Four cultivars of winter barley (Hordeum vulgare L.) and two cultivars of combining pea (Pisum sativum L.) were grown in the field in the UK (52°N) and irradiated under banks of UV-B lamps in 1994/95 (barley) and 1996 (pea). Supplementary UV-B radiation was applied to treated plots as a proportional addition to the UV-B dose received under a control plot. Treated plants received a UV-B enhancement simulating the consequence of a 15% reduction in the amount of stratospheric ozone. No significant effect on yield and few significant effects on growth, pigment composition or chlorophyll fluorescence variables were detected. However, interplot variability was such that yield differences of <8·5% (pea) and <21·6% (barley) had less than a 95% probability of being detected as significant at the 5% level. The results indicate that yields of pea, and probably barley, would not be markedly affected by the increase in UV-B associated with a 15% reduction in stratospheric ozone. However, given uncertainties, such as the possible interactions between the effects of UV-B and those of other environmental factors, the possibility of significant crop responses to stratospheric ozone depletion cannot be excluded.

A simple model of canopy expansion and senescence with accumulated thermal time from sowing was used to describe differences in canopy development and potential size across a range of sites in the UK between 1992 and 1995. The principal model inputs were nitrogen, temperature and sowing date. The model was calibrated across six sites within the major wheat growing areas using canopy data collected during the 1992/93 and 1993/94 growing seasons and was validated using data collected in the 1994/95 season. The model was able to predict the time course of green area index (GAI) over a season with an r2[ges ]0·87 for the five English sites, and an r2=0·68 for the single Scottish site. This model may prove to be a useful approach to forecasting the potential canopy size, based upon an estimate or measure of the total nitrogen available to the crop (both from applied fertilizer and the soil).

Autumn-sown sugarbeet (Beta vulgaris L.) responses (sugar yield, plant N-uptake and juice quality) were studied in relation to the residual NO3−-N in a soil of southwestern Spain which, for the previous five years (1989–93), had received high N rates, in accordance with conventional fertilization schedules used by farmers in the area. Three different combinations of fertilizers, supplying equal amounts of N, were used during the fertilization period (1989–93): a mineral fertilization treatment (MF, a complex 15N-15P2O5-15K2O) and two organo-mineral fertilization treatments (an olive mill wastewater sludge compost, AC, and a depotassified concentrated beet vinasse, V). All these treatments also received a top-dressing with urea (46% N). A control treatment (C), without fertilization was included for comparison.

During the major part of the beet growing season, the presence of almost four times as much mineral N in the 0·100 cm soil layer of previously fertilized plots (AC, V and MF) than in the unfertilized one (C), led to a significant increase (P<0·05) in total fresh weight yield and N-uptake, but also to a significant decrease (P<0·05) in sugar content and beet processing quality. The time course of NO3−-N concentration in sugarbeet petioles and the evolution of the nutritional state of leaf-blades gave advance information about the final response of the crop to the different fertilization treatments. Besides N, Na was the element which, due to the repeated and high fertilization rates applied, had a major effect in reducing the technological quality of the sugarbeet.

The effect of late season insect infestation on seed yield, yield components, oil content and oil quality of two canola species (Brassica napus L. and B. rapa L.) and two mustard species (B. juncea L. and Sinapis alba L.) was examined over 2 years. In each year, ten genotypes from each species were evaluated with late season insects controlled with either methyl parathion or endosulfan insecticides, and without insecticides. Major late season insect damage in 1992 was caused by cabbage seedpod weevil (Ceutorhynchus assimilis Paykull), while diamondback moth (Plutella xylostella L.) and aphids (primarily cabbage aphids, Brevicoryne brassicae L.) were major insect pests in 1993. Insecticide application was very effective in controlling diamondback moth larvae and adult cabbage seedpod weevils, but only partially effective in controlling aphids. Higher numbers of diamondback moth larvae were observed on mustard species compared to canola species. S. alba was completely resistant to cabbage seedpod weevil and there was no damage due to this pest observed. Aphid colonization was observed on plants from all species, but infestation on S. alba and B. rapa occurred too late to have a major effect on seed yield. Seed oil content of canola species was significantly reduced by insect damage although oil quality (indicated by fatty acid profile) was not affected by insect attack. Uncontrolled insect infestation reduced seed yield of canola species by 37 and 32% in B. napus and B. rapa, respectively. Least yield reduction occurred in S. alba, where average yield reduction from plants in untreated control plots was <10% of insecticide treated plants. S. alba, therefore, has good potential as an alternative crop suitable for northern Idaho because it can be grown with reduced late season insecticide application.

