The effect of drought on the growth and subsequent recovery of container-grown perennial, Italian and hybrid ryegrass plants was assessed in a glasshouse. Dry-matter production and percentage of water-soluble carbohydrates were measured, and nondestructive measurements of growth components (leaf extension, leaf appearance and tillering) were made.

Drought had an effect upon all the variables recorded. Italian ryegrass was most severely affected by drought in terms of tillering, leaf extension and subsequent recovery. Selecting for improved recovery growth was considered to be of more economic importance than selecting for improved growth during drought.

It was concluded that subjecting pot-grown plants to drought, although in many ways unrealistic, was a very useful technique when screening a large number of different genotypes for drought tolerance and recovery.

Hindlimbs of pigs were dissected at 4-week intervals from 9 to 29 weeks after birth. Allometric growth ratios of the gluteal muscles, biceps femoris and semitendinosus were calculated relative to gastrocnemius. Relative growth in weight of the proximal limb muscles was greater than that of the distal muscle, gastrocnemius. The greater relative growth of proximal muscles was not due to greater relative growth of muscle fibre diameters, nor to greater relative growth of muscle cross-sectional areas. In biceps femoris and gluteal muscles, growth in the area of musole cross sections did not keep pace with the radial growth of muscle fibres. The relative longitudinal growth of proximal limb bones exceeded that of distal bones, and the relative longitudinal growth of biceps femoris and semitendinosus exceeded that of any of the limb bones. New sarcomeres were added to muscle length at a faster rate in biceps femoris and semitendinosus than in the peroneus longus located distally in the limb.

Four sheep were maintained on a pelleted diet based on barley straw, sunflower-seed meal and barley which was offered at 2 h intervals by mechanical feeders. In each of two periods approximately 3 weeks apart, methane production was measured continuously for 6 h in each animal. Despite the frequent feeding regime, methane output varied markedly with time increasing after feeding and then declining. Serial correlation analysis indicated a rhythmical variation of period 2 h which was confirmed by Fourier series analysis for all but one data set. The observations suggest that even with frequent feeding, there is considerable deviation from steady state in the rate of carbohydrate fermentation in the rumen.

Protein synthesis was measured in wether sheep by constant intravenous infusion of [3H]tyrosine. The specific radioactivity of plasma tyrosine at plateau was used to calculate tyrosine flux and the rate of protein synthesis in the whole body was estimated. For wethers fed hay and concentrates tyrosine flux was 2·46 mmol/h and protein synthesized was 5·29 g/kg body weight per day. Corresponding values for wethers fed barley straw were 30–35% lower.

Fractional rates of protein synthesis in individual muscles were between 2 and 3% per day for diaphragm, longissimus dorsi, gastrocnemius, semitendinosus and vastus lateralis muscles from wethers fed hay and concentrates, but the value for vastus intermedius was higher. Corresponding rates for wethers fed barley straw were 18–36% lower.

This study was carried out at Elminia University farm in two years (1978 and 1980) to evaluate the effect of some growth regulators on the production of sweetmelon and muskmelon. It was found that plants treated with some growth regulators were earlier and yielded better than untreated ones, except that in the first trial (1978), the total yield of plants treated with indole acetic acid (IAA) was less than that of the control. The highest early and total yields of both sweetmelon and muskmelon resulted from spraying ethrel on the foliage. Fruit weight and length and flesh thickness were increased by some growth substances compared with the control for both crops. Also, percentage of total soluble solids and ascorbic acid concentration increased markedly as a result of growth-regulator treatments for sweetmelon and muskmelon. Generally, two sprays of ethrel solution produced the most consistent effects on yield and yield quality in the two trials with both sweetmelon and muskmelon.

A new and detailed model, involving meteorological, crop and soil variables, is proposed to provide daily estimates of moisture deficits in soils under cereal cropping in Britain. The model incorporates developments in the calculation of potential evapotranspiration specifically for cereal crops. Four processes of loss of water are considered, namely drainage, evaporation of free water from the crop canopy, evaporation from the soil surface and transpiration by the crop. Thus the model is applicable at all stages of the cropping cycle. Above-ground and root system development of the crop are modelled and available and extractable water capacities of a wide range of soils are estimated. Thus the demand for water and its availability are varied with crop species, stage of development and soil type as well as with meteorological variables.

The calculation of water losses is not dependent on arbitrary assumptions about the division of losses between the four processes considered or between different horizons of the soil.

Extreme simplicity of input data requirement has been maintained. The model has been programmed in FORTRAN, and is compatible with Meteorological Office data archives.

The new model, described in a previous paper (Francis & Pidgeon, 1982), for estimating soil moisture deficits under cereal crops in Britain, was evaluated against experimental neutron probe data for eight test crops. The test crops covered a wide range within Britain of growing-season weather and soil types for both winter and spring cereals. Comparisons were also made with estimates of three other models, those of Ritchie, Rhoades & Richardson (1976), Jensen, Wright & Pratt (1971) and Smith & Douglas (1975).

