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    Effects of plant growth regulators on vegetative development and seed production of birdsfoot trefoil (Lotus corniculatus L.) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University, Palmerston North, New Zealand
    (Massey University, 1991) Supanjani, Supansani
    Effects of chemical manipulation of a crop of birdsfoot trefoil (Lotus corniculatus L.) grown for seed in two consecutive years were investigated in this study. In the first year, treatments included Cultar (paclobutrazol) at 0.5 or 1.0 kg a.i./ha, Cycocel (chlormequat chloride) at 1.5 or 3.0 kg a.i/ha and Alar (daminozide) at 2.0 or 4.0 kg a.i./ha applied twice at either the late vegetative stage (October) or at the early flowering stage (November). None of these treatments affected seed yield (average 549 kg/ha),or umbel components (pods per umbel, seeds per pod and thousand seed weight). In the second year, at the same stages of plant development, Cultar and Cycocel were applied at the same rates as previously, with an additional treatment added using RSW-0411 (triapenthenol) at 0.5 or 1.0 kg a.i./ha. Again, no seed yield improvement was obtained by any chemical treatment, but average seed yield being increased 27% from 769 kg/ha by 6 days delay in harvesting from 41 to 47 DAPF. Shoot length was reduced by chemical applications, especially at the time of rapid growth, and Cultar had the strongest and longest retarding capability. However, plant branching was not improved by any treatment. Although early flowering pattern was increased by October Cultar application at the higher rate and peak flowering pattern by November Cultar application at either rate, total reproductive structures at harvest in treated plants were similar to those in untreated plants due to flower abortion. Cultar applications in the first year had no carry-over effects on seed production in the second year, but delayed early plant growth in terms of ground cover. Plant growth regulators had no effect on the quality of the subsequently harvested seeds. Effects of Cultar, Cycocel and RSW-0411 applied at higher rates in October reproductive abortion were examined in flowers produced during the flowering season in the second year. Chemical treatments increased flower abortion by 20%, especially in the early flowers. However, there was no effect on abortion of pods in an umbel, on abortion of ovules or seeds in a pod, or on seed weight. Time of flowering also modified flower abortion rate (late flowers having up to 48% greater flower survival than early flowers), and seed development rate (being slower in early season flowers), had no effect on pod abortion and seed abortion (average 44% and 70%, respectively). Flower abortion was first found as early as 10 DAOF. Pod abortion occurred consistently after flower opening, and ovule or seed abortion occurred particularly in the early stages of seed development.
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    Evaluation of Lotus corniculatus for increasing the efficiency of growth in young deer : a thesis presented in partial fulfilment of the requirement for the degree of Masters of Applied Science, Animal Science option at Massey University
    (Massey University, 1997) Adu, Emmanuel Kwadwo
    A grazing trial with lactating red deer (Cervus elaphus) hinds and their calves (EXPERIMENT 1), and an indoor digestion and calorimetric study (EXPERIMENT 2) were conducted at Massey University, New Zealand during 1996, to measure the feeding value of Lotus corniculatus compared to perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture for increasing the efficiency of growth in young deer. Half of the hinds and their calves were grazed on Lotus corniculatus and the other half were grazed on perennial ryegrass/white clover pasture during summer (Chapter Three) in a rotational grazing system. Half of the hinds in each group suckled pure red calves with the other half suckling hybrid (0.25 elk : 0.75 red deer) calves. The indoor experiments (Chapter Four) involved feeding one animal of a pair on either freshly cut perennial ryegrass or freshly cut Lotus corniculatus during autumn and spring, in metabolism cages and calorimetry chambers at maintenance (1M) and twice maintenance (2M) levels of energy intake. 1. EXPERIMENT 1 (CHAPTER THREE). Liveweight gains of hinds and their calves, weaning weight of calves and voluntary feed intake of hinds were measured on Lotus corniculatus or perennial ryegrass/white clover pasture during lactation in summer 1996. The percentage of dead matter in both the forage on offer and diet selected was lower in Lotus corniculatus than in perennial ryegrass/white clover pasture. The condensed tannin (CT) levels in Lotus corniculatus and perennial ryegrass/white clover pasture were 21 g and 1.6 g total CT/kg DM respectively. Organic matter digestibility (OMD) was higher for Lotus corniculatus than for perennial ryegrass/white clover pasture. Hinds grazing Lotus corniculatus had higher voluntary feed intake (VFI) and liveweight change than hinds grazing perennial ryegrass/white clover pasture, and liveweight gain and weaning weight of calves were greater on lotus. Liveweight gain and weaning weight of hybrid deer were superior to pure red deer calves, with pre-weaning liveweight gain of hybrid deer calves grazed on Lotus corniculatus exceeding 500 g/d for the first time. CT in Lotus corniculatus was more tightly bound in red deer oesophageal fistula (OF) extrusa samples than in comparable studies with sheep. 