Canola (Brassica napus L.), yellow mustard (Sinapis alba L.) and intergeneric crosses of S. alba×B. napus were assessed for resistance (antixenosis) to the cabbage seedpod weevil (Ceutorhynchus assimilis Paykull). Pod trichomes did not appear to be a major factor in the resistance of S. alba to weevils. The number of feeding punctures and eggs per pod in S. alba was not significantly different in pods with trichomes than in those where the trichomes had been removed. Choice and no-choice laboratory tests examining feeding punctures and eggs laid per pod suggested that resistance in S. alba is not conferred in the intergeneric cross, S. alba×B. napus. Similar data on feeding and weevil oviposition were found in field test plots. However, despite many eggs being laid in S. alba×B. napus hybrid plants, fewer cabbage seedpod weevil larvae developed to exit the intergeneric hybrid pods. Glucosinolate analyses of leaves, pods and seeds showed that S. alba plants have a high concentration of p-hydroxybenzyl glucosinolate in all three plant parts, but B. napus has no p-hydroxybenzyl. Interestingly the intergeneric hybrid examined in this study had 62% and 60% of p-hydroxybenzyl concentration in the leaves and seeds, respectively, than was found in the S. alba parent. However, pod tissues contained very little (3%) compared with the S. alba parent. It is possible, therefore, that the adult cabbage seedpod weevil feeds on the pods of the intergeneric hybrid and lays eggs in the pod, because of the low concentration of p-hydroxybenzyl glucosinolate, but the larvae then fail to develop as they feed on the seeds containing high concentrations of p-hydroxybenzyl glucosinolate. It should be noted also that this hybrid produced pods that were more similar in physical shape to canola pods and that this may also be a factor determining cabbage seedpod weevil feeding and subsequent egg laying. In addition, both B. napus and the intergeneric hybrid produced 3-butenyl and 4-pentenyl glucosinolates in their pods, and degradation products (3-butenyl, and 4-pentenyl isothiocyanates) from these glucosinolate types, are known to be stimulatory kairomones that attract cabbage seedpod weevil. Further studies are being conducted to examine these factors in more detail.

Ammonia (NH3) volatilization may decrease the fertilizer efficiency of surface-applied slurry and may cause the unwanted deposition of nitrogen (N) in oligotrophic ecosystems. We studied the effect of soil water content on the infiltration of slurry liquid and how infiltration affected NH3 volatilization. NH3 volatilization was measured with dynamic chambers through which air was drawn continuously. Slurry spiked with bromide (Br−) to trace slurry infiltration was applied to a loamy sand in steel cylinders (diameter 6·7 cm and height 12 cm) adjusted to water contents of 0·01, 0·08, 0·12 and 0·19 g H2O per g soil (g g−1). At different time intervals after slurry application the soil columns were cut into slices and Br−, ammonium (NH4+) and nitrate (NO3−) concentrations were determined. At soil water contents >0·12 g g−1 nitrate content increased significantly from 24 to 72 h, and at 96 h NO3− content was equivalent to 75–130% of the NH4+ present at 0·5 h after slurry application. Nitrification may have contributed to a low NH3 volatilization from 24 to 96 h by reducing NH4+ concentration and contributing to acidity, and most of the NH3 volatilization occurred, therefore, during the first 24 h after application. Low soil water content enhanced the infiltration of slurry liquid and hence the mass transport of NH4+ into the soil. Transport of NH4+ by diffusion, on the other hand, was highest at the highest water content. Transport of NH4+ from the slurry at the soil surface down into the soil at 0·01 g g−1 reduced NH3 volatilization to c. 70% of the volatilization from slurry applied to soils at higher water contents. Diffusion of NH4+ into the soil did not significantly decrease NH3 volatilization.

The solvent extraction of alkanes from faeces and herbage samples at two different temperatures (cold: 15–25°C and hot: 65°C) was studied in four samples of different matrix types (cattle faeces, sheep faeces, hill grass and heather), in two experiments performed at Villaviciosa, Asturias, Spain in 1994. Two internal standards (IS) of different chain length (C22 and C34) were used to estimate alkane concentrations. Significant differences were detected in alkane extraction derived from temperature of extraction, IS and sample matrix. At the cold temperature, long-chain alkane extraction was not complete, resulting in errors in the estimation of alkane concentration when a long-chain alkane (C34) was used as the only internal standard. However, under hot extraction, long- chain alkanes were completely extracted by the heptane, although estimates made with C22 or C34 as IS were not identical. These results suggest that it would be appropriate to use two internal standards with short and long carbon chain, such as C22 and C34, in routine analyses to establish the completeness of alkane extraction, even under hot conditions, by calculating the relative ratio of both IS in extracts compared to the original C22[ratio ]C34 ratio added to the samples. Any increase or decrease in expected peak areas could be adjusted for all the alkanes in the extracts, and the accuracy of alkane concentration measurements (and therefore the reliability of estimates of intake and especially of diet selection) would be improved.

