Rosebery is a 295 ha rolling downland North Otago property in the Airedale district, 10 km west of Oamaru. The proximity of the farm to the coast gives a shorter winter (100 days) than that generally experienced further inland. However, the same challenges experienced in coping with the seasonal variations are shared with other North Otago farmers. Having lived in this area for all of my 46 years, farming in family partnerships for 12 years, from 1969–1981, and since then with my wife Gail in our own right, I believe I have a reasonable level of awareness of farming a unit such as ours in this district.
Download
(122 KB)Farm profitability is under pressure, with depressed product prices and a rising exchange rate combining to reduce farmer incomes. While exchange rate movements do affect short-term profitability, longterm trends have a much greater effect upon farm profits. While commodity prices are cyclical, over time they fail to keep up with inflation. An analysis of international commodity prices from 1949 to the present day demonstrates a reduction in real terms for all agricultural commodities. An analysis of prices received by New Zealand farmers since the 1950s shows a similar trend. The efficiency of sheep production, measured as lambing percentage and wool weights, has not demonstrated the improvements achieved by other sectors. Milkfat production per cow has doubled over the past 80 years, broiler chicken feed conversion efficiency has doubled over the past 20 years, wheat yields are two and a half times greater now than 70 years -ago, while lambing.percentage and wool weights hXVc not-significantly-improved-since-I-950.Sheep. and beef farms maintained profitability by increasing stocking rate and stock numbers per labour unit, and diversifying .into more profitable stock, such as deer. The pressures facing farmers in the mid 1990s are being faced by other farmers elsewhere in the world, and have existed since intensive farming began in New Zealand. To farm profitability today, as in the past, farmers need to continue to capitalise on technology, and modify farm outputs to match market demand, at a greater rate than?%tip~titEK -~~ - Keywords: agricultural profitability, agricultural production, commodity prices, New Zealand
Download
(136 KB)North Otago soils are all of sedimentary origin but range in topography from flat alluvial and terrace soils to hill soils. Most of the farmed soils are yellow-grey earths on the rolling downlands or plains. Yellow-grey earths on the downlands have dense subsoils that limit water movement during wet winters and rooting depth during dry summers. Plains soils have shallow depths to gravels limiting water holding capacity and making irrigation necessary for intensive pastoral production. The relationships between soil nutrient levels and pasture production has been shown to be of the diminishing returns type. Soil nutrient levels for near maximum pasture production on North Otago soils are Olsen P 20-25, sulphate-S 10-12, organic-S 15-20 and quick test K 5-8. At high stocking rates profitable responses in pasture and animal production can still be gained at higher Olsen P levels. The decision support nutrient model (OUTLOOKTM) has been developed to help farmers apply fertiliser at optimum rates for economic production. Keywords: economic production, North Otago, phosphorus, potassium, sedimentary soils, sulphur, yellow-grey earths
Download
(117 KB)The contributions to grasslands research and practice of the internationally notable New Zealand Scientist, Dr Raymond Wilkie Brougham are reviewed. He made significant contributions to the fundamental understanding of processes in pasture establishment, pasture growth particularly its relationship with leaf area and light interception, and to grazing management effects on the botanical and genetic composition of grassland communities.
Download
(619 KB)
The performance of three different multi-species pastures (MSP), or mixed herb leys as they are also known, was compared with that of a standard ryegrass–white clover pasture (cvs Grasslands Super Nui–Grasslands Huia), over a 3-year period at two dryland sites. The MSP treatments had grass and legume species selected for compatibility and growth and aimed to provide a contrast in quality and production. The herb species, common to each of the MSP treatments, were chicory, plantain, sheep’s burnet and yarrow. The dry matter production of the MSP treatments was significantly higher than that of the ryegrass–white clover pasture (P<0.05) in all three years at one site and in one year only at the other site. Seasonal growth comparisons showed higher summer growth (P<0.05) for MSP treatments compared with ryegrass–white clover and similar autumn growth. Contribution to production of herbage components demonstrated less grass (P<0.05) and more legume and herbs in the MSP treatments. A lucerne-based MSP gave the best overall performance. Keywords: herbs, legumes, Medicago sativa, feed quality, Trifolium pratense
Download
(155 KB)Increasing resistance of gastro-intestinal nematode parasites to anthelmintics and consumer resistance to the possibility of residues in animal products have prompted research on the effect of pasture species on nematodes and animal performance. Lambs (either infected with high rates of gastrointestinal nematodes or maintained nematode-free) were grazed on pure swards of chicory, high- or low-endophyte ryegrass, cocksfoot, tall fescue, lucerne, lotus, white clover or plantain. Infected lambs that grazed chicory had lower faecal egg counts and adult nematode populations, and higher carcass weights, than lambs grazed on plantain or the grass species; lambs that grazed legumes generally had intermediate counts, populations and weights. When kept parasite-free, carcass weights were up to 48% greater than in the nematodeinfected treatments. On farmlets run over 3 years, substituting 30% of the ryegrass area with lucerne or replacing the ryegrass with a multi-species mix consisting predominantly of bromes, tall fescue, phalaris, timothy and red and white clover, had no effect on gastrointestinal nematode larvae, lamb faecal worm egg or adult nematode numbers. It is concluded that a diet of pure chicory affects internal parasite populations but the small proportion included in the farmlet studies had no effect. Keywords: Cichorium intybus, Dactylis glomerota, Festuca arundinacea, gastro-intestinal nematodes, lambs, Lolium perenne, Lotus corniculatus, Medicago sativa, pasture species, Plantago lanceolata, Trifolium repens
Download
(130 KB)The effects of ryegrass genotype, nitrogen (N) fertiliser and soil type on the level of plant losses by “pulling” during grazings were studied over 2 years. Plots of high-endophyte pipeline perennial ryegrass lines, coded A1 and A3, were established on the Dairying Research Corporation No. 2 Dairy in May 1994. Three plots of each line were sown on a Te Kowhai silt loam and three on a Te Rapa peaty silt loam soil. Half the area of each plot received nitrogen fertiliser (30 kg N/ha) after grazings from September 1995 to February 1996. Line A1 pulled more than did A3. Pulling was worse on the peat than on the silt loam, and was highest during summer–autumn 1994–95, which included a prolonged dry spell. N fertiliser increased post-flowering tillering, especially for A1. A1 had a higher leaf shear strength (6.21 vs 5.91 kg, SED = 0.087) and a wider leaf (3.40 vs 3.22 mm, SED = 0.054) than A3. It is argued that these morphological differences were important contributors to the observed pulling differences. Since A1 outyielded A3, we consider that plant losses owing to pulling did not constitute a serious loss of herbage dry matter. Keywords: dairying, leaf morphology, leaf shear strength, Lolium perenne, nitrogen fertiliser, persistence, pulling losses, tiller dynamics, tillering
