Effects of treating wheat straw with caustic soda solution and of providing a cottonseed meal supplement were studied with 40 Friesian heifers (280 kg live weight) in individual pens. Responses were measured in terms of food intake, growth rate and food conversion ratio.

Wheat straw was coarsely-milled and fed ad libitum, untreated (U) or alkali-treated (T); both types of straw were supplemented with urea and minerals. Half the animals on each type of straw were fed 500 g cotton-seed meal (C/day.

Straw intake was higher with T than with U (P < 0·01) and unaffected by the cotton-seed meal supplement, being 4·53, 4·71, 6·58 and 6·56 kg/day on treatments U, UC, T and TC respectively. Alkali treatment and the cotton-seed meal supplement improved live-weight change (P < 0·001), being –6, 189, 334 and 495 g/day respectively. In vivo digestible organic matter in the dry matter, calculated from lignin ratios, was 59, 60, 64 and 64 respectively.

Rumen VFA concentrations were significantly higher, molar proportions of acetic acid lower, propionic and n-butyrie acids higher in animals on T than on U. Plasma urea and rumen ammonia concentrations were lower on treatment T than on U.

It was concluded that wheat straw which is coarsely-milled, NaOH-treated and sprayed with urea and minerals provides sufficient nutrients to allow cattle to grow and that additional gain obtained by feeding cotton-seed meal was predictable in terms of its energy contribution to the diet.

Forty pregnant sheep were allocated to four groups and maintained indoors in individual pens on a pelleted diet. During the last 6 weeks of pregnancy and the first 6 weeks of lactation groups were infected daily with 4000 larvae of Ostertagia circumcincta or remained as controls in a cross-over design. Thus groups were either not infected (CC), infected only during pregnancy (IC), during lactation (CI) or during both pregnancy and lactation (II). Food was offered on the basis of body weight at the beginning of pregnancy and lactation. Food intake, body-weight change, faecal egg counts, plasma pepsinogen and milk production were measured weekly, wool growth and fibre diameter during 21-day periods and tensile strength of wool over the whole experimental period.

Eggs were seen in faeces of only three sheep infected during pregnancy, but in all sheep infected during lactation; maximum mean values were 467 ± 144 and 222 ± 58 eggs/g fresh faeces in CI and II sheep, respectively. Pepsinogen concentrations rose after 1 week of infection during pregnancy and lactation; peak values were 868 + 57 and 1104 ± 146 m-u/l, respectively.

Infection reduced food intake by 16% during lactation but had no effect during pregnancy. There were significant interactions between pregnancy and lactational treatments on intake during lactation. Infection during lactation increased bodyweight loss; mean values were 57, 40, 114 and 78 g/day for groups CC, IC, CI and II respectively. Milk production was decreased during weeks 4–6 of lactation, mean values being 1·59 and 1·32 kg/day in control and infected groups, respectively.

Infection reduced wool growth and wool fibre diameter by 20 and 7%, respectively, during the final 3 weeks of infection during lactation. The staple strength of wool grown during the experiment was reduced by 14, 45 and 23% in IC, CI and II groups, respectively. Infection moved the point of greatest wool tenderness from parturition in control sheep to a time during the period of infection, particularly when infection occurred during lactation.

Data collected from 1968 to 1981 were used to study the effects of annual precipitation and its distribution on grain yield of three barley and six wheat varieties from 19–47 environments.

The percentage of the variation in grain yield explained by annual precipitation varied with variety and species (5–31% in barley and 31–79% in wheat). The distribution of precipitation was the major factor affecting grain yield, although it varied with variety, and explained 72–92% of the variation in barley and from 75 to 98% in wheat.

Only 33 of the 144 simple correlation coefficients between grain yield and precipitation during each of the 16 fortnightly periods were significant. The expected average effect on yield due to additional precipitation above the mean showed positive effects in barley during the presowing and heading to flowering periods; no consistent trend was found in the wheat.

