New Zealands grassland industries are entering a new phase of rapid technological and structural change. A complex mix of factors fuels this including institutional reform, Government science policy, growth in telecommunications, trade reform, and changes in consumer expectations and societys values towards the environment and new technology. Developing a common inspirational purpose, picking and investing in a best bet future scenario, managing constraints to productivity gains, and increasing technology transfer and farmer learning are some of the challenges that those in the grassland sector must met. Keywords: future scenarios, grassland research, land inventory, production, productivity
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The New Zealand dairy industry recognises that to remain competitive it must continue to invest in research and development. Outcomes from research have ensured year-round provision of low-cost feed from pasture while improving productivity. Some of these advances, discussed in this paper, include the use of white clover in pasture, understanding the impacts of grass endophyte, improved dairy cow nutrition, the use of alternative forage species and nitrogen fertiliser to improve productivity, demonstration of the impact of days-in-milk on profitability, and the use of feed budgeting and appropriate pasture management. Keywords: dairy, profitability, research and development
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(187 KB)Being part of a group farm monitoring project and then a farm systems study has enabled the Hannas to develop their farm business to where they can supply livestock to meat processors under futures contract arrangements. The recognition and development of farm-monitoring protocols has enabled them to identify key weight and weight gain targets. A database of weights, pasture growth and pasture cover information has enabled them to predict numbers, weights and supply times. The result of this farm monitoring has been a 35% increase in productivity over the past 5 years. Lambing % has increased from 112 to 146% survival to sale. Bull beef cattle numbers have increased by 430% as the area suitable for running them has been fenced and developed. The Hannas have classified their land into capability units and farm these units accordingly. They recognise the strong link between farming profitably and sustainably and believe that the demonstration of sustainable farming practices will be a requirement to enter into high value markets in the future. Winning of the supreme Waikato Farm Environment award in 1999 was a reflection of this philosophy. Keywords: bull beef, futures contracts, monitor farm, sustainability
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(169 KB)Meat New Zealand invests in Research and Development (R&D) projects to increase pastoral industry profitability. It annually seeks to measure the benefit to industry by independent benefit:cost analysis on completed projects. The analysis to date shows an eight to one return for each dollar invested. The Sheep and Beef Videos have been very successful projects carried out by Meat New Zealand. These successes are outlined along with an Australian beef industry project BeefCheque. Common threads are drawn from each of these programmes such as peer support and commitment, participatory learning, industry partnership, learning expertise and farmer ownership. Meat New Zealand has implemented these principles in other R&D investment areas and encourages other industry participants to do the same. Keywords: behaviour change, Monitor Farm Programme, motivation, groups, profitability
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(186 KB)The discovery in 1981 that ryegrass endophyte is responsible for ryegrass staggers has required a total revision of our understanding of ryegrassbased pastures. The effects on grazing livestock range from obvious clinical disorders to chronic impairment of productivity. On the other hand, endophyte infection is essential to ryegrass persistence in most of New Zealand, protecting the plant from some invertebrate pests and from over-grazing, and perhaps promoting its tolerance of moisture stress. Vigorous, endophyte-infected pastures sometimes include less clover than pastures relatively free of endophyte. Active compounds produced by the endophyte have been identified, and conditions causing high levels of them have been documented in part. Endophyte strains which do not produce the compounds responsible for livestock toxicoses offer exciting new possibilities in grassland agriculture. Keywords: invertebrate pests, mycotoxicoses, Neotyphodium lolii, perennial ryegrass, ryegrass staggers
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(210 KB)The discovery in 1981 that ryegrass endophyte is responsible for ryegrass staggers has required a total revision of our understanding of ryegrassbased pastures. The effects on grazing livestock range from obvious clinical disorders to chronic impairment of productivity. On the other hand, endophyte infection is essential to ryegrass persistence in most of New Zealand, protecting the plant from some invertebrate pests and from over-grazing, and perhaps promoting its tolerance of moisture stress. Vigorous, endophyte-infected pastures sometimes include less clover than pastures relatively free of endophyte. Active compounds produced by the endophyte have been identified, and conditions causing high levels of them have been documented in part. Endophyte strains which do not produce the compounds responsible for livestock toxicoses offer exciting new possibilities in grassland agriculture. Keywords: invertebrate pests, mycotoxicoses, Neotyphodium lolii, perennial ryegrass, ryegrass staggers
