Voluntary intake and apparent digestibility of tree willow (Salix matsudana Χ alba) and of osier willow (Salix viminalis) were measured with male sheep and goats and voluntary intake only with male deer. Both willow species had been selected for extremely rapid growth, and were grown in coppices on high fertility soil. In a first experiment spring primary growth of both willows was fed to sheep, goats and deer in early summer, whilst in a second experiment summer regrowth (i.e. secondary growth) of osier willow was fed to sheep and goats in autumn.

Although the ratio of readily fermentable to structural carbohydrate (0·51–0·70) and total N concentration (18–24 g/kg D.M.) in primary growth of the willows was less than normally found in high quality fresh temperate forages, the values were similar to those of many dried forages normally used as supplements. Averaged over sheep and goats, voluntary intake of digestible D.M. was 22% less for osier than for tree willow, this being associated with higher concentrations of lignin (197 ν 182 g/kg D.M.) and of condensed tannin (66 ν 29 g/kg D.M.) in the osier willow. The lower digestible dry-matter intake was attributable to both lower voluntary intakes and lower digestibility of the D.M. (0·57 ν 0·64). Both voluntary intake and apparent digestibility of secondary growth willow were lower than that of primary growth.

When expressed as functions of the amount required for maintenance, voluntary metabolizable energy intake of goats was approximately double that of sheep, both for primary growth (2·2 ν 1·1) and for secondary growth (1·8 ν. 0·7) willow. This was attributable to consistently higher voluntary D.M. intakes/kg W0'6 by goats, and to a trend for higher digestibility than sheep, which attained significance in Expt 2but not in Expt 1. The ratios of dry-matter intake/kg W075 per day for sheep: deer: goats fed primary growth willow were 1·0:1·5:1·9, with deer thus being intermediate between the other two species. There were no differences in voluntary intake (g/kg W0·75 per day) of sheep, goats and deer fed a high quality lucerne hay.

It was concluded that willows grown during spring and summer could adequately be used as supplementary feed during summer droughts and that willow could be used most effectively if fed to goats, followed by deer, with sheep being the least efficient. Tree willow is a preferred choice to the osier willow used here, and it was further concluded that like Lotus pedunculatus, high concentrations of lignin and condensed tannin, both of which are produced by the same biochemical pathway, are likely to be limiting nutritive value of the more leafy osier willow.

An experiment was conducted to examine the effect of fertilizer (triple superphosphate) and stocking rate on animal and pasture productivity on Sumba Island, Eastern Indonesia. The Ongole heifers used in the 1-year experiment gained weight during the wet season and lost weight during the dry season at stocking rates of 0·5 and 1·0 head/ha when grazing native Themeda pasture. The dryseason weight loss was arrested when a prepared seed-bed pasture, which contained 21 % Siratro at the start of the experiment was grazed at a stocking rate of 1·5 head/ha. Increasing the stocking rate to 2·5 head/ha on this pasture resulted in an increase, in the weed component of the pasture from 12 to 84% in 1 year.

The mineral content of plucked samples of pasture indicated that levels of Ca and Mg were generally adequate for growing beef cattle and that Na supplementation would be beneficial. Plant N concentration was below 1·5% in the Themeda and Imperatacomponent but above this in the legume at the prepared seed-bed site. The P concentration in the Themeda and Imperata was always below the 0·24 % level required by cattle, as it was in the legume at the end of the experiment.

The introduction of herbaceous legumes into pastures under set stocking conditions can lead to pasture instability.

