In spite of the entomophilic structure of the rape flower, which is very attractive to nectar- and pollen-gathering bees, the crop gives good yields without insect pollination.

The aim of this study was to determine whether the inclusion of a condensed tannin (quebracho tannin, QT) and/or the elevation of dietary protein could reduce Trichostrongylus colubriformis establishment and existence in the small intestine of lambs. Thirty-six lambs (mean liveweight 32·6±3·9 kg) were randomly allocated to one of six experimental groups, groups 1–5 were parasitized with a trickle infection of 3000 infective Trichostrongylus colubriformis larvae daily, whilst group 6 remained as uninfected controls. Experimental diets were formulated to contain 222 g CP/kg (high protein) or 97 g CP/kg (low protein) with or without the inclusion of 50 g QT/kg. All six animal groups were fed the low protein diet, group 2 fed low protein diet+QT, for one month prior to infection (groups 1–5). Once nematode eggs were observed in the faeces, diets were abruptly changed in three experimental groups. Group 1 remained on the low protein diet, group 2 remained on the low protein+QT diet, group 3 changed to the high protein diet, group 4 changed to the high protein+QT diet, group 5 changed to the low protein+QT diet and group 6 remained uninfected and fed the low protein diet. Production, haematological and parasitological parameters were monitored at regular intervals. Results show that parasitized animals fed the high protein diet achieved growth rates similar to those of uninfected low protein-fed lambs. Inclusion of dietary QT did not depress liveweight gain. Total daily faecal egg counts declined after feeding the high protein diet. Inclusion of QT into the low protein diet also reduced faecal egg counts to similar levels observed in the high protein-fed lambs. The inclusion of QT into the high protein diet did not further reduce faecal egg counts. No significant differences in the haematological parameters measured were observed between infected animals (groups 1–5), suggesting that the beneficial effect of dietary QT in the low protein diet is unlikely to be mediated through an immune response. These data suggest that the inclusion of QT in low protein diets may be an alternative to feeding high protein diets to reduce nematode burden in lambs.

The effect of daily herbage allowance on herbage intakes and growth rates lambs grazing perennial ryegrass and red clover was investigated in two experiments. Herbage allowances defined as g herbage D.M./kg live weight (LW)/day were controlled by varying the areas of plots grazed for 2 days by groups of six lambs.

In the first experiment five herbage allowances in the range 20–120 g D.M./kg LW/day were offered on two areas of a perennial ryegrass (cv. S. 23) sward that received nitrogen fertilizer applications of 39 or 78 kg N/ha/28 days. In the second experiment five herbage allowances in the range 30–160 g D.M./kg LW/day were offered on perennial ryegrass (cv. S. 23) and red clover (cv. Hungaropoly) swards.

Asymptotic curves were fitted to describe the relationship between herbage allowance and daily intake of herbage. In Expt 1 nitrogen fertilizer rates did not affect the yield of herbage or animal performance. In Expt 2 intakes were higher on the clover sward than on the ryegrass sward at the higher herbage allowances.

The asymptotic curves to describe the relationship between herbage allowance and growth rate of lambs differed widely between periods. Growth rate of the lambs increased linearly with increase in digestible organic matter intake. Live-weight gain per unit of digestible organic matter intake was higher on the red clover than on the ryegrass.

The conclusion is drawn that if the herbage present to ground level is not more than three times the daily intake of the animals, intake of herbage of the animals may bo restricted.

The dipping of sheep and cattle, as a means of eradicating ‘scab,’ lice, ticks, etc., and the diseases which it is now known the latter may transmit, has met with such success, that compulsory dipping is now in vogue in most pastoral countries. Where compulsory dipping obtains, there must of necessity be some system of the standardisation of dips. In Queensland and South Africa, the respective Governments issue official formulae from which the stockbreeder can prepare his own dipping fluid. Only such proprietary dips, as are duly recognised by the Government, may be employed. In the United States, the regulations for the sale of proprietary dips are still more stringent. The quantity of active substance, usually sodium arsenite, nicotine or cresylic acid, is defined within very narrow limits. Further, no proprietary dip is now recognised, unless the manufacturer can furnish a ‘Field Tester,’ by means of which the stockbreeder can himself determine, in a simple and fairly trustworthy manner, the percentage of active constituent in his bath.

