The great majority of the fibre-type arrays from the backs of eighty Merino lambs were Plain (including Coarse Plain); Plateau and other arrays also occurred. In most samples no medulla could be seen in the pre-natal parts of halo-hairs examined in benzene, but the presence of medullary substance was demonstrated. All HH were shed and apparently replaced by fine fibres. The shape of the tip curls of early CT fibres in some samples altered with age, apparently by 'setting' in a line of yolk. HH grades ranged from I to VII and there were probable strain differences in grade and medullation.

A total of 599 primary and 2595 secondary follicles and their fibres were identified by dissection. Primary follicles contained HH, SS, Sk, or early CT fibres, secondary follicles only CT or Hi. Sickle fibres commonly occupied most of the PL follicles except where the array was Plateau.

1. The cutaneous evaporation rates of three animals of different genotype have been determined under artificial heating in a climate laboratory and during exposure to field conditions. Cutaneous evaporation rates were measured from the backthoracic region using a ventilated capsule technique.

2. In both climate-laboratory studies and field observations cutaneous evaporation showed little relationship with either rectal temperature, respiratory rate or skin temperature.

3. Basal cutaneous evaporation rates in the unheated chamber at 10 a.m. were found to be 40% lower in animals which were housed overnight than in those which entered the chamber following exposure to the early morning sunlight.

Since sugar beet was first grown on farms it has been difficult to establish single seedlings at the required spacing because each seed unit was liable to produce a cluster of seedlings. Plant breeders have introduced varieties with monogerm seed and these were used between 1960 and 1962 to see if they led to any savings in labour with hand and machine thinning and to determine the yields of beet after these treatments. The trials described show that, after machine thinning, predetermined final plant populations with 90% of single seedlings were obtained and, when a herbicide was effective in weed control, the labour requirement was about 5% of that required to hand single a crop from multigerm seed. When singled by hand the monogerm varieties required 90 % of the labour needed to single a multigerm crop but the mean yield per acre of the monogerm varieties used was at least six tons per acre less than that from a commercial variety with multigerm seed.

Large-scale field trials in sugar beet were undertaken between 1961 and 1963 to examine the effects of chemical or mechanical weed control followed by machine thinning in terms of labour economy and yield of the crop. The seedling populations were left untrimmed by hand and, where the weed-control measures were completely effective or nearly so, the crops were left unweeded. Yield samples were taken both by hand and by machine so that the potential yield as well as the likely commercial yield might be determined. The chemical and mechanical methods that were studied saved about 75% of the normal labour demand and gave root yields 91.5% of those following hand work.

1. Three varieties of wheat with white grain and eleven with red grain were examined for a-amylase content of the grain and for resistance to germination in the ear when harvest was delayed.

2. There were large differences between varieties in a-amylase activity. These were due partly to differences in susceptibility to germination in the ear, which always resulted in increased a-amylase activity. There were also large differences between varieties in the a-amylase content of grain which had no visible indication of germination. These differences were not related to susceptibility to germination and were confirmed by a glass-house experiment in which the ears were always dry from emergence to harvest.

1. Three creep feeds containing 14, 18 and 22% crude protein of similar protein quality (as measured by total lysine and total methionine plus cystino content) but with similar levels of other nutrients were given ad libitum to 210 pigs, the progeny of thirty large White sows from 21 to 56 days old.

2. At 21 days old, each litter was reduced to seven piglets by killing one, two or three pigs at random. The whole pig was analysed for protein, ether extract, ash and dry matter.

3. At 56 days, 3 further pigs were killed in each litter and analysed in a similar manner.

1. The intake of grazing wethers was estimated from the in vitro organic matter digestibility of herbage samples collected from sheep with oesophageal fistulae, and total faecal collections.

2. Body water, estimated by isotope dilution, was used to estimate total body energy from estab-lished regressions relating body water to body composition.

3. Total body energy was then related to live weight by regression analysis, giving a value of 2044 kcal. per lb. over the range 68-90 lb. empty body weight. From this it was estimated that 2.41 lb. D.O.M. was required per lb. live-weight gain within this range.

4. Energy for maintenance was calculated by deducting D.O.M. required for gain from D.O.M. intake. These values were related to live weight by regression analysis to give a value of 1.31 lb. D.O.M./day for the maintenance of a 100 lb. sheep.

1. The feed intake of four dry and of twenty pregnant and lactating ewes has been measured. Hay and dried grass cubes alone or in combination were studied on indoor conditions by direct measurement of intake and digestibility while the intake on grazing was measured by the chromic oxide-faecal nitrogen method.

2. For dry sheep, hay (61% O.M. digestibility) limited intake to 780 g. D.O.M./day and with added grass cubes there was a steady increase so that intake with cubes alone (although their apparent O.M. digestibility was 56%) was 1140 g. B.O.M./day. Pregnant ewes showed similar intakes and only with ewes carrying twins and triplets was there a slight decline in intake with advancing pregnancy.

3. The digestibilities of the diets were similar for pregnant, and lactating ewes.

1. Seed plots of five perennial rye-grass varieties, S23, S24, S321, Melle Pasture and an experimental type, Ba6280, were established in 18 in. rows.