2. EXPERIMENT 2 (CHAPTER FOUR) Energy losses as methane, urine and heat were consistently lower when the deer were fed Lotus corniculatus (21 g total CT/kg DM) than perennial ryegrass (< 1 g total CT/kg DM), but faeces energy losses were similar for the two forages. The efficiency of utilisation of ME for growth (kg) was lower in autumn-grown than in spring-grown perennial ryegrass, and tended to be greater in autumn-grown Lotus corniculatus than autumn-grown perennial ryegrass. No significant differences existed in faecal N and urine N losses in deer fed the two forages, and N retention was similar in deer fed Lotus corniculatus and perennial ryegrass. Presence of CT-binding salivary proteins in deer but not in sheep is advanced as a reason for N retention not being greater on lotus. 3. The overall conclusion from this thesis was that as a summer feed during deer lactation, the feeding value of Lotus corniculatus is higher than that of perennial ryegrass/white clover pasture but essentially similar to that of other special purpose feeds developed for deer production such as chicory (Cichorium intybus) and red clover (Trifolium repens). The most cogent explanations for the higher performance in deer fed Lotus corniculatus is the higher VFI and the greater efficiency with which ingested energy was utilised. Because of the presence of salivary CT-binding proteins in deer, forages with higher CT concentrations are suggested for the realisation of the beneficial effects of forage CT on the efficiency of protein digestion in farmed deer. Two such forages are sulla (Hedysarum coronarium; 35-60 g CT/kg DM) and Lotus pedunculatus (50-100 g CT/kg DM). The incorporation of Lotus corniculatus into the pastoral agricultural system of NZ may be hindered by the slow establishment of the plant, and by the special management system required. It may be better suited agronomically to warm low to medium fertility hill country conditions, such as found in East Coast areas, where competition from other plant species is less.
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    Seed production in birdsfoot trefoil (Lotus corniculatus L.) : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Seed Technology at Massey University, Palmerston North, New Zealand
    (Massey University, 1989) Li, Qingfeng
    This thesis reports the results of three years' research on seed production of birdsfoot trefoil (Lotus corniculatus L.). Previous work by other researchers has suggested that a protracted flowering period is a major factor limiting seed production in this legume. The research programme was begun in 1986 with an investigation of the cause(s) of this protracted flowering period. By carefully examining the growth and flowering behaviour of tagged shoots formed at different times of the year, it was identified that the protracted flowering pattern in this plant is caused by the continuous production of shoots with the capacity to flower. The continuous development of new shoots replacing older flowering shoots was the main cause of the long flowering period. Results of the first year's research also showed that seed yield is primarily determined by the number of inflorescences produced. In turn, inflorescence numbers are primarily dependent on the number of shoots available at the time of flowering. It was suggested by the results that manipulation of the number and branching of shoots should be an important management strategy for improving seed production in this plant. The second stage of the study involved a number of hand removal and cutting treatments designed to investigate the possible effects of shoot removal on plant growth and seed production. Hand removal of crown shoots affected branching behaviour in this plant. Removal of young crown shoots at different growth stages resulted in a range of plant structural forms which influenced seed production potential. Cutting treatments, the major effect of which was to remove a section of shoot from the top, showed no obvious beneficial effects on seed yield in birdsfoot trefoil. In the third stage studies were extended to investigate a more practical situation in which plant growth regulating chemicals (paclobutrazol (PP333), ethofumesate (Nortron) and fatty alcohols (Fatol Super)) were used to manipulate shoot growth and development. Research at this stage involved both widely spaced individual plants and plants grown in a sward to simulate commercially practised situations. Results showed that PP333 is a promising pre-peak flowering shoot manipulator which acts by promoting branching. Nearly a 40% increase in seed yield was consistently obtainedin two years' experiments when this chemical were applied during the time from the pre-bud stage to the early flowering stage. Nortron showed its value in sward situations when applied at early plant development stage. However, Nortron was of limited value when it was used as a post-peak flowering shoot manipulator because of its injurious effect on plant growth and flowering. Fatol Super showed some potential as a post-peak flowering shoot manipulator, particularly when applied to spaced plants, but was less effective in sward situations. This reduces its value for use in the narrow row or sward seed production systems currently practiced in New Zealand for birdsfoot trefoil.