Yields from five of the plots on the Park Grass Continuous Hay experiment at Rothamsted, started in 1856, were examined to see if any long-term trends could be detected over the last 100 years. Three of the plots examined are unfertilized; two receive inorganic nutrients every year; all are harvested twice a year. In 1959 the harvesting procedure was changed: yields for the periods before and after this change were examined separately and together. On none of the three unfertilized plots was the slope of the regression of total yield (i.e. first and second cutscombined) on time significantly (P < 0·05) different from zero in either the 1891–1958 or 1960–1992 periods. On both the fertilized plots, there were significant declines in yield with time over the 1960–92 period, assuming that the effects of autocorrelation are sufficiently small to be ignored; there were no consistent changes between 1891 and 1958. There were some significant trends on the five plots when the two cuts were considered separately.

A linear regression model was fitted to the data in an attempt to separate the effects of meteorological variables (rainfall and sunshine hours over selected parts of the year) on total yield from possible long-term effects brought about, for example, by the increasing concentration of CO2 in the atmosphere. On four of the five plots this model accounted for between 12 and 21% of the yield variance in the pre-1959 period and between 45 and 63% after 1960. On the fifth plot, which received the highest level of N, the model accounted for 29% of the variance in the first period but only for 16% in the second period. When a linear trend with time was included in the model, this was not significant on any of the plots over the entire 1891–1992 period, although some significant trends appeared when the two periods were considered separately. The model was also fitted with the atmospheric CO2 concentration in place of the linear trend with time: again there were no consistent trends.

Neither changes in the concentration of CO2 in the atmosphere over the last century nor increasing inputs of combined N in rainfall or in dry deposition have had any detectable effects on yield in these plots.

Several delignifying agents, used in various paper-making processes, have been compared for their ability to remove lignin and increase the digestibility of several roughages in laboratory experiments using a spray method of treatment recently suggested by Wilson & Pigden (1964). The chemicals were dissolved in small quantities of water which were then used to moisten the roughage. No washing was done after treatment. Sodium hydroxide was the most effective chemical; at a rate of 10 g per 100 g of roughage, the lignin content of ground maize cobs was reduced by 26% and rumen dry-matter digestibility increased by more than 100%. Bleaching powder was as effective as sodium hydroxide in removing lignin, but residual chlorine apparently inhibited rumen microbial digestion.

Maize cobs, wheat and paddy straws, sorghum stover and sugar cane tops, though of widely differing initial digestibility, were brought to an equal level of rumen digestibility if treated with 4% or more of sodium hydroxide. Drying the treated roughage at 100 degrees instead of at room temperature increased digestibility only in the case of maize cobs. The alkali spray treatment was as effective in increasing the digestibility of chaffed as of ground wheat straw. Data are presented which show the amounts of residual alkali in treated roughage as a function of time after treatment and of concentration of alkali used in the treatment. Further, data are presented which show the loss of nutrients from treated roughage if washed as in the traditional method.

In experiments at Sutton Bonington between 1967 and 1970, which tested 0–300 kg N/ha applied in spring, maximum oil yields of both autumn- and spring-sown oilseed rape were obtained by applying 200 kg N/ha. The seed-oil content was reduced by nitrogen application but only seriously when 300 kg/a was applied. Responses to high levels of potassium (180 rather than 60 kg K20/ha) were only obtained at 200 kg N/a. Successive increments of nitrogen from nil to 300 kg/ha improved plant growth, increasing leaf area and the dry weight of leaves and stems. The last increment from 200 to 300 kg N/ha was less effective and either reduced or did not affect pod production.

In one experiment 300 kg N/ha stimulated husk growth, apparently at the expense of seed growth, with 200 kg/ha giving the highest proportion of pod dry matter as seed. More nitrogen always raised number of seeds per pod, but only increased seed weight in one autumn-sown experiment.