Download
(154 KB)Lamb performance was evaluated for three consecutive summer–early autumn periods on ryegrass (Lolium perenne), white clover (Trifolium repens), chicory (Cichorium intybus), plantain (Plantago lanceolata) or lotus (Lotus corniculatus). Lamb liveweight gains, fasted liveweights at slaughter and hot carcass weights tended to be highest on legumes and chicory and lowest on plantain and ryegrass. Greasy wool weights were significantly higher on lotus and white clover than on chicory, plantain and ryegrass. Greasy wool weight was significantly related to fasted liveweight (R2=0.94–0.99). Protein (%) in herbage accounted for 83–92% of the variability in animal performance; food intake accounted for 57–69% of the variability and was negatively correlated with hemicellulose and cellulose (R2=97.2 and 80.9%, respectively). Thus quality of feed was more important than intake alone in determining animal performance. Keywords: carcass weight, Cichorium intybus, greasy wool weight, intake, lamb performance, Lotus corniculatus, Lolium perenne, Plantago lanceolata, Trifolium repens
Download
(132 KB)Increasing concerns about food quality and animal fat in the human diet have promoted research into the effects of different forage species on carcass quality and fat content. This trial investigated the effect on carcass composition and the intensity of sheep meat flavour and odour of five different pure pasture species: Grasslands Lancelot plantain (Plantago lanceolata), Grasslands Puna chicory (Cichorium intybus), Grasslands Huia white clover (Trifolium repens), Grasslands Nui high-endophyte perennial ryegrass (Lolium perenne) and Grasslands Goldie lotus (Lotus corniculatus). Although pasture species did affect meat quality and fat content, there appeared to be an inverse relationship with carcass weight: larger lambs had more fat, which was related to difference in body size and relative maturity rather that pasture species. Pasture species also influenced muscle ultimate pH, sheep meat odour, foreign odours, and flavours, but did not affect sheep meat flavour. Keywords: Cichorium intybus, meat flavour, Lolium perenne, Lotus corniculatus, meat odour, Plantago lanceolata, Trifolium repens
Download
(147 KB)Plantago lanceolata L. is a herb species with a broad distribution in grasslands throughout the temperate world. The leaf is highly palatable to grazing animals, providing a mineral- rich forage. The species is rapid to establish, grows on a wide range of agricultural soils and is tolerant of drought and of many common diseases and pests. Two productive upright cultivars of plantain have been bred, Grasslands Lancelot and the more erect winter active Ceres Tonic. Plantain contains a range of biologically active compounds, often in large quantities. The antimicrobial compounds present can inhibit rumen fermentation and change the volatile fatty acid composition of the rumen. These changes have potential to affect bloat, animal performance and milk composition. The performance of animals grazing plantain has varied from excellent in mixed pastures to poor on nitrogen-fertilised pure swards. Animals grazing plantain have been observed to have a reduced incidence of scouring and dags in some trials, but despite a mild anthelmintic effect detected in the laboratory, field trials have failed to detect any significant reduction in worm burdens. The most likely use of plantain on farms is as a component of mixed pasture swards. Its contribution is likely to be greatest where grass growth is less vigorous and where there are gaps in the sward. These conditions are likely to be found in low fertility dryland pastures. It is unlikely to be the dominant species and could be expected to contribute less than 20% of the sward, except where the grass or legume growth is poor. Keywords: perennial forage herbs, Plantago lanceolata, plantain
Download
(176 KB)In a Grasslands Ruanui perennial ryegrass (Lofium perenne L.) sward at Palmerston North, root mass, root appearance, tiller population density, tiller appearance and death rates, and leaf extension and leaf appearance rates were measured at 2-monthly intervals over a 12-month period, commencing November 1988. Tiller appearance was lowest in November, but was also low in May, increasing to a peak in August. Root appearance showed a pronounced peak in August. Leaf extension and leaf appearance rates were low during the period of high root and tiller formation in August, but high in November when tiller and root formation were low, suggesting co-ordination of these processes, with sequential activation of tillering, root formation and leaf formation activity winter. Principal component analysis to gain an objective overview of these data indicated a primary peak of activity in August (spring), and a secondary peak in March (autumn). The seasonal patterns observed for Grasslands Ruanui ryegrass appear to be different from those reported in the literature for Ellett and Grasslands Nui cultivars. ---.----._- - - - Keywords: leaf extension rate, Lolium perenne, principal component analysis, root growth, tiller appearance
Download
(93 KB)
The variable seasonal pattern of pasture production is dominantly influenced by rainfall in the semiarid and sub-humid high country regions. A decision support system for predicting seasonal rainfall has been developed and tested using the rainfall data from 14 sites in the semi-arid, sub-humid and humid high country zones. The prediction system improves the chances of making a correct or incorrect but conservative risk management decision from 50:50 to as much as 92:8 dependent on the site’s weather characteristics and the length of rainfall records available. The system provides support for risk management decisions such as whether to employ the buffers of stocking rate adjustments and feed conservation measures usually present in most high country farming systems to cope with the variability in seasonal pasture growth. The method has particular applicability in the semi-arid and subhumid areas of the inland basins and foothills and the mid Waitaki area. Keywords: decision support, high country, rainfall, risk management, semi-arid, sub-humid
Download
(157 KB)Two experiments were designed to provide practical guidelines to improve the effective use of browse plants as ruminant feed, especially during dry summers. The effects of planting stock and cutting management on forage yield and quality of Tangoio hybrid willow (Salix matsudana x alba), Kinuyanagi willow (Salix kinuyanagi) and erect dorycnium (Dorycnium rectum), a small leguminous shrub, were determined over one summer from 1- and 3-year-old trees. Experiment 1 was arranged as a 2×2 factorial with 2 species and 2 planting stock in 5 randomised complete blocks. Experiment 2 was also arranged as a split plot design with cutting heights allocated to main plots and species × frequency to sub-plots in 3 randomised complete blocks. At the hill country site (Ballantrae), the yields of Tangoio (66 g DM/tree) and Kinuyanagi (27 g DM/tree) were low, owing probably to the low soil nutrient status and the harsh climatic conditions. Poor regrowth after the summer harvest at Ballantrae suggested that willows can be utilised only once during the growing season in such environments. At the lowland site (Aokautere), Tangoio was higher yielding (P<0.05) than Kinuyanagi, with erect dorycnium the lowest yielding. Erect dorycnium was ineffective as drought fodder in the Manawatu owing to its relatively low yield. Tree forage digestibility and total nitrogen content were higher in Tangoio than Kinuyanagi (P<0.05) but were not affected by stock type and cutting height. Harvesting twice during the growing season increased the edible forage yield by 27% (P<0.05). Total condensed tannin content was higher in Kinuyanagi than Tangoio, a possible disadvatange. Unrooted stem cuttings were as productive as rooted cuttings (P>0.05) and are cheaper to establish. Tangoio and Kinuyanagi have potential as drought fodder in addition to their traditional roles in soil conservation and rehabilitation. Keywords: browse, cutting management, Dorycnium rectum, multipurpose trees, planting stock, Salix kinuyanagi, Salix matsudana x alba