The new model gives the best fit for six of the eight test crops, with root-mean-square errors (RMSE), taken over the whole season, of less than 10 mm of deficit and having small random bias. RMSE seldom exceeds 10 mm for any section of any season. By contrast, the other three models have whole season RMSE values in the range 10–40 mm. The model of Ritchie et al. (1976) generally overpredicted deficits early in the season and thereafter performed erratically; those of Jensen et al. (1971) and Smith & Douglas (1975) generally underestimated deficits. For two test crops where the new model performed poorly, serious inadequacies in crop growth and/or meteorological input data were identified as the reasons.

A sensitivity analysis for the new model emphasized the importance of the soil variables that were incorporated and the need for rudimentary crop growth information to supplement default assumptions.

It is concluded that the new model, having average RMSE values similar to expected neutron probe measurement errors, offers significant advantages over other models in estimation of soil moisture deficits. The new model could further provide a basis for extension to other crops or to description of the distribution with depth of soil moisture deficit.

Abnormally low concentrations of morphine in capsules of poppy (Papaver somniferum L.) in the 1970–1 season were associated with heavy fungal colonization. The effect of fungal colonization on the morphine production of capsules was later studied in a series of field, glasshouse and in vitroexperiments.

In a field experiment morphine concentration of severely colonized (> 30% surface cover) intact capsules was 20% less (P <0·01) than slightly colonized (< 10% surface cover) capsules. Colonization of these field-grown capsules was generally localized in the top half and the morphine concentration of the top half was about 20% less than the bottom half for all colonization categories. In contrast, glasshouse-grown capsules were free of fungal colonization and the top and bottom halves had similar morphine concentrations.

In a field experiment studying the effect of fungicides, 2 kg benomyl (50% a.i.) + 2 kg mancozeb (80% a.i.)/ha were applied as a spray at 10-day intervals from flowering till 1 month after commercial harvest and plants were harvested at weekly intervals from 10 days after full bloom. The mean dry-matter yield of sprayed capsules was 11% greater (P <0·01) than non-sprayed with a similar trend for morphine concentration and morphine yield. In addition, the sprayed treatment significantly reduced the area covered by sporulating lesions on the surface of the capsule after dry maturity. This superficial fungal cover had a NNE orientation in both sprayed and non-sprayed capsules.

In an in vitroexperiment using capsules from the field fungicide study, fungi were isolated from the interior of green capsule wall tissue as early as 17 days after flowering. Colonization increased with successive harvests and culturing of fungi from the interior of capsule wall tissue showed the presence of fungi in both sprayed and non-sprayed capsules with no difference in the degree of colonization.

Two of the major fungi isolated from the field experiment were identified as Dendryphion penidllatum (Corda) Fr. and Alternaria alternata (Fr.) Keissler and the individual effect of these was assessed in an in vitro experiment using ground capsule material. D. penidllatuvi and A. alternata reduced the morphine concentration of ground capsules in 24 days to 7 and 11% respectively of non-inoculated controls.

The high activity of rumen urease is a major limiting factor in the usefulness of urea as a protein replacement supplement in ruminant diets (Bloomfield, Garner & Muhrer, 1960). The efficiency of urea utilization can be increased by decreasing the activity of rumen urease or by modification of urea in the products which are slow ammoniareleasing (Helmer & Bartley, 1971). An arbitrary formaldehyde treatment of urea was observed to lower the hydrolysis in the intact rumen (Pal & Negi, 1977). In a systematic study carried out in our laboratory a series of urea formaldehyde complexes (UFC) was prepared and their in vitro hydrolysis studied (Lall et al.1980; Makkar et al. 1981). Phosphoric acid is known to catalyse the reaction between aldehyde and urea. In the present study the complexes of urea and formaldehyde (UFC) and urea, formaldehyde and molasses (UFMC) in the presence of a catalyst (phosphoric acid) were prepared and their in vitro ammonia production is presented.

The introduction of new protein evaluation systems for ruminants presupposes means to measure the ruminal protein degradability of feeds (Burroughs, Nelson & Mertens, 1975; Roy et al. 1977; Vérité, Journet & Jarrige, 1979). One potentially useful method to get such estimates is the nylon bag technique (Mehrez & Ørskov, 1977). This method, however, does not take into account the flow of feed particles from the rumen. By adjusting rumen degradation results obtained in sacco with the outflow of the feed from the rumen more accurate estimates of the actual degradability is possible (0ørskov & McDonald, 1979).

Abortion and stillbirth ranges of 1·8–16·1% and 1·26–6·5% respectively have been reported among Friesian cattle by Asker & El-Itriby (1957), Ragab & Asker (1959), Juma (1968) and Kassir & Juma (1968). Abortions and stillbirths occurred more frequently among heifers than among cows (Philipsson, 1971). Calving interval varied between 367 and 474 days, the first interval being the longest (Ragab & Asker, 1959; Zaki, Abdel Razek & Dessouky, 1965; Marples& Trail, 1967; Trail &Marples, 1968; Anon. 1969; Knudsen & Sohael, 1970; McLntyre, 1971; Kiwuwa, 1972).