Serial harvests of one experiment indicated that the maximum seed and oil yield was obtained by cutting plants before they were fully ripe, thus avoiding seed loss through pod shatter. The oil content of the bulk samples reached a peak about a week before maximum oil yield, probably because later-ripening seed did not reach full maturity. All nitrogen levels delayed flowering, but only the highest delayed maturity in the autumn-sown crop.

A total of 140 British Friesian cows in their second or later lactation and with a mean calving date of 27 October (s.D. 18 days) were used in a randomized-block experiment over a 3-year period. The experiment was designed to examine the effects of level of concentrate given during the winter period, in addition to ad libitum access to grass silage, on total lactation performance. The silage had a mean dry-matter content and digestible organic matter in the dry matter of 206 and 698 g/kg respectively and the mean inputs of concentrates on the five treatments were 0–64, 0–89, 1–14, 1–38 and 1·59 t/cow (treatments 1–5 respectively). Sixteen replicates per treatment were housed in individual stalls during the winter period in order to facilitate the measurement of silage intake and the remaining animals in each year were maintained as a single group.

All animals in each year grazed together as a single group at pasture at a mean stocking rate of 6–0 cows/ha and without supplementary concentrates.

Level of concentrate supplementation had a significant linear effect on the intake of silage dry matter with the relationship between total intake of silage dry matter over the winter period (kg, y) and concentrate dry matter input (kg, x) being described by equation (1)

Seeds of oilseed rape (Brassica napus L.) can persist in the soil over several years by becoming secondarily dormant and can then germinate to create volunteer plants in following crops. As well as agricultural impacts caused by volunteers, gene dispersal in time – particularly from genetically modified cultivars – can be another undesirable consequence. Conventionally bred and transgenic seeds were tested in 2001 and 2002 in laboratory experiments, and in a field experiment, by burying seeds in the soil to determine the variation in dormancy and persistence capacity.

In the conventional group of cultivars tested in the laboratory, the level of dormancy was 13–76% in 2001, and 3–76% with an extended group in 2002. The transgenic group of cultivars was 1–31% dormant. In the burial experiments the number of viable seeds recovered in the conventionally bred cultivars ranged from 34–90% in 2001, and 7–68% in 2002. In the same studies the transgenic cultivars developed persistence levels from 12–79% in 2001, and 46–67% in 2002. Since dormancy levels of conventionally bred cultivars from 2 harvest years in the laboratory tests correlated significantly (r=0·71), it appears that there is a genetic background to secondary dormancy. There was also a significant correlation (r=0·61 in 2001 and 0·80 in 2002) between the results from laboratory and burial experiments. This indicates that the laboratory approach can simulate the situation in the field. Ageing over 6 months decreased the capacity for seed persistence to about a fifth of the level shown when freshly harvested. As a consequence of ageing and environmental impacts on persistence, only seeds from the same location and harvest year should be used for testing genetic variability. The high genetic variability among currently available rape seed cultivars gives breeding strategies a good chance of ideotyping low persistence genotypes and minimizing the risk of gene dispersal in time.

Despite the successes of the Green Revolution, about a billion people are still undernourished and food security in the developing world faces new challenges in terms of population growth, reduced water resources, climate change and decreased public sector investment. It is also becoming widely recognized that poverty is a cause of environmental degradation, conflict and civil unrest. Internationally coordinated agricultural research can play a significant role in improving food security by deploying promising new technologies as well as adapting those with well-established impact.

In addition to the genetic challenges of crop improvement, agriculturalists must also embrace the problems associated with a highly heterogeneous and unpredictable environment. Not only are new genetic tools becoming more accessible, but a new generation of quantitative tools are available to enable better definition of agro-ecosystems, of cultivar by environment interactions, and of socio-economic issues, while satellite imagery can help predict crop yields on large scales. Identifying areas of low genetic diversity – for example as found in large tracts of South Asia – is an important aspect of reducing vulnerability to disease epidemics. Global strategies for incorporating durable disease resistance genes into a wider genetic background, as well as participatory approaches that deliver a fuller range of options to farmers, are being implemented to increase cultivar diversity.