2. Each variety was subjected to hard grazing by sheep in September, at ear initiation in spring, and 3 weeks following ear initiation; one series of plots was left ungrazed. Three levels of spring nitrogen, 2, 4 and 6 cwt./acre ‘Nitro-chalk’ (21%N), were applied to subplots.

3. S321 produced significantly more seed heads and Ba6280 gave significantly fewer heads than S23, S24 and Melle. September grazing increased head production by 15%, whilst the two spring grazings gave fewer heads than the ungrazed plots. An increase in the rate of nitrogen application in spring favoured head production.

1. Four mature, fistulated Africander steers were used to study the effect of four different high concentrate diets on the concentration and rate of production of steam V.F.A., and on concentrations of certain constituents found in the blood, rumen digesta and urine of these animals. Each steer received each diet for 4 weeks in a Latin square design and samples of blood, rumen digesta and urine wore taken in the last week of each monthly period. The diets were based on maize grain with a protein-mineral-vitamin A supplement and contained varying proportions of roughage, namely, 0, 10, 20 and 30% of the quantity of concentrate.

1. Growth and development in relation to yield were studied in the two maincrop varieties King Edward and Majestic in 1959 and 1960. The effects of seed size and spacing were also investigated.

2. The total tuber yield, and more particularly the ware yield, of Majestic was greater in both years. This was associated with a longer period of tuber bulking in this variety, due, in 1959, to earlier tuber initiation, and in 1960, to earlier tuber initiation and greater persistence of tuber bulking. Large seed outyielded small seed, although the difference, particularly in ware yield, was relatively small. The seed size effect was associated with a difference in the length of the bulking period, in consequence of a difference in the time of tuber initiation. Total yield tended to increase with decrease in spacing distance; ware yield increased as spacing distance decreased from 24 to 18 in., but there was little difference between 12 and 18 in. spacing. In general, low seed rates performed better than might be expected.

1. A factori al experiment involving four varieties (Ulster Chieftain, Arran Pilot, Craig's Royal and Ulster Torch) and three times of planting (28 March, 13 April and 2 May) was undertaken with a view to investigating the effects on growth development and yield of these factors. Only a limited amount of data was obtained in respect of Craig's Royal, because of its extreme variability in the first two times of planting. In addition, data in respect of King Edward and Majestic planted on the second date in an adjacent experiment are discussed.

2. In general, yields from Ulster Torch were about twice as great as those from Ulster Chieftain, with the other varieties occupying intermediate positions. The total yield of Ulster Chieftain increased with delay in planting, while in Arran Pilot, Craig's Royal and Ulster Torch, yield was greatest at the intermediate planting date, slightly lower than this at the first, and lowest at the third. Ware yield as a proportion of the total increased with delay in planting.

1. The yield and mineral composition of a timothylucerne mixture at different stages of maturity were determined in selected growing periods under the climatic conditions of Northern Ontario.

2. An alteration in temperature from cool to warm or from warm to cool conditions appeared to favour increased forage production, but the rate of increase in dry-matter yields declined more under cooler conditions.

3. Forage yields obtained on a second cutting increased with delayed harvesting of the first cut, and yield reductions from an early harvest were not economically compensated for by increased yields of dry matter of the second cutting.

1. Two series of experiments designed to investigate the effects of delaying planting potato seed tubers after drawing ridges in preparation for planting and of consolidation of soil beneath seed tubers on the growth and yield of potatoes are described and the results discussed.

2. Delayed planting reduced the yield of saleable ware-size (> I¾ in.) tubers in one year by as much as 1.7 + 0.59 tons/acre, but had little effect in the other years, and it is argued that the effect was dependent on the tilth obtained in preparation for planting, the soil moisture content at the time the ridges were drawn, the amount of moisture lost during the delay period, and the rainfall after planting.

1. In each of 6 digestibility trials, comprising a total of 21 measurement periods of 3-4 days, two steers were fed on herbage cut from the top of the sward, two on the remaining bottom growth and two on a mixture of equal parts of these fractions. Within each period the fractions were similar in digestibility although the top growth had a higher content of nitrogen.

2. The trials were divided into three groups, according to time of year, for the purpose of calculating regressions of digestibility on faecal nitrogen concentration. Regressions calculated in the usual manner on a between-period basis (i.e. within animals) had constant terms which differed significantly among animals but not from one fraction of the herbage to another.

Concentrations of rumen volatile fatty acids, ammonium and protein nitrogen and free microbial count in groups of sheep fed fresh herbage have been compared with concentrations in groups supplemented with pure carbohydrates.

Rumen ammonia concentrations in sucrose and cellulose-supplemented sheep tended to be lower before feeding than in sheep fed herbage only, but this difference disappeared after feeding. Ammonia concentrations in sheep supplemented with starch, and those receiving herbage only were similar before feeding, but the rise after feeding was less for the starch-supplemented group. The rise in volatile fatty acids after feeding was greater when part of the herbage was replaced with an equal weight of dry matter of starch, but lower when replaced with ucrose or cellulose.

Observations on the onset of the breeding season in a flock ofSouthdown ewes in subtropical Australia (latitude 27° S.) indicated that the mean date of onset during the years 1962-65 was 3 March, with annual means ranging from 11 February to 17 March. There was evidence that, under some circumstances, ovarian activity may be initiated before the summer solstice.

The onset of the breeding season was later in ewe lambs than in yearling and adult ewes and the mean age at puberty was 239 days.