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    The effects of condensed tannins upon nutrient digestion and metabolism and upon animal production in sheep fed Lotus corniculatus : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University
    (Massey University, 1995) Wang, Yuxi
    A series of indoor metabolism and grazing experiments were conducted at AgResearch Grasslands and Massey University, Palmerston North, New Zealand, to study the effects of condensed tannins (CT) in Lotus corniculatus (birdsfoot trefoil; cv. Grasslands Goldie) upon nutrient digestion and metabolism and upon animal production using sheep as the experimental animal. Half of the animals in each experiment were supplemented with polyethylene glycol (PEG; MW 3500). PEG specifically binds and inactivates CT without affecting other nutrients and is indigestible; hence effects of CT were specifically defined by comparing control sheep (CT acting) with PEG supplemented sheep (CT inactivated). A rotational grazing system with some restriction in feed allowance was used in most of the grazing experiments. For the indoor experiments, sheep were held in metabolism crates and fed fresh L. corniculatus from overhead belt feeders at hourly intervals. 1. The effects of CT in L. corniculatus (35 g total CT/kg DM) upon nutrient digestion and upon metabolism of methionine, cystine and inorganic sulphate in plasma were determined. PEG was continuously infused into the rumen of half the sheep. Principal measurements in the two groups were plasma irreversible loss rate (IRL) and interconversions of methionine, cystine and inorganic sulphate using 35S labelling. Action of CT considerably reduced the concentration of ammonia and molar proportions of iso-butyric acid, iso-valeric acid and n-valeric acid in rumen fluid, but had no effects upon total volatile fatty acid (VFA) concentration and molar proportions of major VFAs. CT greatly increased the IRL of plasma cystine (13.1 vs 7.0 µmol/min) and reduced IRL of plasma inorganic sulphate (36.8 vs 48.1 µmol/min) but had no effect upon methionine IRL. Action of CT increased transulphuration of methionine to cystine (4.37 vs 1.24 µmol/min) and increased cystine flux to body synthetic reactions (11.89 vs 5.41 µmol/min). CT had no effect upon the proportion of methionine total flux transferred to sulphate (0.05 vs 0.06; i.e. oxidation) but markedly reduced the proportion of cystine flux transferred to sulphate (0.09 vs 0.27). CT had no effect upon the apparent digestion of cellulose and minerals, slightly depressed DM, OM and hemicellulose apparent digestion and markedly reduced the apparent digestion of nitrogen (N). Action of CT also reduced protozoa numbers in rumen fluid. 2. The productivity of lactating ewes (Exp 1) and weaned lambs (Exp 2) grazing swards of L. corniculatus, lucerne (Medicago sativa; cv. Grasslands Oranga) and a mixture of lucerne and lotus were compared in two grazing experiments in the 1991/1992 summer. Total CT content was 32-57 g/kg DM for lotus, 8-10 g/kg DM for the mixture and was negligible for lucerne (< 2 g/kg DM). In Experiment 1, ewe wool production and lamb live weight gain (LWG) did not differ between forages, but ewe LWG was greater on lotus than on lucerne (251 vs 65 g/d), with the mixture being intermediate (115 g/d). In Experiment 2, voluntary feed intake (VFI; 1.76 vs 1.65 kg OM/d), LWG (228 vs 183 g/d), wool production (2.78 vs 2.25 kg) and carcass weight (20.4 vs 17.8 kg) were greater for lambs grazing lotus than lucerne; lambs grazing the mixture had similar VFI (1.63 kg OM/d) to those grazing lucerne, but wool production (2.49 kg) was intermediate between lucerne and lotus lambs. Lotus did not affect carcass fatness (GR 13.1 vs 12.8 mm). It was concluded that L. corniculatus supported high levels of sheep productivity, with the results suggesting that part of the response may be due to increased protein supply from action of CT in the digestive system. 