The unpredictable effects of environment on productivity can be buffered somewhat by crop management practices that maintain healthy soils, while reversing the consequences of rapid agricultural intensification on soil degradation. Conservation agriculture is an alternative strategy that is especially pertinent for resource-poor farmers.

The potential synergy between genetic improvement and innovative crop management practices has been referred to as the Doubly Green Revolution. The unique benefits and efficiency of the international collaborative platform are indisputable when considering the duplications that otherwise would have been required to achieve the same impacts through unilateral or even bilateral programmes. Furthermore, while the West takes for granted public support for crucial economic and social issues, this is not the case in a number of less-developed countries where the activities of International Agricultural Research Centres (IARCs) and other development assistance organizations can provide continuity in agricultural research and infrastructure.

Intake and faecal and urinary output of nitrogen, potassium and phosphorus by steers grazing high quality pasture at either of two intake levels were measured in three trials lasting 10–12 days. Intake was estimated from total faecal D.M. and in vitro D.M. digestibility of hand-plucked pasture. A known proportion of urine was sampled by a nonsurgical technique.

Average urinary mineral output between trials ranged from 93 to 134 g N/day, or 40 to 51% of consumed N; 74 to 137 g K/day or 33 to 76 % of consumed K and no more than 1 g P/day, or 2 to 4% of consumed P. Faeces contained 36–62 g N/day, or 16–24% of consumed N; 12–46 g K/day, or 8–21% of consumed K and 10–23 g P/day, or 44–74% of consumed P. The volume of urine passed differed widely between days for individual steers and between steers within each trial. In trial 3, daily output ranged between 5–8 and 54.71 by different animals. For two steers over three 24 h periods, frequency of urination ranged between 13 and 73/24 h; urine volumes between 7.6 and 51.2 1/24 h; urinary excretion of N between 81 and 137 g/24 h and of K between 58 and 90g/24h.

Urinary N and K concentrations were higher at night than during the day, ranging in trial 3 from 0.8 to 14.1 mg N/l, and 0.6 to 9.9 mg K/l. No clear diurnal patterns were found for P.

Nineteen feedstuffs were evaluated for total digestible nutrients (TDN), digestible energy (DE) and metabolizable energy (ME) using growing pigs. DE values, on a drymatter basis, ranged from 1570 kcal/kg D.M. (grassmeal) to 4890 kcal/kg D.M. (BP Grangemouth protein). ME averaged 97·4% of DE for cereal feeds and 81·9% of DE for protein feeds, the ratio of DE to ME being significantly affected by the crudeprotein content of the feedstuff:

ME/DE × 100 = 99·7–0·18 × crude protein (%): r = –0·94; P < 0·01.

TDN was more closely related to ME than DE:

DE (kcal/kg D.M.) = 45 TDN + 156: r = 0·92; P < 0·01,

ME (kcal/kg D.M.) = 43 TDN + 71: r = 0·98; P < 0·01.

ME values were corrected to both 30% and 0% nitrogen retention. Correction to 30% retention caused a maximum change of 3% in ME value while correction to 0% retention had a variable effect related to protein content of the feedstuff:

(ME(N0)/ME) × 100 = 98·3–0·113 × crude protein (%): r = –0·80; P < 0·01.

