crop after pasture, where lodging was most severe.

Non-protein N was low and only accounted for 5–8% of the total grain N content. The mean grain. N uptake with no fertilizer N applied was 82, 70 and 49 kg/ha in barley sown as the first, second and fourth or later tillage crop respectively. The apparent recovery of fertilizer N was largest in fourth or later barley.

Two trials with 82 and 54 Chios ewes and one with 44 Damascus goats were conducted during 1973–4 to study the effects of partial suckling on lactation performance and the growth rate of the lambs and kids. The treatments studied were: (a) continuous (24 h a day) suckling; (b) partial (8 h a day) suckling and (c) partial with decreasing duration of suckling from 8 h daily to residual suckling, i.e. 20 min after each milking.

No significant differences were found in either the 35-day milk yields (commercial milk yield+milk sucked) of ewes or the 70-day milk yields of goats between animals suckling continuously and those suckling partially. However, the 35-day and 70-day commercial milk yields of ewes and goats on the partial suckling treatments were significantly higher than those of ewes and goats on the continuous suckling treatment. Residual suckling of ewes from 36 to 120 days after lambing resulted in an increase in the total milk yield but not in the milk sold. Significant differences in milk yields were found between ewes nursing one and those nursing two lambs. The corresponding mean values for the 35-day milk yield were 78 and 94 kg and those for the 120-day milk yield 205 and 238 kg.

Up to weaning (35 days for sheep and 70 days for goats) the growth rate of lambs and kids on the partial suckling treatments tended to be poorer than that of those on continuous suckling. After weaning, however, the growth rate of the partially suckled lambs and kids as well as that of the lambs on residual suckling from 36 to 120 days were as good as that of those suckling continuously so that the differences in the final weight were not significant.

It is concluded that partial suckling in sheep and goats is profitable in the early stages of lactation provided that the milk left to the young and the intake of solid feed are sufficient to sustain satisfactory growth.

Sheep weighing 27 kg live weight were fed ad libitum three pelleted diets containing alkali-treated ground rice hulls (0, 5 and 15 g NaOH/100 g rice hull dry matter) in a 1:1 ratio with ground non-alkali-treated lucerne and were fed a fourth diet comprising the above control pellet fed ad libitum with a wheat grain supplement to determine the effects of alkali treatment and of energy supplementation on the digestion of cell walls and to assess the dynamics of flow of digesta through the gastrointestinal tract.

Flows of organic matter (OM) and nitrogen (N) to the duodenum were not different for the four diets, but daily whole digesta flow past the duodenum was greater (P < 0·01) for the two alkali-treated diets. Alkali treatment of rice hulls increased the percentage of total digestion of OM that occurred in the foregut (68%) compared with non-alkali-treated diets (52%), did not increase total volatile fatty acid concentration in rumen liquor, or adversely increase rumen pH. The capability of rumen microbiota to synthesize ammo acids was not adversely affected by alkali treatment. The percentage unit digestibility of cell wall constituent OM in the whole tract was increased approximately 1·6-fold by alkali treatment. Grain supplementation increased diet digestibility.

Scanning electron microscope studies revealed confirmatory visual evidence of enhanced degradation of alkali-treated rice hulls in the tract. It is clear from these studies that alkali treatment has caused sheets of silicified cuticle on the outside of rice hulls to dissolve and to lift away from the underlying lignocellulosic (palisade) matrix. It is also clear that this matrix material is itself heavily mineralized. Disappearance of silica across the gut wall was greatest for animals fed alkali-treated diets. No clinical signs of urolithiasis were seen. Sheep readily coped with the sodium intake (33 g/day) associated with alkali-treated diets, partially by an increased water consumption and a greater ruminal and intestinal absorption of this electrolyte.

It is calculated that the OM intakes recorded and nutrients released from alkalitreated rice hull diets provided between 500 and 600 kcal net energy/day.

The effects of six amounts (0, 17, 34, 51, 68 and 85 kg N/ha) of fertilizer N, applied at sowing time as calcium ammonium nitrate, on the crude protein (N × 6·25) content of barley straw sown as the first, second and fourth or later tillage crop after grazed pasture were studied over three seasons at a total of 126 sites. In addition total N uptake and apparent recovery of fertilizer N were calculated for each cropping sequence.

The mean crude protein content of the 126 sites was 4·1% without N, increasing to 4·8% with 85 kg N/ha. Maximum protein content with 85 kg N/ha ranged from 4·4% in 1971 to 5·4% in 1973. It was highest in the year which gave the lowest straw yields. Protein content was higher when the barley was sown as the first or second crop after pasture than when it was sown as the fourth or later crop. Incremental of fertilizer N gave only small increases or decreases in straw protein contents. Over all sites straw protein content amounted to about 36% of grain protein contents. There was a significant positive relationship between grain and straw protein contents.

