Two groups of five and six ewes were studied through two separate winters by monthly wool and skin samples in an attempt to follow the changes leading up to fleece casting, which occurred extensively in only two animals.

Although no fleece break was observed, the animals that cast most showed the biggest decrease in fibre diameter. They also had a decrease in staple length where the wool was not cast.

Follicle inactivity increased during the observations reaching a peak at the end of the winter, and the animals that cast most had most follicle inactivity. It is concluded that casting was associated not with fleece break but with increased follicle inactivity coupled with premature release of the fibres from the follicles.

1. The extraction of leaf protein from autumn-grown perennial ryegrass is described.

2. The composition, chemical analysis and rate of feeding of two mashes compared in the experiment are given. The same basal cereal mixture was used in each ration, with fish meal added to one and leaf protein and minerals to the other.

3. Two groups of three birds were kept on each ration. Nine-month-old Brown Leghorn × Light Sussex pullets, in full lay, were used.

4. The birds were given a 6 weeks' preliminary period on a uniform ration to accustom them to the experimental conditions and to ascertain their potential egg production.

5. In a 10-week feeding trial no difference occurred in the number of eggs or the total weight of eggs laid by the birds fed on either ration.

6. A small loss of body weight occurred in the birds in both treatments.

7. Egg-quality determinations indicated that the specific gravity of the eggs was not affected by the differential feeding. Yolk height was greater in eggs from birds fed on the ration containing fish meal. This ration also resulted in a higher number of eggs with rough shells and containing a higher content of foreign bodies.

8. The eggs from both treatments had low ‘Yolk-colour indices’, showing that the leaf xanthophylls were not present in quantities in the leaf-protein extract.

The study reported examined the physiological changes between two groups of 6 Friesian-cross cows in mid-lactation; one group grazed outdoors without shade, the second group was housed indoors in an open-sided barn and fed cut-and-carry forage from the grazing area. All cows were machine-milked at 05.00 and 15.30 h daily. At 14.00 h dry bulb temperatures averaged 29·5 °C outdoors and 29·0 °C indoors whilst black globe temperatures were 36·2 and 29·5 °C respectively. Relative humidity averaged 76% outdoors and 72% indoors, and the temperature-humidity indices were 79·1 and 78·3, respectively. Cows in the outdoor group had higher rectal temperatures (40·4 v. 39·0 °C; P<0·01), respiratory rates (87·9 v. 62·9 breaths/min; P<0·01) and skin temperatures (41·2 v. 38·2 °C; P<0·01) than those indoors, but lower haematocrit (26·2 v. 34·9%; P<0·01) and haemoglobin levels (10·4 v. 13·2 g/100 ml; P<0·01). Cows in the outdoor group had a higher sweating rate than those indoors (559·7 v. 68·6 g/(m2×h); P<0·01), largely due to a high radiant heat load (as indicated by slightly higher black globe readings). The results of the current study show that the barn used in this study was effective in protecting cows from solar heat. Further field studies to determine the effectiveness of lower cost strategies to reduce heat stress, including showers and shade that can be accessed by grazing cows, are needed.

Substrate and nitrogen metabolism of ruminant muscle was studied in vitro using a perfused sheep hemidiaphragm preparation. Glucose, acetate, propionate and butyrate were taken up by the perfused muscle at a constant rate over 2 h. Rate of acetoacetate uptake declined over the perfusion period. Net production of 3-hydroxybutyrate over the perfusion period was observed.

Release of alanine and glycine by the perfused muscle could not be accounted for by protein breakdown, implicating muscle as a site of synthesis of these amino acids. The perfused muscle metabolized aspartate and arginine to a considerable extent, but the branched-chain amino acids only to a small extent. Only a small proportion, approximately 5%, of the alanine produced by the perfused muscle was derived from glucose.