Diverse cultivars of winter wheat (Triticum aestivum L.) were grown in the field in 1993/94 and 1994/95 at Reading UK in temperature gradient tunnels at normal atmospheric (c. 370) or elevated CO2 concentration (c. 700 μmol CO2 mol−1 air). In 1993/94, grain yield of cv. Avalon was insensitive to mean temperature (between 8·8 and 10·9°C), while elevated CO2 increased yield by 1·3 t ha−1 (12·6%). In all other cultivars, warming reduced grain yield and CO2 increased grain yield. In 1993/94, in cvs Galahad and Mercia the effects of CO2 and temperature on yield were additive. However, for cv. Hereward in both years and for cv. Soissons in 1994/95, there were negative interactions between the effects of CO2 and temperature on yield: the maximum benefit of doubling CO2 to grain yield, 4·5 and 2·7 t ha−1 (65 and 29%) respectively, occurred at cooler temperatures; there was no benefit from doubling CO2 (i.e. 0%) once the temperature had increased above the seasonal mean by 2·2–2·6°C in cv. Hereward and by 1·3°C in cv. Soissons. The beneficial effect of doubling CO2 on grain yield in cvs Galahad, Hereward, Mercia and Soissons was negated by an increase in mean seasonal temperature of only 0·7–2·0°C. Warming decreased root dry mass at anthesis in 1994/95 while it increased at elevated CO2 (49 and 186%, coolest and warmest regime, respectively). Carbon partitioned to roots declined progressively with warming, while at elevated CO2 there was an average of 56% increase in allocation to roots. The relative impacts of both CO2 and temperature were greater on root dry mass than on either grain yield or total above-ground biomass, while the effects on grain and biomass yield varied considerably between cultivars, suggesting that the impact of rising CO2 and temperature are likely to be dependent on cultivar.

A method is proposed for correcting for competition effects in yield trials by joint regression of plot yields on to the yields of neighbours. Estimation of the variety effects and competition coefficient along with tests of significance are described for a sugar-beet trial with single-row plots where competition effects are assumed to extend only to plants in immediately adjacent rows. For designs which are balanced for neighbouring varieties it is feasible to estimate separate varietal competition coefficients which may be partitioned into components for sensitivity and aggressiveness. An example is given of this extended model fitted to a competition diallel of seven species. While species differed in their sensitivity to competition there was no essential difference between inter- and intra-species behaviour. The model is used to assess comparative varietal performance in monocultures from performance in small plot trials.

(Note that the general term ‘variety’ is used throughout this paper to refer to progenies at any stage in a selection programme.)

Three wheat experiments are described in which a range of plant populations were shaded during different periods of development; in two of the experiments plant thinning was also carried out at a number of growth stages. Shading during the period of ear development caused an appreciable decrease in grain yield by decreasing the number of grains per ear. Shading during the grain filling period also reduced grain yield, this being brought about by decreased grain size. Thus in contrast to the barley experiments reported earlier (Willey & Holhday, 1971), these particular results gave no indication of a potential surplus of carbohydrate for grain filling and an associated limited ear capacity. However, when plant thinning was carried out at anthesis to make more carbohydrate available for grain filling in the remaining ears, grain yield per ear did not increase. It is argued, therefore, that grain yield probably was determined at least partly by a limited ear capacity. Plant thinning at earlier stages showed how the development of competition during the ear development period progressively reduced the potential capacity of the ear; the greater competition of higher plant populations accelerated this reduction in ear potential.

From an examination of the effects of plant population, it is suggested that the number of grains per ear is the component having greatest influence on the decline in grain yield at above-optimum populations. The possible importance of the number of grains per unit area as an indicator of ear capacity on an area basis, and as a determinant of grain yield per unit area, is emphasized. A close relationship between grain yield per unit area and number of grains per unit area is illustrated for a number of plant-population response curves, and it is suggested that the decrease in grain yield at high populations is probably determined by a decrease in the number of grains per unit area. Evidence is presented to substantiate the idea put forward in the barley paper that this decrease in the number of grains per unit area may be attributable more to a lower production of total dry matter by the high populations during the later stages of ear development, than to an unfavourable partitioning of such dry matter between the ear and the rest of the plant.

Teat orders were determined for 76 litters of Large White and Large White × Landrace pigs. Regression analysis within litters revealed a relationship between suckling position and weight both at birth (P<0·01) and at 3 weeks of age (P<0·001), with the heavier piglets tending to occupy the more anterior teats. The correlation coefficients, however, were very small (r = –0·16 and –0·22 respectively). The correlation between birth weight and 3-week weight was much larger (r = +0·47); and a comparison of pairs of litter-mates showed that a difference in birth weight of 0·25 kg or more persisted at 3 weeks in the majority of cases, regardless of which piglet suckled the more anterior teat. Birth weight accounted for much more of the variation in 3-week weight than did teat number, and, when the effect of birth weight had been taken into account, teat number accounted for only an additional 2·3% of the variation. Even so, the anterior teats did appear to confer some advantage which was independent of that of the birth weight of the piglets suckling these teats. From the results of this and other studies it is concluded that there is only a weak relationship between suckling position and weight at birth and 3 weeks. Other unidentified factors are probably of more importance for the within-litter variation in weight gain of suckling pigs.