Nitrogen uptake in the straw without fertilizer N was 19, 18 and 12 kg/ha in barley sown as the first, second and fourth or later tillage crop after grass. The total uptake of N in the grain and straw combined was 93, 102, 107, 109, 111 and 116 kg N from applications of 0, 17, 34, 51, 68 and 85 kg/ha of fertilizer N. The mean apparent recovery of fertilizer N in the straw varied from 12% with 17 kgN/ha to 8% with 85 kg N/ha.

Fairfield Smith's law relating the error of a field experiment to the size of its plots is well established by observation and in general use, but it appears to have no theoretical basis. It is here shown by computer simulation that it could arise in many ways as a good approximation, provided the range of plot sizes considered is not unreasonably large.

Ground lucerne was treated with different concentrations of sodium hydroxide (NaOH) and potassium hydroxide (KOH) in a ‘dry crystal’ process, prior to pelleting.

Data for feed characteristics and related utilization by sheep fed these diets are reported. NaOH and KOH had effects of different magnitude on the digestibility of cell-wall constituents (CWC). An increase of nitrogen (N) in the cell wall (CWN) induced by tha alkali treatments, resulted in depressed nitrogen digestibility. The residual alkali and high electrolyte intakes produced higher rumen pH, but values were more stable than for sheep fed the control diet.

Data for the quantity of ammo acids consumed and their flow rates at the proximal duodenum for 33 diets fed to sheep have been statistically analysed by both univariate and multivariate methods. Analysis of variance of net loss (g/day) between mouth and duodenum of individual and total acida was not conclusive. Canonical variate analysis which takes regard of the correlations between different acids both within and between diets provided a conoise method of discriminating between diets. The advantage of this method in generating a unified account of digestion within the rumen is that it effectively reduces the problem from one of many dimensions to a situation where only the first few transformed variables need to be considered.

Two cocksfoot varieties, Be 6394 and Be 6392, selected for high in vitro digestibility (IVD) were compared with S. 37 under sward conditions. The pattern of extension growth in reproductive tillers, the associated changes in N and water-soluble carbohydrates content (WSC), and IVD of individual plant organs were studied.

Ten days after the mean date of head emergence, the most digestible plant organs were the leaf blades and the inflorescences; the lower internodes had the lowest IVD. At the mature hay stage the ranking was leaf blades > upper sheaths > inflorescence > lower internodes > upper internodes. At each stage N content was highest in the upper portions of the reproductive tiller, whilst the highest WSC content was found in the basal internodes.

After completion of extension growth in the lower three of the five or six internodes which showed appreciable extension at flowering, there were markedly greater increments in weight per unit length in Be 6394 and Be 6392 than in S. 37. The WSC content of the stem was higher in Be 6394 and Be 6392 than in S. 37. The IVD of the lower internodes declined more rapidly in S. 37 than in Be 6394 and Be 6392.

Results are discussed in relation to formulating a model for improved nutritive quality in conservation crops, and in relation to the height of harvesting such crops.

Early stages in the development of reproductive tillers of cocksfoot were studied in uncut swards, and in regrowth after cuts taken at a critical stage.

In uncut swards, initial stages of stem extension (up to 10 cm) occurred over 3 weeks. During this period the last three or four leaves initiated on the tiller became visible externally. Tillers with stems of less than 2 cm generally had one or two partially emerged blades. Those with stems 2–6 cm long carried two, three or, occasionally, four partially emerged blades; the sheaths of two, and sometimes three of these leaves extended beyond the stem apex. Hence, for tillers with 2–6 cm stems, even lenient defoliation involving the removal of only one expanded blade would result in the severance of a further two, three or four developing leaves; at an earlier stage only one or two developing leaves would be severed.

In the regrowth studies it was found that defoliation of reproductive tillers whose apices were below cutting height and which, at the time of cutting, had stems of up to 8 cm, led to contrasting effects: some made only negligible regrowth, whilst others made rapid extension growth. Some of the most rapidly extending tillers retained no leaf blades, and therefore the alternative effects of defoliation cannot be completely explained in terms of leaf retention. Other possible mechanisms contributing to these effects are discussed.

Data collected over a period of 11 years at the Ebini Livestock Station in the intermediate savannahs of Guyana were analysed to determine the effect of breed or cross, sire, sex, year and season of birth of calf, and age and length of calving interval of the dam on weights at birth and at 4, 8 and 12 months of age, in Santa Gertrudis, Sahiwal and Brahman cattle. The heritability of body weights at the different ages was estimated.

The effect of rainfall on dry-matter (D.M.) yield, D.M. content and crude protein (CP) content of eight barley and three wheat varieties was studied under semi-arid conditions in Cyprus for 5 years. The best variety was 628 barley, which gave the highest mean yields (6·7 and 0·69 t/ha of D.M. and CP respectively), showed the highest response to annual rainfall (33 g D.M./mm rainfall) and gave high yields in all environments, D.M. yield was not affected significantly by earliness but late varieties had higher D.M. and lower CP contents than early varieties. All varieties showed around average stability. Regression coefficients between D.M. yield and mean yield of varieties for all environments ranged from 0·81 to 1·14 and were not related to D.M. yield of varieties.

