Six heifers have been measured every week, for 5 weeks before calving and 6 weeks after calving, with the object of ascertaining what errors would be introduced by taking one set of measurements during such a period, as representing the size of the heifer at parturition.

The gross standard error was found to be 0·834 cm. in measuring shoulder height and back length and 0·605 cm. in measuring height to the elbow.

During the period these heifers were growing as follows: shoulder height, 0·159 cm. per week; back length, 0·124 cm. per week; and elbow height, 0·079 cm. per week.

When allowance was made for growth the net personal errors of measurement gave standard errors of 0·636 cm., 0·727 cm., 0·547 cm. respectively for shoulder height, back length and elbow height, and the errors were, apparently, distributed normally.

Bahia grass (Paspalum notatum Flugge) plants were grown in growth chambers at Gif, France, and at Gainesville in Florida, demonstrating that the species is a long-day plant and greatly influenced by light quality during the photosynthetic period. Flowering occurred in all instances when the middle of the dark period was interrupted with red or red + far-red light. With nightly interruptions of farred light, flowering occurred only when a sufficient quantity of far-red was present during the photosynthetic period. Plants grown under short days with nightly interruptions of red, far-red or red + far-red light had less starch accumulation and greater leaf growth and dry weight than plants grown without nightly light interruptions, whatever the light quality during the photosynthetic period. The treatments did not affect the partitioning of assimilates and flowering in the same way.

1. A total of forty pigs (four litters) were slaughtered at weekly intervals from birth to 5 weeks of age.

2. Results are given for the changes in weight of different parts of the digestive organs and their contents with increasing age, and for the content of NaCl and of total acidity in the stomach contents.

3. Stomach pH was on average more alkaline than pH 3.4 at all ages up to 5 weeks; the average pH of the duodenum was 6.5 and of the small intestine 6.4.

4. Total NaCl and total acidity in stomach contents remained roughly constant from birth up to 5 weeks of age. No free HCl was detected in any of the stomach contents of the pigs.

5. The consistency of the stomach contents varied with the age of the pig; the hard milk clot which was characteristic of the contents at 2–3 weeks of age appeared softer and more broken in older pigs.

Individual leaf blades of onion plants were treated with 14CO2 57, 71, 93 and 112 days after transplanting. The distribution of labelled translocates was determined 24 h after labelling. The older the plant the more of 14C-assimilate left the source leaf; 112 days after transplanting, leaves 1–7 all exported more than 70% with leaf 7 showing a maximum export of 93 % of the fixed carbon. In the early stages of the development, the leaves, pseudostem and the bulbs were the major sinks in decreasing order. But the bulbs became the dominant sink at 71 days and at 112 days the bulbs almost monopolized the import of the radiocarbon, with 90 % of the exported 14carbon being recovered from them. The bulbs received their 14carbon supply from all the leaves but particularly the basal and middle region leaves. Roots were a weak sink and received their 14carbon supply only from basal leaves. The stem and mature leaf blades were unimportant sinks throughout the life of the plant.

Kloka spring wheat grown on a sandy-loam soil was given 50, 100, 151 or 201 kg N/ha as fertilizer, was irrigated during drought or not irrigated, and was sprayed with CCC (2-chloroethyltrimethylammonium chloride) or not sprayed. Samples, taken approximately weekly from brairding to heading and less frequently to maturity measured the production of dry matter. The dried samples were analysed for percentage N, P, K, Ca, Mg and Na and the uptakes of these were calculated to measure the effects of treatments on the composition of the crop and the weights of nutrients it contained.

Increasing amounts of fertilizer-N up to 151 kg N/ha increased the maximum weight of straw without irrigation and up to 201 kg N/ha with irrigation; similarly, maximum weights of ears were with 100 kg N/ha without irrigation and 151 kg N/ha with irrigation. The maximum weight of straw was at flowering and of ears at maturity. Irrigation increased yields of straw and ears, more with the two larger than with the two smaller amounts of fertilizer-N. Spraying with CCC decreased the yield of straw, and did not affect the yield of ears.

Increasing amounts of fertilizer-N increased percentage nutrients in the green crop and in the straw, and of N, P and Mg in the ears. Effects of irrigation and spraying with CCC on composition differed between nutrients and between ears and straw, sometimes increasing, sometimes decreasing, and sometimes having no effect, on percentage in dry matter.