1. The length of oestrus in mares varied from 3 to 54 days, although in most cases it was 7–8 days.

2. The length of dioestrus varied from 5 to 30 days, but in most cases was 11–16 days.

3. Ovulation occurred in most cases on the last day of oestrus, but a considerable number of ovulations occurred on the 1st and 2nd days before the end of oestrus, and in a few cases from the 5th day before the end of oestrus to 1 day after the end of oestrus.

4. Artificial insemination of mares was equally effective in the intervals of 24, 48 and 72 hr. before ovulation but was unsuccessful in intervals of 2 and 4 hr. after ovulation.

5. Pregnancy was diagnosed in all mares by rectal palpation on the 23rd day and in one mare as early as the 16th day.

6. The foetus developed in the opposite horn of the uterus to the ovary which ovulated at the onset of pregnancy in five out of seven mares.

7. Ovulation occurred in one mare on the 23rd day of pregnancy.

8. Gonadotrophic hormones had no effect when given in the anoestrous period (November to March).

9. Ovulation was induced in 20–40 hr. in most cases after the intravenous injection of 1000–2000 mouse or rat units of pregnancy urine extract intravenously, provided a fairly mature follicle was present in the ovary at the time of injection.

When this ovulation occurred, the duration of oestrus was shortened.

Deficit irrigation (DI) improves water use efficiency (WUE), but the reduced water input often limits plant growth and nutrient uptake. The current study examined whether arbuscular mycorrhizal fungi (AMF) could alleviate abiotic stress caused by low phosphorus (P) fertilization and DI.

A greenhouse experiment was conducted with potato grown with (P1) or without (P0) P fertilization, with AMF (M1+: Rhizophagus irregularis or M2+: Glomus proliferum) or AMF-free control (M−) and subjected to full irrigation (FI), DI or partial root-zone drying (PRD).

Inoculation of M1+ and M2+ maintained or improved plant growth and P/nitrogen (N) uptake when subjected to DI/PRD and P0. However, the positive responses to AMF varied with P level and irrigation regime. Functional differences were found in ability of AMF species alleviating plant stress. The largest positive plant biomass response to M1+ and M2+ was found under FI, both at P1 and P0 (25% increase), while plant biomass response to M1+ and M2+ under DI/PRD (14% increase) was significantly smaller. The large growth response to AMF inoculation, particularly under FI, may relate to greater photosynthetic capacity and leaf area, probably caused by stimulation of plant P/N uptake and carbon partitioning toward roots and tubers. However, plant growth response to AMF was not related to the percentage of AMF root colonization. Arbuscular mycorrhizal fungi can maintain and improve P/N uptake, WUE and growth of plants both at high/low P levels and under FI/DI. If this is also the case under field conditions, it should be implemented for sustainable potato production.

1. Cereal plant density affects yield and growth parameters of fundamental importance. An experiment is described in which growth and development, and yield and yield components of barley grown over a wide range of density were examined.

2. Four varieties of barley—Proctor, Plumage-Archer, Domen, and Moore—were grown at densities approximately equivalent to 35, 70, 140 and 280 lb/acre. Density was found not to affect seedling establishment or plant survival, but there was a variety effect on seedling establishment.

3. Varietal differences were seen in maximum tiller number, and the percentage of tillers surviving to form ears. These differences were most marked between the six-row variety and two-row varieties. The effect of increasing density was to increase the maximum tiller number, but this was followed by different rates of tiller death until early June, after which there was no further compensation for tiller number. Ear emergence and ear number were affected both by variety and density.

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.