The fraction of the variation in D.M. yield explained by the variation in annual rainfall varied with variety from 25% to 67%. Multiple regression analysis using the annual rainfall and the rainfall 1 and 2 months before harvesting produced a slightly, but not significantly, higher correlation over the simple correlation between D.M. yield and annual rainfall. Varietal response to annual rainfall, as expressed by the regression coefficient between D.M. yield and annual rainfall, was positively related to D.M. yield (r = 0·84, P < 0·01).

The correlation coefficients between D.M. content and annual rainfall ranged from −0·46 to −0·92 while that of CP content and annual rainfall, though not significant in most cases, also tended to be negative.

The body composition of 24 pigs reared at different rates of growth from 25 kg live weight was estimated when they each weighed about 90 kg live weight. Feed conversion corrected for the energy requirements of maintenance (CFCR), external and ultrasonic measurements, and measurements of Evans Blue, deuterium oxide and potassium-42 were applied simultaneously to each pig, and were used to predict the weights of the fat-free mass, lipid, and dissectible fat and lean.

The best individual predictors of body composition were CFCR, deuterium oxide and potassium-42, but Evans Blue, external and ultrasonic measurements were not as closely associated with the four body components.

In combination, it was generally found that two predictors could predict the weight of a body component more closely than either predictor in isolation.

In a field study it was found that application of high P induced Zn deficiency symptoms on onion (Allium cepa L.) plants, increased P concentration but decreased that of Zn. Conversely, application of Zn tended to increase Zn concentration of both tops and bulbs and lowered P concentration. Effectiveness of Zn varied with the amount of P applied. Evidently P and Zn are mutually antagonistic. Using sub-soil on the top of raised beds and heavy P fertilization appear to be responsible for inducing Zn deficiency in onions in northern Nigeria.

Five potato varieties were grown at four sites over 2 years, and assessed for yield, specific gravity and for sloughing, texture and discoloration following steaming. Variation in discoloration was attributed to differences between sites. Genetic differences were established for specific gravity, sloughing and texture, all of which were positively correlated. Genotype × environment interactions and years × sites interactions contributed to the variation for these and the remaining variables.

The effect of six intervals between harvests and three levels of N application on the number of tillers was studied in four ryegrass (Lolium) varieties in the first harvest year and in two varieties in the second and part of the third harvest years in a field experiment. Weight/tiller was recorded in the first 2 years and weight/green leaf and number of green leaves harvested were recorded in the first year.

There was a large negative interaction between level of N and interval between harvests in respect of number of tillers, the number being increased by N with short intervals and tending to be reduced by N with long intervals. The interaction was larger in the second and third years than in the first. The negative interaction in respect of number of tillers and number of green leaves harvested was associated with a reduction in the percentage increase in yields of dry matter, digestible organic matter and N due to the application of N as the interval was increased. It is suggested that one should in general avoid a combination of high N and long intervals between harvests with present varieties of perennial ryegrass.

The effects of interval between harvests, N application, variety and time of year on number of tillers and weight/tiller are discussed in relation to their effects on yield to show how tiller information can contribute to a better understanding of the ways in which yields are achieved. Rather low yields in the late summer and early autumn of the second harvest year were in many instances attributable to a rather low number of tillers rather than to low weight/tiller.

There was a considerable increase in number of tillers between the end of one growing season and the early part of the next, suggesting that the period in which this increase is achieved may be an important one in relation to the continued vigour of the sown species.

A reduction in annual yield of green leaf with extension of interval from 6 to 10 weeks with N applied resulted from a reduction in the number of green leaves harvested/harvest and in the number of harvests, which outweighed an increase in number of green leaves harvested/tiller and in weight/green leaf. Increasing the level of N with intervals of 3–6 weeks increased the number of tillers, the number of green leaves harvested per tiller and per unit area of ground and weight/green leaf and hence consistently increased green leaf yield.

Ten winter wheat varieties, representing a range of milling and bread-making quality were grown in a split-plot field trial with two levels of irrigation and three levels of nitrogen fertilizer. Grain yield was increased by irrigation and by fertilizer treatments. Application of 90 kg N/ha applied in granular form increased yield by 12.4 and 6.1% and grain protein by 13.0 and 33.7% for the irrigated and non-irrigated plots respectively. A further 45 kg N/ha applied as an aqueous foliar spray of urea (0.125 kg/1) at anthesis increased protein by 12.4% for the irrigated plots and by 8.8% for the non-irrigated plots with little effect on yield. The varieties differed significantly in yield and protein content, resulting in negative regressions of yield and protein content at each N treatment. The production of protein (weight N/unit area) was similar for all varieties, but flour extraction was reduced by the urea treatment. Varietal differences in flour extraction were stable and not correlated with either 1000-grain weight or test weight. Loaf volume was increased by the granular N fertilizer but not by the urea spray, despite the increase in flour protein and a decrease in flour α-amylase activity, indicating that applications of nitrogen after anthesis are likely to be later than the optimum for improving bread-making quality.