Thirty-two growing bullocks were fed long barley straw ad libitum in each of three experiments; urea was added to the latter or to a diet of straw supplemented with either 1·36 or 2·72 kg meal. The amount of urea fed was 75 g per animal daily. In a fourth experiment, a basal allowance of 3·64 kg chopped hay was fed to thirty-two bullocks weighing 287 kg; in addition 4·55 kg of meal was fed in which none, one-half or all the supplemental nitrogen was supplied as urea. Rate of gain and straw intake of animals given straw only was similar to that of animals given straw and urea. Feeding 1·36 kg of either rolled barley or rolled barley supplemented with 10% soyabean meal, in addition to straw, did not elicit a response from urea. A response was obtained from urea when 2·72 kg of a barley–soyabean meal mixture was fed with straw. Blood urea concentrations generally reached a maximum at the third week of urea feeding and declined thereafter. Addition of urea to straw raised blood urea to about the same extent as incorporating urea with 1·36 kg of rolled barley. Blood concentrations were higher when the urea was fed with meal than when mixed with molasses. Nitrogen retention from urea was not significantly increased by feeding 1·36 kg of barley with straw ad libitum as compared to the retention on an all-straw ration. Slightly more nitrogen was retained when urea was added to rolled barley instead of a rolled barley–soyabean meal (10%) mixture. A ration of hay (3·64 kg) and 4·55 kg of barley promoted gains which were not significantly different from those of animals fed additional nitrogen as soyabean meal or urea. This indicates that the foregoing ration supplied enough nitrogen to meet the animals' requirement.

Experiments wore carried out to compare wet and dry feeding for bacon pigs and to study the effect of temperature of feed on the utilization of wet feed. There was no significant difference in growth rate between wet and dry feeding; food conversion ratios tended to be lower on wet feeding and were significantly lower in one experiment. There were no significant differences in growth rate or food conversion between wet feed given at 5 °C, 13 °C or 35 °C. None of the treatments had any significant effect on carcass characteristics. Nitrogen balance and digestibility studies confirmed the results of the production trials. There were no significant differences in the digestibility of dry matter or nitrogen between wet and dry feeding or between extreme temperatures of the feed.

Three experiments were performed in which variation in metabolizable energy (M.E.) determinations was studied using a total of 137 laying hens. Consistent breed differences in classical M.E. estimates were found, and there were statistically significant differences between pullets within strains. Estimates were obtained of the within-bird variation in classical M.E. determinations and, from the estimated variance components, standard errors of the mean classical M.E. value were predicted for determinations using various numbers of pullets of one breed and various numbers of measurements per pullet.

The effects of different levels of first-winter nutrition over 3 years were studied on the subsequent life-time production from the hill of groups of North and South Country Cheviot ewe hoggs (sheep between 6 months and 1½12 years).

Lamb production was examined in terms of the percentage of lambs born and reared per ewe alive at each lambing and was expressed as a mean of five lamb crops. An overall measure of flock life-time production was calculated from the data on lamb production. This was the total number of lambs weaned at a mean 15 weeks in each treatment group over five lamb crops expressed as the mean per experimental animal alive at 6 months.

All productive components were analysed for differences between breeds, treatments, and weight-classes, i.e. those animals above or below average weight at 6 months.

There were no significant treatment differences in life-time production, although the treatment groups showed different trends with increasing age. Higher production in early life following higher levels of first-winter nutrition was associated with less efficient later production and poorer ewe survival in a hard hill environment.

It is concluded that improvement in first-winter nutrition above that available on the hill is undesirable and uneconomic without equal improvement in adult nutrition.

Two flocks of Merino wethers ranging in age from 3 to 87 months grazed a poor (L) or high (H) quality pasture for 3 months. The flocks were then combined, and intake was estimated while the sheep grazed four different pastures in succession. In a second experiment, flocks of Merino, Border Leicester, Southdown and Dorset Horn ewes of varying ages grazed in succession six pastures on which intakes were estimated and live weights recorded. The digestibility of the diet selected, as estimated from the faecal nitrogen concentration, declined with age by 0·053 units per month in Exp. (2) and curvilinearly in Exp. (1). In both experiments faecal output of sheep of similar breed receiving similar treatments increased with age to approximately 3 years and declined thereafter. In neither experiment was there a significant allometric relationship between intake and live weight.