Increasing fertilizer-N increased the maximum weight of N, K, Ca and Na in the crop. P and Mg increased with up to 151 kg N/ha, but was no more with 201 kg N/ha. Maximum weight of N, P, Mg and Na was found at or near maturity, of K at heading and of Ca at flowering.

An attempt to find the effect of humidity on hatchability and at the same time indicate the optimum humidity for incubation was carried out by subjecting eggs in one incubator to various levels of humidity and comparing the results with eggs hatched as a Control in a second incubator of identical design.

Hatchability was depressed by excessively high levels of humidity but in general satisfactory hatches can be obtained between 40 and 70% R.H.

The pattern of mortality, the incidence of Malposition I but not Malpositions II, III and VI were affected by humidity level.

The optimum level found, c. 50% R.H., was lower than the previously accepted optimum and may be accounted for by a number of factors including egg size.

The mean concentration of plasma albumin in 30 Finnish Landrace x Dorset Horn ewes subjected to intensive breeding decreased as the number of pregnancies increased from three to seven; it also changed significantly within a pregnancy. Gamma globulin concentration was not affected by the number of pregnancies but decreased significantly within a pregnancy. Total plasma protein was affected like albumin by the number and stage of pregnancy.

Plasma volume increased by 23 % in the latter third of pregnancy.

Two chickpea pure lines, one being short and wide in stature and the other tall and narrow, were crossed. Parents, F1 and F2 generations were grown in the field to study the inheritance of plant dimensions, as well as their correlation with seed yield. Heritability, in broad sense, for plant height and width was 36 and 20% respectively. Estimated minimum number of genes for plant height was two and for plant width was three pairs of genes. Plant height showed correlation values of 0·43 and -0·67 with yield of seed and 1000 seed weight respectively. There were no significant correlations between plant width and the same two yield components.

The yields of four tropical grass/legume pasture mixtures were studied over a 4-year period. These mixtures had the following composition: H, Cynodon nlemfuensis var. robustus, together with the legumes Centrosema pubescens (Benth.), and Stylosanthes gracilis (H.B.K.); J, Pennisetum purpureum (Schum.) plus the two legumes in H; K, treatment J mixture plus Panicum maximum (Jacq.); and L, a mixture of treatments H, J and K. Each treatment paddock was grazed in rotation between 19 April 1966 and 21 November 1969.

The mean annual dry-matter yields over the 4 years of grazing were approximately 37 ± 5·7, 41 ± 2·6, 44 ± 10·2 and 47 ± 8·7 t/ha for treatments H, J, K and L respectively. The overall mean for the four treatments was 42 ± 5·1 t/ha/annum.

It was observed that the dry-matter yield of the three mixtures in J, K and L, containing the tall grass species, was significantly superior to that of treatment H; however, they were not statistically different among themselves.

After the second year of grazing Stylosanthes gracilis diminished gradually and it was almost absent from the swards by the final year of grazing, while Centrosema pubescens maintained its stand throughout the experimental period.

With the exception of phosphorus and sodium, levels of mineral elements in the pastures were above the recommended allowances for various classes of livestock.

The average level of zinc was only slightly below the recommended value.

One of the difficulties which hinder the extended use of the nut-oil-cakes (palm kernel, coconut and ground-nut) is the prevalent impression that these cakes deteriorate rapidly on keeping. In recent articles dealing with these cakes frequent reference has been made to this point. Thus Voelcker (9) in his Annual Report for 1914 states that “one inconvenience attaching to palm-nut and coconut cakes is that they do not keep as well as linseed and cotton cakes and that there is a tendency for them to turn rancid.” In his Report for 1915, however, he says, “I have come across but few instances either with palm-nut cake or meal, in which these have been rancid or not in good condition.” Murray (8) states that manufacturers should realise that they still have to reassure farmers regarding the keeping qualities of palm kernel cake. In a later article in the Journal of the Board of Agriculture (3) it is stated that “palm-nut kernel cakes in the past have had the reputation of soon going rancid…. At the present day, before the kernels are crushed they are subjected to a process of cooking, by which the ferment that causes the oil to turn rancid is rendered inactive.” The validity of this latter assertion seems doubtful in the light of the recent work of Calder (2) which shows that the lipase, present in the resting seed in the form of its zymogen, is not destroyed during the manufacture of the cake, the mass of crushed kernels not being sufficiently heated in every part prior to pressing to secure this object completely. Similar statements have been made as to the liability of coconut and ground-nut cakes to become rancid on storing (3,4).