3. A grazing experiment was conducted for 22 weeks in the 1992/93 summer to study the effects of CT upon lamb LWG, wool growth and rumen metabolism, and to compare the productivity of lambs grazing L. corniculatus and lucerne. PEG was given orally twice daily to half of the lambs grazing each sward. Lotus contained 34 g total CT/kg DM in the diet selected, whilst there was essentially no CT in lucerne. Compared to lambs grazing lucerne, lambs grazing lotus had slightly lower VFI, and higher LWG, carcass weight gain, carcass dressing-out percent and wool growth. PEG supplementation had no effect on these measurements or upon the composition of rumen fluid in lambs grazing lucerne. However, in lambs grazing lotus, PEG supplementation reduced wool growth (10.9 v. 12.1 g/day), slightly reduced LWG (188 v. 203 g/day), increased rumen ammonia concentration, and increased the molar proportions of iso-butyric, iso-valeric and n-valeric acids and protozoa numbers in rumen fluid. PEG supplementation did not affect carcass gain, carcass fatness or the molar proportion of rumen acetic, propionic or n-butyric acids in lambs grazing lotus. 4. The effects of CT in L. corniculatus upon the lactation performance of ewes rearing twin lambs was measured in an 8 week grazing experiment in the spring/summer of 1993. Half of the ewes were supplemented orally twice daily with PEG. Lotus contained 45 g total CT/kg DM in the diet selected, with an in vitro digestibility of 73%. The results showed that action of CT slowed down the decline in milk production and secretion rates of protein and lactose after the attainment of peak lactation, resulting in more milk (21%), more milk protein (14%) and more milk lactose (12%) secretion in mid and late lactation compared to CT inactivated ewes. CT reduced milk fat percentage but not fat secretion rate. CT had no effect upon VFI, LWG and wool growth of lactating ewes rearing twin lambs. Plasma urea and glucose concentrations were reduced due to action of CT. CT had no effect upon concentrations of non-esterified fatty acids (NEFA), growth hormone and insulin in the plasma, had no effect upon molar proportions of acetic, propionic and n-butyric acids in rumen fluid, but markedly reduced concentrations of ammonia and molar proportions of iso-butyric, iso- and n-valeric acids in rumen fluid. 5. The effect of CT upon the true and apparent digestion of methionine and cysteine in the small intestine (SI) of sheep fed L. corniculatus containing 30 g total CT/kg DM were determined, using sheep prepared with rumen and abomasal cannulae. An indigestible liquid phase marker chromium ethylene diamine tetra acetic acid (Cr-EDTA) was continuously infused into the rumen of all sheep, and PEG was continuous infused into the rumen of half the sheep. The true digestibility of methionine and cysteine in the SI and their absorption sites in the SI were measured from continuous intra-abomasal infusion of plant homogenate from L.corniculatus containing 35S-labelled protein. Action of CT substantially reduced the true digestibility of methionine (0.72 v 0.88) and cysteine (0.66 v 0.81) in the SI, but increased the total amount of plant methionine and cysteine absorbed in the SI due to reduced rumen degradation. Action of CT slowed the digestion of both 35S-methionine and 35S-cysteine in the SI, and increased the flux of both amino acids in the mid and latter thirds of the SI. CT increased abomasal flux (as a proportion of eaten) of total methionine (0.88 v 0.76) and total cysteine (0.74 v 0.62), and increased absorption of total methionine (0.72 v 0.63 g/g eaten) but not total cysteine (0.49 v 0.48 g/g eaten) from the SI. Calculated endogenous loss of cysteine at the terminal ileum was greater than for methionine and both appeared to be increased by action of CT. It was concluded that action of CT in L. corniculatus increased wool growth rate in high wool producing sheep and increased milk production in lactating ewes without affecting VFI, thus improving production efficiency. It was deducted that the improved animal production was probably due to the action of CT reducing rumen protein degradation, increasing non-ammonia nitrogen (NAN) flux into the SI, increasing essential amino acid (EAA) especially methionine absorption from the SI, and increasing the flux of cystine to body synthetic reactions. Further researches are needed to study the effects of CT in the range 10-20 g/kg DM on animal production and nutrient metabolism, and to study the effects of forage CT upon milk production and composition in dairy cows.