Download
(141 KB)The North Otago area has a climate that often fluctuates from severe drought to flood in a short space of time. The climatic extremes, and some unsustainable land use practices can put the area’s fragile loessial soils at risk of water and wind erosion. This paper outlines an approach used in North Otago which has enabled the community to identify its sustainability and environmental issues and begin to make changes to land use and farmer attitudes. A group of key farmers was brought together to oversee the preparation of Sustainable Land Management Guidelines for the downlands. (This group became the North Otago Sustainable Land Management Group – NOSLaM Group.) From this grew a wide-ranging community-driven project with a full-time co-ordinator, and a vision to have most land users adopting sustainable farming systems. This should ensure the area is ready to meet the world market demands for environmental quality in food and fibre production. The Group will promote individual environmental farm plans which will have a monitoring component. Some farmers will work towards some form of property accreditation such as ISO 14001. This pilot project will be highlighting the economic benefits of environmentally sound farming methods, through seminars, field-days, newsletters and a demonstration farm. The Group is working in partnership with farmers, the processing industry and marketing people to identify market opportunities for the area’s food and fibre produced by environmentally friendly farming systems. Keywords: cultivation, environment, Environmental Farm Plans, erosion, guidelines, ISO 14001 accreditation, market opportunities, monitoring, sustainable land use, sustainability
Download
(135 KB)The Hakataramea Valley is located north of Kurow midway between the east coast and the Mackenzie Basin. It is bounded on the east by the Hunter Hills and the west by the Kirkliston Range, which rises to 1800 metres. The catchment is 56 km long with an average width of 21 km, and drains 800 km2. Almost half the area is in terraces and fans, 20% hills and 30% high country. the dry eastern parts of the valley have less than 500 mm of rain, but rainfall increases rapidly with altitude to about 1000 mm on the mountains in the west. Summers are normally hot and dry with about 80 days of moisture deficit. Winters can be long with heavy frosts. Because of these great variations in climate and topography every farm has its own possibilities and problems. Moa hunters were the first inhabitants of the area. European settlement saw the valley split into a few large runs. Subdivision followed and there are now 55 properties with an average size of around 600 ha. Cropping was widespread on some of the rich farms on the lower west side but sheep, followed by cattle, are now the major source of farmers’ income. The exceptions are the two or three cropping–grain and grass seed and/ or two large-scale deer properties.
Download
(88 KB)
The Waitaki Plains has 30127 ha of irrigation. The sheep, beef and cropping properties have been converted to dairy farms over recent years. Between 1989-90 and 1994-95 dairy cow numbers increased from 14 000 to 39 000, mainly as a result of large operations being established. The herd size in the same time scale has increased from 292 to 443 cows per farm. Performance has also increased dramatically, with per cow production going from 260 kg milksolids (MS)/cow in 1986-87 to 362 kg MS/cow in 1995-96. The excellent stock performance is reflected in the financial gains that farmers have made. The potential for increased performance now comes from improved grass quality and growth. Keywords: dairy conversion, dairy farming, Waitaki Plains
Download
(119 KB)New Zealand dairy farmers are increasingly using supplementary feeds in an attempt to overcome the quantitative and nutritional limitations of pasture. The use of rolled maize grain and pasture silage supplements was evaluated on a farmlet basis for two seasons. Supplementary feeding resulted in 88 and 82 g milksolids (MS)/kg dry matter (DM) at stocking rates of 3.24 and 4.48 Friesian cows/ha respectively. At the lower stocking rate the responses during spring, summer and autumn were 11, 53 and 113 g MS/kg DM respectively. Small spring responses were attributed to poor use of the spared pasture and cow condition that resulted from supplementary feeding. Large autumn responses were due to extending lactation length. Responses were less variable at the high stocking rate. If large amounts of supplements are used, the stocking rate must be sufficient to ensure high rates of pasture utilisation are maintained. A second farmlet trial compared rolled maize grain, maize silage, and a nutritionally balanced ration at 4.41 Friesian cows/ha. Offering 1.04 - l.23 t DM/cow of supplement increased annual pasture net herbage accumulation by 1.8 t DM/ha, and MS production by up to 96kg/cow (32%). Maize grain resulted in the largest response, although responses to maize grain and maize silage were similar when the differences in metabolisable energy (ME) content were accounted for. The balanced ration produced the lowest response, both to DM and ME, and was 20% less than that predicted by the CNCPS nutrition model. ME content is the key nutritional parameter which will determine the likely MS response to supplements. Keywords: balanced ration, dairying, farm systems, grain, milksolids, silage, supplementary feeding
Download
(119 KB)Recent developments, such as the introduction of milk quota and concern about nitrogen (N) losses in dairy farms, have started a downward trend in N inputs. Consequently there is renewed interest in white clover in the Netherlands. From May 1990 to April 1993 two 60-cow dairy systems based on either grass-N swards or grass-clover swards were compared. Because of the expected yield difference of 15–20%, the grass-N and grass-clover farm had pasture areas of 34 and 41 ha, respectively. The grass-N and grass-clover swards were fertilised with 275 and 69 kg N/ha/year, respectively. The main objective was to compare both systems on their technical, environmental and financial performance. With similar amounts of concentrates, the annual milk production per cow was slightly higher in the grass-clover system, the difference occurring during the grazing season. Gross margin per cow was also higher in the grass-clover system, but the lower stocking rate gave a lower gross margin per ha. Nitrogen surplus and energy use were approximately 15% lower with grass-clover than with grass-N. The technical and environmental results demonstrate that white clover-based swards are a viable option for the future, but at present dairy farming is still very intensive and for most dairy farmers it is financially unattractive to switch from grass-N to grass-clover. Keywords: dairy system, energy use, gross margin, milk production, nitrogen balance, Trifolium repens
Download