Improved agronomic practices could alleviate the adverse effects of the low and unevenly distributed precipitation by reducing losses and increasing storage of water in the soil. Breeding could contribute greatly towards high and stable yields in drylands.

Thiaminases from different sources exhibit varied responses to change in pH and to differing activators, cosubstrates and inhibitors. These properties are used in an attempt to characterize the extracellular thiaminases of 17 strains of Bacillus spp. isolated from the rumen contents of animals affected with cerebrocortical necrosis and to compare these with the endogenous thiaminase present in the rumen content of such animals and with other known thiaminase-producing bacteria. Statistical analysis of the results obtained using different activators classified the isolates into two main groups corresponding to the presence of thiaminase I or thiaminase II. The pH characteristics of the rumen content enzyme differed significantly from any of the bacterial isolates examined.

A study using 1150 lambs to estimate genetic and phenotypic parameters of some weight and fleece traits was carried out on coarse-wool Barki sheep. The weight traits were birth, weaning, yearling weights and daily gains whereas fleece traits included kemp score, staple length and greasy-fleece weight.

Heritability estimates of weight traits were within the range 0·25–0·30. Those of fleece traits were 0·16, 0·21 and 0·43. The repeatability estimates of fleece traits were 0·18, 0·38 and 0·53 for staple length, greasy-fleece weight and kemp score respectively.

Phenotypic correlations between body weight and fleece traits were mostly positive. Genetic correlations between greasy-fleece weight and body weights were mostly positive and of medium values. Those between kemp score and body weights were mostly negative, ranging from medium-high to high.

Observations were made in three successive years on the dentition of Scottish Blackface ewes of 1½–4½ years old in a large hill flock in southern Scotland.

The number of permanent incisor teeth was not a reliable guide to age, since at each age there was variation about the modal number. The length of the central permanent incisors increased slightly with age, and associated with this there was a slight forward movement in the position at which these teeth occluded with the dental pad. The modal position was 1 mm behind the anterior point of the dental pad of gum. About 1·5 % of the observations had bite positions deviating by 5 mm or more from the mode.

Keeping the females during their first winter on low-ground pasture instead of the hill led to earlier eruption and slightly longer central incisors, but had little effect on bite position.

The heritability of the number of incisors present at any one age was estimated to be 0·39 ± 0·11 by paternal half-sib correlation and 0·80 ± 0·27 by daughter-dam regression. Estimates of h2 for incisor length were less than half these values and those for the measure of bite position were very small and not significantly different from zero.

For the ages up to 3½ years old, there were low but statistically significant correlations of number of incisors with ewe live weight (0·1–0·2) and fleece weight (around 0·1), incisor length with fleece weight (around 0·1) and at 1½ years old only between the bite measure and both weights (0·1). Weight of lamb weaned by the ewe was uncorrelated with these dental traits.

It is concluded that in this flock, culling on the dental characters studied would not have improved performance, and selection would not change the position of the bite.

Phosphates and nitrate were added to the gel used for fluid drilling without affecting its properties as a seed carrier. The addition of monosodium phosphate promoted early seedling growth but at concentrations higher than 30 g/1 it became phytotoxic. Nitrate added to the gel reduced plant growth and decreased the number of seedlings emerging. Ammonium phosphate was found to be an effective addition to the gel and could be used in the form of a proprietary liquid ammonium polyphosphate fertilizer. The earlier emergence of fluid-drilled germinating seeds and the enhanced growth brought about by phosphate addition to the gel increased plant size compared with that of the dryseeded controls. The results are discussed in relation to the early production of marketable-size carrots.

A study was carried out for 2 years in the arid zone of the northern region of the Sudan to investigate the effects of watering intervals on flowering, growth, yield and yield components of three groundnut cultivars. The variation in air temperature prevailing above the canopy through frequent and extended watering intervals affected the periodicity of flowering. MH 383 gave the highest pod yield and it was drought tolerant compared with Ashford and Turkish cultivars. Pod losses were smaller with longer watering intervals. Number of pods per plant was the yield component most affected by watering. Leaf area index increased with frequent watering and reached a value of 5·8. Net assimilation rate decreased at first, but later increased with the pegging of gynophores.