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(210 KB)The Technosystem intensive grazing system, now called TechnoGrazing, was developed by Rangitikei farmer, Harry Wier, during the past 25 years and is being adopted successfully on New Zealand pastoral farms. The TechnoGrazing concept is a most effective advance in subdivision and grazing management, achieving very intensive and efficient pasture utilisation, with a quantum leap in animal production. It requires only a minimum investment in plant and equipment, a low labour input, and is a sustainable grazing system when practised properly. Pastoral farmers using TechnoGrazing systems in different regions are now achieving greater profits and impressive results, especially for dairy beef and sheep finishing, and several examples are described. Keywords: controlled grazing, intensification, liveweight gains, pasture utilisation, Techno- Grazing
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(168 KB)
Peat soils cover approximately 94 000 ha of productive land in the Waikato and are an important soil resource for the region. Much of the research on peats in the 1950s60s concentrated on the development of raw peats and later in the 1970s on nutrient deficiencies such as copper and selenium. Little to no work was undertaken on soil fertility/soil nutrient relationships of developed peat soils. In 1996, a series of eight field trials was established across a range of developed peat soils in the Waikato to investigate such relationships. The trials continued for 3 years. Results showed that the optimum Olsen P soil test for sustaining near maximum pasture production was 3545, that K soil tests were of limited use on well developed peats and that winter leaching of S was likely to be important. The Anion Storage Capacity (ASC) test was found to be a valuable tool in indicating the degree of development of peat and in turn allowing interpretation of fertiliser responses. From these introductory investigations of nutrient requirements on peat soils some guidelines and recommendations are presented. Keywords: anion storage capacity (ASC), Olsen P, pasture production, peat, soil test
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(273 KB)Land application of farm dairy effluent (FDE) is preferred over pond treatment because of the potential reduction in environmental impacts, and recycling of valuable nutrients. Recent findings from the past 5 years of research by AgResearch and Dexcel are presented to provide an overview of the effects of applying FDE to pastures. Results indicate that significant pasture responses to applying FDE at increasing rates of N were found in both the mowing and grazing trials. There was no difference in pasture responses between FDE and urea when applied at the same rate of N. The ryegrass content of pastures increased with increasing N rates whether from effluent or urea. N and nitrate-N concentrations in the herbage showed some increases but were not excessive at rates up to 400 kgN/ha/yr. Pasture concentrations of other nutrients (except K) were unaffected by the rate or form of nitrogen applied. Both pasture K and soil K levels were significantly higher under the effluent treatments. Nitrate and calcium leaching increased significantly under the highest rate of N application (400 kgN/ha/yr). Spreading FDE over a sufficiently large area (1520% of the farm) can reduce inputs of K to near maintenance requirements and restrict N inputs to about 80 120 kg N/ha/yr, thereby avoiding potential animal health and environmental problems. A behavioural study showed that cows disliked grazing pastures recently treated with FDE. This study also showed that there was a significant and rapid decline in faecal coliform counts on pasture following effluent application. Keywords: faecal coliforms, farm dairy effluent, FDE, groundwater, nitrate leaching, pasture, soil
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(230 KB)Land application of farm dairy effluent (FDE) is preferred over pond treatment because of the potential reduction in environmental impacts, and recycling of valuable nutrients. Recent findings from the past 5 years of research by AgResearch and Dexcel are presented to provide an overview of the effects of applying FDE to pastures. Results indicate that significant pasture responses to applying FDE at increasing rates of N were found in both the mowing and grazing trials. There was no difference in pasture responses between FDE and urea when applied at the same rate of N. The ryegrass content of pastures increased with increasing N rates whether from effluent or urea. N and nitrate-N concentrations in the herbage showed some increases but were not excessive at rates up to 400 kgN/ha/yr. Pasture concentrations of other nutrients (except K) were unaffected by the rate or form of nitrogen applied. Both pasture K and soil K levels were significantly higher under the effluent treatments. Nitrate and calcium leaching increased significantly under the highest rate of N application (400 kgN/ha/yr). Spreading FDE over a sufficiently large area (1520% of the farm) can reduce inputs of K to near maintenance requirements and restrict N inputs to about 80 120 kg N/ha/yr, thereby avoiding potential animal health and environmental problems. A behavioural study showed that cows disliked grazing pastures recently treated with FDE. This study also showed that there was a significant and rapid decline in faecal coliform counts on pasture following effluent application. Keywords: faecal coliforms, farm dairy effluent, FDE, groundwater, nitrate leaching, pasture, soil