(158 KB)Conversion of sheep and beef farms into dairy units has resulted in research on appropriate fertiliser rates and pasture species to achieve maximum productivity in minimum time. An onfarm trial involving five different mixtures of pasture species (based on fescue, prairie grass, an improved mixture, farmer mixture or original pasture), three rates of nitrogen as urea (0, 50 or 100 kg/ha of N applied half in March and half in August) and four rates of superphosphate (0, 250, 500 or 1000 kg/ha applied annually in March) was established in Canterbury on a Waimakariri sandy silt loam with border-dyke irrigation and an Olsen P of 5 pg/ml. The trial was grazed by dairy cattle as part of the general rotation; plots were not fenced individually. Pasture growth rates were measured pre- and post-grazing using a calibrated pasture probe. Botanical dissections ,were made seasonally and soil samples were taken annually. Pasture dry matter production was greatest from the prairie grass, “improved” mixture and the original pasture, involved often contain a high proportion of annual and perennial, low-producing species. Grass species, nutrient status and management have been identified as the limiting factors in dairy conversion (Kleyngeld & Kleyngeld 1992). Ryegrass and white clover are still the most common species used in pasture renovation (Maloney 1991). However, short-rotation ryegrasses are favoured by some dairy farmers, and in new dairying areas such as Canterbury, optimally producing species may differ from those used in the more traditional North Island dairying areas (Charlton & Belgrave 1992). Nitrogen (N) is recognised as a strategic tool for increasing grass production in winter-spring in summerdry areas (Thomsoneta/. 1991) as well as for extending the milking season for factory supply herds in Southland (Kleyngeld & Kleyngeld 1992). High rates of nitrogen (217 and 324 kg/ha per year) have been found to increase annual net herbage accumulation by 23 and 27%, respectively, in the Waikato, but clover content declined significantly (Harrisetaf. 1994). Maintenance fertiliser requirements have been related to desired stocking rate in the past, based on animal production system and soil type (Computerised Fertiliser Advisory System (CFAS), reaching 13 000,ll 000 and 16 000 kg/ha in years Cornforth & Sinclair 1984). Recently responses in milk one, two and three, respectively; production from yield have been recorded to very high rates (100 kg/ha- IT the fescue increased with time; the ‘farmer’ mix performed poorly. Nitrogen at 50 kg/ha was generally sufficient to produce maximum yield increases. Increasing superphosphate increased production; this effect decreased with time. Change in Olsen P reflected superphosphate inputs and after three years of differential superphosphate application the Olsen P status was 8, 14, 27 or 42 (corresponding to 0, 250, 500 or 1000 kg/ha superphosphate). Keywords: Bromus wildenowii, dairy conversion, dry matter production Festuca arundinacea, Loliumperenne, nitrogen, Olsen P, superphosphate
Download
(124 KB)I have been farming all my working life in partnership with my brother Graeme in a family company known as V.Q. Sutton & Sons Ltd. While I managed our town supply dairy farm in Redwood Valley, west of Nelson, Graeme managed our sheep and beef farm at Kikiwa, near Nelson Lakes. With the impending deregulation of the town supply industry and the growing realisation that our assets were held in high-value Nelson land, we diversified into horticulture, establishing 5 ha of kiwifruit, but we soon realised our strengths were in grassland farming.
Download
(118 KB)
Given the complexity and different social perceptions surrounding many resource management issues, the challenge facing science is to develop understanding, knowledge and learning environments to better inform and support decisionmakers. This paper describes one such cooperative research initiative designed to address an invasive weed problem (Hieracium spp.) in the tussock grasslands of the South Island high country. The cooperative and integrated process combines knowledge from both farmer experience and conventional science to provide relevant and practical strategies for action. Resulting strategies are described, and their potential and limitations within overall pastoral system approaches are discussed. The benefits of this approach for both scientists and farmers are outlined. Keywords: community-based research, hawkweed invasion, high country, Integrated Systems for Knowledge Management, tussock grasslands
Download
(306 KB)The symposium acknowledges the significance of the South Island high country and its pastoral use. Interest is focused throughout the symposium on pastoral practices, even though both the origins and the solutions to the present situation are much wider in scope. The first paper itself outlines physical, ecological, economic, technological and cultural influences at work over history and prehistory to give rise to the present situation. It notes the role of market forces, not just affecting wool prices in the traditional pastoral industry and in its renaissance in recent decades, but also affecting the demand for land for other uses and purposes. It describes role of myths and icons in the shaping of past and contemporary high country issues. Keywords: high country, history, icons, land use, market forces, myths, pre-history
Download
(188 KB)An assessment is made of the factors influencing high country pastoral production, their degree of science validation and an estimate of their effect on total run production. Fertiliser, and introduced pasture species suited to the rate of fertiliser input are the main avenues for increased biological productivity; and stock nutrition and breeding as the means of producing a specialised product. Keywords: economics, fertiliser, high country, pasture species, sheep, stock
Download
(127 KB)Nutrient balances are recognised as the key to understanding the environmental context for sustainable management in pastorally used mountain lands and for monitoring possible effects of pastoral practices on the life-supporting capacity of soil. The paper draws on a larger survey of recent and current soil fertility research in the high country to examine briefly, three themes in nutrient cycling. The role of nutrient accessions to open systems is recognised for improved range. Current long-term revegetation studies show the need to take account of income from rock weathering. The importance of understanding the role of different plant species, soil amendments and pastoral practices in activating or impeding nutrient cycling proper is indicated from recent studies involving monitoring of exchangeable aluminium, comparing lupins with other legumes and studying the effects of planted conifers on the mineralisation of grassland organic matter. The dimensions and magnitudes of grazing-induced -nutrient-transfers-are-outlined-in-relation-to-their. risks of loss from periodic hydrologic events, as well as recognising the roles of pasture improvement and grazing management in accelerating nutrient cycling. Keywords: aluminium, grazing transfers, mineralisation of organic matter, nutrient balances, nutrient cycling, rock weathering, sustainable management
Download
(142 KB)Herbage yields of 12 timothy cultivars and 4 control grasses were compared over 4 years under 50 250 and 500 (with irrigation) kg N/ha/year in the South Island high country near Lake Tekapo. Timolhy produced high yields (10.9-12.2 t/ha/year) of quality herbagc under high nitrogen and irrigation. Mean yields at 50 and 250 kg N/ha/year were 4.8 and 7.1 t/ha/year respectively under dryland conditions. Differences between the timothy cultivars were small but Grasslands Kahu was the top- or near the top-performing of the 12 cultivars tested at all times. Keywords: cultivars, high country, Phleum pratense
