Studies on the adaptation of cattle to the hydrolysis of biuret and on the response of rumen ammonia level to the introduction of 50, 100 or 150 g of feed-grade biuret showed that (1) the rate of ruminal adaptation to the hydrolysis of biuret increased to a maximum effective level of about 350 mg/24 h/100 ml within 10 days when a readily available energy source was fed, (2) a single dose of 50, 100 or 150 g/day of biuret was associated with a prolonged increase of rumen NH3 concentration. The magnitude of the increase was 8–9 mg/100 ml for every 50 g of added biuret, (3) adapted rumens retained their biuretolytic activity for several weeks, and responded to the re-introduction of biuret into the diet by increasing to a near maximum rate within 24–48 h.

There is evidence that a large volume of saliva containing a significant quantity of urea is poured into the rumen, and also that blood urea is diffused into the rumen through the ruminal epithelium (Houpt, 1959; Weston & Hogan, 1967). Egan (1965) reported that, with sheep fed a low protein cereal hay, cellulose digestion in the rumen was increased by abomasal urea infusion. Furthermore, the utilization of recycled urea nitrogen has been investigated in sheep (McIntyre, 1971) and cattle (Vercoe, 1969) using the intraruminal and intravenous infusion techniques. The objective of the present experiment was to determine whether or not the abomasal administration of urea to adult goats fed a low quality hay would influence the nitrogen retention in the body.

The effect of morphactin sprayed at 0, 0·5, 1·0, 1·5 or 2·0 mg/1 on the concentrations of several nutrients in snapdragons (Antirrhinum, majus L.) were studied under glasshouse conditions. Snapdragon plants treated with morphactin increased in K, and Mg but decreased in Ca, Mn, Cu, Fe, and Zn. Action of morphactin and nutrient element relationships are suggested.

There is little information available on the effect of growth rate on muscle distribution in sheep. Although Lohse, Moss & Butterfield (1971) and Lohse (1973) have reported data on muscle distribution of Merino sheep, the growth rates of animals in both these studies were neither controlled nor reported. In another experiment using Merino sheep, Lohse, Pryor & Butterfield (1973) studied the effect of a period of live-weight loss on the relationship of selected muscles to total side muscle during subsequent re-alimentation. They found that the interrupted growth path decreased the proportion of total side muscle formed by the weight of ten muscles which had previously been classified as muscles with a high growth impetus (Lohse, 1971). Data are presented herein for the muscle distribution of sheep grown along three growth paths.

A series of five field trials with cattle was carried out to study the comparative efficiency of utilization of urea and biuret in various maintenance and production nutritional situations. It was shown that in maintenance diets with energy intake above 8 Meal/head/day and where half of the nitrogen requirements of the animals was contributed by one of the two non-protein nitrogen (NPN) sources, biuret was utilized 30% more efficiently than urea. No difference in the degree of utilization of urea or biuret was apparent when the energy was reduced to 6·7 Meal/head/day. On the other hand, a high intake of nitrogen in production rations had a masking effect on the nitrogen contribution of the NPN sources and no significant differences in bodyweight gain were recorded.

In 1945 we reported (Dick & Bull, 1945) the first observations on the effects of molybdenum in the diet of ruminants in limiting the accumulation of copper in their tissues.

Further observations (Dick, 1952) indicated that there was a third factor which materially altered the control by molybdenum of copper accumulation and this factor, present in lucerne hay, was identified as inorganic sulphate (Dick, 1953a). It was also shown that sulphate regulated molybdenum excretion (Dick, 1953b) in the urine and hence the level of molybdenum in circulating blood (Dick, 1953c).

The duration of the breeding season was studied in 33 Suffolk × Galway ewe lambs which had a mean live weight of 45·9 ± 1·4 kg. The mean dates of onset and cessation of oestrous activity were 8 November ± 1·4 days and 12 January ± 2·6 days, respectively. The mean number of heat periods exhibited was 4·37 0·3 and the duration of the breeding season was 81 ± 5·7 days. Only 18·2 % of animals had ≥ 6 heat periods while 45·5 % of animals had ≤ 3 heat periods. The incidence of silent heats was 9·2 %.

Ramularia beticola was prevalent in sugar-beet seed crops in Oxfordshire, Gloucestershire and Lincolnshire in July each year from 1966 to 1971, and defoliated some crops prematurely. It was scarce in Bedfordshire, Huntingdonshire and Essex, and this distribution could not be related to method of growing the crop or density of plant stand. A method is described for assessing leaf spot incidence in beet seed crops after bolting is complete. Fungicide sprays delayed disease development by ca. 2½ weeks.

A total of 580 Friesian cows from four dairy farms selected at random were grouped by teat shape. The incidence of teat cup crawl was recorded at the time of afternoon milking.

Teat cup crawl was significantly higher (27·4%) in the cows with cylindrical shape teats than in cows with funnel shape teats (8·1%).

Milk yield was significantly higher in the cows with funnel shape teats than in cows with cylindrical shape teats. There was significant reduction in milk yield due to teat cup crawl in both groups of cows, the reduction in milk yield being higher in the cows with cylindrical shape teats.

Sulphur deficiency in agricultural crops has never been regarded as a significant problem in Great Britain. However, the widespread use of sulphurfree fertilizers and the introduction of Clean Air Acts together with increased crop yields necessitate a reappraisal of the situation. S.E. Scotland is an area where atmospheric sulphur dioxide levels are considerably lower than most other regions of Britain (Junge, 1972). The concentration of sulphur in precipitation is also relatively low (Stevenson, 1968) and therefore the area is likely to be affected by restricted sulphur supplies. A survey of the sulphur content of soils and corresponding herbage was carried out in this area during 1972 and 1973.

Some misconceptions concerning the application of Griffing's fixed effects model I and mixed effects model B are discussed.

A general model of lysine deposition in cereal grains is presented. By inserting into the model values for the lysine contents of various individual protein fractions, equations have been derived which relate total lysine content to total nitrogen. The equation for barley has been used to predict the likely variation in lysine content for this species and the results are compared with published data.