Saponins of Quillaja saponaria bark and the water extract obtained on homogenization of Yucca schidigera plants were used during urea-ammoniation to reduce ammonia loss. In Expt 1, chaffed wheat straw (2–5 cm length) was urea-ammoniated (50 g kg−1 urea, 400 g kg−1 moisture) for 25 days at 37°C with and without Quillaja saponins (QS) or Yucca plant homogenate, YPH (corresponding to 1 and 2 g kg−1Yucca powder). The crude protein (CP) content of untreated straw was 34 g kg−1. After 25 days, CP values of 90 g kg−1 (urea; no saponin), 82 and 86 g kg−1 (urea+QS at 1 and 2 g kg−1) and 102 and 92 g kg−1 (urea+YPH at 1 and 2 g kg−1) were obtained. The ammonia-nitrogen bound (as percentage of urea-nitrogen added) to straw after the treatment was 39 (urea; no saponin), 33 and 36 (urea+QS at 1 and 0·2 g kg−1), and 47 and 40 (urea+YPE at 1 and 2 g kg−1). As the extent of ammonia bound to straw was higher with Yucca plant powder, especially at 1 g kg−1, Yucca plant powder at 0·75 and 1 g kg−1 was used in Expt 2. In Expt 1, the Yucca plant extract was used after homogenization of the Yucca plant powder, which is not feasible at farm level. Therefore, two simpler approaches (overnight soaking of the powder in water (Yucca powder extracted, YPE) and mixing of Yucca powder with the straw followed by urea-ammoniation (Yucca powder, YP) were used besides homogenization. Otherwise, conditions for the urea-ammoniation treatment were similar to those in Expt 1. The ammonia–nitrogen bound (as percentage of urea-nitrogen added) to the straw varied from 47 to 54% in the presence of the Yucca plant powder, which was substantially higher than that observed in its absence (38%). The ammonia-binding efficiency of Yucca plant powder to the straw was highest at 1 g kg−1. Among the three methods tried, addition of the Yucca powder to straw followed by treatment with urea was the easiest, and the binding efficiency was similar to that observed when using the powder after homogenization. In both experiments, the true dry matter- and NDF-digestibilities, calculated organic matter digestibility and metabolizable energy, as well as rate and potential extent of gas production, were significantly higher (P<0·05) in the treated straw than in the untreated straw. These values were affected neither by the source of the saponins nor the manner in which the Yucca powder was applied.

A grazing experiment, conducted for 55 days (from 4 March to 29 April) in the late summer/autumn of 1997, at Massey University, Palmerston North, New Zealand, compared the reproductive efficiency and wool growth of ewes grazing Lotus corniculatus (birdsfoot trefoil) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) dominant pasture (pasture). Half the ewes grazing each forage were given daily oral polyethylene glycol (PEG: molecular weight 3500) supplementation to inactivate the condensed tannins (CT) in lotus. A rotational grazing system with 200 mixed age ewes (54·2±0·88 kg/ewe; 50 ewes/treatment) was used.

The effect of forage species and PEG supplementation upon voluntary feed intake (VFI), concentration of plasma metabolites, reproductive efficiency, wool production and wool characteristics was measured during two synchronized oestrous cycles. The ewes were restricted to maintenance feeding for the first 12 days of each oestrous cycle and then increased to ad libitum for the 6 days prior to and including ovulation. Lotus contained 17 g total CT/kg dry matter (DM) in the diet selected. There were only trace amounts of total CT in pasture. In vitro organic matter digestibility (OMD) was higher for lotus (0·82 v. 0·74) than for pasture, whilst lotus contained less nitrogen (N; 37·8 v. 44·5 g/kg OM).