The intake of the L group was consistently greater than that of the H group when both groups grazed together. The differences were correlated with the quantity of green feed available. The faecal output of Dorset Horns, Merinos, Southdowns and Border Leicesters at 28·7 months of age was calculated to be 451, 402, 346 and 588 g per day respectively in Exp. (2). Mean digestibility of the diet selected estimated by the faecal nitrogen procedure was 65·1, 63·0, 64·7 and 64·5 units at 28·7 months for the Dorset Horns, Merinos, Southdowns and Border Leicesters respectively. Differences between breeds in faecal output and in the digestibility of the diet were significant.

Statistical analyses were carried out on the data obtained under strictly controlled conditions in metabolism stalls with 41 different rations fed to 127 adult non-pregnant dry cows, and with 14 other different rations fed to 35 adult non-pregnant lactating cows that had calved 2–6 months earlier and whose daily milk production ranged from 11 to 20 kg. The authors have calculated and studied the correlations between faecal and urinary calcium losses, calcium excretion in the milk, digestible calcium, and calcium balance, and the 75 other nutritive factors which were analysed for each of the 55 above-mentioned experimental diets. The results showed that calcium metabolism is regulated in the digestive tract, and the fact that the lactation calcium requirements increase at the same time as the amounts of digestible calcium and the calcium balance corroborates this statement. But except for this endogenous factor of resorption, the fate of the dietary calcium does not depend on the ingested amounts but on the nature itself of the components of the diets and their proportions in the diets. Cereals, and especially barley, have from this point of view a particular beneficial effect. These factors act on the absorption of calcium and thus directly on the balance, since the daily urinary excretion of calcium is generally small and independent. It has also been demonstrated that the balance is not inevitably negative in cows with a daily milk production of 11–20kg, and that a careful composition of the rations should enable one to equilibrate it.

The other nutritive factors do not work on calcium utilization, but a close parallel exists between digestibility, urinary excretion and balance of both calcium and magnesium.

Statistical analyses were carried out on the data obtained under very strict conditions in metabolism stalls with 41 different rations fed to 127 adult non-pregnant dry cows, and with 14 other different rations fed to 35 adult non-pregnant lactating cows that had calved 2 to 6 months earlier and whose daily milk production ranged from 11 to 20 kg.

The correlation between faecal and urinary losses of magnesium, magnesium in milk, digestible magnesium, and magnesium balance and the other nutritive factors of the 55 above-mentioned experimental diets have been calculated.

The magnesium absorption is enhanced by increasing magnesium and calcium intake, while nitrogen and, to a lesser extent, fat, giving higher faecal losses, have an opposite effect. There is no influence at this level of lactating requirements.

The urinary losses of magnesium are not related to the magnesium intake and digestibility, and the balance is thus directly proportional to the digestible amounts. But this balance is decreased when the diet contains more dry matter or energy, to the benefit of urine in dry cows. We were not able to determine whether this balance reduction also benefits the milk production in the lactating cows.

Our results demonstrate that the faecal endogenous losses of magnesium can be highly variable.

The balance of magnesium is frequently but not inevitably negative in cows with a daily milk production of 11–20 kg.

Samples of prefemoral, thoracic and intestinal duct lymph have been collected under acute conditions from three cows grazing pasture and the lipid composition compared with that of plasma.

The concentration of lipids in peripheral lymph was 16–36% of that found in plasma; the fatty acid compositions of peripheral lymph lipids were similar to those of plasma.

Of the fatty acids present in intestinal and thoracic lymph 86 and 76% were esterified as triglycerides, 10 and 13% as phospholipids and 3 and 5% as cholesterol esters, respectively. Saturated and mono-unsaturated fatty acids were preferentially esterified as triglycerides whereas di- and tri-unsaturated acids were associated more with phospholipids. The content of di- and tri-unsaturated fatty acids was greater in the triglycerides and phospholipids derived from the intestine than in those found in plasma.

