An experiment was done to see if three varieties of wheat (Jufy I, Yeoman and Cappelle) of widely different tillering propensities differed in their response to early spring application of nitrogen; and, concurrently and conjointly, to assess the effects of unproductive tillers on the growth of productive shoots.

None of the varieties responded to the higher of two levels of nitrogen. The presence of a large number of unproductive tillers appeared to have only a transitory effect on the growth of productive shoots; the latter were able to grow rapidly after the death of tillers and caught up with productive shoots which had been subjected to much less inter-tiller competition.

The percentage of the total buds produced that dropped before reaching the mature pod stage was estimated as 86·7% in Baladi, a local strain of field beans, and 93·7% in Giza 1, a variety introduced from Egypt. The drop was appreciable both before and after fertilization. There were indications that both inadequate insect pollination and inter-ovary competition contributed to the reduction of pod yield.

Self pollen was detected on the stigma in the bud stage 2–3 days before the flower was open. Estimates of natural cross-fertilization ranged from 35·8 to 42·1%, indicating that self-pollination did not lead to complete self fertilization. Hand manipulation of the flowers increased pod set in most of the cases but the line 1W did not respond to this treatment and proved to be highly autofertile.

Suppressed development of edible portion in carcasses from cattle fed hay during the early feeding period (216–340 kg live weight) was followed by compensatory growth during the intermediate (341–409 kg live weight) and final (410–454 kg live weight) periods. However, when silage in the early feeding period was followed by corn concentrate in the intermediate period, no increased ‘edible portion’ development was achieved beyond that produced by continuous silage. The final feeding period (corn concentrate) resulted in a decline in ‘edible portion’ percentage in cattle that previously received concentrate in the intermediate period whereas those that previously received silage remained at about the same percentage.

Cattle fed hay during the early period had less (P > 0·01) carcass weight, less (P > 0·01) fat cover, and more (P > 0·01) reticulo-rumen weight than those fed corn silage for the same period, regardless of slaughter weight.

In the heavy (409 and 454 kg) slaughter groups, cattle fed silage in the early period had higher (P > 0>05) marbling scores than those fed hay. Feeding silage in the intermediate period resulted in lower colour (P > 0·01) and firmness (P > 0·01) scores in the longissimus dorsi muscle than feeding concentrate at that time. The dietary regimes used in these studies resulted in widely varying growth rates among treatments with consequential differences in the average age of the animal groups at slaughter. Therefore, the treatment effects observed seem to be easily explicable on the basis of age differences.

The body composition of eight Merino wethers was estimated from the tritiated water (TOH) space and live weight at intervals during a cross-over experiment in which they were fed to either maintain a uniform live weight (about 34 kg) or to lose and, later, recover live weight over a 17-week period. The diet was a pelleted mixture of lucerne and wheat.

The multiple regression equations used for these estimates were established from the chemical analysis of 24 sheep, including six from the cross-over experiment, which were killed at intervals during these two feeding regimens. The inclusion of TOH space in addition to live weight in the regression equations decreased the standard error of the estimates of body water, fat and energy by two-thirds. Correction of TOH space and live weight for gut water did not increase the precision of the equations.

Shoop which ate, during the first 4 weeks of the experiment, one-third of the amount of food required to maintain their original live weight, lost 16% of their weight and 30% of their total body energy. This weight loss consisted of 45% water, 39% fat and 13% protein. It appeared that tissue was mobilized inefficiently to meet a sudden energy deficit.

When food was offered ad lib. to these sheep after they had maintained a liveweight deficit of about 11 kg for 8 weeks, they regained their weight in 5 weeks but only 75% of their energy deficit. This was due to the high content of water (60%) and low content of fat (23%) in the regained tissue.

The sheep that lost weight and then recovered it were, over-all, about 86% as efficient in their use of food to maintain body energy and produce wool as the sheep that maintained their original weight.

Investigations into the non-protein nitrogen composition of grass silages using the 50 cm strong cation-exchange column of Spackman, Stein & Moore (1958) to determine the basic amino acids led to difficulties in the determination of ethanolamine in the presence of high concentrations of ammonia, and of histidine in the presence of δ amino-n-valeric acid. An alternative technique for the ion exchange chromatography and estimation of histidine, lysine, ornithine, ethanolamine, arginine and ammonia on a weak cation-exchange resin has been developed. This method enables small amounts of ethanolamine to be determined in the presence of large amounts of ammonia and values for the ethanolamine content of a number of silage samples are presented. When used in conjunction with the technique of Spackman et al. (1958) the δ-amino-n-valeric acid content of grass silages could also be determined in the presence of histidine.

The estimation of amines produced by the microbial decomposition of herbage proteins during ensiling has previously involved their initial separation from the amino acids followed by quantitative partition chromatography. An alternative method for the estimation of these amines by ion-exchange chromatography on a weak cation-exchange resin is described. This method permits the colorimetric determination of β-phenylethylamine, tyramine, tryptamine, 5-hydroxytryptamine, putrescine, cadaverine and histamine without interference from the amino acids. The efficiency of this technique has been investigated using standard solutions of the naturally occurring amines and samples of good quality and of high pH spoilt silages.

