1.Two experiments were carried out to investigate the possibility of sustaining good growth rates and high feed conversion efficiency on restricted levels of feed under conditions of high temperature and humidity.

2. Large White pigs were used over the weight ranges 50-90 lb. and 90-160 lb. live weight.

3. In Exp. 1, three groups each of eight pigs were fed on three planes, high, medium and low, the aim being to restrict energy intake while providing adequate protein intake for good growth. In Exp. 2, two groups each of eight pigs were fed on the medium plane from 50-90 lb. live weight and thereafter one group remained on the medium plane, while the other was fed a very low plane. The very low plane consisted of a daily feed allowance of 31b. 4oz. from 90 to 1601b. live weight. All the pigs were individually fed.

Dorset Horn and Corriedale ewes (breeds with low and high wool growing capabilities respectively) with single lambs were fed ad libitum on a pelleted roughage-concentrate diet. Following weaning at 6–7 weeks of age (live weight (LW) ca. 15 kg), ten entire male, ten female and ten castrate male lambs of each breed were housed in single pens and fed the same diet ad libitum. Body composition (fat, protein, water, ash and energy) was estimated from tritiated water space at 5 kg LW increments from 10 to 55 kg. Fleece weight was also estimated on each occasion.

The relationship between the weight of body components and fleece-free fasted live weight (W) for each sheep was described by a two-phase piecewise linear model, the slope in each phase representing the average composition of weight gain. In the first phase, the composition of weight gain did not differ between breeds and contained similar amounts of fat and protein (14%), 66% water and 5% ash. Within breeds females tended to be fattest. There were significant differences due to breed and sex in all body components in the second (fattening) phase. The fat content of gain was lower in Dorset Horn ewes and wethers (45 and 51% respectively) than in corresponding Corriedales (64 and 58%) with the males being even lower (44 and 41% respectively). Dorset Horns entered the fattening phase at a significantly higher W (26 kg) than Corriedales (23 kg), there being no sex difference within breeds. The combined effect of lower slope and higher weight at the commencement of the phase change in the Dorset Horns was to produce a considerable breed difference in fatness in the second phase of growth in ewes and wethers. Possible physiological reasons for the differences are discussed.

The mineral content of N, P and K in leaves, stems, roots and seed of field beans, subjected to four watering regimes were compared in 1976 and 1977, and of a foliar nutrient spray in the latter year.

N, P and K content increased in all treatments with the increase in plant size and then declined at about the time of podding and death of the leaves.

Water shortage reduced the amounts of N, P and K throughout the growth period and for the seed at final harvest; the decrease was more pronounced in 1976 than in 1977. The plants under stress conditions benefited from the foliar nutrient spray more than the unstressed plants.

1. The1951 clover experiment. No significant effects on the mean yield of nectar were obtained, but the higher dose of phosphate significantly increased the frequency of zero samples during August, the main flowering and sampling period; so also did the higher dose of potash in the presence of high nitrate. In general those treatments which depressed nectar secretion resulted in a larger proportion of flowers opening before mid-August. Accelerated flower production appeared to result from more rapid growth during August.

2. The 1952 clover experiment. The treatment effects on quantity of sugar per floret were compared with those on final stem weight. Treatment effects on sugar/floret on particular sampling occasions were compared with the effects on relative ‘growth rate’ during the preceding period. Additional phosphate always resulted in greater and more rapid growth, but it only reduced the nectar yield in the presence of the highest level of potash. In the presence of low doses of potash nectar secretion was consistently poor. Additional potash did not increase the nectar yield if it resulted in greater or more rapid growth; if it did not affect size or growth rate it increased the nectar yield. Clonal differences in nectar production were greater than treatment ones.

3. The responses of the four species used in this series of experiments are compared. The results of other workers on the effects of fertilizer treatments on nectar production are discussed in relation to those reported here. If the balance between different fertilizers and their effects on growth are considered, as well as nectar yields, contradictions between the results of various workers can be explained. It is suggested that when potash tends to limit growth nectar secretion is likely to be consistently poor, but that when growth tends to be limited by nitrogen or phosphate a relative surplus of potash will promote good secretion.

Reference is made to work on the relation of the sugar supply in plants to nectar secretion and on the relation of fertilizers to the sugar supply. Tentative recommendations are made which require confirmation in field tests.

