The pigeon pea (Cajanus indicus or C. cajan) grown extensively in India, Africa, and other tropical and semitropical countries has attained considerable prominence as a stock food in Hawaii, where it is being grown as an important field and pasture crop in some sections. Its culture and utilisation in Hawaii have been exhaustively treated in a bulletin of the Hawaii Agricultural Experiment Station written by F. G. Krauss(1).

Sampling methods for the estimation of annual production and mean egg weight have been examined, and an attempt made, by a combination of theoretical considerations and practical observations, to derive general expressions for the standard error of such estimates. Numerical values of these errors have been tabulated in a form suitable for direct application by the practical poultry worker.

The author wishes gratefully to acknowledge the assistance and criticism given him by Dr F. Yates, and by Mr F. J. Dudley of the National Institute of Poultry Husbandry.

Much work has been done in America, on the Continent and in this country, to determine the effect of different finely-ground naturally-occurring phosphatic substances on plants of various natural orders, grown under differing conditions as to the character of the soil and the use of other nutrient substances. In a few cases results or conclusions appear to conflict. Not nearly so much attention has been devoted to the effect of artificially prepared insoluble salts of phosphoric acid on the growth of plants. When these are employed in the absence of ammonium salts, and acid soil substances, definite information should be obtained as to the powers possessed by plants themselves of utilizing insoluble phosphates. With the object of making a contribution to such knowledge, oats, peas and swede turnips were grown in artificial soils made up of white sand and pure chalk, and the particular salt of phosphoric acid under investigation. The other essential nutrient substances were supplied in a dilute solution of salts.

1. An experiment was performed to compare some methods of supplying calcium to intensively kept chickens.

2. The calcium content of a mash was adjusted to contain low (0·13%), normal (1·16%) and high (2·14%) amounts, and each of these mashes was fed to groups of chicks having access to: (a) no grit, (b) flint grit alone, (c) limestone grit alone, (d) both flint and limestone grit.

3. The addition of flint grit significantly improved the efficiency of food utilization on all diets, whether limestone grit was provided or not.

4. On all three mashes the total amount of calcium grit consumed was greater in the presence of flint grit than when it was fed alone.

5. As the level of calcium in the diet increased, the amount of limestone grit consumed decreased, whether it was fed alone or in the presence of flint grit.

6. The best results, judged on a live-weight basis, were obtained when the normal calcium mash was fed with flint grit alone, followed by the low calcium mash with both flint and limestone grit, followed by the normal calcium mash with no grit.

7. On the basis of the efficiency of food utilization, the low calcium diet with flint and limestone grit was best followed by the normal calcium diet with flint grit alone.

8. Access to limestone grit reduced the efficiency of food utilization in all but the low calcium diet.

As part of an ongoing investigation of ovine neuroendocrine mechanisms relating to photoperiod and eventually to wool growth, the diurnal variation of depilation force (an index of the strength of attachment of wool fibres to the skin of sheep) was investigated in Merino wethers and Border Leicester Merino ewes. Circadian rhythms were demonstrated in depilation force in both ewes and wethers. Further experiments were performed to investigate circadian endocrine rhythms which may have some bearing on the observed rhythm in depilation force. Circadian rhythms 180° out of phase with the depilation force rhythm were observed in plasma cortisol concentrations and in pineal serotonin N-acetyltransferase activities in Merino wethers.

The influence of dietary nutrients on carcass composition, rate of tissue deposition and the development of specific tissues, major and minor muscles in particular has been well documented for pigs reared in a temperate environment. Attempts have also been made in this environment to simulate artificial tropical conditions and, on the consequence of such conditions, to predict the nutrition and growth of the pigs.

Dairy cows were inseminated on the basis of oestrus detection alone (Control, n = 206) or in conjunction with milk progesterone profiles (Experimental, n = 204). Milk samples were taken at 4–5 day intervals to determine oestrous cyclicity and on alternate days (at strategic times) to determine the time of ovulation. Progesterone profiles were consulted routinely as an aid to oestrus detection, and also to identify and aid diagnosis of cows with reproductive disorders. Cycling cows not observed in oestrus were inseminated on the basis of their progesterone profile alone. Animals showing oestrus within 2 days of a progesterone-timed insemination were inseminated again. In Experiments 1 and 2, inseminations were given from Day 42 post partum, but AI was delayed (mean time of 68±1·1 days after calving) in Experiment 3.

