The effects of copper supplements on the performance up to 45 lb. live weight of early weaned pigs were measured in two experiments. Copper sulphate included as 0·1% of the diet had no apparent adverse effect on the piglets, even when it was introduced immediately after weaning at about 8 lb. live weight, but improved rate of gain by 6 and 12% and feed conversion efficiency by 5 and 6% in the two experiments, respectively. The length of the period of slow growth after weaning was reduced in both experiments. There was no clear advantage in delaying the introduction of the high-copper diet until the pigs weighed 17 or 26 lb.

The second experiment was a 2 x 2 factorial, the second factor being the presence or absence in the diet of antibiotic (present throughout in the first experiment). Antibiotic appeared to have slight beneficial effects on growth rate and feed conversion, which were additive to the effects of copper so that the best results were obtained from the diet containing both copper and antibiotic.

In a continuation of the first experiment it was found that the early copper treatment had no effect on rates of gain and feed conversion between 55 and 200 lb. live weight or on carcass measurements. The inclusion of a copper supplement in the diet from 55 to 200 lb. improved feed conversion by 4% and rate of gain by 3·5%, reduced the thickness of streak and increased the ratio of width to depth of eye muscle. None of these responses was affected by the copper treatment prior to 55 lb. live weight.

A grass/clover ley (mainly S26 cocksfoot and S 100 white clover 3 years, 1951–53) and a pure grass stand (S 37 cocksfoot 6 years, 1954–59) on the same site had threefold replication of four irrigation treatments: O, unwatered control; C, kept near field capacity throughout; A and B, intermediate between O and C. All plots received the same basic P and K dressing, and half-plots got N dressings either as N1 and N2, or as N2 and N4, the nitrogen being applied in the spring and after every cut except the last at rates: N1 0·15; N2, 0·30; N4, 0·60 cwt. N/acre. Cuts were taken at about 3 or 4 week intervals in the summer, and yields expressed as dry matter.

A comparison is made between a maize-rich diet containing 7% white-fish meal and a similar diet in which the protein supplement consisted of 6% ex. soya bean meal together with 0.3% L-lysine hydrochloride and 0.2% DL-methionine. The vegetable protein diet plus the amino acids proved in every way equal to the fish meal diet.

When the essential amino acids in the diet of weanling pigs are properly balanced as little as 10% digestible crude protein will support maximum growth.

The results obtained when 6% ex. dec. groundnut meal was used as a protein-rich supplement were not so favourable.

1. Studies of tissues distribution in beef carcasses of East African ‘Boran’ cattle revealed very high correlations between the separable tissue analysis of the full tenth rib sample joint and of the full side.

2. A comparative study of tenth rib sample joints, from twelve steers and five cows cut at various positions along the length of the rib showed that the full rib sample gave a higher correlation (r = 0·948), with the full side in respect of all tissues except the subcutaneous fat, than any other sample joint. The subcutaneous fat of the whole side could not be predicted with reliability by the use of any rib sample, the highest correlation (r = 0·558) existing between the half-rib sample and the full side.

3. From detailed carcass studies of thirty-two steers and eight cows, including the twelve steers and five cows mentioned above, prediction equations are presented for estimating the percentages of lean, total fat, and butchers' bone in whole carcasses from single complete tenth rib samples. Standard deviations being 1·53% for lean, 1·34% for total fat in steers, 1·13% for total fat in cows and 0·88% for butchers' bone.

4. Where X1, X2 and X3 are respectively the percentages of lean, total fat and bone in the sample joint the prediction equations recommended are as follows:

For the prediction of lean

(i) In carcasses of either sex.

(f) Percentage of lean in the carcass = 0·431X1 + 0·475X3 + 33·58 (subject to a standard deviation of 1·53%).

For the prediction of total fat

(i) In steer carcasses.

(d) Percentage total fat in carcass = 0·664X2 − 0·78 (subject to a standard deviation of 1·34%).

(ii) In cow carcasses.

(e) Percentage of total fat in carcass = 0·641X2 + 0·23 (subject to a standard deviation of 1·13%).

For the prediction of bone

(i) 100 −(equation (f) +equation (d) or (e)).