Mature Merino ewes (n = 500) were allotted at random to embryo removal (day 35; day 0 = day of oestrus detection), foetal removal (day 90) or lambing groups. These groups were further randomly divided into four single-sire mating groups. From day 1 until day 35 ewes were individually penned and fed either 50 or 150% of a maintenance ration (0·5 M or 1·5 M respectively). At day 35 single embryos were removed from anaesthetized ewes in the embryo removal group and all other ewes were endoscoped to confirm pregnancy. These ewes were then returned to pasture. Plasma samples were taken from all ewes on days 2, 4, 16, 23, 30 and 35 for analysis of glucose concentration. At day 90, ewes allotted to the foetal removal group were anaesthetized and plasma samples were obtained from the ewe's jugular vein and the umbilical arteryand vein. Ewes were then hysterectomized and the foetus was weighed and measured. Functional cotyledons were dissected from the uterus and chorio-allantois and all tissues were weighed. The remaining ewes (lambing group) were supervised at lambing and lambs were identified, weighed and measured.

Live-weight changes from weaning and wool production and quality were measured in ewe and ram lambs at their first shearing (11 months of age). Ovulation rates in the first two oestrous seasons of the ewes and wool production at their second shearing (2 years of age) were also measured.

During the 35-day treatment period, mean live-weight changes of ewes were –4·9 and + 1·8 kg in the 0·5 M and 1·5 M groups respectively. Pregnancy rates were similar in both groups but embryos from 0·5 M ewes weighed less than those from 1·5 M ewes (1·7 ± 0·04 ν. 1·9 ± 0·05 g; P < 0·005). Foetuses taken at 90 days from 0·5 M ewes were smaller than those from 1·5 M ewes but these differences reached significance (P < 0·025) only in the measurement of chin–crown length (8·0 ± 0·09 ν. 7·6 ± 0·11 cm). Correlations between foetal weight and total cotyledon weight, chorio-allantoic weight and empty uterine weight were all significant. Plasma glucose concentrations of ewes in the 0·5 M group were significantly (P < 0·001) reduced by day 9. Differences between the two nutrition groups in maternal and umbilical plasma glucose concentrations at day 90 were not significant, though foetuses from 0·5 M and 1·5 M ewes removed a mean of 30 and 11% respectively of available glucose from the umbilical vein. Differences in live weight between 1·5 M and 0·5 M animals at weaning and in the post-weaning period were not significant (P > 0·05). Wool production and woolquality were similar for both groups. Spontaneous ovulation rates measured on four occasions during the postpubertal oestrous season and on three occasions the following year were not significant (P > 0·05). Treatment with pregnant mare's serum gonadotrophin (PMSG) increased ovulation rates in the ewes of both groups; however, the differences failed to reach significance (P > 0·05); mean (± S.e.) ovulations per ewe were 4·8 ± 0·61 ν. 4·6 ± 0·60 for 1·5 M and 0·5 M group ewes respectively.

The withdrawal of food from Clun Forest ewes pregnant with twins produced signs of pregnancy toxaemia accompanied by a significant decrease in the concentration of glucose, a significant increase in the concentration of ketones, non-esterified fatty acids (NEFA) and 3-hydroxybutyrate in plasma and a significant decrease in total entry rate and irreversible loss of glucose. A single intramuscular injection of 0·05 or 0·2 mg/kg of triamcinolone acetonide had no significant effect on the concentration of glucose, ketones or 3-hydroxybutyrate in plasma or on the total entry, irreversible loss or recycling of glucose in ketotic or in normal pregnant sheep. The low dose had a significant effect on the concentration of NEFA in plasma. Recovery from the clinical signs was slow after either dose of steroid but appeared to be hastened by the onset of parturition which was more rapid after the higher dose.

The discrepancies between nursery plots and field plots, found by previous workers when investigating yield problems with wheat, are discussed. The reason for these differences is given, and the true optimum plant density identified.

It is shown that the intensity of competition for water and soil nutriments influences the optimum plant density, and that a high intensity of competition is associated with a low optimum plant density. A summary of literature is given, and the varying values for the optimum seed rates in different parts of the world interpreted in the light of water and soil nutriment supplies.