Twenty fine-wool, ruminally cannulated lambs (average weight 45–9 kg) were used in a completely random design to evaluate the ability of three internal markers to predict dry matter digestibility and two external markers to estimate faecal output. Lambs were allotted randomly to one of four diets: 100% prairie hay (PH), 100% lucerne hay (LH), 50% prairie hay:50% sorghum grain (PS) and 50% lucerne hay: 50% sorghum grain (LS). The trial consisted of a 14-day adaptation period followed by a 7-day total faecal collection period. Feed and faecal samples were subjected to 96 h ruminal fluid and 48 h acid-pepsin digestions, followed by extraction with acid detergent (IVADF) or neutral detergent (IVNDF) solution. Dry matter digestibility (DMD) calculated from feed:faeces ratios of IVADF, IVNDF and acid detergent lignin (ADL) was compared with in vivoapparent digestibility. Ytterbium-labelled forage (YLF) and dysprosium-labelled faeces (DLF) were pulse-dosed via ruminal cannulae, and faecal Yb and Dy excretion curves were fitted to a one-compartment, agedependent model for estimation of faecal output, paniculate passage rate (PPR) and mean gastrointestinal retention time. In vivoDMD in lambs fed PH was greater (P <005) than DMD calculated from IVNDF, IVADF and ADL. In lambs fed LH and LS, in vivoDMD did not differ (P >005) from marker estimates. In vivoDMD for lambs fed PS did not differ from IVNDF or IVADF estimates but was greater than (P <005) the ADL estimate. No differences (P> 005) were observed in recovery among the three internal markers for any of the diets. Faecal output for lambs fed PH did not differ {P >005) from marker estimates but was overestimated by 15 to 20% by YLF and DLF. Faecal output for lambs fed LH was similar to the estimate from YLF, but less than (P <0–05) the estimate with DLF. For lambs fed PS, faecal output did not differ from marker estimates, but YLF and DLF values were 16% lower and 17% higher, respectively. No significant differences were observed in actual and estimated faecal output for lambs fed the LS diet. Estimates of PPR with DLF were numerically greater than YLF estimates for all diets except LS. Correspondingly, mean gastrointestinal retention time was less (P <005) for DLF compared with YLF for all diets except LS.

Water requirements and metabolism were studied in eight each of Barki and Rahmani sheep and eight Baladi goats. The animals were individually housed in the shade in semi-open pens that were located in a non-desert area. The experiments were carried out during spring, summer and winter seasons, and each experiment lasted for 3 weeks during each season. After a preliminary period of 1 week, an 8-day period was then followed during which body weight, daily feed intake and daily drinking water were recorded. Rectal temperature and respiration rate were also recorded in the early morning and late afternoon. Four animals from each group were then weighed and injected intravenously with tritiated water, TOH (001 mCi/kg body weight) and blood samples were collected during a 4-day period to estimate total body water (TBW) and water turnover rate (WTR).

In all seasons studied, the Rahmani sheep had higher TOH disappearance rate (^-values) and WTR and consequently shorter biological half-time (1½) than the Barki. Moreover, the Barki sheep showed less thermal discomfort than the Rahmani particularly during the summer. Although the Rahmani sheep ingested more water than the Barki sheep during the summer, the Rahmani sheep had a lower percentage of TBW and their calculated water loss revealed that they were in negative water balance during this season. Accordingly, the Barki sheep seem to perform better than the Rahmani in newlyreclaimed desert areas. Baladi goats appear to be more adapted to unfavourable environmental conditions than sheep. This is based upon the findings that they had lower k-values, lower WTR, longer tiand higher TBW, than the two breeds of sheep.

Laboratory silos were prepared from lucerne (Medicago sativa)which had been treated with a number of chemical and biological additives. The additives used were the acid additive, formic acid, the sterilant, formaldehyde, the oxidative enzyme, glucose oxidase, and the starch hydrolysing enzyme complex, Termamyl. Silos were prepared in duplicate and pairs of each treatment were opened at 0, 2, 9, 20 and 60 days ensilage. The pH, volatile fatty acid patterns and dry-matter yields were determined and the composition of the residual fibre was determined for cellulose, hemicelluloses, lignin and phenolic acids. The only treatment to enhance the rate of fall in pH was formic acid. The rate of decline in pH of the silages treated with glucose oxidase was not significantly different from the other treatments. The starch degrading enzyme complex did enhance the loss of starch from the lucerne but it did not appear to have any significant effect on the silage characteristics measured. No loss of true lignin was observed from the fibre but most of the phenolic acids present were removed. All the treatments appeared to have a significant effect on the cellulose content which was in contrast to earlier work on ryegrass silages where no effect was observed. On the other hand, the treatments had less effect on the hemicellulose fraction than was observed in the previous work with ryegrass. These results can be explained by differences in the structures of the fibres from lucerne and ryegrass.

Mineral concentrations of soft tissue and bone were measured in carcasses from cattle slaughtered serially across a wide weight range. Seventy-four small framed Angus steers and 71 Holstein steers were selected to represent diverse mature types. Cattle were individually fed ad libitumeither a maize grain or maize silage diet, housed inside a barn or in outside pens and slaughtered over five weights within breed. After slaughter, a half-carcass was separated into soft tissue (lean and fat) and bone. Tissues were ground, freeze-dried and K, P, Ca, Mg, Na, Fe, Cu, Zn and Mn were measured. Concentrations of minerals were analysed by covariance analysis, using carcass weight as a covariate.