In the presence of amino acids, at twice the concentration found in plasma, and insulin, some amino acids showed a net uptake by the diaphragm but when cysteine was omitted from the perfusate, all amino acids with the exception of arginine showed a net output. Evidence was obtained that protein synthesis was reduced in the absence of cysteine. The output of Nτ methylhistidine by the preparation was much higher than could be accounted for by estimates of protein breakdown using isotope dilution techniques. These data are, however, consistent with the view that Nτ methylhistidine is not a good index of muscle protein breakdown in sheep.

The influence of four seeding times on herbage dry matter (DM) yields and clover content of white clover (Trifolium repens L.)/orchardgrass (Dactylis glomerata L.) mixtures was evaluated at Truro, Nova Scotia and Charlottetown, Prince Edward Island from 1985 to 1988. Sacramento, Sonja and Milkanova white clover/orchardgrass mixtures were assessed under simulated grazing (four or five harvests per year) over two production years at each location.

Delaying seeding from May to August reduced total herbage DM yields significantly in the first production year, from 8·1 to 3·3 t/ha in Truro and from 11·0 to 7·2 t/ha in Charlottetown. Late seeding significantly reduced clover content in the herbage of the first two harvests in the first production year but, by the mid to late-season harvests, white clover content had increased to levels similar to those of the May seeding. Estimated white clover DM yields were highest in June, and dropped in the second production year at both locations. Sonja and Milkanova white clovers consistently outyielded Sacramento in herbage DM yields and clover content in both locations irrespective of seeding dates.

Rape (Brassica campestris L.) is well adapted to the Bangladesh climate and is an important oil crop of the northern part of Bangladesh. It requires a shorter growing season than any other crop of this kind but is less resistant to drought, which causes considerable damage to the crop by reducing total green area during late December and January and results in a poor yield. Considerable increase of rape-seed production will be possible through the elimination of drought by irrigation, the right supply of nutrients and application of proper cultural practices. We report here on studies of the effect of fertilizer under irrigated and non-irrigated conditions on the seed yield, oil content and some seed yield associated characters of rape and the importance of irrigation in rape cultivation in Bangladesh.

In the Sudano-Sahelian zone of West Africa there is potential for groundnut (Arachis hypogaea L.) to be grown as a dry-season crop where irrigation is available. However, there are substantial variations in the temperatures during the post-rainy season that can be expected to influence growth and yield. An experiment at the ICRISAT Sahelian Centre was done in order to study the effect of sowing date on phenology, yield and the processes of yield determination for four groundnut cultivars under irrigation in the dry seasons of 1990/91 and 1991/92. Starting on 15 November, eight sowing dates at 2-weekly intervals were tested. Sowing date significantly affected phenology (time to emergence, flowering and maturity) with groundnut sown in November/December taking the longest time to reach these phenological stages. November and December sowings gave the highest pod yield within each year, despite the lowest crop growth rates (B), and yield declined progressively as sowing occurred later (50% decrease by March) despite increasing B. The observed responses appear to have been due to the effect of temperature differences during the pod-filling phase on partitioning. Partitioning (p) to pods was optimized at c. 30 C, with some indication of cultivar differences in partitioning response to temperature. Across all the environments, cultivars displayed substantial differences in yield stability. When sown late, yields were low and lines with high partitioning were the best. When sown early in the post-rainy season, cultivars with a high B value were the better choices. Plant habit differences and B suggest that radiation interception was a limitation to yield, particularly when the crops were sown in the cool months of the year. However, haulm yield and crop growth rates were not consistently affected by sowing date across the years, and cultivars demonstrated different degrees of stability for B. It is concluded that where pod has a price advantage over fodder, irrigated groundnut for the dry season should be sown in November to allow the crop to develop under the relatively cool temperatures that maximize pod yield. Further agronomic research is suggested to maximize B for individual cultivars for given sowing dates.