1. A report is given of an experiment to investigate the extent of genotype-environment interaction in the growth rate and reproductive phenomena of certain strains of mice when kept in two food and two temperature environments. Evidence of interaction was found in both characters.

2. The results are considered to be of sufficient interest to justify further work along these lines.

This might either take the form of extensive studies involving many strains and environments chosen more or less at random, or in more limited investigations where the genotypes and environments are especially chosen because of marked differences.

The effect of level of N fertilizer on the composition, yield and quality of 21 crops was studied in experiments on adjacent sites of the same field to aid in the development of fertilizer recommendations.

Yield of each of the crops first increased and then either remained the same or declined with further increases of N fertilizer. Interpretation by means of a simple model enabled response curves to be characterized by two parameters; one representing the beneficial component of the response and the other the detrimental component. Both varied greatly from crop to crop.

The magnitude of the beneficial component of the response of most non-leguminous crops was largely determined by the potential demand of the crop for nitrogen; the exceptions were some root crops which responded less than would be expected on this basis. The adverse component was serious with root crops and those crops that are in the soil for only a short period. High levels of N increased the ratio of foliage to storage root dry weights even when total dry matter was unaffected. The changes were associated with a considerable increase in the % N in the dry matter of the roots.

When crops were grown with their optimum levels of N fertilizer a simple linear. relationship between the mean %N in the dry matter and the total weight of dry matter per unit area covered all crops. Simple relationships also existed between total dry matter of non-leguminous crops and (a) the amount of N taken up by the crop from unfertilized soil, (b) the recovery of added fertilizer by the crop and (c) the beneficial component of the response of crops harvested before October.

Percentage N in the dry matter at harvest was not a sensitive indicator of the extent to which plant growth was restricted by lack of nitrogen; a difference of 0·1% N in the plant material was associated with a 10% increase in yield.

N fertilizer levels influenced the % dry matter and the incidence of crop disorders such as rotten roots and tissue discoloration, but the effects were seldom appreciable with practicable levels of fertilizer application.

Pre-anthesis stem reserve contribution to grain yield was assessed in two spring barley cultivars of contrasting height. It was greatest in the taller, but final grain yields were similar. Partitioning of total reserve capacity to various plant parts showed that the leaf and sheath below the peduncle were most important, followed by stem internodes which had increasing reserve capacity up to internode 4.

It is suggested that stem reserves are valuable for yields commonly achieved in U.K. commercial practice.

High grain yields were associated with large positive increases in stem dry weight after anthesis. This would indicate that the source capacity to boost yield is more than proportional to that required to fill the grain alone.

The effects of copper deficiency and of copper excess on mature Merino and Border-Leicester ewes were studied experimentally over a period of 3½ years with five evenly matched groups of each breed which were all depastured together as one flock on terrain where sheep develop cobalt and copper deficiency. All were treated with the equivalent of 1 mg. Co/day. Copper was administered thrice weekly in doses which provided for individuals of the respective groups the equivalent of nil, 1, 5, 50 and 100 mg. Cu/day.

All of the individuals that received only cobalt became anaemic; they lost weight and developed marked symptoms of copper deficiency.

The supplement of 1 mg. Cu/day was sufficient to delay the onset of these symptoms, but it failed to increase significantly the concentration of copper in the blood and it was insufficient to ensure normal myelin formation in the central nervous system of lambs born of the ewes which had received this treatment for 2 years prior to mating.

Field experiments were carried out in north-east Scotland on potatoes to measure the responses to, and the two-factor interactions between, nitrogen, phosphate, potash and dung, and have given the following results:

1. The responses to nitrogen, phosphate and potash are quite variable from centre to centre, but the mean results show moderately large increases to all three nutrients.

2. The mean responses to both nitrogen and phosphate are the same in the presence as in the absence of dung. The response to potash is reduced by two-thirds in the presence of dung.

3. There is a general trend for both nitrogen and potash to increase the linear component of the response to phosphate and vice versa. Nitrogen and potash show practically no interaction effects.

4. Dung produces a considerably larger increase in yield in the absence than in the presence of fertilizers.

5. The nitrogen and potassium contents of the tubers show appreciable effects of the nitrogen, potash and dung treatments.

6. Suitable fertilizer dressings are suggested for potatoes grown in the absence and presence of dung.