Mean ovulation rates (OR) for CT-acting and PEG sheep grazing pasture and lotus were respectively 1·33 v. 1·35 and 1·78 v. 1·56, with corresponding lambing percentages being 1·36 v. 1·36 and 1·70 v. 1·42. Fecundity (number of corpora lutea/ewe ovulating) was greater for ewes grazing lotus than pasture (P<0·01), and tended to be greater for CT-acting than for PEG sheep grazing lotus (P=0·06). In unsupplemented sheep, ewes grazing lotus had increased plasma concentrations of branched chain amino acids (BCAA; 57%) and essential amino acids (EAA; 52%) compared to ewes grazing pasture.

In ewes grazing pasture, PEG administration had no effect on plasma concentrations of urea and free amino acids, VFI, reproductive efficiency and wool production. However, in sheep grazing lotus, plasma concentrations of urea were significantly lower and concentrations of most amino acids were significantly higher for CT-acting than for PEG supplemented ewes (CT not acting); there was no difference in VFI between these two groups. Compared to ewes grazing pasture, ewes grazing lotus had similar VFI but produced more wool with longer staples and thicker fibre diameter, with there being no effect of PEG supplementation.

It was concluded that feeding lotus increased the efficiency of both reproduction and wool production without an increase in VFI, and that a possible cause was the action of CT in increasing plasma EAA and especially BCAA concentration.

A rotational grazing experiment using weaner deer was conducted at Palmerston North, New Zealand, during the autumn, winter and spring, to compare the voluntary feed intake (VFI), liveweight gain (LWG) and carcass production of deer grazing chicory with those grazing perennial ryegrass/white clover pasture. Deer were either treated with anthelmintic at 3-weekly intervals (T) or anthelmintic was withheld until trigger-treatment (TT) criteria were attained. Pure red and 0·75 red: 0·25 elk hybrid stags and hinds were given forage allowances of 5 kg DM/deer/day in autumn and early-mid winter, 6 kg DM/deer/day in late winter and 7 kg DM/deer/day in spring. Deer grazed chicory or pasture in autumn and spring, with all deer combined on pasture during winter when chicory was dormant. Organic matter digestibility of diet selected was greater for chicory than for pasture in both autumn and spring.

Anthelmintic-treated deer grazing pasture in autumn had significantly higher VFI and LWG, contributing to higher carcass weights, than TT deer. Anthelmintic treatment had no effect on these measures for deer grazing chicory in autumn. Clinical signs of lungworm infection were evident in pasture TT deer during autumn and winter, and in chicory TT deer grazing pasture during winter. Faecal egg counts (FEC) were significantly greater for pasture TT deer during autumn and early winter than all other groups. Faecal lungworm larval counts (FLC) were significantly greater for chicory TT deer following transfer to pasture, than for all other groups in early winter, although both FEC and FLC were low. Faecal larval counts were poorly related to clinical signs of lungworm infection during autumn, but were a better guide in winter. Plasma pepsinogen concentrations appeared unrelated to gastrointestinal parasite infection. Trigger-treated deer grazing pasture required five anthelmintic treatments during autumn and winter. The chicory TT group required no anthelmintic treatment when grazing chicory during autumn, but required two treatments after transfer from chicory to pasture during winter.

There was no effect of anthelmintic regime on VFI and LWG in spring, and LWG was greater for deer grazing chicory than those grazing pasture. Hybrid deer had greater spring LWG and carcass weights than red deer when grazing chicory, but similar LWG and carcass weights when grazing pasture.

It was concluded that grazing chicory offers the potential for reducing anthelmintic use in farmed weaner deer, particularly during autumn.

The current study was to determine the effects of growth hormone-releasing peptide ([His1, Lys6]-GHRP) on growth performance and carcass traits in pigs, and to determine whether the results were comparable to those of recombinant porcine growth hormone (r-PGH) treatment. Thirty Landrace and Yorkshire pigs (40–45 kg) were randomly divided into three groups, each group consisted of two boars, five gilts and three barrows. Peptides were administered daily by intramuscular injection with the following schemes and dosages: Group A ([His1, Lys6]-GHRP, 200 μg/day in 0·5 ml saline), Group B (r-PGH, 3 mg/day in 0·6 ml saline), and Group C (sterilized physiological saline, 0·5 ml/day). [His1, Lys6]-GHRP caused significant improvements both in pig growth and carcass traits. The average daily gain (ADG) and feed efficiency of the [His1, Lys6]-GHRP treated group were higher than those of the control, but less than with the r-PGH treatment. The net increase in the ADG by [His1, Lys6]-GHRP was c. 14%, and was 23% by r-PGH (both P<0·01). The feed efficiency was improved 17% by [His1, Lys6]-GHRP (P<0·01) and 20% by r-PGH (P<0·01). On the other hand, the back-fat thickness in both [His1, Lys6]-GHRP and r-PGH treated groups (1·76±0·041 cm and 1·72±0·040 cm, respectively) was considerably less (P<0·05) than that of the control group (1·81±0·040 cm). In addition, the lean cuts percentage and the rib longissimus muscle area were comparable in the [His1, Lys6]-GHRP and r-PGH treatments (lean cuts percentage: 57±2·0% and 57±1·5%, respectively; rib longissimus muscle area: 32·8±0·91 cm2 and 32·9±1·10 cm2, respectively), and both were significantly (P<0·05) greater than those of the control group (lean cuts percentage: 53±1·5%; rib longissimus muscle area: 28·3±1·61 cm2). In conclusion, [His1, Lys6]-GHRP appeared to be a promising tool for controlling carcass fat in pigs.