Work in controlled conditions (Cooper, 1964; østgård & Eagles, 1971) has indicated that, under short photoperiods and low temperatures, Scandinavian grass varieties tend to grow more slowly than those from lower latitudes, and are, therefore, more resistant to cold and freezing stresses. This has been confirmed in field experiments (Håbjørg, 1979). These grasses would therefore be expected to cease growth earlier in the autumn when grown in the British Isles. However, this mechanism does not appear to operate under lengthening days; indeed, there is evidence to suggest that their growth is particularly stimulated by the combination of cool temperatures and long days (Cooper, 1964; Hay & Heide, 1983, 1984). This raises the possibility that varieties from Norway and Sweden could produce more dry matter than grasses of more southern provenance in the spring in upland areas, when low temperatures are associated with rapidly lengthening photoperiod (12·5–15 h) and moderate to high levels of irradiance (> 200 W/m2) (Hay, 1985).

The research was carried out at the animal experimental station of the National Agricultural Research Institute of the French West Indies (Guadeloupe) in 1999. Effects on intake and digestion by sheep of addition of Gliricidia leaves to a diet of 35-day-old Digitaria decumbens (pangola) hay, have been studied. In a first trial (a 4×4 Latin Square design), four rams were fed four diets: hay (G0); hay plus 1300 g of Gliricidia (G0·25), hay plus 2600 g of Gliricidia (G0·50), hay plus 3900 g of Gliricidia (G0·75). Total dry matter intake (DM), hay and Gliricidia intake, total tract and rumen digestibility of DM and its components, microbial and total nitrogen flows were estimated. In a second trial (a 2×2 Latin Square design), the same animals received hay (G0) or Gliricidia (G1·00) ad libitum to estimate the rumen turnover of pangola and Gliricidia fibrous particle. Neutral detergent fibre and crude protein content of the Digitaria decumbens hay and Gliricidia were 746 and 51, 458 and 198 g/kg dry matter respectively. Total dry matter intake (DM) varied from 42·7 to 76 g DM/kg LW0·75 from G0 to G0·75. The rate of substitution of pangola by Gliricidia (decrease of pangola intake for one unit Gliricidia consumed) was 233 g/kg. The digestibility of cell-wall linearly decreased with increasing level of Gliricidia in the diet. No digestive interaction was registered in the mixed diets. The total nitrogen and microbial nitrogen duodenal flows increased with the level of Gliricidia in the diet. The rumen turnover of fibrous particles of Gliricidia was double that of pangola. The incorporation of Gliricidia in diets increases their nutritive value by higher intake and intestinal nitrogen duodenal flows, but no positive digestive interaction was observed between pangola hay and Gliricidia leaves.

Azospirillum brasilense was treated with nitrosoguanidine and five antibiotic-resistant mutant strains isolated. Variations in growth, N2-fixation, ultraviolet-dark survival and level of antibiotic resistance were found between the mutant strains. Mutant strains STR 112 and KR 2051 showed maximum nitrogenase activity, glutamine synthetase activity and hydrogenase activity (H2 uptake) at 32 °C and 40 °C respectively. Inoculation of cheena genotypes with A. brasilense and its mutants led to significant increase in associative nitrogen fixation, dry weight of roots and grain yield compared with the uninoculated control, with significant strains × genotypes interactions in calcareous soil. It was also noted that under laboratory conditions Azospirillum inoculation may have produced its response by hormonal means and/or associative N2-fixation.

The growth, development and yield of three soya-bean varieties, Hampton, Kent and CNS, were compared in two field experiments during 1974 and 1975 in Nigeria. The results, which were similar for both years, showed that the varieties differed significantly in the order Hampton > Kent > CNS for the development per plant of leaf area, number of branches, number of nodes, number of mature pods, number of seeds, pod and seed yields, husk dry weight and seed to husk ratio as well as seed yield per hectare. The differences between the varieties in seed yield could be genetic but leaf area development seems important as well. Hampton therefore appears to have the potential for high seed yield under the prevailing local conditions.

A total of 76 cows in seven, trials over a 3-year period were given a supplement of 53 g magnesiiun phosphate (supplying 11 g Mg and 10 g P/day) in 1 kg of concentrate for 21 days after starting to graze spring pasture. In contrast with 79 comparable cows given no supplement, there were significant improvements in the concentrations of magnesium and phosphorus in the blood of the cows, and significant reductions in the incidence of individual cows with low values.