Download
(93 KB)The integration of investigations into usable farming packages involves both development of particular technologies and conceptual frameworks. This is illustrated for the high country in the particular technologies of hay winter feeding, legume rhizobia seed coating, irrigation, mid-rainfall low input development with perennial lupin, in-situ winter feed systems, ultra-fine wool production, and rabbit and hieracium control. Attitudes or concepts are illustrated by the changing views on high country erosion, environment gradients and specie niche, feed banks, special purpose pastures, farm monitoring, product specification and computer expert systems. Keywords: concepts, high country, New Zealand, technologies
Download
(111 KB)
A series of seed production trials was established at Kimihia Research Centre, Lincoln, Canterbury to investigate row spacing sowing date and sowing rate requirements for Endura, the hexaploid cultivar of caucasian clover. In 1991 a trial with 30 cm or 45 cm row spacings with a sowing rate of 8 kg/ha coated inoculated seed was used. Although there were no significant differences in the first year (101 kg/ha cf. 111 kg/ha), the 45 cm row spacing yielded significantly higher than the 30 cm row spacing, in the second year (709 kg/ha cf. 371 kg/ha). Wider rows produced more flowers per unit area – 448 m-2 for 45 cm compared with 288 for 30 cm. In 1992 a sowing rate trial was established using 2 kg or 6 kg/ha of coated and inoculated seed in 45 cm row spacings. The lower sowing rate treatment of 2 kg/ha produced a significantly higher seed yield, of 208 kg/ha. The effect of sowing date (December, January, February) on seed yields was investigated. All sowing date treatments were sown at 6 kg/ha in 45 cm rows. The highest seed yield of 126 kg/ha was from January sowing. Weed seed content in the field-dressed samples harvested was associated with sowing date and decreased with each progressive sowing. The results indicate a strong negative correlation between plant density and seed yield. With early sowing, weed control is vitally important for successful seed production. Keywords: row spacing, seed yield, sowing date, sowing rate, Trifolium ambiguum
Download
(128 KB)The ability to spread underground through rhizomes, retention of a strong tap-root and a reputation for pest and disease tolerance, make caucasian clover (Trifolium ambiguum Bieb.) (CC) an attractive possibility for improving legume performance in coastal Bay of Plenty dryland dairying pasture. Large plots (0.125 ha) of Grasslands Kopu white clover (T. repens) (WC) and Endura CC were sown in spring (September 1994) as pure species swards following maize cropping and all but one 7 m wide strip undersown with ryegrass (Lolium perenne) in the following winter (July 1995). From September 1995, subplots within pure clover and undersown areas were treated with nematicide (oxamyl, fenamifos) and fungicide (metalaxyl, prochloraz) and mown to coincide with dairy cow grazing for determination of herbage yield. By the second spring, growth rates of CC matched those of WC and were superior by up to 60% through the second summer resulting in 9% greater total yield for CC pastures. Accumulated yield of CC pasture from September 1995 to June 1996 was significantly greater than WC (11.8 and 10.9 t DM/ha respectively). Caucasian clover was less responsive than WC to nematicide and fungicide treatment. With the methods used, CC can be established and perform well by the second year under dairy grazing in warm northern regions, and may provide for better summer production than WC. No difference was observed between the clover species in acceptability or pasture utilisation by dairy cows. Keywords: dryland dairying, northern New Zealand, pasture establishment, pasture growth, pesticide responses, Trifolium ambiguum, Trifolium repens
Download
(172 KB)Caucasian clover (Trifolium ambiguum M.Bieb) representing a range of 2x (diploid), 4x (tetraploid) and 6x (hexaploid) material together with ecotypes from the Caucasus region were established in a trial at Lincoln, Canterbury (43”38’S) in October 1993. Measurements were made from individual plants during summer 1994-95. The diploids were earliest to flower followed by the tetraploids and finally the hexaploids, which reached peak flowering in mid December. The hexaploids produced the most florets per inflorescence (115, 101, 96 from 6x, 4x, 2x respectively), the most inflorescences per plant (162, 101, 129 from 6x, 4x, 2x) and the highest seed yield(g) per plant (26, 9, 11 from 6x, 4x, 2x). There was large variation for all the seed production components within the three ploidy levels. For example, the hexaploid cultivar Endura consisted of plants that varied from 25-510 inflorescences per plant. The seed yield components of plants were associated with active spring growth. There was evidence of wide spreading plants producing lower numbers of -inflorescences-per-m2-andseed-yield-per-unit-area; The hexaploid material produced the greatest potential seed yields (1330,685, 1000 kg/ha from 6x, 4x, 2x respectively). There was a 5-fold difference between the lowest-yielding 6x cultivar, Prairie (570 kg/ha), and the highest-yielding KZ2 (2720 kg/ha), a selection from Monaro. Major gains are possible through selection but it is important to select for improved seed yield per plant (not just flowers) and to maintain a wide genetic base. Commercial crops yield approximately half that attained from research plots, whtch suggests a commercial yield of 900 kg/ha is possible from Endura. This compares favourably with other legumes but requires development of crop management practices that ensure consistently high seed yields. Keywords: Caucasian clover, genetic variation, Kura clover, seed components, seed yield, TrifIium ambiguum
Download
(133 KB)The potential of natural reseeding to increase the density of caucasian clover (Trifolium ambiguum M.Bieb.) swards in tussock grassland environments was investigated. Rates of pollination were high on all sites and viable seed was produced by mid March on sites ranging in altitude from 600 to 1100 m a.s.l. Hard seed, expected to survive passage through the grazing animal and germinate in the dung, was present. Rhizobia that effectively nodulate caucasian clover are absent from New Zealand soils and nodulation of seedlings and rhizome roots is dependent on spread of inoculant rhizobia in the soil. Lateral movement of rhizobia in soil did not exceed 6 cm per year, only slightly less than recorded rates of rhizome expansion. There was no evidence of movement of rhizobia in wind-blown dust or on sheep’s hooves. Natural reseeding has the potential to ‘thicken-up’ swards of caucasian clover, but the slow spread of rhizobia indicates that nodulation failures will limit the extent of spread into unsown areas. Keywords: caucasian clover, reseeding, rhizobia, rhizomes, Trifolium ambiguum
Download