In an experiment to investigate growth in relation to nitrogen concentration and nitrogen uptake, Proctor was compared with four other varieties of barley at two levels of irrigation and two levels of nitrogen fertilizer by means of weekly samples throughout the growing season. The varieties were Deba Abed, a new variety recommended for high fertility conditions where feeding quality grain is required, and three exotic varieties, chosen for their high concentration of nitrogen in the grain.

Irrigation stimulated tillering, although certain varieties responded more strongly than others; irrigation also led to a higher specific growth rate. Certain of the exotic varieties had high growth rates early in the season but growth fell off earlier due to earlier ear emergence. Maximum leaf area index was greater in the irrigated treatment at the high nitrogen fertilizer level. The adapted varieties had higher maximum leaf area indices than the exotic varieties, although some of the exotics had higher rates of leaf area growth early in the season; there were also differences in the way in which the varieties responded to irrigation. Irrigation and variety both affected the rate at which the percentage nitrogen in the shoot fell with time.

Analysis of these data indicates that nitrogen uptake early in the season was an important factor determining the total amount of nitrogen taken up by the plant. It was also shown that the relative rate of decline of the specific growth rate and the specific rate of nitrogen uptake differed between varieties. Analysis of the specific growth rate indicated that differences in leaf growth, rather than net assimilation rate, led to the varietal differences. The differential response to irrigation is discussed with reference to drought resistance.

Studies were conducted on the quantity and distribution of fat in 104 half-sib Angus steers which had received various combinations of hay, corn silage, and corn concentrate. Groups were slaughtered at live weights of 216, 284, 340, 409, and 454 kg. The weights of mesenteric, cod, pelvic, kidney and total excess carcass fat were determined. Four linear measurements of subcutaneous fat, three cross-sectional area measurements of intermuscular fat, and the intramuscular fat in seven muscles were observed. The results showed that the feeding regimes had marked influences on the quantity and location of fat, particularly during the early feeding period (216–340 kg live wt.). Feeding hay during this period generally resulted in less fat deposition than feeding corn silage, but the suppression of intramuscular fat deposition was not evident until the animals were subsequently fed higher energy rations to heavier weights (409 and 454 kg). The results indicated that it may be possible to design dietary regimens that suppress waste fat but allow intramuscular fat to be deposited.

The results described above imply that one might influence the deposition of intramuscular fat by proper design of the diet in the early feeding period. Although this possibility exists, it is noted that quantities of chemically extractable fat are not identical with quantities of marbling fat and hence changes in the former may not alter the visible quality of the meat.

A quantitative evaluation of the pigment in Murrah buffaloes of both sexes ranging in age from 1½ to 7 years revealed that dorsal areas had most pigment, while the lateral body areas and the extremities were intermediate and the ventral and axillary regions revealed the least pigment. Maximum concentration of melanin granules occurred in stratum cylindricum, which gradually declined towards stratum corneum which was fully non-pigmented in axilla, groin, inter-digital and inter-dewclaw areas.

Pigment granules blackened in silver preparations and were seen concentrated as protective ‘nuclear caps’ in the supranuclear zone of the cells of stratum germinativum. The infranuclear light-staining cytoplasm contained PAS reactive glycogen granules.

The length of wool grown per day, on closely clipped patches of the skin of two sheep exposed to an ambient temperature of 2 °C for 4 days, was reduced to 30% of normal. For individual fibres, this decrease was directly proportional to their normal growth. Fibre diameter was not affected. Growth in a warm 4-day period succeeding the cold period returned to normal and remained normal thereafter.

A method of establishing indwelling catheters in the jugular vein and carotid artery of the pig by way of the blood vessels of the ears is described. The methods used to maintain these catheters patent for long periods are also detailed.

The effects of several dietary regimens on the fat-free mass and the dry-matter, ash and potassium-40 content of selected bovine muscles were estimated. Muscle data from 104 half-sib Angus steers were secured at several stages of growth and after several feeding regimens. The results indicated that a hay diet, by comparison to a higher energy silage diet in the early feeding period (216–340 kg live weight), suppressed the fat-free weight, reduced the dry-matter content and increased the ash content of several muscles. These effects of early diet were reversed, however, when the animals were subsequently fed higher-energy rations and slaughtered at heavier weights (409 and 454 kg live weight). Data on potassium-40 gamma emissions by composite muscle samples confirmed the existence of age- or weight-associated decreases and suggested possible dietary influences on potassium levels in bovine muscles. The trends in these data indicated that low dietary energy (hay feeding) in the early feeding period delayed the decline in muscle potassium that normally accompanies maturation.

