Short-term grazing trials with daily blood sampling were carried out on Welsh mountain ewes in early lactation.

1. A small decrease in serum magnesium levels and a very marked decrease in serum inorganic phosphorus levels, were observed in two groups of four ewes, when one group was transferred from an old pasture to a fertilized (high nitrogen and potash) fresh spring ley, and the others to a similar fresh ley but untreated. There was little effect from the fertilizer treatment on the magnesium, calcium, potassium, sodium or phosphorus content of the herbage.

1. Lactating ewes, fed an artificial diet deficient in magnesium, showed no ill effects while they received an adequate supplement of magnesium acetate. Sudden withdrawal of the supplement resulted in acute hypomagnesaemia, hypocalcaemia and loss of appetite within 48-72 hr. One animal developed tetany within 3 days after withdrawing the supplement. Appetite and serum magnesium and calcium levels could all be restored by givingmagnesium acetate supplement.

1. Three experiments designed to investigate the effects of consolidation and aeration of soil beneath potato seed tubers before planting, and inter-row grubbing after planting, on the growth and yield of potatoes are described and the results discussed.

2. Consolidation of furrows beneath seed tubers by tractor wheels at planting had no effect on total weight of ware-size tubers produced but increased the weight of mis-shapen waresize tubers. It is argued that this effect was related to soil moisture content and tilth at planting time.

Grundy & Healy (1950) developed a method of ‘restricted randomization’ applicable to factorial experiments of 2n or 3n type laid out either in quasi-Latin squares of size 8 × 8 or 9 × 9, or in blocks of 8 or 9 plots. This method of randomization, while in no way affecting the validity of the normal analysis, prevents the appearance of designs with obviously undesirable features. Grundy & Healy gave an example of a quasi-Latin square inwhich the main effect of one factor corresponded to the pattern:

1. A feeding trial involving 128 individually fed Large White pigs was carried out using four levels of dietary energy in combination with four levels of crude protein in the ‘growers’ rations of bacon pigs. Growth rate, food conversion efficiency, carcass quality and nitrogen balance were the parameters measured.

The number of spermatozoa in bull semen was determined by electronic counting, light scattering and absorptiometry. Electronic counting was found to be accurate, fast and reliable and seems to be the method of choice.

Determination of the light scattering was found to be the more sensitive of the indirect methods, but absorptiometry also yields consistent and reliable results. The accuracy obtained by absorptiometry was found to be independent of the sensitivity of the instrument.

Pre-mating, pregnancy and lactation periods correspond approximately with summer, winter and spring and any effects either of physiological status or nutritional conditions are confounded with the natural rhythm of wool growth. Within this framework, barren ewes produced slightly more wool than in-lamb ewes in winter and considerably more during the period of lactation. Improved nutrition during winter produced no increase in wool production, although it had a marked effect on live-weight maintenance. During lactation, improved nutrition resulted in an increase in wool production. The implications of the nutritional and seasonal rhythm of wool productions are discussed in relation to the adaptation of the breed to its environment.

Ammonium nitrate and ammonium sulphate wore compared as top-dressing applications in thirty-six field experiments on winter wheat and eighty-nine on grassland in various parts of Great Britain in 1956-62. The rates of application were 35-60 lb./acre of nitrogen for winter wheat and 30-100 lb./acre for grassland in one application only.

1. In grass seed crops accurate assessment of the optimum harvest date is made difficult by the lack of knowledge of seed ripeness. In order to define ripeness in physiological terms studies have been initiated the first of which is described in this paper.

2. Samples of Aberystwyth S. 321 perennial ryegrass (Lolium perenne L.), S. 143 cocksfoot (Dactylis glomerata L.), S. 48 and S. 352 timothy varieties (Phleum pratense L.) were taken at 3-day intervals from inflorescence emergence to seed harvest. These were analysed for total 80 % ethanol soluble carbohydrates (TSC) reducing sugars, sucrose and starch, whilst duplicate samples were air-dried for determination of thousand seed weight and percentage germination.

Individual variation in the triple relationship of food intake, live weight and gain was examined in 40 twin calves. Appetite largely determined food intake.

Regression analyses of fortnightly gain on protein and starch equivalent and mean weight are presented. Gain per lb. of P.E. or S.E. showed real but irregular changes from fortnight to fortnight. The food differential between heavier and lighter animals decreased during adaptation to new surroundings and diets.

1. Laboratory experiments compared alternative ways of placing urea for wheat. Urea greatly increased the pH in the seed-row; placed in contact with seeds, it killed many plants, but did not when placed 1 in. to the side of the seed.