(191 KB)Grasslands Kara cocksfoot, Grasslands Nui ryegrass, Grasslands Roa tall fescue, Grasslands Gala grazing brome and Grasslands Maru phalaris were sown as single grass species with either white or Caucasian clover during December 1993, on a Lismore stony silt loam in Canterbury. Plots were irrigated and rotationally grazed by sheep. Total herbage produced during the first measurement period (September 1994 to July 1995) averaged 13.6 t DM/ha. All white clover-based swards produced similar yields, but with Caucasian clover, phalaris-based swards produced the most and ryegrass and grazing brome the least. Production tended to be lower from pastures sown with Caucasian than white clover (12.9 cf. 14.2,kg DM/ha). During the second measurement period (July 1995 to May 1996) total production was similar with both legumes. When evaluated over both measurement periods, phalaris and tall fescue gave the highest and cocksfoot and ryegrass the lowest production when sown with white clover, while cocksfoot and grazing brome were the lowestproducing swards with Caucasian clover. Ten --months-after-sow.ing,-white-cIover-contributed-in excess of40% of the DM in all swards except with ryegrass and grazing brome where it contributed 20%. The proportion of white clover then declined in all pastures over the following 20 months, ryegrass-based swards having the highest (10%) and cocksfoot the lowest (1%). When sown with Caucasian clover the legume content of swards increased during the 12 months from spring 1994 in swards containing phalaris, tall fescue and grazing brome. The proportion of legume in -cocksfoot swardsmdeclined-continuously from 22 to 4% over the 20 months while it increased continuously from 4 to 28% with ryegrass. The legume content in lo-month-old pastures was higher when sown with white than with Caucasian clover but this ratio was reversed by 28 months. This occurred with all pasture types but was most pronounced with ryegrass and cocksfoot pastures. The present experiment shows Caucasian clover can make a major contribution in irrigated pastures in Canterbury. ‘Wattie Bush, RD 22, Peel Forest, Geruldine Keywords: Bromus stamineus, Dactylis glomerata, Festuca arundinacea, grazed pastures, herbage production, Lolium perenne, Phalaris aquatica, Trifolium ambiguum, Trifolium repens
Download
(210 KB)
This paper reports results of the first year of soil biochemical and microbiological monitoring programme carried out to establish “normal” ranges of values for these soil attributes. Study was conducted on 24 farm sites on yellow-brown loam soils around the Waikato area. Twelve dairy farms and a similar number of sheep–beef farms were selected on the basis of high productivity. Soil samples (0–75 mm depth) were collected at 3- monthly intervals and the following measurements were carried out: soil microbial- C, N, S and P, CO2 evolution, substrate-induced respiration, anaerobic mineralisable N, dehydrogenase activity, fluorescein diacetate (FDA) hydrolysis, amounts of soluble-C and N, extractable NO3 and NH4, soil pH, Olsen P, KH2PO4 extractable SO4-S and organic S, and hydraulic conductivity. Climatic data, records of fertiliser and other additives and productivity were also collected to interpret the variations in these properties. Variables measured from the Horotiu and Tirau silt loam soils showed considerable similarity, however, Otorohanga soils had significantly higher amounts of total and extractable soil C and N. As expected, being a higher input system, soil nutrient status (P, SO4, NO3 and NH4) on dairy farms was generally higher than the sheep–beef farms. The most significant difference was for the Olsen P values, which were about 60–70% higher under dairying. Soil pH on dairy farms was significantly higher than sheep– beef farms. However, total C and N values were significantly higher under sheep–beef than dairy farms. Similarly, the amounts of mineralisable N in all seasons were much higher for the sheep–beef than dairy farms. Apart from total microbial S, none of the other microbial biomass measurements showed any significant effect of season or difference among the soil types. This lack of seasonal effect on microbial biomass can be attributed to the unusual mild seasonal variation during the study. For the various microbial biomass measurements, sheep–beef farms generally had significantly higher values than dairy farms. Microbial C, N, SO4 and total S values were significantly higher for sheep–beef than dairying. The ratios between soil C, N to microbial C, N and microbial C:N showed no consistent pattern between the farm types. Keywords: C and N, enzyme activity, microbial biomass, seasonal variations, soil fertility
Download
(152 KB)Sustainable land management is now embedded in New Zealand law in the form of the Resource Management Act, 1991. Nutrient budgets and soil tests are seen as important tools for monitoring soil chemical sustainability. Nutrient budgets require that all inputs and outputs of nutrients from a farm are quantified. The aim is to ensure inputs and outputs are in balance thus producing a sustainable system. Recent experience suggests that using the study group (or Landcare group) approach is an effective way of introducing the nutrient budgeting approach to farmers. At the same time a computer software package (‘Overseer’) for assisting the calculations involved is being developed and tested. P nutrient budgets for two Waikato dairy farms suggest that surplus P is being produced. Such information provides a basis for future decisions on P fertiliser inputs to balance the P requirements for production against those for sustainable land management. Nutrient budgets can be aggregated to the regional and national level as required. By being able to calculate nutrient budgets in this way, New Zealand will be in a good position to _ demonstrate a commitment.to.nutrient.management~ thus ensuring continued and perhaps enhanced market access for our agricultural products. Keywords: dairying, nutrient budgets, study groups, sustainable land management
Download
(76 KB)Alternative methods of selenium (Se) supplementation have been evaluated in Merino sheep grazing irrigated pasture at Tara Hills Research Station near Omarama. Unsupplemented ewes and lambs were extremely Se deficient and production losses were high. Barium selenate (DeposeI@) injections, intraruminal Se pellets (Permasele) or the strategic grazing of recently Se-topdressed (Selcotee) pasture for at least one month pre-joining all gave a rapid and large rise in the Se status of ewes and met ewe requirements for 12 months. The barium selenate and intra-ruminal pellet treatments allowed a substantial transfer of Se to lambs at birth, and lambs would not require further Se supplementation until after weaning. With strategic grazing and oral treatments it is necessary to provide lambs with supplementary Se as early as possible. A single application of Selcote Ultra* prills at 1 kg/ha was effective in supplying adequate Se to Merino wethers for 24 months. Deposel, infertility, liveweight, Permasel, Selcote, Selcote Ultra, selenium, sheep, white muscle disease, wool
Download
(143 KB)An hypothesis, that the invasion of hawkweeds (Hierucium species) into South Island high country was triggered by fertiliser application from about 1950, is examined. Reference is made to the historical occurrence of hawkweeds in New Zealand, volumes and patterns of fertiliser application to high country, and experimental and observational information about the response of hawkweeds to soil fertility. Both mouse ear (H. pilosella) and king devil (H. praealtum) hawkweeds show marked and rapid increases in vegetative growth and flowering when available soil nutrients are increased. The response of hawkweeds to soil fertility is much greater than that of fescue tussock (Festuca novae-zelandiae) but appears similar to that of most introduced grasses, legumes and weeds. A specific P effect is inferred to explain why sheep’s sorrel (Rumex acetosella) became an important weed of tussock grasslands before hawkweeds. Keywords: fescue tussock, hawkweeds, Hieracium, high country, sheep’s sorrel, soil fertility,
Download
(127 KB)