5. A practical test of the equations referred to in the text is given in Table 4.

1. Forty-nine 33 factorial experiments in 1957–60 tested the response of sugar beet to 0·6,1·2, 1·8 cwt. N, 0·0,0·5,1·0 cwt. P2O5 and 0·8 1·6 2·4 cwt. K2O per acre. On forty-one of the sites, the experiment was repeated in the presence of 12 tons FYM per acre. There were also six trials in which the rates of mineral fertilizer had been altered to suit local conditions.

2. Optimum dressings for sugar yield without FYM were 1·0 cwt. N, 0·5 cwt. P2O6 and 1·6 cwt. K2O per acre. This closely agrees with results of experiments made in 1934–39. Exceeding the optimum nitrogen dressing decreased sugar yield although the yield of tops was increased. The main value of dung for beet was in the N, P and K it provided. With FYM, optimum dressings were only 0·6 cwt. N, 0·0 cwt. P2O5 and 0·8 cwt. K2O per acre.

3. Response to nitrogen differed greatly from field to field and the best guide to the nitrogen requirement of a field was the previous cropping. Beet which followed two or more cereal crops needed more nitrogen on average than beet which did not. Response to phosphate and potash did not differ much in different experiments and the national optimum would have been satisfactory for nearly all fields. The only use of soil analysis was to identify the very few fields which needed more than the average dressing of phosphate. The efficiency of phosphate and potash manuring could be slightly increased by taking soil type into account.

Potatoes

1951–53, Ulster Chieftain; 1954–56, Majestic, came after spring barley, with threefold replication of four irrigation treatments. All plots received the same basic P and K dressing, and half-plots got N dressings at N1= 0·5, N2 = 1·0 cwt. nitrogen/acre. Under main crop all plots received farmyard at 15 tons/acre, in addition. The ‘early’ potatoes were lifted about mid-July: the main crop at the beginning of October, a few weeks after killing of the haulms by a spray.

Nitrogen applied at ear emergence to winter wheat or spring barley grown in pots with various levels of basal nitrogen fertilizer, increased grain and total dry weight much less than similar amounts of nitrogen applied in March or April. No nitrogen was absorbed after ear emergence from unfertilized soil, or from the early application, and at maturity equal amounts of nitrogen had been absorbed from early and late applications.

Early nitrogen increased final ear number by increasing the number at emergence and also increased grain size. Late nitrogen had negligible effect on yield of ears present when it was applied and caused the production of new shoots with small ears. Nitrogen applied at both times increased leaf area duration after ear emergence similarly; early nitrogen by increasing area at ear emergence and late nitrogen by delaying senescence of existing shoots and causing production of new shoots. The efficiency in grain production of the leaf area present after ear emergence was less with late than with early nitrogen, mainly because of the low efficiency of the shoots produced after ear emergence.

These results differed from those of field experiments in which early and late nitrogen usually increased grain yield similarly, probably because in the field there were no late unproductive tillers and all the late nitrogen was utilized in increasing grain yield of existing shoots. Another difference was that nitrogen uptake from soil in the field continued until maturity.

Denitrification has been studied in a range of near-neutral Ghanaian soils. The technique used was to add nitrate, alone or with glucose, to 10 or 15 g. samples and incubate at 30° C. and 70 or 160% of the water holding capacity. Changes in the nitrate and total nitrogen contents were then determined over a period of 14 days. Only small or non-significant losses of nitrogen occurred in the unsaturated soils, but larger and rapid losses were observed in the saturated samples. In the samples from under standing forest or old grassland denitrification proceeded without addition of a carbonaceous substrate, but a small addition was required in the cultivated and young grassland soils. The amount needed was much less than has been shown necessary for an equivalent nitrogen loss in a number of temperate zone soils. Evidence was obtained that nitrification and denitrification could proceed simultaneously in the same sample. It is c6nsidered that this supports the concept of a micro-mosaic of aerobic and anaerobic spots in a wet soil.

1. Twenty Southdown-Romney wether lamb carcasses of a mean hot carcass weight of 39·2 lb. (range 31·2–43·8 lb.) were frozen. Each frozen carcass was divided down the back-bone to give two sides and each side was divided into four parts: leg, loin, 9–10–11 rib cut, and fore. A method of obtaining samples from the parts and from the sides is described. The samples were analysed for water, fat (uncorrected), and residue (uncorrected). The dried residue was analysed to give an ash percentage and a Soxhlet correction factor so that total fat (ether-extract), protein (dried fat-free, ash-free residue), and ash were determined.