1. The structure of the muzzle of the cow, its blood supply and the histochemistry of its glands have been studied.

2. The nasolabial glands are multilobular compound tubulo-acinar glands similar in structure to salivary glands. They secrete a watery mucincontaining fluid. It is suggested that they may be sweat gland homologues.

3. Arterio-venous anastomoses are present in the muzzle. Their possible function is discussed.

4. Although this investigation has shown how much the muzzle differs from the rest of the integument no particular function can be ascribed to it on the basis of the findings described.

In 1984 and 1985, the growth of axillary buds of Brussels sprouts plants was studied at Cockle Park, Northumberland, UK. Bud growth commenced in late September or early October and continued at all nodes until the final harvest in December. Total bud yield increased at a broadly constant rate until late November but at a decreasing rate thereafter. Plants produced c. 100 nodes with buds ≥ 5 mm diameter. The largest buds were c. 40 mm diameter and 25 g fresh weight. Bud size increased from the base of the stem upwards to between the 20th and 40th nodes and then decreased towards the apex. Nodes 20–40 (20% of the total) produced c. 40–45% of total bud yield. The size profile of leaves along the stem followed a similar pattern to the buds and the largest buds were in the axils of the largest leaves. There were close relationships between bud fresh weight and size, bud fresh weight and size, bud fresh weight and volume and log10 bud fresh weight and log10 bud size (r2 ≥ 0·995). The density of buds was c. 0·8 and bud fresh weight doubled for each 5 mm increase in bud diameter.

Current photosynthesis of the leaf canopy was apparently the major source of assimilates for bud growth. A C14 tracing experiment suggested that growth of individual buds was mainly supported by their subtending leaves. There was no evidence of re-translocation of dry matter from dying leaves or the stems to buds or of substantial production of dry matter by the buds themselves. Rates of bud photosynthesis were only about 10% of the rate of leaves. The continued increase in bud fresh weight and size at the lowest nodes when leaves were senescing rapidly and after they had abscissed was probably mainly the result of water uptake rather than dry matter accumulation.

The relationship between cortical area and fibre area has been examined in the N/N, N/ +, + / +, + /nr and nr/nr genotypes of the New Zealand Romney, using skin biopsies taken at birth, 1, 3 and 16 months of age. The presence of the nr gene was shown to reduce significantly the relative cortical area. Within the genotypes there was an increase in relative cortical area with increasing age and in two-tooth ewes of N/N and N/ + there was an increase in relative cortical area in winter compared to summer.

Fibre growth rates in length for primaries and for prenatal and post-natal secondaries were found for lambs between 1 and 3 months and for 16-monthold ewes. In N/N, N/+ and nr/nr primary fibre growth tended to be increased and post-natal secondary fibre growth tended to be decreased relative to + / + values.

In both cortical area and fibre growth rate the greatest genotypic effect was shown by the primary fibres.

Some estimates of cortical volume have been made by combining the information on cortical area and fibre growth rate and the relationship of these factors to follicle density and mean fibre area has been discussed. Finally, an indication has been given of how the associations of all these four factors might be usefully examined in some British breeds.

Measurement of the variation in reproductive characters between genotypes of Phleum pratense showed that inflorescence length had a significant variance and was correlated with seed yield/plant. Genotypes with the longer inflorescences showed a quicker response to a long photoperiod and had a longer period of inflorescence development, and there was an indication that selection for increased inflorescence length might affect the production of leaves. A genetic analysis of a 6 x 6 half diallel cross showed that additive and non-additive effects were evident in the control of inflorescence length under natural conditions, but the non-additive effects were almost entirely suppressed under glasshouse conditions.

Pigs were grown at controlled rates of live-weight gain from 20 to 55 kg and from 55 to 87 kg live weight, at which weight they were slaughtered. Six growth-rate treatments were compared and were referred to as High-High (HH), High-Moderate (HM), High-Low (HL), Moderate-High (MH), Moderate-Moderate (MM) and Low-High (LH). The right-hand side of each carcass was divided into the four primary jointsand each joint was physically dissected into bone, skin, subcutaneous fat and lean meat. The boneless tissue of each joint was analyzed for moisture, ether extractable fat and nitrogen.

It was found that an increase in the rate of live-weight gain in the first growth period, tended toimprove the efficiency with which feed was converted into live weight. In the second growth period the efficiency of feed conversion was dependent on the rate of gain both in that period and in the preceding period. Restricted growth in the first period improved the efficiency of feed conversion both in the second period and over the entire experimental period compared with rapid early growth. The implications of compensatory growth are discussed.