The di- and tri-unsaturated fatty acids in intestinal and thoracic lymph were transported mainly in the form of triglycerides (45–62%) and phospholipids (21–33%). Cholesterol esters were quantitatively of minor importance in the transport of these fatty acids in lymph. The intestine does not appear to play any major role in the formation of the high concentration of cholesterol ‘linolenate’ found in bovine plasma.

The process of lipid digestion in the cow appears to be similar to that found in sheep.

Field experiments with Italian ryegrass cut four times a year compared aqueous ammonia with ammonium sulphate and with a mixture of ammonium nitrate and urea (equal parts by weight). In 1963 four rates of nitrogen, 224, 448, 672 and 896 lb/acre, were applied as single and split dressings of injected aqueous ammonia, as solid ammonium sulphate and as injected solution of ammonium sulphate. There was little difference in total dry-matter yield between a single injection of aqueous ammonia and the split dressing of solid. Injecting ammonium sulphate solution eliminated scorch caused by single applications of solid supplying 448 lb N/acre or more and gave significantly greater dry-matter yields. A single application of 448 lb N/acre provided enough nitrogen to sustain the response of the grass to the end of the season.

In 1964 a single injection of aqueous ammonia was compared with ammonium nitrate/urea applied as solid or solution at 280, 560 and 840 lb N/acre. There was no difference in total dry-matter yield between aqueous ammonia and ammonium nitrate/urea at rates of 560 and 840 lb/acre. At 280 lb/acre a split dressing of solid produced most dry matter. More than 280 lb N/acre was required, therefore, as a single application in spring to last the whole season, but this rate of nitrogen applied as a split dressing was almost sufficient to give maximum yield.

In both experiments the seasonal distribution of dry matter was similar for single and split applications except in 1963 when large single injections of ammonium sulphate produced greater yields at the third cut than the split applications. The percentage of nitrogen recovered in the harvested grass decreased as nitrogen rate was increased and was greater from single than split applications. Recovery of nitrogen from aqueous ammonia was less efficient from four injections than one, and was greater in 1964 than 1963 due to better penetration of the sward by injector tines. Least nitrogen was recovered from surface-applied solutions of ammonium nitrate/urea. Regressions of dry-matter yield on nitrogen yield showed that single injections of aqueous ammonia were as efficient as other fertilizers tested.

The Woburn Market-Garden experiment was started in 1942 to investigate the development of a market-garden type soil from an ordinary agricultural soil on light land by applying organic manures regularly. The ‘organics’ used were farmyard manure, sewage sludge, and composts of these with straw and farm waste. The use of sewage sludge was discontinued in 1961 and the yields of the crops up till then were published by Mann & Patterson (1963).

In an experiment to determine the effect of photoperiods of 11, 13 and 15 h on the floral development of five determinate varieties of Phaseolus vulgaris it has been shown that long photoperiods bring about the abscission of flower buds on the main axis and secondary branches of three varieties native to South America. On the basis of these results it is concluded that under field conditions it is the long photoperiods of the British summer which are largely responsible for the poor development and eventual abscission of flower buds in these varieties for most of the growing season.

Fifty-two Large White gilts, arranged in thirteen groups of four litter sisters, were allocated at mating to one of four treatment groups. These treatments, arranged as a 2 × 2 factorial, allowed daily energy intakes in pregnancy of 8·3 Meal (H(e)) or 5·2 Meal (L(e)) and of average daily intake during lactation of 20 Meal (h(e)) or 13·8 Meal (m(e)). Daily intakes of protein, minerals and vitamins were similar for all treatments. There were no consistent differences in health or breeding regularity between the treatments.

The H(e) sows had a net gain in pregnancy 22 kg greater than the L(e) sows. Feeding the higher level in lactation (h(e) resulted in a reduced sow weight loss during lactation of 20, 12 and 10 kg in the first, second and third parities respectively, as compared with the m(e) sows. There were no consistent effects on the numbers of pigs born apart from the first litter in which L(e) sows produced significantly larger litters at birth. The higher energy intakes in pregnancy and lactation led to very similar increases in the weights of the piglets, of the order of 0.1 kg at birth, 0.4 kg at 3 weeks of age, and 1.1 kg at 8 weeks of age. Sowsgiven the same overall energy intake throughout their reproductive life (H(e) m(e), L(e) h(e)) at the end of the third litter had similar live weights and had produced a similar total weight of weaned pigs. The practical implications of these results are discussed.