Phosphorus requirements for maintenance and growth were assessed by giving to growing lambs and non-pregnant ewes diets low in P and to growing lambs a diet containing the quantity of P recommended by the Agricultural Research Council (1980).

Seven 14-week-old lambs were given ad libitum a pelleted diet containing 1·88 (LP) or 2·75 (NP) g P/kg D. M. for 13 weeks. There was no effect of P intake on feed intake or growth during the first 8 weeks when the P intake of the LP groups was 1·07 of Agricultural Research Council (1980) requirements. During the last 5 weeks the P intake of the LP group was only 0·87 of Agricultural Research Council (1980) requirements and growth and feed intake were higher in the male but not female lambs in the NP group. From the 3rd week the plasma concentration of P was significantly lower (P <0·001) in the LP group. Mineralization of selected bones was less in the LP group.

After 14 weeks on the diet, balance trials with 32 P were carried out on the lambs from each dietary group. P intakes ranged from 1 to 3 g/day. An additional balance trial was undertaken with eight 2-year-old female sheep consuming a hay diet (1·5 g P/day).

The endogenous faecal excretion of P by the growing lambs on the LP diet and ewes was 12·2 ± 0·8 and 12·7 ± 1·00 mg/kg live weight/day respectively, very close to the value (12 mg/kg live weight/day) adopted by the Agricultural Research Council (1980). The absorbability of the P in the concentrate and hay diets was 0.71 ±0·267 and 0·74 ± 0·0218 respectively, the former agreeing with and the latter higher than the corresponding value for Agricultural Research Council (1980).

Protein synthesis was measured in non-breeding sheep and in sheep at two stages of lactation by constant intravenous infusion of [3H] tyrosine. In early lactation plasma tyrosine flux was 50% higher than in non-breeding ewes and it remained somewhat higher in late lactation. Estimates of protein synthesis per day in the whole body showed similar changes.

In early lactation the weights of the longissimus dorsi and semitendinosus muscles were respectively 37 and 28% lower than those for non-breeding ewes, but both muscles regained weight in late lactation. There were corresponding changes in the total protein, total RNA and total lipid contents of both muscles.

The fractional rates of protein synthesis in the longissimus dorsi and the semitendinosus were between 2 and 3% per day, but it was higher in heart muscle. At both stages of lactation the synthesis rate in the longissimus dorsi was similar to that in nonbreeding ewes, but in the semitendinosus and in the heart synthesis rates were lower in lactating animals. In both skeletal muscles the total protein synthesized per day was lower in early lactation because their total protein contents were lower at this time. It is concluded that the maternal skeletal muscles may undergo a controlled depletion during lactation.

The inheritance of resistance to Globodera pallida was studied in seedling progenies derived from Solanum tuberosum ssp. andigena CPC 2802 (H3) and S. vernei and compared with resistance to G. rostochiensis derived from S. tuberosum ssp. andigena CPC 1673(H1). The resistance of CPC 2802 was originally thought to be due to a major gene (H3), but results presented here demonstrate that it and that derived from S. vernei are inherited in a similar manner quite distinct from the major gene inheritance from CPC 1673 (HI). It is concluded that the resistances derived from CPC 2802 and S. vernei are both polygenic in nature. These findings are discussed in relation to breeding policy and screening methods.