There was no treatment effect on carcass length, but hindleg length and ham circumference measurements showed that the proportion of gammon in the side was lower in the HH pigs compared with the other five treatments. This was confirmed by the weight of the gammon joint expressed as a percentage of the trimmed side. There was also a decrease in the proportion of shoulder and an increase in the proportion of middle in the HH pigs. Differences between the other five treatments were small. The changes in conformation were due largely to the effect on fat distribution throughout the side particularly in the gammon and back regions.

The HH treatment resulted in a significant increase in the percentage fat in the side compared witheach of the other five treatments. Within these five treatments there was no significant difference in the percentage fat in the side. This suggests that equal importance may be attached to the rate of live-weight gain in both the growing (20–55 kg) and finishing (55–87 kg) periods in determining the fatnessof the bacon weight carcass.

The treatments had little effect on the chemical composition of the fat-free boneless meat.

The results are discussed in relation to current growth theory.

An experiment using eight pens each of twenty-five pullets was conducted to investigate the suitability of sesame cake meal as a protein concentrate for laying pullets. In meal mixtures supplying equal amounts of crude protein, sesame cake meal gave slightly lower production than fish meal and earthnut cake meal, but the differences were of doubtful statistical significance. Body weights appeared to be maintained less well on sesame cake meal, but only by an unimportant amount.

The authors thank Prof. R. G. Baskett for his advice and constructive criticism, and Miss M. E. Osborne for the care and attention devoted to the management of the pullets.

A field experiment to test effects of cultural treatments on eyespot (Cercosporella herpotrichoides Fron.), lodging and yield of winter wheat, begun in 1952 (Salt, 1955), was continued on the same site in 1953. In 1952 only eyespot and lodging were severe, but in 1953 take-all (Ophiobolus graminis Sacc.) and weeds were severe also.

Squareheads Master 13/4 and Cappelle, each sown at 1½ and 3 bushels/acre, were top-dressed at four different dates with ammonium sulphate at 0, 2 and 4 cwt./acre. Sulphuric acid (12½% b.o.v. at 100 gal./ acre) was sprayed on four of the eight blocks of ten plots in March to control eyespot.

Halving the seed rate decreased the percentage of severe eyespot from 63 to 52%, decreased the area stunted by take-all from 36 to 14% and increased yield by amounts ranging from 8·3 cwt. in nitrogendeficient plots to 2·6 cwt./acre in plots well supplied with ammonium sulphate. The fertilizer applied to Squareheads Master at 0, 2 and 4 cwt./acre had little effect on the incidence of eyespot lesions at harvest, but increased the area lodged from 23 to 53 and 60% respectively; it decreased the area stunted by takeall from 47 to 19 and 10% respectively, and increased yield from 13 to 17 and 18 cwt./acre. Cappelle did not lodge and the fertilizer decreased take-all patches from 51 to 28 and 18% respectively, and increased grain from 15 to 20 and 21 cwt./acre. The time when nitrogen was applied to either variety had no important effect on disease incidence or yield.

Sulphuric acid sprayed in 1953 on blocks unsprayed in 1952 and so having a higher initial infection of eyespot and weeds, decreased the area lodged and the area covered by weeds, but did not decrease the percentage of straws with eyespot below that in unsprayed plots.

Dissection data from an experiment involving 12 buffalo, nine ♂Friesian × ♀Egyptian native Baladi (½ Friesian) and nine ♂ Friesian × ♀ ½ Friesian (¾ Friesian) bulls were used to examine the growth and partition of fat between depots and its distribution in different regions of the carcass.

Growth of total dissectible carcass fat (TCF) and its component depots (subcutaneous (SCF); intermuscular (IMF); kidney knob and channel (KKCF)) and total offal fat (TOF) and its component depots (caul (CF); mesenteric (MF); heart (HF)) relative to total body fat (TBF = TCF + TOF) was examined.

Relative to TBF, no significant differences in growth coefficients or adjusted means of TCF, TOF, carcass SCF and carcass KKCF were found between genotypes. Compared with ¾ Friesians, buffaloes had lower rates of deposition of CF and IMF, lower proportion of TBF deposited as MF and a greater proportion of HF.