Two calves (Zebu × Australian Illawara Shorthorn and Shorthorn) of about 7–8 months of age were exposed to controlled atmospheric conditions. Cutaneous evaporation from the shoulder and belly areas of these calves was measured by the capsule method. Density of the sweat glands in the shoulder and belly areas of these calves was measured, using a biopsy punch. Density was estimated by counting the hair follicles.

(1) The Zebu cross sweats more than the Shorthorn, at least from the shoulder area, and this is related to its higher sweat gland density as compared with that of the Shorthorn.

(2) In the Zebu cross cutaneous evaporation from the shoulder area is greater than that of the belly and this is associated with the differences in the number of sweat glands.

(3) In the Shorthorn cutaneous evaporation is the same from both shoulder and belly areas and the number of sweat glands in these regions is also the same.

Early-weaned lambs were penned indoors for 6 weeks and individually fed to appetite on cold-stored ryegrass (Lolium perenne) or indigenous Agrostis-Festuca herbage of differing maturity. In another experiment similar lambs grazed for 12 weeks on swards of perennial ryegrass or Agrostis-Festuca. Live-weight gain (LWG), herbage organic-matter intake (OMI) and digestibility (OMD) were measured. In the indoor experiment ryegrass was 4–6 percentage units higher in OMD than was Agrostis-Festuca;first harvests were superior to later harvests by the same amount. The intake of ryegrass was 22% greater than that of Agrostis-Festuca. The correlation between OMI/W'73 and herbage cell-wall constituents was —0·80, and that between OMI/W'3 and OMD was 0·78. OMI/W0·73 increased progressively up to about 13 weeks of age.

LWG was higher on ryegrass than on Agrostis-Festuca; and LWG on the early harvests of each herbage type exceeded those on the later harvests. LWG was significantly correlated with the intake of digested organic matter (DOMI) (r = 0·85).

In the grazing experiment, OMD, OMI and LWG were all lower than in the indoor experiment. LWG on ryegrass was again superior to that on Agrostis-Festuca, and the difference was partly explained by the relationship between DOMI and LWG which had been established indoors.

These results suggest that the increase in the growth rates of hill lambs consequent on the improvement of indigenous Agrostis-Festucaswards would be less than that due to the provision of sown pastures of perennial ryegrass.

The digestibility of protein of mixed whole rumen bacterial cells and Streptococcus bovis were determined in Bos bubalis and goats. The bacterial cells were labelled either with 35S or 14C in vitro incubation and were injected in a single dose into the rumen after protecting by formaldehyde treatment. Faeces were collected for 6 consecutive days and radioactivity excreted in the faeces was measured. The digestibility of bacterial protein ranged from 81·7 to 96·8% in both the species.

The incidence of Sclerotinia sclerotiorum (Lib.) de Bary infection in poppies (Papaver somniferum L.) was assessed 9 days before dry maturity in a field experiment which incorporated the effect of nitrogen and phosphorus fertilizer and fungicidal sprays. Infection occurred mainly on the lower stem in the leaf axils.

Nitrogen fertilizer (100 kg N/ha) had no effect on the incidence of Sclerotinia infection but phosphorus fertilizer (100 kg P/ha) increased the incidence from 19% of plants infected to 39%. Fungicides (2 kg benomyl, 50% a.i., plus 2 kg mancozeb, 80% a.i./ha) applied at 10-day intervals from flowering till harvest reduced the incidence of Sclerotinia infection to one third that of non-sprayed treatments.

Sclerotinia infection occurred late in the crop and had little effect on the dry-matter yields of terminal main-stem capsules, lateral branch capsules or stem and leaves but it did influence the distribution of morphine within the plant. The morphine concentration of terminal capsules was lowered by 13% but the concentration of lateral capsules increased by a similar amount giving a total capsule morphine concentration and yield which was similar in both infected and non-infected plants.