2. The weights of the two sides of the twenty carcasses were similar, although the loins of the left sides were highly significantly heavier than those from the right sides and the right fores were highly significantly heavier than the left fores.

3. The mean percentage composition of the two sides of the carcasses studied were similar. Likewise each of the four parts showed close similarity between sides except for the residue and protein percentage of the loin in which the left sides had significantly more protein percentage than the right sides. In all the uncorrected chemical components a significant side × carcass interaction was found.

4. An analysis of the sampling errors showed that the variance of a treatment mean was decreased only slightly by increasing the number of samples per side or by sampling both sides instead of one. Any substantial increase in precision can be achieved only by increasing the number of carcasses per group.

1. Longissimus dorsi muscles from twenty Landrace and twenty Large White pigs of accurately known history, which had been reared under identical conditions at a Progeny Testing Station, and killed at similar weights, were sampled for ultimate pH and colour at the levels of the 5th, 7th, 9th, 11th, 13th and 15th thoracic, and of the 1st, 3rd, 5th and 6th lumbar, vertebrae.

2. The mean ultimate pH at all ten locations in Landrace muscles was invariably lower than at corresponding locations in Large White muscles, the difference being minimal at the level of the 15th thoracic vertebra, but being highly significant overall.

3. The scatter of ultimate pH values was markedly different between the breeds at the levels of the 5th and 9th thoracic, and of the 1st and 6th lumbar, vertebrae.

4. The mean colour at all locations, except 1st and 5th lumbar vertebrae, was higher in Large White muscles than at corresponding locations in Landrace muscles: the difference was especially marked at the level of the 5th thoracic vertebra.

5. Only in longissimus dorsi muscles from Landrace pigs were there significant correlations between ultimate pH and colour.

1. In two continuous digestibility trials carried out in 1960 and 1961, groups of three wether sheep were fed on oven-dried herbage which had been selectively collected from natural pastures during December 1959 to March 1960 and December 1960 to March 1961. The organic matter digestibility and the digestible crude protein content of the herbage and the nitrogen concentration in faeces were measured over periods of 5 days. The fresh faeces of dairy cattle grazing the natural pastures were regularly sampled and analysed. Regressions of organic matter digestibility and digestible crude protein content on faecal nitrogen were evaluated. From these equations and the composition of the dairy cattle faeces the digestibility of the herbage grazed was calculated.

2. The herbage consumed by the cattle had a significantly higher organic matter digestibility and digestible crude protein content than the collected material. This difference, which increased as the season progressed, indicates that dairy cattle became increasingly selective in their grazing as the pasture deteriorated in quality.

3. There was a marked yearly difference in digestibility-faecal nitrogen relationships and in the quality of the consumed forage. The grass eaten in 1959-60 had a higher digestibility and lower digestible crude protein content than in the following year. These differences may be part attributable to a seasonal difference in rainfall.

4. The organic matter digestibility of the grazed herbage ranged from 52·71 to 65·03% and the digestible crude protein content from 3·08 to 7·43% For milk production, the herbage consumed is low in digestible protein in relation to the total amount of digestible nutrients.

1. Gibberellic acid had no effect on the germination of six species of small-seeded legumes.

2. Seven varieties of Trifolium repens L. plants were treated with gibberellic acid and their responses determined. All varieties showed an increase in petiole length and individual leaf area due to an increase in cell numbers; a decrease in stolon numbers and length was also noted. The total leaf area per plant remained unchanged. Total dry weight, shoot dry weight and root dry weight were each significantly reduced.

3. The stolons lost their normal diageotropic response and became negatively geotropic and it is postulated that the stoloniferous habit may be due to a gibberellic acid/indole-acetic acid interaction.

4. Because treated plants of Wild white clover closely resembled untreated plants of Ladino clover it is postulated that endogenous levels of gibberellins may play an important part in the development of varieties and in the evolutionary process as a whole.