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    Nutritional studies on Lotus corniculatus containing condensed tannins to increase reproductive rate and lamb growth under commercial dryland farming conditions : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2004) Ramírez-Restrepo, Carlos Alberto
    Five rotational grazing experiments were carried out at Massey University's Riverside farm, in the Wairarapa, on the East Coast of the Southern North Island, New Zealand, to compare the effects of feeding Lotus corniculatus L. (birdsfoot trefoil; cv. Grasslands Goldie) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) dominant pasture upon sheep year round productivity. These studies also investigated under grazing, seasonal and annual net herbage accumulation rate and seasonal dynamics of undisturbed (i.e. non-grazed) net herbage accumulation rate of L. corniculatus relative to that of grass-dominant pasture. Aspects of in vivo digestibility of dry matter (DMD), organic matter (OMD), digestible organic matter in the dry matter (DOMD) and metabolisable energy (ME) concentration of L. corniculatus at different stages of maturity over the spring, summer and autumn were investigated in three indoor digestion trials. 1. Two field experiments (Chapter 2) were conducted during spring to assess the effects of grazing mixed age undrenched ewes on L. corniculatus (n = 50) or pasture (n = 50) and their lambs (mainly twins) on live weight (LW), wool production, faecal nematode egg count (FEC) and dag score. In Experiment 1 (18 October 2000 to 21 January 2001) and Experiment 2 (3 October 2001 to 2 January 2002) both forages were fed ad libitum. Total condensed tannin (CT) concentration in the diet selected was 24 to 27 g CT/kg DM for L. corniculatus and 1.4 to 1.5 g CT/kg DM for pasture. The LW gain, weaning LW and wool production were consistently greater (P < 0.001) for lambs grazing L. corniculatus, in either Experiment 1 (258 vs. 189 g/day; 36.1 vs. 30.1kg; 1.17 vs. 0.98 kg) and in Experiment 2 (247 vs. 162 g/day; 31.8 vs. 24.1kg; 1.17 vs. 0.81 kg), respectively. Ewe and lamb dag scores were strongly and positively correlated with dag weight (P < 0.001) and generally increased with time in sheep grazing pasture, whilst grazing on L. corniculatus consistently reduced dag score. FEC in ewes grazing pasture showed a post-parturient rise (PPR) following lambing, whilst ewes grazing L. corniculatus had a reduced PPR in FEC. Up to day 70, FEC in lambs grazing L. corniculatus was lower than that for lambs grazing pasture, but between day 70 and the end of both experiments (approximately day 90), FEC in lambs grazing L. corniculatus increased to similar values as for pasture-fed lambs. FEC was not correlated with dag score or dag weight in ewes or lambs grazing pasture, but these indices were weakly and positively correlated in ewes and lambs grazing L. corniculatus, suggesting that lowering FEC on L. corniculatus also reduced dag formation. It was concluded that under dryland farming conditions, the use of L. corniculatus during the spring/early summer lactation period can increase lamb LW and wool production, whilst eliminating the need for pre-lambing anthelmintic drenching and probably reducing the amount of insecticide needed to control flystrike. These effects compared to pasture are probably due to higher digestibilty, higher ME concentration, higher voluntary feed intake (VFI), and to the effect of CT in reducing rumen protein degradability and controlling internal parasites in sheep grazing L. corniculatus. The absence of endophyte in L. corniculatus may have also have contributed to these effects. 