A comparison of eighty-eight steers and heifers, representing equal numbers of Herefords and 3/4 Hereford–1/4 Brahman cross-breds, showed that the cross-bred dressed higher (60·3 % against 58·7 %) and that the cross-bred carcasses had more flank (6·9 % against 5·6 %).

In two out of three palatability experiments, Hereford meat was more tender and, in one experiment, juicier than cross-bred meat. When breeds were compared as to colour of meat, cross-bred was judged darker. Also, heifer meat was judged darker than steer meat.

The kinetics of the isotopic exchange of phosphate ions in soils with and without phosphate added in the laboratory were examined in relation to the amount and origin of the CaCO3 they contained. The isotopic exchange index, ‘Pr/Pe’, and the recovery of added phosphate were inversely proportional to carbonate content in soils containing carbonates of similar geological origin; soils from the Lower Lias showed the biggest change in Pr/Pe with carbonate content.

In soils from the Cretaceous Chalk, the first-order rate of isotopic exchange of the ‘slow’ phosphate fraction was constant. It increased to a larger but constant value in the soils incubated for 6 months after adding phosphate in the laboratory. This rate constant is therefore specific to the calcium phosphates in a group of soils derived from the same calcareous parent material and with similar phosphate manuring.

Two pairs of identical twin steers and six other adult cattle were killed, and their carcasses and tissues examined as necessary to study: (a) the muscle changes resulting from severe weight loss from starvation; (b) the reversability of such changes, as shown at various stages in recovery of the animals' weight.

Decrease in the cross-sectional area of muscle following starvation was associated with reduction in muscle fibre diameter. There was no suggestion of the complete loss of any fibres; thus, with regain of live weight, recovery both of whole-muscle dimensions and muscle fibre diameter, appeared to be complete.

1. Over 3 years, different levels of first winter nutrition were imposed on groups of North and South Country Cheviot ewe hoggs (lambs). In 1956–57, three levels, high, mid and low, were fed indoors. In 1957-58, only two levels, high and mid, were fed indoors, with the low level being represented by hill wintering. In 1958–59, two levels were represented by away wintering and hill wintering.

2. Low-plane feeding was designed to simulate average hill wintering, creating a 10% loss in live weight. Mid-plane feeding was designed to maintain live weight at approximately the same level throughout the winter. High-plane feeding was designed to produce a live-weight gain of 15–20% in 1956–57 and the maximum gain possible in 1957–58.

1. An experiment designed to investigate the effects of heavy dressings of nitrogen, inter-row distance and ‘method’ of sowing on the yield of a lucerne-cocksfoot ley is described and the results discussed.

1. The results are reported of three experiments in which metabolism trials were carried out with milking cows given artificial diets low in magnesium with or without supplementary magnesium.

2. In Exps. 1 and 2, the basal diets provided cither about 13 or about 9 g. of magnesium/day, that is an intake of magnesium similar to that found previously with cut-grass diets (Rook & Balch, 1958) which produced hypomagnesaemia. The ‘availability’ of the magnesium of the artificial diets was, however, of the order of 25–35 % and higher than that of cut-grass diets, and for all cows the artificial diets provided magnesium in excess of requirements, as indicated by the excretion of measurable amounts of magnesium in the urine and the maintenance of normal concentrations of magnesium in the blood serum.

1. Over 3 years, different levels of first winter nutrition created the following live-weight differences between groups of North and South Country Cheviot ewe hoggs at 12 months of age. High plane (H.P.) and mid-plane (M.P.) fed groups born 1956 were 34–35% and 11–13% heavier, respectively, than low plane (L.P.) fed groups, H.P. and M.P. fed groups born 1957 were 47–57% and 18–24% heavier, respectively, than hill-wintered groups. Away wintered groups born 1958 were 9–12% heavier than hill-wintered groups. All group differences were highly significant.

2. From 12 months onwards all groups were run together on the same hill and received similar management. Live weight and live measurement response of the total treatment groups and of the heavy and light hoggs within the groups prior to treatment were studied over the summer after treatment from 12 to 18 months.

It has been shown that lucerne/grass mixtures, especially those containing a high proportion of cocksfoot, can make a valuable contribution to the winter feeding of livestock when the autumn growth is allowed to stand in the field until the winter. For instance, Hughes (1954) showed that it was possible to carry store cattle right through the winter on such herbage with little supplementary feeding. Other experimental work (Barker, Hanley & Ridgman, 1955) has shown that mowing or grazing this autumn growth in September may lead to poorer production in subsequent years than October defoliation. It therefore seemed desirable to determine the effect of date of grazing in the winter on the subsequent yield of a lucerne/grass ley and two experiments for this purpose were carried out at Cambridge from 1953 to 1957.

A summary of the objectives of the present studies has been presented in a previous paper (Lazenby & Rogers, 1962): traditional methods used in the selection of improved grass varieties were reviewed together with a history of varietal assessment and some recent research developments of importance to both grass breeder and grassland agronomist. For full evaluation of selection criteria, the performance of the grass plant should be studied when the variables potentially affecting growth and development are controlled individually and in combination. Results were reported of an experiment designed to study the behaviour of one variety of Lolium perenne, S. 24, grown in different densities and under two moisture règimes. Data presented were total yield per unit area and the botanical components of such yield—number of plants, yield por plant, number and weight of sterile and fertile tillers—together with a statistical appraisal of their interrelationships (Campbell, 1962).