Timothy [S. 50], meadow fescue [S. 53], perennial ryegrass [S. 23], Italian ryegrass [S. 22] and cocksfoot [S. 143] were grown together in all possible pair combinations at two levels of fertility, in a pot experiment. Dry weight of herbage and tiller counts were determined at 136 and 198 days from sowing. The data were analysed for competitive effects by the application of the diallel analysis technique of Durrant (1965). The competitive effects were largely compensatory in type with dominant species such as Italian ryegrass and perennial ryegrass increasing in mixtures, relative to their pure stand values, more than species such as timothy and meadow fescue declined. This resulted in a tendency for the mixture means to exceed their mid-constituent values.

The competitive effects on the reciprocal differences were seen to be predominantly of the alpha type; that is, there was a constant increase or decrease in one or more species when grown with others. The alpha values were found to be correlated with the unmixed species values so that ƀ, the mean effect, wasappropriately calculated from alpha. The over-all value of ƀ was –1.216, which means that for each gram difference in weight between the species when grown by themselves there was 2.452 g increase in difference between the species when grown in mixtures, the larger species increasing and/or the smaller species decreasing. There were significant differences in ƀ values between harvests, the ƀ competitive effects being approximately twice as large in the more mature plants. Although the alpha competitive effects increased in magnitude with time the species order remained relatively constant, and in terms of competitive ability the species could be placed in the ascending order, meadow fescue, timothy, cocksfoot, perennial ryegrass and Italian ryegrass.

Tiller number showed a similar pattern, but the ƀ values were smaller, and not significant. Nevertheless competition had differential effects upon the plant weight/ tillering relationship and it is possible that the resultant morphological changes would influence the re-growth quality of the species.

The conclusions derived from the analysis of reciprocal differences in this work is compared with earlier examples.

The primary growth of eight varieties from three species—white clover (3), red clover (4) and lucerne (1)—was sampled at fortnightly intervals during 2 years and the percentage N, P, K, Ca, Mg, Na and in vitro dry-matter digestibility (IVD) were determined.

Differences between species, date of sampling and years were highly significant for all constituents. Clover was significantly different from lucerne for all constituents except P, and white from red clover with the exception of Ca. There was a steady decrease in N, P, K, Na and IVD with advance of date of cutting but no marked trend in Ca and Mg. Some constituents changed considerably from first to second year, decreasingin the case of Ca, and increasing for N, P andNa; the remainder K, Mg, and IVD changed only 4–8%.

The varieties did not give the same relative results in the 2 years for P, K and Ca content, but there was no interaction for N, Na, Mg, IVD content. Species differences accounted for mostof these interactions.

Percentage composition is discussed in relation to the needs of cattle and it is concluded that these herbage legumes provided sufficient Ca, Mg, N, K, and Na (white clover, and the firsttwo cuts of S. 123 red clover and lucerne only) for milk production and growth. The level of P fell below the quoted needs of a 20 kg/day milking cow but was adequate for growth.

Winter wheat grown on a sandy-loam and on a clay-loam soil was given ammonium sulphate alone or treated with the nitrification inhibitor, 2-chloro-6-(trichloromethyl)- pyridine, drilled with seed, in autumn. In spring, dressings of treated or untreated ammonium sulphate or of calcium nitrate, were broadcast. 75 or 150 lb N/acre were given on the sandy loam and 50 or 100 lb on the clay loam. Plants were sampled during growth and grain yield was measured.

Without fertilizer-N, the wheat yielded 17 cwt/acre on the sandy-loam and 46 cwt on the clay, and with the double dressings given in spring yields were 52 and 56 cwt/ acre. On the light soil, treated ammonium sulphate given in autumn increased yield by 3–5 cwt/acre with the single dressing and by 5–4 cwt/acre with the double one.