White clover (Trifolium repens) is the traditional pasture legume in New Zealand but its persistence and production in the low fertility, summer-dry hill country of the North Island is poor. In a preliminary trial to assess the persistence of alternative perennial legumes, two species, Adesmia bicolor and a prostrate cultivar of Trijoiiumpratense were studied over a 2-year period on an ash soil over a range of slopes, aspects and fertility I’evels. The ZI pratense cultivar was still present at trial completion, contributing to higher total legume levels (9.5%) than in the resident pasture plots (7%). The second trial examined the potential of the previous two species along with accessions of Trifolium semipilosum, Trifoolium fragiferum and T. repens (cv. Grasslands Prestige) over 3 years in a paddock of clay hill soil commencing in 1994. After 2 years the 3: pratense and introduced T. repens lines were still present in the easy plots while the T. semipilosum cultivar was the only introduced legume to persist on the steeper slopes. The mean total legume content on both steep and easy slopes from the last harvest (April 1996)-was-similar-to pre-trial levels. The persisting introduced legumes “replaced” resident species rather than increasing total legume levels. The potential of the prostrate T. pratense cultivar for use in hill country should be further investigated. Keywords: Adesmia, hill country, legumes, low fertility, persistence, Trifolium repens
Download
(709 KB)The establishment from seed of 8 perennial legumes was investigated in 3 trials in drought-prone regions. Two trials, in central Hawke’s Bay, aimed to determine the extent of establishment of 6 test species (Astragalus cicer, Coronilla varia, Dorycnium hirsutum, Dorycnium pentaphyllum, Lotus corniculatus, Lotus tenuis) and 2 standard species (Medicago sativa, Trifolium repens). The third trial, in Central Otago, aimed to identify the most effective strain of Rhizobium loti for nodulating D. hirsutum in the field. In Hawke’s Bay, establishment of all species was satisfactory. Seedling emergence ranged from 0.2% (T. repens) to 25% (A. cicer, C. varia, D. hirsutum), but emergence levels for all species varied between trials. Herbage yields of A. cicer (4 t DM/ha), C. varia (3 t DM/ha) and L. tenuis (3.7 t DM/ha) were relatively high, and they could have potential as forages. Inoculation of seed of D. hirsutum with R. loti strain ICC211 resulted in 60% of seedlings being nodulated, compared with 25% where strain ICC224 was used. Foliage weights of all plants inoculated with strain ICC211 (154 mg) were higher than those inoculated with strain ICC224 (52 mg). Strain ICC211 is recommended for inoculating D. hirsutum. Keywords: dryland legumes, nodulation, plant establishment, revegetation
Download
(146 KB)Better persistence and reliability of white clover (Trifolium repens L.) is critical in achieving a more competitive New Zealand farming industry. To persist, white clover must establish well and withstand the accumulated stresses of competition from associated grasses, grazing, variable soil fertility, drought, plus pest and disease pressure. These factors vary markedly with environment and farming system, making the choice of appropriate grazing management, plant nutrition, companion species and cultivar difficult. White clover is particularly vulnerable to mismanagement and environmental stresses during spring when plant size is at its smallest. This vulnerability is further compounded by the current trend in dairying to apply high rates of nitrogen (N) which favours grass growth more than clover growth. A faster grazing rotation and/or higher stocking rates can offset the adverse effects of N on white clover by utilising the additional grass produced and reducing competition for light. Irrespective of N inputs, frequent defoliation during spring favours white clover persistence by increasing grass tiller density, resulting in better ground cover and in lower soil surface temperatures in summer. There is a threshold above which the density of associated grass suppresses clover growth. This is most prevalent in swards containing browntop, cocksfoot and kikuyu, which are more competitive against white clover than tall fescue, timothy and perennial ryegrass. Plant breeding efforts to improve persistence concentrate on increasing the rate of stolon formation and decreasing the rate of stolon death. These efforts include selecting genotypes that have better spread and persistence in association with different grasses, and genotypes that continue to grow with lower inputs of phosphate. Changes in root morphology have enhanced persistence under moderate drought stress, while significant improvements in resistance to clover cyst nematode, root-knot nematode and clover flea offer real hope in reducing the impact of these pests. Developing cultivars with higher stolon growing point densities at a particular leaf size should improve persistence while maintaining the greater yield potential. Keywords: climatic stresses, competition, diseases, grazing management, pests, plant breeding, plant nutrition, Trifolium repens L.
Download
(147 KB)Red clover (Trifoolium pratense L.) can provide high quality summer feed but has declined in popularity owing to its poor persistency in temperate grazing systems. From 1991 to 1996 the incidence of nodal rooting of prostrate selections of red clover was quantified and the survival of the resulting plantlets was tracked over time, under grazing conditions. Three field experiments were conducted using Astred, Grasslands Pawera, F2419 and Grasslands Turoa selections of red clover. The main experiment comprised 3 harvests (plants and plantlets dug up) of 3 red clover selections, in a randomised complete block design with no grazing. The subsidiary plantlet survival experiment followed the life and death of 160 plantlets from the three selections under rotational grazing to 5 cm, over a period of 48 weeks. The numbers of plantlets produced per parent plant of each selection were 37, 16 and 5 for Astred, F2419 and Turoa, respectively (P~O.001). Astred produced significantly larger plantlets (PcO.001, mean = 130.6 g/ DM/plantlet) over 7 months than F2419 and Turoa -(means-=.31.5.and.lO~g/DM/plantlet,.r.espec~y)~ At week 48 plantlet survival ranged from 84% (Astred) to 27% (Turoa) (P~O.001). The experiment at Ballantrae consisted of oversowing 20 kg/ha of 2 clover selections (Pawera, creeping selection) into sprayed pasture in 1991. Plant density, pasture composition and herbage accumulation were measured until 1995, with all treatments continuously stocked at 16 ewes/ha. Pawera contributed only 1.1% to herbage accumulation during the second year when oversown on hill country and ~-disappeared from the sward-soon-after.XIn-averagei the creeping selection made up 3.2% of the total sward herbage accumulation from years 2 to 5. It was concluded that the spreading red clovers represented by Astred and F2419 selections have the potential to be more persistent than crown red clovers under grazing. Keywords: nodal rooting, plantlet, spreading red clover, Trifolium pratense
Download
(100 KB)Ostrich are currently being promoted as an alternative to sheep, cattle and deer. Although current bird prices are not sustainable, New Zealand and overseas experience to date suggest ostrich can be farmed successfully and profitability long term. Climate and terrain of the east coast of New Zealand suit ostrich physical requirements. It has been suggested that production systems will develop in which grazed herbage will provide 60% or more of the nutritional requirements. The ability to graze low-cost herbage combined with a reproduction rate of about 25 progeny per hen per year indicate that ostrich production systems may be three times more efficient than beef or deer at turning feed into lean meat. The low fat and low cholesterol meat is likely to be the primary product and is already being sold in international markets. There is also a market for the leather, feathers and oil by-products. Keywords: diversification, east coast, farming systems, meat, ostrich