Intake, digestion and growth were examined in young Merino×Border Leicester wether sheep held for 44 days in either cool (13–15°C, thermal humidity index 56–58) or hot (32–40°C, 50–70% relative humidity, thermal humidity index minimum 83–84, maximum 83–88) environments. The sheep were offered diets of medium quality hay ad libitum alone (Con) or supplemented with either 22 g air-dry/kg metabolic liveweight (W0·75) of barley grain fortified with urea and sulphur (Bar/N) or 10 g air-dry/kg W0·75 of fishmeal (FM). Intake of the Con diet by the sheep in the cool environment was high at 79 g DM/kg W0·75 per day. Sheep in the hot environment had higher rectal temperatures and higher respiration rates (40·1°C v. 39·2°C, 196 v. 56 respirations/min respectively, P<0·01). The hot environment reduced (P<0·05) total dry matter (DM) intake, estimated metabolizable energy (ME) intake, liveweight (LW) gain and nitrogen (N) balance. The provision of supplements did not change total DM intake, but increased (P<0·05) organic matter digestibility, estimated ME intake, LW gain and N balance. Wool growth was increased much more by the FM than by the Bar/N supplement, indicating that the supply of absorbed amino acids was increased substantially by the FM supplement. Neither voluntary intake nor productivity were influenced by any interactions between the thermal environments and the balance of nutrients provided by the diets. In conclusion, in these young sheep consuming a high intake of a medium quality roughage diet, moderate heat stress reduced intake and growth but did not affect the relative responses of the sheep to supplements providing principally fermentable ME or a similar amount of fermentable ME and additional metabolizable protein.

Effects of dietary energy and protein supply on liveweight (LW) gain and gain of protein, fat and ash in the carcass, and weight and gain of non-carcass organs were determined in 118 weaned crossbred lambs from two nutritional histories at Camden, NSW in 1991. Half of the lambs were fed to achieve and maintain LW at 35 kg (LOW group) and half of the lambs were fed ad libitum until they attained 50 kg LW (HIGH group), during a preliminary period of 126 days. In the subsequent experimental period, lambs were allocated to treatments providing 500, 800, 1200 or 1500 g/day of pelleted diets (123 g crude protein, 10 MJ ME/kg dry matter). Diets at each intake contained either 0, 30, 60 or 90 g of formaldehyde-treated casein (rumen escape protein, REP). This resulted in an experiment comparing LOW and HIGH group lambs at four energy intakes, within which were four rates of inclusion of REP. During the 90-day experimental period, LOW group lambs had higher rates of gain of LW, carcass weight and all non-carcass components than did HIGH lambs (P<0·001). At any rate of carcass gain, LOW lambs contained a significantly lower proportion of fat in carcass gain than did HIGH lambs (P<0·05). After adjustment to a common carcass weight, the carcass of LOW lambs contained a significantly lower mass of fat than did that of HIGH lambs at slaughter (P<0·05).

Carcass fat gain in the experimental period was not affected by LW at the start of that period or by nutritional history once initial LW was accounted for as a covariate. Data were consistent with fat deposition being principally controlled by energy intake over the immediate pre-slaughter period. In contrast, responses to energy intake in the rate of gain of carcass muscles, ash, liver, head and feet and gut tissue were significantly greater in lambs of LOW compared to HIGH nutritional history. A significant component of this effect of nutritional history was attributable to LW differences between LOW and HIGH lambs; however, nutritional history still had a significant effect on these parameters once initial LW was accounted for as a covariate. Nutritional history may also have modified carcass composition by changing the partial efficiency of use of available energy for protein deposition without changing the partial energetic efficiency of fat deposition.