The morphine concentration of the stem and leaves of infected plants was 75% greater than that of uninfected plants but the overall morphine concentration of total plant was similar in both infected and non-infected plants. This distribution pattern was interpreted as a result of the restrictive influence of Sclerotinia infection on the vascular system which disrupted the normal translocation of morphine.

Total DNA was extracted and purified from luminal digesta samples (1 g) of 14-week-old (c. 43 kg bodyweight) pigs. Digoxigenin (DIG) labelled PCR products of the beta toxin gene of Clostridium perfringens type C were generated with DIG-11-UTP and chemoluminescent signals of DIG-labelled PCR products were detected on slot blots and recorded with a sensitive charge coupled densitometric camera. Detection limit and correlation of chemoluminescent signals to initial target DNA concentration were evaluated. Detection of the beta toxin gene could be achieved with 100 ag C. perfringens DNA in the presence of 1 μg unspecific DNA. The semiquantitative DIG-PCR assay was used to evaluate the relative abundance of the beta toxin gene of C. perfringens type C in purified DNA extracts from intestinal samples of pigs, which were fed a wheat/barley diet (controls), supplemented with the antibiotic avilamycin (40 mg/kg feed), a xylanase (4000 U/kg feed) or a combination of both feed additives. The antibiotic treatment significantly reduced the amount of PCR product in ileal and colon DNA extracts. Xylanase supplementation significantly reduced the amount of PCR product in colon samples, but led to an increase in jejunal samples. From the results it is concluded, that the antibiotic inhibited growth of C. perfringens type C in the ileum and colon of pigs. The semiquantitative DIG-PCR assay can be used to sensitively monitor the relative abundance of specific pathogens in the intestinal tract.

1. An investigation into the effects of plant population level and irregularity of plant spacing on the yield and quality of swedes is reported.

2. There was no significant evidence that irregular plant spacing, such as might be produced by mechanical singling, gave a lower yield than regular spacing.

3. Total yield of roots was similar for all plant populations tested (range 15,000–50,000) but at low populations both the number and weight of diseased roots was greater than at higher populations.

4. As the population was increased, the drymatter percentage in the roots increased due to the higher proportion of skin on small roots compared with large roots.

Identifying and applying the optimum fertilizer nitrogen (N) rate is a permanent challenge for farmers. Prediction of fertilizer N requirement, based on crop chlorophyll measurements (CMs), relies on a strong relationship between fertilizer N supply and leaf chlorophyll concentration at a given crop growth stage. A methodological approach is described, aiming to develop an algorithm that uses CM inputs to derive the economically optimum fertilizer N rate for top-dressing, without using a reference plot for data normalization. The method was tested on maize (Zea mays L. cvar Jabali) at experimental and farmer sites in the central (‘Bajío’) region of Mexico over 3 years (2010–12). Increasing fertilizer N supply at planting significantly influenced chlorophyll concentration at the seventh unfolded maize leaf stage (GS 17 on the Zadoks scale). Maize grain yields increased with increasing total fertilizer N supply and fitted quadratic models, which allowed economically optimum fertilizer N rates (Nopt) to be calculated. The Nopt ranged from 160 to 300 kg N/ha and corresponding grain yields ranged from 7·7 to 14 t/ha. Grouped data analysis (sites–years) confirmed a highly significant relationship between the Nopt and the chlorophyll concentration at GS 17, which could be described by a linear model: Nopt = 513·3–0·58 × CM. This model predicted the top-dressing Nopt within a fertilizer N management regime adapted to local maize cropping systems and led to similar grain yields across test sites compared with the same parameters calculated based on grain yield response trials. The current approach is variety-specific, so development of so-called correction factors accounting for variety-related differences in chlorophyll concentration is described. The results demonstrated the feasibility of the proposed algorithms to support decision-making on the optimum fertilizer N rate to apply in maize production systems with one top-dressing application.

The development of precipitins to Micropolyspora faeni in cattle fed hay treated with a bacterial and mould inhibitor is compared to that in herds fed untreated hay. The results indicate that, even when fed only treated hay, exposure to M. faeni was such that a considerable proportion of precipitin-free cattle did develop precipitins.