2. A combine-drill was modified so that, by simple adjustments, fertilizers could be placed in contact with the seed, or at 1 in. to the side of the seed, or broadcast over the seed-bed.

3. Fifteen experiments with spring barley and one with spring wheat, made from 1960–62, compared yields from urea with yields from ammonium sulphate; calcium nitrate and sodium nitrate were tested in seven and in six experiments, respectively.

Records of fertility and birth weights were examined in eight breeds of goat, indigenous to, or imported into, the subtropical environment of Israel. These included the local Syrian Mountain, Negev and Damascus breeds, and the imported Malta, Appenzeller, Saanen, Fawn German and Anglo- Nubian.

All breeds of goat, local or imported, kidded at the end of winter and in early spring, and all, save the late-maturing Damascus and part of the Anglo- Nubian, kidded for the first time at the age of 1 year.

In imported breeds of goat which acclimatized well in the subtropical environment fertility was not impaired.

1. The percentage of intramuscular fat (and its iodine number), of moisture (fat-free), and of total, myofibrillar, sarcoplasmic, stroma and non-protein nitrogens in lumbar 1. dorsi muscles, and their ultimate pH, fibre diameter, cross-sectional area and weight (both absolutely and as a percentage of the total musculature) were determined at bacon weight in two male and two female litter-mate pigs from each of four pure-bred sows mated with one boar of the same breed. Such data were obtained for pigs of Large White, Landrace and Welsh breeds.

1. The effect of undernutrition on the levels of five enzyme activities has been observed in liver biopsy specimens taken from Suffolk-cross ewes in late pregnancy.

2. There was no significant effect on the levels of three important NADPH2-generating enzymes (i.e. glucose-6-phosphate, 6-phosphogluconate and tsocitrate dehydrogenases) when comparisons were made between groups of animals at the same stage of pregnancy. However, the proportion of very low 6-phosphogluconate dehydrogenase levels assayed in livers of the undernourished ewes was significantly increased as parturition approached.

This study compared ¾ Hereford–¼ Brahman calves with Hereford calves under Imperial Valley conditions. The calves produced in four successive crops were all paternal half sibs.

The cross-bred calves outgained the Hereford calves in the summer both on pasture and in the feedlot; the reverse was true for feedlot gains during the fall and winter, the period of non-stressful weather in the Imperial Valley for British type cattle. Possible causes for the breed by season interaction are discussed.

1. Three species of grass, rye-grass (two varieties, S 23 and S 24) cocksfoot (variety S 37) and timothy (variety S 48) were cut at various stages of maturity, dried and given at several planes of nutrition to sheep in respiration chambers. The detailed chemical composition of the grasses and the apparent digestibility of the constituents were studied.

1. Four cuts of rye.grass S 23, three cuts each of cocksfoot S 37 and timothy S 48 and two cuts of rye-grass S 24 taken at different stages of growth and artificially (heat) dried were fed to mature sheep in a series of experiments designed to measure their value as sources of energy. The four cuts of rye-grass S 23 were each given to three sheep–two of the animals receiving it at five different levels of intake and the third at two levels. The other grasses were each given to four sheep at two levels of intake. The fasting heat productions of the sheep were measured at the beginning and end of the grass feeding periods. Altogether 152 experiments were made.

1. Fourteen muscles from a normal 46-week-old Friesian heifer and from its 40-week-old half-sister, which showed the pronounced muscle hypertrophy of ‘doppelender’ cattle, were analysed for moisture, hydroxyproline, sodium, potassium, total nitrogen, and intramuscular fat: the iodine number of the latter was determined. In four of the muscles sarcoplasmic, myofibrillar and stroma nitrogens were also estimated.

2. Hypertrophy was associated with a mean increase in the percentage of total nitrogen, with markedly lower percentages of hydroxyproline and of intramuscular fat, and with a decreased K/Na ratio.

1. The effect of undernutrition on the levels of plasma glucose, N.E.F.A. and ketone bodies was observed in fourteen Suffolk-cross ewes late in pregnancy by comparing with data obtained on seven control ewes of comparable pregnancy status. An attempt is made to relate these changes with plasma triglyceride levels, liver fat deposition and plasma pigmentation.

2. Evidence is presented which shows that while plasma glucose values are normally distributed, plasma N.E.F.A. levels show a positively skew distribution. This abnormality is corrected by transforming plasma N.E.F.A. values to their logarithms.

1. The metabolizable energies and net energies for fattening and for maintenance of the organic matter of sixteen dried grasses have been related to their apparent digestibilities and to their chemical compositions.