The relationships between carcass weight and concentrations of all soft tissue minerals except Na and Zn were not affected by diet, breed or type of housing. Concentration of Na decreased with increasing carcass weight and at a slower rate in soft tissue of grain-fed cattle than in soft tissue of silage-fed cattle. Concentration of Zn increased with increased carcass weight in Angus, while in Holsteins it decreased. Soft tissue of Angus and Holsteins had similar concentrations of Fe and Mn. Holsteins had higher concentrations of the other minerals in soft tissue than Angus, possibly because they were at an earlier stage of maturity at the same carcass weight. Carcass weight had no effect on K, Ca, Fe or Cu content of soft tissue.

Diet influenced concentrations of P, Ca and Na in bone and affected the relationship of bone Fe to carcass weight. Due to their later stage of maturity at the same carcass weight, Angus had less K and more Ca, Na and Zn in bone than Holsteins. Carcass weight had no influence on K, P, Mg, Na, Cu or Mn content of bone.

These data provide baseline values for future studies, show that breed mature size differences in mineral concentrations of soft tissue and carcass bone may exist and that diet may influence concentration of soft tissue Na and some bone minerals.

In a greenhouse experiment, the effect of soil sodicity (exchangeable Na percentage 3, 10, 20, 40 and 60) and Zn (0 and 10 mg Zn/kg soil) on soil solution chemistry of Mn was investigated under submerged conditions. Calculated amounts of NaHCO3 were added to Typic Ustifluvent sandy loam soil to obtain required sodicity levels. The soil solutions collected under the atmosphere of N2 gas by gravity were analysed for pH, pE, EC and Mn. Soil submergence decreased pH and pE, and increased Mn concentrations in all the treatments. Maximum Mn concentration was obtained at 14-day submergence. Increasing sodicity levels increased soil solution pH and decreased Mn concentrations. A significant negative correlation (r = -0·74**) was observed between soil solution Mn and pH. Despite large variations in pH, pE, ionic strength and Mn concentration in soil solution, the values of expressions: pH+½log Mn2+ + ½log Pco2 and pMn+2pOH were fairly constant and close to the theoretical values of 4·4 and 17·2 respectively, indicating that the MnCO3-Mn2+ system regulated the solubility of Mn2+ in the sodic soils. Addition of ZnSO4 did not have appreciable effects on the soil solution pH, Mn and solid phases of Mn.

The total glycoalkaloid (TGA) content of tubers of ten potato cultivars exposed to the light for 42 h significantly increased (P < 0·001). on average, above that of tubers kept in the dark. There were significant differences in the percentage changes in TGA content (P < 0·05) and in the intensity of tuber greening after exposure (P < 0·05) between cultivars although there was no correlation between the two characters.

The effect of P applications and native vesicular-arbuscular mycorrhiza (VAM) on the growth and P nutrition of red clover plants was studied in two acid hill soils with similar edaphic characteristics.

Mycorrhizal and non-mycorrhizal plants were compared under sterilized soil conditions. Plant growth increased on P addition in both soils, but the effect of mycorrhiza in improving drymatter production and P uptake was significant only in one of the soils. Fourteen and twenty-five mg/kg Olsen-P were needed in this soil to obtain the same yields by mycorrhizal and non-mycorrhizal plants, respectively. Results are explained in terms of a different effectiveness of the two fungal populations, and the possible effect of the soil sterilization process on percentage VAM infection is discussed.

Two experiments were done in which the yield, digestibility and protein content of several autumnsown triticale cultivars were compared with rye and, on one occasion, ryegrass. Rye and an earlyflowering triticale cultivar (A208) had the highest early season yields and, at that stage, all cultivars and species had high digestibility.

When harvesting was delayed, the yield of later flowering cultivars (A386 or the latest flowering variety, A876) was greatest. When the plots were cut and harvested again, the intermediate and late maturing varieties (e.g. A386, A876–10) gave the highest yields of digestible dry matter. It was concluded that there was no advantage in using a mixture of cultivars as in the commercially available ‘Trical’ and that the available cultivars offered farmers useful alternatives in harvesting strategy and breeders the opportunity to develop earlier high-yielding triticale cultivars.

Three experiments are reported in which the photosynthetic rates of potatoes grown with various amounts of applied nitrogen (N) fertilizer were measured. Rates of photosynthesis in leaves of plants grown without applied N reached levels as high as those receiving N in all experiments. The rate of photosynthesis in the uppermost leaves of the variety Pentland Crown was found to increase during the season, whereas in Estima rates remained the same. Decline in the rate of photosynthesis with leaf age was more rapid in strongly shaded leaves than in less shaded leaves which were found to be photosynthetically active 8 weeks after expansion.