On the heavy soil the inhibitor had no effect on yield. Dressings of 50 lb N/acre in autumn or spring increased yields equally, but with 100 lb N/acre the spring dressing increased yield slightly more than autumn dressings. Calcium nitrate at 75 lb N/acre was significantly better than ammonium sulphate on the light soil.

The inhibitor did not affect the speed with which N was taken up, or the total uptake, from fertilizer given in spring.

In tests with seedlings in the glasshouse, significant differences in susceptibility to downy mildew, caused by Peronospora farinosa f. sp. betae, were observed between individual stocks of sugar beet. The resistance of a particular stock in glasshouse tests was not always a reliable guide to its resistance in the field. There were also serious discrepancies between the results of tests with seedlings and those with mature plants in the field, suggesting that the resistance of certain stocks, relative to one another, may vary with increasing age of the host plant. This contention was supported by evidence from a field experiment in which the susceptibility of several sugar-beet stocks was compared throughout the growing season. It also appears that changes in environmental conditions affected resistance to downy mildew more in some stocks than in others.

Progenies of selected plants that had not shown severe symptoms of downy mildew, after exposure to natural inoculation with P. farinosafor more than 3 months in the field, were much more resistant than the parent stocks. This showed that a single generation of selection under suitable conditions can significantly improve the resistance of sugar-beet breeding stocks to downy mildew.

An inbred sugar-beet line of American origin showed exceptional resistance to downy mildew in experiments under glass and in the field. Inoculated plants of this line usually showed no symptoms of the disease and P. farinosa did not produce conidia on them. These results show that sources of extreme resistance are present in cultivated sugar beet and suggest that an excellent control of downy mildew in Britain may eventually be achieved through the use of resistant varieties.

A Bolex S1 ciné camera, Kodachrome II colour reversal 8 mm film and a Specto analysis projector provided acceptable records of heifer behaviour from dawn to dusk throughout the year. Films are available on application.

Two groups of heifers showed logical and persistent behavioural responses to clement and inclement weather. Their daily behavioural routine was a response to, and in turn was modified by, the weather. Their group behaviour was readily recorded by time-lapse photography but an easy study of the more individual reactions of sheep was not possible from time-lapse film due to problems of identification and flock turbulence.

Heifers responded to bright sunshine predictably but differently in summer and winter, a definite response to a change in the direction of the incident wind being recorded in warm summer sunshine. A hitherto unrecorded reaction to unusually cold, strong, dry wind, viz. vigorous, non-stop grazing in the absence of effective upwind obstructions— requires verification.

Shelter usage was largely related to the incidence of wind-driven rain and, on the area of study, the slope of rainfall and the direction and strength of the wind which brought heavy rain were the main factors affecting sheltering activity. This unfortunately meant that shelter usage was synonymous with the fouling and poaching of sheltered ground.

After establishing a permanent omasal fistula in a ram, solutions containing histamine with or without formic or acetic acid were introduced directly into the omasum. It was found that histamine, together with formic or acetic acid, stopped feeding and rumen motility, but formic acid and histamine, infused separately, had no effect on food intake.

A co-ordinated trial has been carried out at sixteen centres to compare the following three feeding methods for growing pigs: (1) ‘sow and weaner’ type meal up to 120 lb live weight, followed by ‘finishing’ type meal to slaughter; (2) ‘sow and weaner’ type meal from start to slaughter; (3) as (2), but the cereal and supplement components given separately (not mixed).

Using the sow-and-weaner type meal throughout, rather than changing to a lower protein diet at 120 lb live weight, resulted in slight improvements (less than 2½%) in over-all growth rate and feed conversion; these improvements were not sufficient to compensate for the higher feed costs. None of the carcass measurements was significantly affected.

Lack of mixing of the cereal and supplement components did not harm the performance of the pigs and so farmers who produce their own cereals and buy concentrates may reduce costs by the elimination of mixing.

Initial pH of buffalo semen as measured electrometrically is 7.2 ± 0.025 and the buffering capacity 1.40 ± 0.026. Sulphamezathine in glucose–egg yolk–bicarbonate diluent depressed fructolysis in buffalo semen. This depression is considered to be a factor in the better maintenance of motility in this than in other media investigated. The more alkaline pH of this medium also appears to be beneficial in preserving motility on storage.