1. Information, obtained in the metabolism experiments described previously (Rook et al. 1958; Rook & Balch, 1958), is given on the intake and oxcretion, of calcium, phosphorus, sodium, potassium, water and dry matter by milking cows receiving winter-stall diets or cut-grass in the stall.

2. Grass diets cut from swards at an early stage of growth gave a lower intake of calcium, a lower Ca:P ratio and a lower intake of alkaline earth alkali (Ca + Mg – P in g. equiv./day) than did typical winter diets or a grass diet cut from a sward at a mature stage of growth.

3. The intake of potassium was considerably higher with the grass diets (mean value, 327 g./day) than with the typical winter diets (mean value, 181 g./day). The intake of sodium, however, showed a similar range for cut-grass and winter stall diets, but the lowest average intake, of about 10 g./day, was with an early cut of a cocksfoot/rye-grass sward.

4. The water ingested with the food was highest with the cut-grass diets but this was largely compensated for by a decrease in the water drunk. In a few individual animals, however, diuresis developed a few days after the feeding of grass was commenced and this was associated with a marked increase in the water drunk.

5. No major difference in the metabolism of sodium, potassium or water was observed between the cut grass diets and the winter diets and the results obtained do not support the view that the fluidity of faeces of cattle at pasture in the spring is indicative of diarrhoea and is associated with an excessive loss of nutrients via athe faecal route.

6. There was no evidence to suggest that the development of hypomagnesaemia was related to the amounts of calcium, phosphorus, sodium and potassium consumed and excreted with the cut grass diets.

The effect of undersowing on a spring oat crop with four long-term ley mixtures was investigated. Ryegrass, cocksfoot, timothy and general-purpose mixtures were used; broad red and white clovers were included in all mixtures and two levels of nitrogen applied, no nitrogen (n0) and Nitro-Chalk at 3 cwt./acre.

1. Panicle number was reduced by all the undersown mixtures except when cocksfoot was the only grass sown (mixture B).

2. The weight of individual grains was slightly reduced by undersowing with a ryegrass-dominant general-purpose mixture (D) in the absence of Nitro-Chalk, and there was also an indication of a lowering of the total number of grains per panicle when Nitro-Chalk was applied.

3. All the herbage mixtures reduced the percentage of kernel at both nitrogen levels under the ryegrass-dominant mixture (A), but only at one level of nitrogen when cocksfoot (mixture B) or timothy (mixture C) were the only grasses sown.

1. The effect of feeding three levels of concentrates on the organic matter digestibility of two kinds of herbage was determined in four Latin square trials with four wether sheep.

2. Analysis of variance of the trials showed that the organic matter digestibility of all mixed feeds was significantly higher than that of the corresponding herbage. With one exception, the organic matter digestibility of the mixed feeds within each trial was not significantly different.

3. The digestibility coefficients of the concentrates, derived by difference, were invariably high and exceeded 100% for four levels of addition. This indicated a marked improvement of the digestibility of herbage when it was fed with certain levels of concentrate.

4. A possible explanation of the increase of digestibility was discussed and the practical implications of the results indicated.

1. Measurements of the temperatures of the extremities, rectal temperatures, respiratory rates and heart rates have been made in calves during exposure at environmental temperatures within the range – 5·0° –45·0° C.

2. Large variations in the skin temperatures of the extremities were recorded between environmental temperatures of –5·0° and 25·0° C. At environmental temperatures above 25·0° C. the extremity temperatures and the skin temperatures of the trunk were similar.

3. Feeding and localized infra-red irradiation of part of the trunk of the animals resulted in marked increases in the skin temperatures of the unheated extremities.

4. Evidence was obtained that the variations in the skin temperatures of the extremities were brought about by changes of blood flow to these parts.

5. Respiratory rates varied also with the environmental temperature at which the animals were exposed. When the animals were exposed to localized infra-red irradiation of the trunk the increase in respiratory rate was significantly greater when the extremities were initially warm than when they were cool.

6. In addition to spontaneous fluctuations in the skin temperatures of the ears at environmental temperatures of 10·0°–25·0° C, periodic increases in the skin temperatures of the ears were observed in all the calves at an environmental temperature of – 5·0° C. The increase in the skin temperatures of the ears persisted throughout the 7 hr. exposure to an environmental temperature of – 5·0° C.