A field experiment was carried out in three wet seasons of 1982, 1983 and 1984 with various combinations of urea and organic nitrogen sources to investigate the nitrogen transformation and productivity of rice crop in a waterlogged situation. The treatments used were: (i) control (No), (ii) FYM + urea, (iii) Sesbania + urea, (iv) urea, the levels of nitrogen being 60 and 90 kg/ha and the proportion being 50:50 between organic and chemical sources where such combination was used. The soil samples were analysed for ammonium, hydrolysable and non-hydrolysable forms of nitrogen at 15, 30 and 45 days after transplanting. The release of hydrolysable and non-hydrolysable nitrogen was superior in the urea-Sesbania combination while the release of NH4·N was slightly better in FYM-urea combination. Yield of rice and apparent nitrogen use efficiency were highest in sole urea treatment and almost similar in FYM-urea and Sesbania + urea combinations. A statistical nitrogen-transformation model outlined the relationship among the various forms of soil nitrogen under submergence. The model suggested a strong correlation among the different forms of nitrogen during the earlier period of submergence.

Carcass measurements including chemical composition and specific gravity data from 40 male and 40 female quails killed at 42 days of age were evaluated for use as an indirect means of estimating carcass fat. The results indicated that carcass fat was highly negative correlated to water (r = —0·93 and —0·87 for males and females, respectively) and that the inclusion of carcass protein improved the accuracy of prediction a little (r = -0·93 and -0·88). Carcass fat was only moderately related to specific gravity (r = —0·55 and —0·42) and the reliability as estimator of carcass fat was less than water or protein. Also, body weight was positively related to carcass fat (r = 0·71 and 0·42).

Different photoperiodic treatments within 2 types of light dark cycles ranging from 24 to 30 h were applied to Peking ducks. The first consisted of constant photoperiods (1, 8L: 16D; 2, 14 L: 10D; 3, 18L:6D; 4, 14L: 13D; 5, 14L: 16D and 6, continuous light) and the second of intermittent cycles (1, 6L:2D:2L:14p; 2, 6L:4D:2L:12D; 3, 6L:6D:2L:10D; 4, 6L:8D:2L:8D and 5, 14L:½D:3½L:6D). The traits studied varied in response according to the photoperiodic regimes used. Rate of lay and eggs laid in the modal 8 h period increased with the duration of the light period in the cycle. Sequence lengths of 1–3 eggs were most frequent under all photoperiodic regimes (constant and intermittent). Length of intra-sequence interval (h) showed an inverse relationship with length of inter-sequence interval. A pause length of 2–4 days was the most frequent for all the different light-dark cycles. Egg weight was heavier in the second season than in the first when the light period of the photoperiodic regime was long. Weights of albumin and yolk showed similar trends to egg weight. The latter differences were significant, while shell weight differences were not significant. Plasma progesterone lvels were lowest in non-laying ducks. The highest values in laying ducks were before ovulation. The highest level of cortisol was shown during the last hours of the dark period. Differences from ovulatory cycle to another were observed.

Gorse (Ulex europaeus) was harvested in late spring, summer, autumn and winter and fed to six goats kept individually in metabolism cages for 21-day periods. The same gorse was also fed to sheep during the first two periods, but not in autumn and winter, as the hardness and sharpness of the needles caused total rejection by the sheep at these times. Measurements of voluntary intake and apparent digestibility were made over the last 7 days of each period. To minimize effect of diet selection the animals were fed at hourly intervals. Dietary lignin concentration was very high, ranging from 170 to 200g/kg D.M. Voluntary metabolizable energy (ME) intake for goats was respectively 1·60, 0·82, 0·72 and 0·41 times maintenance for the four harvesting times, late spring, summer, autumn and winter. Corresponding values for sheep were 0·90 and 0·33 for gorse harvested in late spring and summer. Thus, in late spring and summer, voluntary ME intake by goats was respectively 1·8 and 2·5 times that of sheep. The reduction in ME intake with time was attributed to increases in the contents of D.M. and of lignin + hemicellulose in depressing voluntary D.M. intake and apparent digestibility respectively. Voluntary intake of both supplementary water and total water per unit D.M. intake were consistently less for goats than sheep. From a comparison with published values, it was concluded that the superiority of. goats over temperate breeds of sheep in digestible dry matter intake (DDMI)/kg W0·75 per day increased as the lignin content of the diet exceeded 120 g/kg D.M., indicating that goats must possess some superior mechanism for breaking down highly lignified diets such as gorse and willow. It is proposed that cashmere fibre production from goats grazing gorse for a 7-month period of each year should be evaluated as an alternative to regulating gorse with chemicals.