Results of grain analyses for the content of nitrogen, oil and husk are presented from trials in the F1 and F2 generations of four subject varieties, Condor (Avena sativa), Sierra, Avon and Anita (A. byzantina), nine tester varieties, mainly of north-west European origin and the 36 crosses between them.

Yield of grain crude protein per unit area was positively correlated with grain yield, but nitrogen content of the grain, expressed as a percentage of dry matter, was inversely related to grain yield in both trials. Although the highest values for grain nitrogen content were invariably associated with low grain yields, the highest yielders had average or slightly better than average values for nitrogen content.

Analysis of straw samples from the F2 trial revealed considerable differences between varieties and crosses in the proportion of the total shoot nitrogen (grain + straw) ultimately found in the grain. The proportion of total shoot nitrogen translocated to the grain was positively correlated with the ratio of grain yield to straw yield. High grain yielders took up more nitrogen per unit area from the soil and translocated relatively more nitrogen to the grain from the vegetative tissues than did varieties with low grain yields.

Yields of grain oil were highly positively correlated with yields of grain per unit area but there was no significant regression of oil content on grain yield in either trial. In the F2 trial, oil yield per unit area was positively correlated with oil content of the grain. The variety Avon and its crosses had consistently high oil content.

There was no correlation between yielding ability and husk content of the grain, and some of the highest grain yields were associated with low mean husk contents. High husk content of the grain tended to be associated with stiffer straw.

The results are discussed in relation to improving grain quality in the breeding of new varieties of oats.

Experiments to determine the net availabilities of the metabolizable energy (NAME) of a cereal-based diet and a maize-oil diet for maintenance and lipogenesis and the effect of environmental temperature on the NAME of the cereal-based diet are described. Four 1- to 2-year-old Light Sussex cockerels were used.

The relationship between ME intake and energy retention was linear for each diet. The NAME'S of the cereal-based diet given at 22° and 28 °C (70.6 ± 1.83 % and 73.6 ± 3.54%, respectively) were significantly (P < 0.05) lower than the NAME of the maize-oil diet (84.1 ± 1.85%). It is concluded that the beneficial effect of maize oil on the efficiency of energy utilization is due to a reduced heat increment rather than a reduction in the basal component of the heat production. The higher efficiency from the maize-oil diet led to an increase in the energy retained as fat.

The mean fasting heat production at 28 °C was 15 % lower than at 22 °C (43.2 ± 1.45 and 51.2 ± 1.09 kcal/kg/day, respectively). The NAME of the cereal-based diet was not significantly different when the birds were kept at 22° or 28 °C. The lower metabolic rate at 28 °C was reflected in a lower maintenance requirement and in an increase in the deposition of body fat.

Nineteen experiments were made between 1964 and 1967 on fields where previous sugar beet crops showed symptoms of magnesium deficiency. None, 2·5 or 5 cwt/acre kieserite or 20 cwt/acre dolomitic limestone were tested in a factorial design with none or 3 cwt/acre agricultural salt (crude sodium chloride), and 0.8 or 1.2 cwt/acre nitrogen as ‘Nitro-Chalk’. Additional plots tested kainit (7 cwt/acre) and a large dressing of potash (2 cwt/acre) as muriate of potash.

Kieserite and dolomitic limestone increased sugar yield and the most effective dressing was 5 cwt/acre kieserite, which gave 3·1 cwt/acre more sugar than the crop without magnesium fertilizer. Agricultural salt and the larger dressing of nitrogen were profitable, and neither interacted with magnesium on average; the large dressing of potash also increased yield. The magnesium in the kainit increased yield slightly, but the dressing tested supplied too little to satisfy the crop's requirement of magnesium.

Each year in late summer the percentage of plants showing magnesium-deficiency symptoms was recorded, and a sample of twenty-four plants harvested from each of the magnesium treatments and analysed. All the magnesium fertilizers increased the concentration of magnesium in leaves, petioles and roots, and also decreased the number of plants showing deficiency symptoms.

The magnesium concentrations in plants grown without magnesium differed widely and were related both to the yield response to magnesium fertilizer and to the percentage of plants with deficiency symptoms. Both relationships showed a similar ‘transition zone’ from deficiency to adequate supply, for leaves this was 0·2–0·4% Mg, for petioles 0·1–0·2 Mg and for roots 0·075–0·125 % Mg in the dry matter.

Purified diets prepared from finely ground constituents such as starch, casein, gelatine, cellulose, etc., are not readily acceptable by poultry. This is probably due to their powdery nature, for Coates, Kon & Shepheard (1950) found that chicks grew faster when fed a granulated purified diet than when this was fed unprocessed. Granulation was accomplished by mixing the diet with about a third of its weight of water, pressing the resulting paste through a no. 8 sieve and drying the granules at 40 °C.

The utilization of different levels of protein, supplied mainly as soybean meal, was examined by a feeding experiment with sheep. Measurements of the concentrations of N-containing rumen metabolites and of blood urea showed that protein degradation in the rumen and removal of urea by the kidneys were limited when highly increased amounts of protein were ingested.