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(230 KB)Lake Taupo is a high quality lake in the centre of the North Island, New Zealand. Local government aims to control nitrogen (N) inputs into the lake to preserve lake water quality. In this paper we discuss the implications of this policy for land use and farm management in the Lake Taupo catchment. To do this we used a case study approach, based on a typical farm, to examine the effects of stocking density and management system on farm cash surplus, farm capital value and nitrate leaching. The study showed that intensification of land use is a profitable option for farmers and any restrictions on land use in the Lake Taupo catchment will have large effects on the profitability and value of existing farm businesses. Farm systems can be adapted to reduce N leaching, however the options that we studied all resulted in a decrease in farm cash surplus. Further evaluation and experimentation on new systems is required. Rules that control farm activities in an attempt to control N leaching may not result in the gains desired owing to legitimate adjustments that farmers may make to re-optimise their farm business. Keywords: economic evaluation, farm systems, modelling, nitrate leaching, water quality
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(202 KB)This paper documents the thinking and activities undertaken by a group of dairy farmers charting their own destiny with the assistance of science and industry knowledge. Examples are given of how the group has identified on-farm issues that have no single answer and how they have worked towards resolving these. Challenges for science working with farmers and farmer response to science are noted. Keywords: clover, economics, environment, quality assurance, study group
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(155 KB)The effects of a single, moderate or severe pugging event in early spring on pasture production, clover growth, and N2 fixation were measured during a 1-year study on dairy pasture in the Waikato. Moderate and severe pugging of the poor-draining Te Kowhai soil resulted in annual pasture production decreases of 21% and 45%, respectively. Clover showed a much greater decrease in production than grass (65% vs. 38%) following severe pugging, and indicates that clover is more susceptible to the negative effects of pugging than grass. Nitrogenase activity showed a rapid decrease (up to 90%) within 3 days of pugging, and reflected the measured decrease in air-filled porosity (from 16% in the non-pugged to an average of 11% for the moderately and severely pugged treatments) and measured loss of root biomass. On an annual basis, the total amount of N fixed decreased from 151 kg N/ha in the control to 109 kg N/ha (-28%) and 45 kg N/ha (-70%) in the moderate and severe treatments, respectively. Longer-term effects of the decrease in clover DM yield from a single moderate or severe pugging event each year were modelled using a dynamic dairying model of N cycling. After 10 years, pugging was predicted to decrease N2 fixation, soil organic N and grass growth, and result in a loss in milk production of 21% and 54%, respectively. On a whole farm basis, if moderate and severe pugging occurred on 50% and 10% of the farm, respectively, this would represent a decrease in milk production of 16% (e.g., from 1000 to 840 kg milksolids ha/year). Keywords: dairying, N2 fixation, pasture production, pugging, ryegrass, white clover
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(248 KB)
Two recently released white clover cultivars, Grasslands Kopu II and Crusader, were compared with existing cultivars for at least 3 years in each of five field trials under rotational grazing by either dairy cows or sheep in the Waikato and Manawatu. Kopu II, a large-leaved cultivar with intermediate cyanogenesis and high stolon density relative to its leaf size, performed strongly under dairy grazing with high clover yields in summer, autumn and winter, and improved persistence in year 3 of these trials. Kopu II, along with Kopu and Sustain, also had high soluble carbohydrate content. Crusader is comparable to Huia in leaf size, but has higher cyanogenesis and stolon density than Huia. Crusader outperformed all other cultivars under sheep grazing with high clover yields in autumn, winter and spring. Under dairy grazing, Crusader performed very well in years 1 and 2 but did not perform as well as Kopu II in year 3. Both of these cultivars have performed well in international testing with Kopu II having high yield and stolon density under cattle grazing in Northern USA, while Crusader has been nationally listed in the UK based on NIAB trial results. Kopu II and Crusader represent the first of a new generation of white clover cultivars bred to perform well in both national and international markets. Keywords: breeding, cultivar, dairy, sheep, Trifolium repens, white clover
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(589 KB)The performance of three white clover cultivars (Huia, Tahora and Prop) was monitored in summerdry hill country at the Whatawhata Research Centre for 9 years. The cultivars were oversown into three steep north-aspect paddocks in autumn 1990. White clover abundance was measured every spring using line transects, and stolon fragments were sampled to determine the contribution of the cultivars to overall populations by allozyme electrophoresis on three occasions (1991, 1993, and 1994). White clover abundance declined from ~50% in the first year to ~4% in 1999. There were no significant differences in abundance between the three cultivar treatments after year 2. There were significant differences in the contribution of the cultivars to white clover populations after 5 years as follows: Huia 27%, Tahora 33% and Prop 56%. The implications of these results for introducing new white clover genotypes into summer-dry hill country are discussed. Keywords: 'Grasslands Huia', 'Grasslands Tahora', hill country, long-term, 'Prop', summerdry, white clover