2. During 2001 and 2002 (Chapter 3), grazing trials from February to November were conducted for 279 days (Experiments 1) and 285 days (Experiment 2), to compare the effects of grazing shorn mixed age Romney ewes in light condition on L. corniculatus versus pasture during the mating period (9 weeks, Experiment 1) and 11 weeks (Experiment 2). In Experiment 2, the length of time (days) that ewes need to graze L. corniculatus before mating to maximise reproductive performance was also investigated. Common objectives in both Experiments were to measure forage feeding effects on ewe wool production and LW of their lambs at weaning. In Experiment 1, groups of ewes (n = 100) were fed on either L. corniculatus or pasture at a herbage allowance of 1.8 kg green DM/ewe/day for the first three weeks of feeding and increased to ad libitum (2.3 kg green DM/ewe/day) during the mating period for two cycles. In Experiment 2, groups of 75 ewes grazed L. corniculatus for 42, 21, 10 and 0 days before a synchronised oestrus, with pasture being grazed for the balance of the 42 days. All L. corniculatus groups continued grazing L. corniculatus for a further 5 weeks. Feed allowance was initially 2.0 kg green DM/ewe/day, increased to 2.3 kg green DM/ewe/day during the mating period over the two cycles. At the end of L. corniculatus feeding in both experiments the groups were combined and grazed on pasture until weaning. Total CT concentration in the diet selected was 18 to 29 g CT/kg DM for L. corniculatus, with only trace amounts in pasture. In Experiment 1 mating ewes on L. corniculatus compared to pasture increased number of lambs born and lambs weaned per ewe lambing by 16 and 32% units respectively (P < 0.05), due to more multiple and less single births (P = 0.06) and to reduced lamb mortality (P < 0.05) between birth and weaning. In Experiment 2, increasing the numbers of days of grazing L. corniculatus before ovulation (0, 10, 21, 42 days) linearly increased ovulation rate (P < 0.05), lambs born and lamb weaned by up to 16% units, but had no effect upon lamb mortality. Mating ewes on L. corniculatus increased wool production (P < 0.01) and fibre length (P < 0.05) in Experiment 1 but not in Experiment 2. Grazing L. corniculatus had no effect on lamb birth weight and only small positive effects on weaning LW. It was concluded that, under commercial dryland farming conditions, the use of L. corniculatus during the mating season in late summer/autumn can be used to increase reproductive efficiency and wool production, with the largest responses in years with exceptionally dry autumn periods. These effects are probably due to the higher digestibility and ME concentration of L. corniculatus than pasture and to the CT in L. corniculatus reducing rumen protein degradability and leading to greater essential amino acid (EAA) absorption from the small intestine. Effects of forage CT upon the uterine microenvironment at the time of conception, implantation and early foetal growth, need to be investigated in future studies. It is also suggested that effects of mating on L. corniculatus upon lamb mortality between birth and weaning should be further investigated with ewe numbers/treatment increased from 100 to 350. 3. During the summer of 2002/2003, another grazing trial (Chapter 4: 95 days) compared the effects of grazing L. corniculatus and pasture on LW and the dynamics of nematode parasite infection in Suffolk x Romney weaned lambs fed ad libitum. Half of the lambs (n = 30) grazing either L. corniculatus or pasture received oral anthelmintic at the start and at monthly intervals (regular-drenched groups), whilst the remaining 30 lambs in each treatment only received oral anthelmintic when mean faecal nematode egg counts (FECs) exceed 1,000 eggs/g wet faeces (trigger-drenched groups), which occurred on day 58 only for both groups. Trigger and regular-drench lambs grazed separate areas. Total CT concentration in the diet selected was 40 to 31 g CT/kg DM for L. corniculatus, with only trace amounts in pasture. Regular-drenched lambs grazing L. corniculatus had significantly higher LW gain (298 g/day) and carcass weight gain (133 g/day) than all the other groups, whilst trigger-drenched lambs grazing L. corniculatus had significantly greater LW gain (228 g/day) and carcass gain (99 g/day) than regular-drenched (200; 66 g/day) and trigger-drenched (187; 63 g/day) lambs grazing pasture. Carcass fatness was significantly lower for trigger-drenched lambs than for regular-drenched lambs, when fed either L. corniculatus or pasture. Dag score was consistently lower for regular-drenched lambs grazing L. corniculatus than pasture; trigger-drenched lambs showed similar effects up to day 48, with no differences between the two groups thereafter. Regular anthelmintic treatment maintained FECs at low values, while parasitised lambs on L. corniculatus tended to have higher FECs