Twenty-four sows and their 4- to 7-day-old litters were observed in batches of four for approximately 2h to ascertain piglet teat preferences and timings of suckling periods. In each batch, two litters were then selected to have two piglets exchanged between them while the other two remained intact as controls. In the subsequent 3 h, sows with fostered piglets initiated significantly more suckling periods than controls; but many were disturbed at an early stage and only 35% of such periods resulted in milk letdown (compared with 93% in controls). Many sows displayed aggression specifically towards fostered piglets. Many fostered piglets showed signs of distress and attempted to escape. Fostered piglets were significantly more likely to take 10 sec or more from the start of suckling to approach the udder, and less likely to be sucking at milk letdown. Many of these effects were greater when piglets had to compete with a resident piglet with the same teat preference and all were still evident in the third of the three observation hours.

Very experienced livestock judges and three ultrasonic machines were compared for accuracy in predicting carcass composition.

Sixty-four steers of mixed breed were visually scored for fatness and meat yield by seven judges. Subcutaneous fat depths over the eye muscle at the 13th rib were measured with three different ultrasonic devices prior to slaughter. There was little difference between the ultrasonic machines and the best visual estimates of fatness for predicting weight of commercial trimmed or total dissected fat. Visual estimates of meat yield were not as accurate as the judges' fat scores for predicting carcass composition.

Subcutaneous fat depths measured by ultrasonics were shown to be as well related to carcass composition as the best judge's fat scores.

A dynamic model of rumen processes is constructed. The nine state variables considered are: rumen metabolic volume, non-rumen-degradable β-hexose, rumen-degradable β-hexose, α-hexose, water-soluble carbohydrates, non-protein nitrogen, rumendegradable protein and non-rumen-degradable protein. The dietary and salivary inputs to the rumen may be continuous, or pulsed. Rumen outflow given by the model is compared with data on sheep fed with different diets. Reasonable agreement is obtained when the model is run in the continuous mode, but there are considerable discrepancies between the experimental data and the pulsed model.

A re-examination of the results from 374 sheep used in previovis studies of calcium metabolism show there is a highly significant linear relationship between endogenous faecal loss of Oa and food intake, endogenous loss increasing by about 0·64 mg/day/kg body weight for each 1 g/day/kg body weight increase in food intake. This loss was unaltered by Ca intake or by pregnancy and lactation but was slightly higher in young animals than in adult animals given the same Ca intake on a body-weight basis. It is suggested that a variable factor for endogenous Ca loss, based upon some measure of level of feeding, should be introduced into rationing schemes.

A survey on 17 beef suckler herds in the north-east of Scotland showed that there was no relationship between herd serum copper concentration (range 0·16–0·92 μg/ml) measured within 1 month of mating and the conception rate of the herd calculated from the pattern of calving to that mating. Cows treated with 100 mg copper before mating, in trials on four farms with low copper status and involving 221 animals, did not have an improved conception rate compared with control animals on the same farm. Copper per sewould therefore not appear to be a major factor in determining the fertility of beef suckler herds.

Twenty-eight centres participated in two co-ordinated trials to obtain further evidence on responses of growing pigs (20–86 kg) to different levels of copper sulphate (CuSO4. 5H2O) supplementation, and on effect of lowering the amount of copper in the ‘finishing’ diet. The levels of copper supplied were 141, 232 and 276 mg Cu/kg diet in the ‘starting’ diet in trial 1 and 125, 200 and 250 in the ‘starting’ diets continuing or reducing to 125 mg Cu/kg diet in the ‘finishing’ diets in trial 2. The results varied to such an extent that no definite conclusion could be drawn, but there was a tendency to support rather than dispute the accumulated evidence in world literature that the most effective levels of copper supplementation are from 200 to 250 mg/kg diet throughout the growing period.

Forty-five normal lactating buffaloes from Punjab Agricultural University, Dairy Farm herd, were used for this study and were divided into three groups as group I (control), group II (showers) and group III (wallowing). The study was conducted from May to September in two periods, May–June as period I (hot and dry) and July–September as period II (hot and humid). Potassium concentration was estimated on a flame photometer. The overall average values (m-equiv/l) were found to be lowest in the control group (21·5 ± 1·27) and highest in wallowing (24·3 ± 1·20). Lower values were obtained in period I than in period II. Different correlations of potassium concentration in red blood corpuscles with climatic variables are discussed. Erythrocyte potassium concentration may act as an index of heat tolerance in buffaloes.