As dissected side fat (DSF) increased, the proportion of fat decreased in the distal hind limb and neck, increased in the abdominal wall and adjacent ventral part of the thoracic cavity and remained unchanged in the other carcass regions. Fat growth coefficients differed between genotype groups in all carcass regions except the distal hind limb, fore limb and thorax. A posterior-anterior decrease in growth impetus of fat from the loin (b < 1) towards the neck (b > 1) was traced in buffaloes while the growth coefficients within all dorsal cuts in cattle did not differ significantly from 1. Compared with cattle, buffaloes had more of the DSF occurring in the combined expensive cuts with higher SCF: IMF ratio only at the upper limits of fatness considered in the present work.

It is argued that buffaloes relative to Friesian cross-breds have a beef-type fat partition and that characteristic changes in rates of increase in fat depots relative to empty-body weight and in fat in various regions relative to total fat could be related to the increase in Friesian blood.

In 92 field experiments in Tanzania's major cotton-growing area south and east of Lake Victoria mean yield without fertilizer was nearly 900 kg/ha of seed cotton. The mean direct effect of 224 kg/ha of single superphosphate with 202 kg/ha of ammonium sulphate was 380 kg/ha of seed cotton; with twice as much fertilizer the increment was 525 kg. First and second residual responses made important contributions to the total effect of superphosphate. In most zones the response to each fertilizer was large but in Nassa response to superphosphate was small; in Nzega yields were small and there was no response to ammonium sulphate, perhaps because Calidea dregei caused abscission of bolls; on the acid soils of Ukerewe Island yields and responses to superphosphate were small.

Data are given to show the average amounts of plant nutrients in the soils most used for cotton. Correlations of yields with soil chemical data suggest that some soils lack enough calcium for large yields. A long-term experiment at the Ukiriguru research farm (Le Mare, 1972) showed that productivity of impoverished soil growing cotton every year was recovered and improved by lime with phosphorus and nitrogen fertilizers: the experiments throughout the cotton area indicated that those results were widely relevant.

Ten experiments (1967–9) on sandy soil in East Anglia measured the effect of magnesium fertilizer on yield and cations in sugar beet. Magnesium fertilizer increased sugar yield by up to 0·80 t/ha and on the three most responsive fields it consistently increased top and root dry·matter yields throughout the growing period.

On average, without magnesium fertilizer, the concentration of magnesium in tops progressively decreased from 0·33% at singling to 0·15% at harvest, and in roots from 0·39% to 0·09%. The corresponding decreases with magnesium fertilizer were (tops) from 0·68% to 0·20% and (roots) from 0·48% to 0·10%. Yield was increased by magnesium fertilizers when tops contained less than 0·35% Mg during May, 0·30% during June, 0·22% during July and 0·17% during August. Deficiency symptoms were not visible until the concentration in tops averaged less than 0·2% – the percentage of plants with symptoms increased rapidly at smaller concentrations. Magnesium fertilizer decreased the concentration of calcium in tops and roots but did not affect the concentration of potassium or sodium.

The maximum amount of magnesium, potassium, sodium and calcium in tops (August–September) was 11, 218, 75 and 62 kg/ha respectively; these decreased to 8, 168, 55 and 50 kg/ha at harvesting, showing that only about 75% of the largest amount in tops was present at harvest. The amounts removed in roots at harvest were 9 kg/ha Mg, 75 kg/ha K, 11 kg/ha Na and 26 kg/ha Ca. A dressing of 100 kg/ha magnesium increased the amount of magnesium in the crop at harvest by only 4·5 kg/ha.

The survey shows that objective estimates of the yield of maincrop potatoes can be obtained from small samples carefully selected and dug by hand. Samples taken from about 1000 fields gave estimates of the mean yield of all counties sampled with a standard error due to sampling of less than ± 0·2 ton/acre. The precision of the estimate could have been improved by a better distribution of samples among counties.

The results point to underestimation on the part of the official estimates, in each of the 3 years, especially in the case of high yields in particular counties, and in particular years. The discrepancy between the official and the survey yields is of the order of 1¾ tons/acre, after all necessary corrections have been applied to the survey yields.