than pasture-fed lambs. Relative to trigger-drenched lambs that grazed pasture, grazing trigger-drenched lambs on L. corniculatus had significantly reduced worm burdens of Haemochus contortus, Teladosargia spp., Nematodirus spp. and Cooperia spp. at slaughter, but greater burdens of Trichostrongylus spp., Chabertia ovina, Oesophagostonum spp. and Trichuris ovis were present in L. corniculatus-fed lambs. It was concluded that grazing L. corniculatus under dryland farming conditions compared to pasture can increase LW gain of weaned lambs, whilst reducing reliance on anthelmintic drenches to control parasites. These effects are probably due to increased protein supply from the action of CT enabling the lambs to have a higher LW gain when carrying a parasite burden, and to L. corniculatus better maintaining its high ME value under drought conditions. Using L. corniculatus to finish weaned lambs without anthelmintic drenches for a seven-week period is proposed. 4. A three-year study (Chapter 5; November 2000 to October 2003) was conducted to compare, under grazing conditions, seasonal and annual grazed net herbage accumulation rate and seasonal dynamics of undisturbed (i.e. non-grazed) net herbage accumulation rate of L. corniculatus relative to grass-dominant pasture. Prediction equations to estimate standing DM in L. corniculatus and pasture from the rising plate meter (RPM) and sward surface height were also generated. L. corniculatus and pasture growing in a moderate fertility and low-pH soil (pH 5.35) accumulated similar total herbage masses (24.3 vs. 24.1 t DM/ha) over the 3-year period, with the DM production being greater for L. corniculatus than for pasture during 2000-2001, producing more DM during summer/autumn drought conditions. The net herbage accumulation rate from undisturbed areas of L. corniculatus and pasture were similar in spring, summer and autumn. Seasonal variation in the calibration regressions fitted to estimate herbage mass of L. corniculatus non-destructively, suggested a combination of destructive and nondestructive methods are needed to assess herbage mass. It was concluded that L. corniculatus has the potential to increase the performance of a pasture-based sheep dryland farming system due to its ability to grow in acidic soils, its tolerance of drought conditions during summer/autumn and its seasonality of feed supply. 5. Three digestion experiments involving cryptorchid weaned lambs were conducted for 14 days over the spring, summer and autumn to determine changes in in vivo digestibility of DM, OM, digestible OM in the DM and ME concentration of L. corniculatus at different stages of maturity. In vivo digestibility samples were then used as standards to investigate if the enzymatic in vitro system of Roughan and Holland (1977) could predict OMD and DOMD of CT-containing L. corniculatus. Digestibility of L. corniculatus declined as it matured, but the rate of decline was much less than occurs for temperate grasses and for white clover. It was concluded that the in vitro enzymatic system of Roughan and Holland (1977) can be used to predict OMD and DOMD of L. corniculatus, provided a standard curve involving in vivo data generated with L. corniculatus is used. Using a standard curve with in vivo data from pasture led to bias which increased at lower OMD values. Reasons for the consistent differences between L. corniculatus and pasture standard curves are discussed, including possible effects of residual bound CT in lowering in vitro digestibility. From this series of experiments, this study is the first to report that relative to conventional perennial ryegrass/white clover, mating ewes on L. corniculatus under grazing conditions may reduce post-natal lamb mortality. It is also the first study to show that grazing sheep on L. corniculatus can maintain productivity during spring and summer with reduced dependence on anthelmintic drench input. It is concluded that whole farm modelling, mechanical harvesting and conservation strategies, selection of L. corniculatus germplasm for creeping-type plants more suited to grazing and the integration of new crops containing secondary compounds, such as chicory, should be considered to support major advances in sustainable dryland sheep farming systems.