Experiments with spring barley at Saxmundham, in each year from 1975 to 1978, compared two varieties (Julia v Wing), two amounts of granular N-fertilizer (50 v 100kg N/ha) and two times of applying it (seed bed v top-dressing), a liquid N-fertilizer spray (0 v 50 kg N/ha), mildew fungicides (with and without) and a rust fungicide (with and without), in factorial combination (26).

Leaf diseases were assessed and grain weighed and analysed for % N each year. Thousand-grain weights were measured in 1977 and 1978.

Yields were small in 1975 and 1976 because little rain fell in summer, but larger in 1977 and 1978, years with average rainfall.

Mildew was most severe in 1975 and least in 1978, brown rust most severe in 1975 and 1978 and practically absent in 1976. Granular N-fertilizer was best applied to the seed bed in all years, whether or not leaf diseases were controlled. Late sprays of liquid N-fertilizer increased yield less than equivalent amounts of seed-bed N, but increased % N in grain more. However, because they also decreased grain size, less of the N applied as a liquid was recovered by grain than was recovered from granules given earlier. The mildew fungicides increased yields by ca. 0·25 t/ha in 1975 and 1977, but decreased them in 1976. They had little or no effect on % N in grain, but increased grain size in 1977. The rust fungicide, benodanil, increased grain yields each year and especially in 1978 (0·37 t/ha). It had no effect on grain % N, but consistently increased grain size and so enhanced grain yield and N uptake.

The effect of implantation of trenbolone acetate and oestradiol into lambs soon after birth on the metabolism of alanine in the presence and absence of propionate has been studied in isolated perfused livers obtained from suckling and from ruminating lambs. The effect of butyrate on the metabolism of alanine in the presence and absence of propionate has been studied in livers obtained from the steroid implanted lambs.

Glucose production in the presence of alanine by livers from non-implanted suckling lambs was more than 3 times greater than that by livers from non-implanted ruminating lambs. Steroid implantation did not affect alanine uptake by the livers but metabolism within the livers was altered. Significant interactions were observed between the age of the lambs and whether or not they had been implanted with steroids for the rates of net glucose production in the absence of propionate (P < 0·01) and for the rates of release of urea by the livers in the presence of (P < 0·05) and absence of propionate (P < 0–01).

Propionate did not affect alanine uptake by livers obtained from either suckling or ruminating lambs, but there was a significant interaction (P < 0·05) between the age of the lambs and whether or not butyrate was infused, indicating that butyrate depressed alanine uptake by livers obtained from implanted ruminating lambs perfused in the absence of propionate. Despite this depression of alanine uptake the rates of net glucose production and urea production were unchanged, indicating that butyrate modified the metabolism of alanine in the livers of implanted ruminating lambs in that a greater proportion of the alanine carbon taken up must have been converted to glucose. Butyrate stimulated net glucose production in the presence of propionate and alanine in livers from suckling (P < 0·05) but not ruminating lambs. Butyrate was ketogenic and the release of 3-hydroxybutyrate accounted for 45 and 30% of the carbon taken up as butyrate by livers from suckling and ruminating lambs respectively perfused in the absence of propionate. Propionate was antiketogenic. Propionate inhibited urea formation from alanine by livers from implanted suckling (P < 0·05) and implanted ruminating (P < 0·001) lambs. This effect was diminished by the presence of butyrate. Lactate was released in the presence of propionate and accounted for approximately 12–5% of the carbon taken up as propionate.

It may be concluded that implantation of lambs with anabolic steroids maintains hepatic gluconeogenesis from alanine at rates more closely resembling those found in younger suckling lambs. The effects of the volatile fatty acids on alanine metabolism are likely to be of physiological significance when sheep are fed diets which result in a markedly altered pattern of rumen fermentation.