The experience gained in the survey indicates that the method of sampling adopted provides an accurate and reliable method of estimating the yields of potatoes which could supplement, and, possibly, ultimately replace the present official estimates if more accurate estimates are required. A national scheme, properly designed, which would include all the potato-growing areas in due proportion should not be unduly expensive to operate. Estimates so obtained would not only be generally more accurate than those obtained by the present official method, but, perhaps more important, would indicate far more closely the fluctuation in yield from year to year.

Field studies were made for 2 years on a sandy loam soil under dryland conditions of north-west India with three pigeon-pea varieties in relation to plant density and the application of phosphate fertilizer. Varieties Pusa Ageti and P4785 with better developed root system and profuse nodulation had higher grain and stalk yield, and higher N and P yield than Prabhat. Root and shoot growth and root nodulation were adversely affected with increasing plant densities in the range 50 × 103 and 150 × 103 plants/ha. Stalk and total N and P yield increased with increasing plant density. Plant density of 117 × 103 plants/ha produced maximum grain yield of 1·53 t/ha. Phosphorus fertilizer promoted root and shoot growth, intensity and volume of nodulation and increased grain, stalk, N and P yield. The effect of plant density on grain yield was more pronounced in the presence of phosphate fertilizer. The economic optimum rate of P ranged between 22·1 and 23·1 kg/ha under different plant densities.

1. In 1959 a concentrated granular fertilizer (15% N, 10% P2O5, 20% K2O) was compared with an equivalent mixture of ammonium sulphate, superphosphate and muriate of potash (each supplying 0·75 or 1·50 cwt. N/acre) for potatoes. At Rothamsted (on heavy soil) the two fertilizers gave similar yields, but at Woburn (on light soil) the larger dressing of the concentrated fertilizer gave about 1 ton/acre more potatoes. In similar barley experiments a concentrated granular fertilizer (20% N, 10% P2O5, 10% K2O) was compared with a dilute granular fertilizer (12% N, 6% P2O5, 6% K2O); each was combine-drilled to supply 0·3 or 0·6 cwt. N/acre. At Rothamsted the two fertilizers gave identical yields, but at Woburn the concentrated fertilizer (at the double rate) gave significantly more grain.

Concentrations of rumen volatile fatty acids, ammonium and protein nitrogen and free microbial count in groups of sheep fed fresh herbage have been compared with concentrations in groups supplemented with pure carbohydrates.

Rumen ammonia concentrations in sucrose and cellulose-supplemented sheep tended to be lower before feeding than in sheep fed herbage only, but this difference disappeared after feeding. Ammonia concentrations in sheep supplemented with starch, and those receiving herbage only were similar before feeding, but the rise after feeding was less for the starch-supplemented group. The rise in volatile fatty acids after feeding was greater when part of the herbage was replaced with an equal weight of dry matter of starch, but lower when replaced with ucrose or cellulose.

A field experiment was conducted for 2 years (1993–95) at Central Institute of Medicinal and Aromatic Plants, Field Station, Bangalore, India to evaluate the nitrification inhibitors, benzotriazole, o-nitrophenol, m-nitroaniline and dicyandiamide in a perennial aromatic grass, Java citronella. Citronella responded to applications of high doses of nitrogen (300 kg N/ha/year). The interaction between N doses and nitrification inhibitors was significant. Nitrification inhibitors performed better at the highest N dose (450 kg N/ha/year) and the increase in the essential oil yields was to an extent of 27·3 to 34·6% when compared with ‘N alone’ treatment. The nitrification inhibitors also increased the apparent N recoveries by citronella considerably. The oil content in the herb and its quality were not affected by the treatments. The nitrification inhibitors increased citronella yields and improved N economy.

The object of this note is to call into question the soundness of the generally accepted method by which the so-called apparent protein digestion coefficients of foodstuffs are corrected.

The digestion coefficient for the protein of a foodstuff as ordinarily determined by animal experiment does not afford a strictly accurate idea of the actual digestibility of that constituent. The figure represents a minimum value, and this arises from the well-known fact that the faeces do not consist solely of undigested food residues, but are to an appreciable extent contaminated by nitrogenous products which have been secreted into the alimentary tract and have escaped reabsorption. The nature of this so-termed metabolic material is twofold, being partly protein (mucus, epithelium, etc.) and partly non-protein (residues of digestive secretions, etc.). Before proceeding to a critical survey of the correction method, which is designed ostensibly to enable allowance to be made for the presence of such products in the faeces, it is of essential interest to consider briefly the true significance of the term “protein digestibility.”