1. A group of six lactating ewes, rotationally grazed a low-nitrogen treated plot (40 lb nitrogen applied in early March) and a similar group a highnitrogen treated plot (1001b nitrogen applied in early March and 60 lb at monthly intervals thereafter, all as Nitro-chalk) from mid-April to early July, and the concentrations of serum magnesium and calcium along with food intake and milk yields of the ewes were studied.

1. Herbage harvested from 17 April to 3 July, at approximately 3 weeks after defoliation, from a succession of high-nitrogen paddocks (1001b. nitrogen in March and 60 lb. nitrogen at monthly intervals thereafter, all as Nitro-chalk) and from corresponding low-nitrogen paddocks (40 lb. nitrogen as Nitro-chalk in early March only) was fed to two wethers, and the availability of magnesium and calcium were measured in a series of balance trials.

Analyses of yields for 12 sets of test-crosses of inbred lines of winter beans are given.

Carcass weight, bone weight, bone length, and bone weight per unit length were examined as possible indices of the weight of muscular tissue in lamb and mutton carcasses.

The data from 555 normal pregnancies during a period of 6 years in a flock of Scottish Half bred ewes were examined for relationships between gestation length and litter size, birth weight, sex, and age of ewe. A' comparison of Scottish Half bred gestation lengths was also made with those of Specklefaced Welsh ewes.

The absorption of 28Mg from the gastro-intestinal tract of sheep has been measured on both hay and spring grass diets, each of which supplied approximately the same amount of magnesium daily. A hypomagnesaemic response to the latter diet was accompanied by a reduction in the efficiency of magnesium absorption and was not merely due to the presence of bound magnesium in spring grass.

Magnesium deficiency symptoms in sugar beet have increased recently. Seventeen factorial fertilizer trials, on fields where magnesium deficiency was expected, gave a mean response of 3.7 cwt/ acre of sugar to 5 cwt/acre of kieserite. Magnesium slightly increased the yield of tops, and either did not affect, or improved, juice purity and sugar percentage; it decreased yield on only one field.

The indirect estimation of intake of grazing animals is usually made from faecal index regression equations. Faecal nitrogen content or total faecal nitrogen are widely used to estimate intake. The most precise estimate of intake is obtained for a specific herbage (e.g. Phalaris) and condition (e.g. green, dry, etc,). Lambourne & Reardon (1963) found that the standard error of an estimate of the intake of a single animal, from a general regression equation, was 23%. Arnold & Dudzinski (1963) showed that the precision of estimates from general equations is improved by multiple regression including terms for faecal output. However, as regression relations are obtained from pen-feeding trials and are applied to field grazing, the following discrepancies axe likely to occur. We may have to extrapolate from low intakes in pens to higher intakes in the field; in addition selective grazing in the field can introduce a serious bias. To overcome the latter, when we are not sure about the exact condition of the forage eaten, as when green and dry herbage are both present, an average regression over two or more conditions has to be used. Naturally the precision of estimate then is much lower, because of the uncertainty as to what the animals are in fact selecting.

1. The mean iodine values and melting points of the fats from 16-month-old Romney wethers grazed on different pasture species including: perennial ryegrass or short-rotation ryegrass alone or admixed with white clover were as follows perinephric, i.v. 41.3-46.1, M.P. 47.7-49.4°C; omental, i.v. 43.2-47.4, M.P. 46.6-47.4°C; subcutaneous, i.v. 46.4-50.4, M.P. 44.2-46.0°C and 1. dorsi muscle, i.v. 57.5-60.3, M.P. 39.7-41.5°C. The iodine values were several units higher than those obtained previously (Shorland etal. 1962) for corresponding fats from mature Romney ewes.

Two degrees of compaction, 'heavy' with a flattyred vehicle wheel, and 'light' with a ring roller, were given to the seed beds after sowing barley and globe beet on three contrasted soils. Changes in pore space of the soils and the responses of the crop to the changed physical properties were measured. The sites used were: Barnfield at Rothamsted, a heavy clay loam long under arable cultivation and having little organic matter; Pastures Field at Rothamsted, a field of silty clay loam ploughed after an 8-year ley; Stackyard field at Woburn, a light sandy loam long in arable cultivation and containing little organic matter.

An experiment was conducted to compare the relative performance of fourteen populations of Italian ryegrass at sward and three non-sward densities. The non-sward densities were 3 in sown rows, 6 in square planting and 3 in square planting.Seven of the populations were commercial cultivars and seven were 50:50 mixtures of two cultivars.

1. A colony of honey-bees was put beside a 1/36 acre plot of male-sterile and male-fertile spring beans in 1965, but very little bean pollen was collected and no honey-bees were seen pollinating either male-fertile or male-sterile flowers.

1. The effects of changing the closeness of cutting at different times in the season on the yields and quality of herbage were studied for 3 years on a perennial ryegrass-white clover sward.

The rotation responses of unfertilized cotton were investigated using data obtained over a 28-year period from an experiment comparing ten rotations in various combinations of cotton with fallow and an alternating crop of dura (a sorghum millet) and lubia (a legume).

Experiments were carried out in dry, nonpregnant cows by varying dietary concentrations of calcium and phosphorus. Calcium and phosphorus absorption were measured by balance and isotope techniques. It was found that absorption of calcium or phosphorus increased when the dietary intake of the element increased, but only for a few days.

1. In a 3 x 2 x 2 factorial experiment forty-eight Large White type pigs (twenty-four hogs and twenty-four gilts) were individually and restrictedly fed, at either a 3:1 or 2:1 ratio of water to dry food, a diet containing 70% wheat prepared in either crimped, rolled or ground form. A further six litter-mate Large White type hog pigs were used in digestibility and nitrogen retention studies.

1. Over 3 years monogerm sugar beet seed spacings of up to 5 in apart produced sufficient plants to form an adequate plant population for maximum yields. In the first two seasons the braird from a 5 in seed spacing did not need to be thinned; but in the third it contained over 50,000 seedlings per acre and so had to be reduced by thinning to approximately 30,000 per acre.

1. The rate and pattern of water extraction from the soil by grass swards were examined.

2. Under a continued drought water was removed progressively down the soil profile. The rate of removal of water was similar from all horizons to a depth of over 3 ft in these conditions.

1. From 1960 to 1964 an experiment at Woburn, Bedfordshire, measured yields and the amounts of N, P and K removed by five arable crops (barley, grass-clover ley, potatoes, oats and sugar beet) and by a long ley; each was manured with all combinations of N, P and K fertilizers and with farmyard manure (D) and with both fertilizers and farmyard manure (DN1PK and DN2PK).

Various carcass measurements were obtained from 216 Hereford steers and evaluated in an attempt to find traits or combinations of traits which accurately estimate carcass composition. Carcass weight and trimmed retail cuts from the round proved to be the best single estimators of kilograms of retail cuts. Prediction equations were developed using carcass weight, trimmed retail cuts from the round, longissimus dorsi area, measures of fat thickness at the 12th rib, untrimmed round weight and weight of kidney, heart and pelvic fat in various combinations. Eighty-four to 94 % of the total variation in actual kilograms of retail cuts could be accounted for by using these equations.