Download
(138 KB)The persistence of lucerne (Medicugo sativa L.), red clover (Trifofiumpratense L.), birdsfoot trefoil (Lotus cornicufatus L.) and perennial lupin (Lupinuspolyphyks Lindley), overdrilled with and without companion grasses, was compared at a site representative of dry, acidic, outwash soils in the southern Mackenzie Basin, South Island. Plant populations were monitored for 9 years and legume seedling regeneration and stand recruitment were examined over three consecutive years under grazing by sheep and cattle. Pcrcnnial lupin was the best adapted legume species. Stand density increased by re-seeding. In contrast, few seedlings of birdsfoot trefoil developed as a result of reseeding, and survival of birdsfoot trefoil was generally restricted to the more favourable areas of the mosaic of soil. Red clover did not persist, and the few plants of lucerne that survived lacked vigour. Tall oat grass and cocksfoot showed good vigour and persistence across the mosaic of soil; smooth brome performed well and spread within the more favourable areas. From these results, _p_erennial.lupin,-tall-oat-grass-and-cocksfoot~a~~ to be the best species available for the future development of sustainable pastoral systems in drought-prone outwash landscapes in the Mackenzie Basin. Keywords: dryland, establishment, Lotus corniculatus, Lupinus po&phyflus, outwash soils, pasture legumes, persistence, seedling recruitment
Download
(170 KB)Clover cyst nematode (Heterodera trifolii) reduces growth and nutrient uptake of white clover (Trifolium repens) in New Zealand, and breeding resistant cultivars is the preferred control method for ecological and economic reasons. Resistant and susceptible selections were taken from a wide range of white clover seedlines. Selected plants were intercrossed and reselected over two cycles of selection. Cysts per gram of root dry weight (cysts/ g) was the measure of resistance used, with low cysts/g plants being more resistant. The mean cysts/ g value of the progenies from resistant parents was 69% of the mean value of the progenies from susceptible parents in the first generation, and 38% in the second generation. Root weights were similar, while the resistant selections had 58% and 34% (first and second generations respectively) of the number of cysts in the susceptible selections. There were no immune plants (0 cysts) in the first generation and only two in the second. Counts were made of cysts, eggs per cyst and eggs per plant on clones of two resistant and two susceptible genotypes. The resistant genotypes had lower counts than the susceptible genotypes in terms of cysts per plant (means of 6 cf. 108), eggs per cyst (11 cf. 21) and eggs per plant (35 cf. 1650). The differences in numbers of cysts between resistant and susceptible lines increased during two generations of selection, supporting earlier results that indicated that progress in breeding for resistance was possible. Furthermore, the resistance is also acting on clover cyst nematode egg production which would further reduce recruitment to later generations of clover cyst nematode. Keywords: breeding, Heterodera trifolii, resistance, screening, selection, Trifolium repens
Download
(137 KB)Grasslands Pawera, a late flowering tetraploid red clover cultivar, has transformed what was previously low fertility pastures dominated by browntop and annual grasses with low summer productivity, into legume-dominant pastures over the summer to mid-autumn period on a Bay of Plenty dairy farm. Neither N nor supplements were used on this farm. The red clover was introduced into the pastures by (1) feeding out red clover hay; and (2) grazing red clover pastures after seed set. Milk production (kg milk solids /ha) for the 1995/96 season, compared to the zone average, was: * 24% higher for the full season * 30% higher in the November to April period when pastures were red clover-dominant * 35% higher in the December to February (summer) period. Trials were carried out in the Manawatu in which milk production of Romney ewes, and growth rates of suckling and weaned lambs, were monitored weekly over periods ranging from 10 to 12 weeks. Treatments comprised either red clover or ryegrass– white clover pastures. Compared with ryegrass–white clover * ewes grazing red clover produced 24% more milk * suckling lambs on red clover had 20% higher rates of growth * weaned lambs on red clover had 24% higher rates of growth It is concluded that red clover has the potential to increase milk production and growth rates over what is achievable on ryegrass–white clover pastures. Keywords: dairy cattle, ewes, milk yield, Trifolium pratense
Download
(82 KB)The role of legumes for increasing pasture production and quality to ensure the long-term sustainability prospects for a high country sheep and cattle farm, with reference to options, impediments and future directions. The currently available pasture legumes have serious shortcomings in the face of drought, low soil fertility, aluminium toxicity and competition from Hieracium species. I describe a vegetation study in the Caucasian mountains in the search for more persistent, diverse, aluminium-tolerant and fertiliser-efficient pasture species. Keywords: caucasian clover, high country, Hieracium, oversowing and topdressing, sheep, sustainability, Trifolium repens, Trifolium trichocephalum
Download
(134 KB)Feeding and grazing trials were carried out to establish relationships between formononetin intakes and blood equol levels, and to characterise the build-up and clearance of free and conjugated equal in the blood of sheep feeding on either high (Grasslands Pawera) or low (G27) formononetin red clovers. In the feeding trials, blood equol levels were positively correlated with formononetin intakes, and levels peaked at 2-4 hours after feeding. In the grazing trial, groups of 10 sheep grazed either Pawera or G27 red clover pastures for l-, 2-, or 3-week periods while a control group was on grass-dominant pasture. Analysis of blood equal showed differences in the rates of accumulation and in the mean blood concentrations. Free equol was present in the blood of sheep after one day of grazing on Pawera whereas it was not detected in blood of sheep on G27 until 5 days after grazing began. Blood equal rose to equilibrium levels and remained thus until sheep were removed from the red clovers. The concentrations of equol in Pawera ewes were approximately three times those in G27 ewes. Free equoal was rapidly cleared from the blood and was below the limit of detection by day 2 after transfer to a ryegrass pasture. The 4-day lag between start of grazing and the appearance of free equal in the blood of ewes on G27 offered scope for devising grazing management strategies which might enable use of G27 for flushing without an adverse effect on fertility. Results of trials in 1995 and 1996, in which ewes grazed alternately for 3.5 or 3 days on G27 and then for 3.5 or 4 days on grass pastures (per week) for 4 weeks before and during a 4-week mating period showed that the reproductive performance of ewes was unaffected. Such on/off systems of grazing management, therefore, enable G27 to be grazed safely by ewes around the time of mating. Keywords: equol, ewe fertility, flushing, formononetin, grazing management, oestrogenic compounds, Trifolium pratense
Download
(125 KB)
NZ Grassland Association Inc.
11 Montrose Street, Mosgiel, Dunedin 9024 New Zealand | P: +64 3 477 0712 | F: +64 3 473 6495 | E: nzgrassland@gmail.com
© Copyright NZ Grassland Association Inc. 2011. All rights reserved
Refund Policy | Disclaimer | Privacy Policy | Terms & Conditions