The median interval from calving to first insemination was not significantly different between Experimental and Control groups, but the time of conception was earlier (P < 0·05) and the median calving interval shorter (P < 0·05) in progesterone-monitored cows in Expts 1 and 3. In addition, the percentage of cows served within 21 days of the start of the service period was greater (P < 0·05) in Experimental groups in Expts 1 and 2. This was reflected by an increase in the proportion (P < 0·05) of cows pregnant by 85 and 100 days after calving. The frequency with which the interservice interval equated to the length of the oestrous cycle was increased (P < 0·01) by progesterone testing (84·1% and 53·9% in Experimental and Control cows, respectively). Conception rates did not differ significantly between groups, but the number of double inseminations (P < 0·001) and thus the mean number of inseminations/conception (P < 0·01) were greater in progesterone-monitored cows. Conception rate was lower (P < 0·05) in cows that failed to show oestrus, and to the first insemination in double-inseminated cows.

Progesterone testing reduced (by 44–66%, P < 0·01) the number of cows presented for veterinary examination and the mean time of presentation (P < 0·05), and also influenced the diagnosis made.

Two methods of determining the weight and one method of determining the volume of water imbibed by a soil have been discussed. The results of these methods have been shown to be concordant by an independent method.

The tentative conclusion reached is that the weight of water a soil imbibes can be readily determined by Fisher's method or from the Keen-Raczkowski box, but that the volume of imbibed water cannot yet be directly determined accurately.

The relative unreliability of Bouyoucos's suction method for moisture equivalent determinations is a consequence: (1) of the variation of the suction force maintained with the nature of the soil, (2) of bad reproducibility of the results.

Constant and equal suction for all soils is secured by Schofield's silt-suction method, which may also be made to give fairly well reproducible results. The moisture content at pF 2·9 determined by this method should give a fairly close measure of the moisture equivalent.

While investigating this possibility it was found that the pF curves of stored soil samples may shift considerably with time. In the samples studied the pF at the moisture equivalent has dropped from 2·9 to about 2·4 in 7 years. In view of this shifting the reliability of the silt-suction method for moisture-equivalent determinations has not been definitely ascertained by the experiments reported.

The extent of variation in ratoonability was examined in a range of recently bred short-duration pigeonpea [Cajanus cajan (L.) Millsp.] genotypes in 1989/90, 1990/91 and 1991/92 at the ICRISAT Asia Center, Andhra Pradesh, India. Traits with which this variation could be associated were assessed. Differences in the total ratoon yield of two flushes were significant among the genotypes in each season. In a few genotypes, ratoon yield constituted 50% of the total yield, which could be as high as 5·6 t/ha. Total ratoon yield was positively correlated with leaf area index in the last 2 years of experimentation. The relationship of total ratoon yield to main crop yield was significantly positive in 1991/92 only. The results suggest that there is a large variation in ratoonability among short-duration genotypes and that high leaf area retention at main crop maturity appears to contribute substantially to this variation.

Response to selection primarily for lint yield among spaced plant populations of four American and one African variety of Gossypium hirsutum L., established in 1965—6 at Kimberley Research Station, was studied in three experiments conducted between 1966 and 1970.

In the first experiment, in which single-hill micro-plots of 3–5 plants per hill were used, the mean lint yield of progenies was larger than predicted from single plant heritabilities. In the second experiment, in which single-row plots were used, response to selection for lint yield was generally less than expected. In the third experiment, in which three-row plots were used, response to selection for lint yield was again less than expected and less than manifested in the second experiment. However, in all experiments responses to selection for lint percentage, lint quality properties, and height were close to expectations while some individual progenies substantially out-yielded their unselected parents.

The progressive decline in response to selection for lint yield from the first to thethird experiment, and the discrepancies between the actual responses and the expected responses for lint yield in all experiments, were interpreted mainly on a basis of intergenotypic competitive effects differing in sympathy with plot size and plant disposition.

It was concluded that the objective methods of selection practised were successful when judged on plant breeding criteria. It was also concluded that intra-varietal selection is an important technique by which genetic improvement can be achieved at regional breeding centres with limited resources.

Potato production in the lowland tropics is constrained by lack of affordable supplies of planting material. Therefore, the potential to produce in situ tuber seed from true potato seed (TPS) seedlings and rooted stem cuttings under nursery conditions in the warm tropics was studied, and their yields were compared with those of the same materials obtained under cool conditions. Subsequently, their field performance in the warm tropics was evaluated.