7. It was concluded that, in a temperate climate, variations in the skin temperatures of the extremities of the ox have a thermoregulatory function.

The effect of using a cover crop of spring oats under three managements and two levels of Nitro- Chalk in the seeding year on Italian rye-grass and broad red clover in the first harvest year were investigated and the following results obtained.

1. Undersowing increased the total yield of dry matter in the Italian rye-grass/broad red clover mixture in the first harvest year. Using a cover crop with the April sowing only increased the yield of herbage when frequent grazing was practised in the seeding year. The percentage of broad red clover and the yield and percentage of crude protein in the clover were higher in spring when a cover crop was used. In the hay cut the percentages of clover and of protein were higher in the Italian rye-grass/broad red clover mixture sown without a cover crop and the yield of crude protein was not affected by undersowing.

2. Early sowing in April resulted in a higher total yield of dry matter and Italian rye-grass in the first harvest year. The growth of broad red clover and the yield of crude protein were also increased in the spring grazing but not in the hay cut. The August sowing resulted in higher winter casualties of the Italian rye-grass and broad red clover, but gave a greater density of plants in the following spring than the swards sown in April.

1. A co-ordinated trial has been carried out at twenty-one centres to study the effects of feeding to growing pigs oxytetracycline (10 g./ton) and copper sulphate (2 lb./ton) separately and together. Fifteen centres repeated the test and thus there was a total of thirty-six pens with 245 pigs on each of the four treatments.

2. Growth rate and efficiency of food conversion were significantly improved by addition to the ration of copper sulphate (9·7 and 7·9% respectively) and of oxytetracycline (3·1 and 2·3% respectively). The improvement due to copper sulphate was significantly greater than that due to oxytetracycline. There was no further improvement when both supplements were fed together.

3. The cold dead weight of the pigs was significantly increased by the two supplements, the carcasses were shorter, and the streaks thicker. Supplementation with oxytetracycline resulted in slightly increased fat over the eye muscle and supplementation with copper resulted in increased depth of eye muscle. Percentage yields of fore-end, middle and gammon were not affected by either supplement.

4. None of the treatment × centre interactions was significant.

1. A low magnesium diet is described, consisting of barley straw, sucrose and casein, which induced hypomagnesaemia and one case of clinical tetany in non-pregnant, non-lactating ewes.

2. On the above diet a daily drench of 0·25 g. MgO maintained plasma magnesium levels at 1·60–1·80 mg./100 ml. which was significantly higher than the plasma magnesium level of 1·09–1·20 mg./100 ml. for the unsupplemented group.

3. An experimental formulation of a magnesium heavy pellet is described and its use as a method of supplementation was investigated. On the above diet it was found that two or four heavy pellets also maintained plasma magnesium values at 1·601–80 mg./100 ml. which was significantly higher (P = 0·01) than the level of the unsupplemented group.

4. Five sheep out of the forty ewes used in this experiment were found to have consistently lower plasma magnesium values than the remaining thirty-five.

5. A preliminary trial of the use of heavy pellets as a magnesium supplement in non-pregnant, non-lactating ewes on winter grazing is described. The results of the trial under these conditions were encouraging.

1. The water intakes of ten Holstein × Zebu milking cows, yielding between one and two gallons of milk a day, were analysed on the basis of (a) freewater drunk, and (b) feed-water consumed with the herbage. Trials took place during a 10-day period in both the wet season, 1959 and the dry season, 1960. During both seasons the cows were rotationally grazed on Pangola grass pastures.

2. The results showed a difference of only 24% in total water intake between seasons. However, the mean intake of free water increased from 18·5 lb. per cow in the wet season to 81·5 lb. per cow per day in the dry season, and the intake of feed water decreased from 94·9 to 59·2 lb. per cow per day, respectively. The between cow coefficients of variation were 9·7 and 8·7%, respectively.

3. Results are presented for the drinking habits of Holstein × Zebu cattle grazing Pangola grass pastures. For 567 observed cow-days in the wet season, the cattle were found to drink water on average 0·8 times per day from troughs present in the pastures. For 332 observed cow-days in the dry season, the cattle increased their drinking habits to a mean figure of 1·4 times each day.