Sugar cane (Saccharum sp. hybrid cv. Co 1148) was planted in October alone and in association with potato (Solarium tuberosum cv. Kufri Chandramukhi), coriander (Coriandrum sativum cv. Sheetal), mustard (Brassica juncea cv. T59) and wheat (Triticum aestivum cv. K816) to find the optimum N dose in alluvial entisols of Lucknow, India. The yield of sugar cane was least in association with wheat and most with potato. The optimum N doses for sugar cane were 152, 175, 186 and 231 kg/ha when grown in association with potato, coriander, mustard and wheat respectively. The optimum N dose for sugar cane grown alone was 186 kg/ha.

In a laboratory incubation study, the effect of natural and artificial soil salinity on the soil N2 fixation, nitrogenase (C2H2 reduction) and N2-fixing populations was evaluated in rice soils under two water regimes. N2 fixation was less pronounced in two saline soils and in a normal non-saline soil amended with salt mixture (salinity level of 4 and 30 dS/m) than in a non-saline soil under flooded and nonflooded conditions. Flooded soils amended with rice straw showed higher N2-fixing activity than the non-flooded soils at all salinity levels used in the study. Leaching the saline soil improved N2 fixation. An increase in the soil salinity led to a decrease in the populations of at least three groups of N2-fixing micro-organisms. The population density of anaerobic N2 fixers and Azospirillum in a saline soil increased considerably after leaching or after addition of rice straw. Azotobacter populations were little affected by the salinity levels used in this study. Results indicate that soil amelioration for salinity with leaching and organic matter addition would improve the implicated microbial populations and N2 fixation in salt-affected rice soils.

Acetic acid bacteria were isolated from maize silages and from samples of maize silage exposed to air. The isolates apparently belonged to the genus Acetobacter. By inoculating maize silage with strains of acetic acid bacteria isolated from silage and by monitoring the development of the microbiota of samples exposed to air it was demonstrated that acetic acid bacteria can be responsible for the onset of aerobic deterioration of maize silage. However, acetic acid bacteria and yeasts often developed simultaneously in uninoculated silage samples exposed to air. In all experiments ethanol was oxidized to acetic acid followed by a rapid oxidation of lactic and acetic acids when ethanol was depleted.

We describe a computer algorithm to generate efficient incomplete-block designs for any number of varieties, any number of replicates, and any number of plots per block. It considerably extends an earlier catalogue published in this Journal by Patterson, Williams & Hunter (1978). We describe also some uses of the algorithm for which no efficient designs are available from existing sources.

The effects of winter shearing on ewe live weight, body condition score (BCS) and the concentrations of glucose, non-esterified fatty acids (NEFA), 3-hydroxybutyrate, growth hormone (GH), cortisol, insulin and the thyroid hormones in plasma plus that of oxygen and carbon dioxide in jugular vein blood and packed cell volume (PCV) were measured at weekly intervals over the final 7 weeks of pregnancy in two groups of multiple-bearing shorn and unshorn pregnant ewes.

Shorn ewes lost 47% more live weight than unshorn controls over the period from the day of being shorn to immediately after lambing. There was a significant decrease in BCS in both groups between 45 and 9 days before lambing. Three days after shearing the plasma NEFA concentration was higher in the shorn group but there were no other significant differences between shorn and unshorn groups in the plasma concentrations of NEFA, cortisol or insulin over the remaining 7 weeks of pregnancy. Both the PCV and concentration of carbon dioxide in blood were higher in shorn sheep throughout the final 6 weeks of pregnancy indicating they were making metabolic adaptations to long-term cold exposure. This response may have been mediated via an increase in thyroid hormone concentrations which were higher throughout the 7-week sampling period in shorn animals compared with unshorn controls. A decrease in ambient temperature was associated with a significant increase in the plasma concentration of GH and glucose in shorn animals. At 2 weeks before lambing there was a decrease in the plasma glucose concentration and an increase in 3-hydroxybutyrate concentration in the unshorn ewes, but these changes were not observed in the shorn animals. It is concluded that winter shearing of the pregnant ewe results in an increased loss of maternal body tissues and metabolic adaptations to long-term cold exposure without any of the changes associated with an increase in energy expenditure during the final third of pregnancy.