Tuber yield from TPS seedlings and rooted cuttings transplanted in nursery beds under warm conditions ranged from 50% to < 20% of that obtained in cool conditions, but reductions in tuber numbers were less marked under warm conditions. Survival of seedlings was less than that of stem cuttings, but tuber numbers of seedlings exceeded those of rooted cuttings by a factor of two or more (e.g. 700 m−2 for seedlings v. 224 m−2 for rooted cuttings). Low tuber number is physiologically inherent in cuttings, as is high tuber number in seedlings. Total tuber yields varied significantly amongst clones grown in the warm climate from rooted cuttings, not always in proportion to the number of tubers produced. Differences in tuber yield and tuber number were less marked between the two TPS progenies studied.

The field comparisons highlighted the 30–40% lower yield potential for warm-climate-produced nursery seed materials. Slower emergence and fewer stems apparently were in part responsible for this effect; however, neither tuber number harvested nor the proportion of marketable tubers was affected by site of production of seed materials. Cutting medium-sized warm-produced tubers (mean 23 g), the use of larger sized whole tubers (10–20 g v. 5–10 g) or increasing the planting density of 5 g tubers from 8·8 to 15·5 plants m-2 significantly increased yields by 4·9, 2·25 and 3·5 t ha-1, respectively, but yields were not increased further by 20–40 g tubers nor by 22·2 plants m-2. Small seedling tubers (≤ 5 g) can potentially lead to high stem numbers per unit weight of tubers, but their success in plant establishment was hampered in warm climates, especially in the presence of soil pathogens. Cool-climate-produced seedling tubers and tubers from cuttings can compete physiologically with field-produced seed tubers when used as planting materials in the warm tropics. However, with few exceptions, no crop from tubers produced under warm conditions could match the performance of crops from similar cool-produced tubers when planted out in the warm tropics.

In a study of two coarse wool breeds (Awassi and Karadi) and their reciprocal crosses, data were obtained on the mean fibre length, mean fibre diameter, fibre type ratio, medullation and on the effect of some environmental factors on these traits. Reciprocal crosses showed intermediate values, in growth rate of fibres, percentages of fibre types and medullation, between those of the parental breeds. Sex exhibited a significant effect at weaning only, on fibre length. Heterosis in fibre length, at the two ages, was small and negative. Maternal influence on fibre length was small and not significant. Fibre length in Karadi sheep showed the highest frequency of bimodal distribution whereas Awassi showed the lowest. Awassi × Karadi was closer to Karadi and Karadi × Awassi had greater affinity to Awassi in the frequency of samples showing bimodal distribution.

Reciprocal crosses had larger diameter, at weaning, than those of the parental breeds. At 1 year of age they assumed an intermediate position between the pure bred parents.

At weaning, the two reciprocal crosses showed a highly significant heterosis in fibre diameter; its value decreased with advancing age and it showed no significant effect at 1 year of age.

Maternal influence on fibre diameter was very small and not significant.

Karadi × Awassi and Karadi samples had the highest percentage of samples showing bimodal distribution of fibre diameter.

Samples with bimodal distribution of both length and diameter, indicating two coats, had the highest frequency in Karadi followed by Karadi × Awassi; Awassi showed the lowest value.

Percentages of fine, coarse and kemp fibres were significantly affected by breed and age of dam. Type of birth showed a significant effect only on percentage of coarse fibres.

Karadi wool might be more suitable for carpet manufacturing. It excelled the other groups in the bimodal distribution of both length and diameter as well as in medullation. Cross-breeding increased the bimodality of fibre distribution.

There is currently considerable interest in the use of anabolic compounds to improve the efficiency of animal growth and to produce leaner carcasses. While the majority of work has centred on beef production, the growth performance of sheep is also improved (Galbraith & Topps, 1981). However, little is known of the effects of anabolic steroid hormone administration on wool growth. The few experiments which have been conducted indicate that exogenous oestrogens depress wool output (Slen & Connell, 1958) while exogenous testosterone has consistently enhanced both greasy and clean wool yields (Slen & Connell, 1958; Osborne, 1968; Southcott & Royal, 1971). Little is known, however, of the effects of the synthetic steroids on wool growth. Coehlo, Galbraith & Topps (1981) reported a reduction in wool per unit body weight in sheep implanted with trenbolone acetate and oestradiol-17β, suggesting lowered efficiency of wool growth. Similarly Yasin & Galbraith (1981) noted that trenbolone acetate, in combination with either oestradiol-17β or zeranol, reduced wool output per unit body weight. Neither of these trials attempted to isolate the effects of trenbolone acetate alone from those of the androgenplus-oestrogen combination.

Manufacturing properties and quality of Cheddar, Wensleydale and Cheshire cheeses made either with milk from cows treated with Sometribove, methionyl bovine somatotropin (BST), or with milk from untreated control cows were compared.

The source of milk did not affect manufacturing properties in terms of processing time. Renneting times for Cheddar cheese made from control milk and that made from milk produced by cows treated with BST were 57 and 55 min, respectively. Corresponding values for Wensleydale and Cheshire cheeses were 50 and 53 min and 49 and 46 min, respectively. The source of milk did not influence cheese composition in terms of moisture, fat, protein and salt. When cheeses were submitted to the National Grading Service, those made from milk produced by BST-treated cows were indistinguishable from those made from control milk. The total points scored (maximum 100) for Cheddar, Wensleydale and Cheshire cheeses made with milk from control and BST-treated cows were 89 and 88, 85 and 85, and 86 and 86, respectively.

Steers fed low nitrogen diets were infused intraruininally with water.

Increasing the water load increased the urine volume and urinary urea excretion and depressed the plasma urea level.

The effect of intraruminal water loading was studied in association with intravenous urea loading of 25 and 65 g N/day. When 25 g N/day as urea was infused intravenously, water loading did not significantly increase the urinary urea excretion but the plasma urea level was depressed. At 65 g N/day water loading increased the urinary urea excretion and decreased the plasma urea level.

Significantly different relations between plasma urea and urea load existed for the ad lib. water and the water-loaded treatments but the relation between rumen ammonia level and plasma urea level was not affected by the water loading.

The results are discussed with reference to the recycling of urea.

A study has been made of variations in the shrinkage from the live pig to the carcass and from the carcass to the side of Wiltshire bacon. Most of the variation occurs at the first stage when the losses have a variance of 17·67 lb. compared with only 4·59 lb. and the second stage. Similarly, breed differences were found at the first stage, Wessex and Essex pigs giving 1·1 and 2·7 lb. more carcass respectively than the Large White pigs, but not at the second stage. On the other hand, differences between litter groups were found at both stages.

Correlations made between carcass measurements and yield of carcass and bacon were generally found to be small and positive. Antagonisms were indicated between quantity and quality of bacon, in particular by positive correlations between thickness of back-fat and weight of carcass, and between a desirable proportion of cuts and losses on slaughter. The problem of deciding the relative attention which should be paid to various carcass characteristics is discussed and the need for an index of total carcass merit is pointed out.

Three pot experiments were performed in unheated glasshouses at the University College of North Wales College Farm, Aber, Gwynedd in 1980–1983. Two experiments tested the effects of sowing date and N supply, the third sowing density and nitrogen supply. Extension growth of main-stem leaves was measured by ruler and expressed in thermal time units to allow comparisons between sowing dates. Rate and duration of leaf extension were determined from linear regressions of leaf length against thermal time.

Increasing N supply increased leaf extension rate but had no significant effects on leaf extension duration. Leaf extension rate increased with leaf position on the main shoot, but decreased slightly in leaves extending at the time of stem elongation. Leaf extension duration also increased with leaf position on the main shoot and was related to mean temperature during the leaf extension phase. Plants sown in September were able to compensate for lower radiation receipts by having a faster rate and longer duration of leaf extension, by producing larger leaves with a greater specific lamina area and by partitioning a greater proportion of extension growth into lamina and less into sheaths. In plants sown in June, the largest leaf occurred at a lower stem node and leaves emerging later showed a strong response to N. It is suggested that this is attributable to earlier onset of internal competition for assimilates. Variation in leaf extension rate was the main factor influencing variation in final leaf area. There was a strong positive relationship between leaf extension rate and leaf N content.

Increasing sowing density increased the area of the first four leaves on the main shoot and decreased that of later leaves, changes mainly associated with changes in leaf extension duration. It is concluded that progress in the modelling of leaf area expansion, light interception and dry matter production requires more information about how sowing date, sowing density and N supply interact to influence crop development and leaf growth.