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(194 KB)A whole-farm systems comparison of combinations of perennial ryegrass and white clover cultivars rotationally grazed by dairy cows over two complete seasons evaluated improvements in perennial ryegrass and white clover cultivars resulting from plant breeding efforts. There were four treatments comprised of two ryegrass mixtures and two clover mixtures in a 2 x 2 factorial design, each replicated three times in a randomised block design giving 12, self-contained 4-ha farmlets each stocked at three multiparous Friesian cows/ ha. All pastures were sown in April 1998, using seed obtained through commercial sources, with a high endophyte (>70% endophyte infection) specification for the ryegrass cultivars. A grow out test, carried out after sowing, showed that two of the ryegrass cultivars used in the mix of older cultivars (80R) had less than 70% endophyte infection (Ellett 50%, Nui 62%, Yatsyn 94%) resulting in an average endophyte infection of 69% for that mix. The mix of newer ryegrass (98R) cultivars had an average endophyte infection of 92% (Aries HD 91%, Bronsyn 98%, Samson 87%). While seedling densities (ryegrass and clover) were similar for all mixtures at the start, from late summer of the first year onward, tiller densities were around 30% lower (due to predation of endophyte-free plants and tillers by the Argentine stem weevil) in the 80R treatment. The lower tiller density opened up the sward at an opportune time for clover expansion, which the newer clover cultivars (98C) Sustain and Challenge converted into a higher clover production than from the older clover cultivars (60C) Huia and Pitau. The 80R treatment had a greater spring surplus requiring more conservation than the 98R treatment, which had a more even growth distribution over the year. Differences in endophyte infection levels had a major impact on pasture composition, especially clover content; reducing the endophyte level of seed sown from 90% to 70% may create an opportunity to increase the clover content and quality of young pastures in the Waikato. Keywords: cultivars, dairying, endophyte, perennial ryegrass, tiller density, white clover
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(233 KB)1999/2000 and 2000/2001 were the first two complete seasons of a replicated farm systems trial designed to measure the effects on whole farm profitability (Economic Farm Surplus (EFS) of mixtures of ryegrasses and white clovers released on to the market recently, or at least 15 years ago, and rotationally grazed by dairy cows. All the pastures were sown in late autumn 1998. There were four treatments with all combinations of 1980s (80R), and late 1990s (98R) ryegrasses, and 1960s (60C)and late 1990s (98C) white clovers, each replicated 3.0 times in a randomised block design giving twelve 4-ha, self-contained farmlets stocked with three Friesian cows/ha. Milksolids production was unaffected by either ryegrass or clover cultivar age, but there was a significant ryegrass x clover cultivar interaction reflected as higher milksolids production on the 80R/98C treatment than the 98R/98C treatment in 1999/2000. This was a result of a higher clover content in the 80R/98C pastures compared with other treatments. Although the difference in clover content was still present in 2000/2001, the wetter summerautumn meant the ryegrass maintained a higher nutritive value than in the previous season under dry conditions, so clover content did not affect milksolids production in 2000/2001. There were no main treatment effects on EFS in either season, but there was a significant ryegrass x clover interaction in 1999/2000 shown as a higher EFS on the 80R/98C treatment than on the 98R/98C treatment. Keywords: cultivars, dairying, Economic Farm Surplus, milksolids, perennial ryegrass, white clover
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(214 KB)Recent advances in farming systems, have prompted a re-appraisal of the performance of white clover in New Zealand pastoral agriculture, in response to the question, is white clover delivering? Using recently developed insights into the processes by which our main pasture species, ryegrass and white clover, grow, this paper will briefly examine the establishment of white clover in mixed pastures and the ecological and biological premises of the two main functions of white clover in pastoral ecosystems, which are to 1), support the N economy of pastures via N fixation and 2), provide high quality livestock feed. The impacts of management decisions and environmental conditions are re-interpreted, in order to evaluate realistically (biologically) what our expectations should be. White clover is still able to deliver on function 1, but may not meet expectations in all cases on function 2. Keywords: ecology, environmental impacts, grazing management, herbage quality, light, mixed pastures, N economy, N fixation, plants, populations, ryegrass, white clover
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(172 KB)
Plant and animal production from cocksfoot pasture and lucerne under 10–11 year-old radiata pine trees (200 stems/ha) and from adjacent open pastures (without trees) were measured from the Lincoln University Silvopastoral Experiment. Light intensity under trees was 50–60% of the open pasture. Liveweight gain (LWG) from lucerne was 220 g/hd/d in the open and 158 g/hd/d under trees. On cocksfoot, LWG was 132 g/hd/d in the open and 100 g/hd/d under trees. When converted to LWG/ha, lamb production from open pastures was double that from shaded pastures for lucerne (5.1 and 2.5 kg/ha/d) and cocksfoot (3.4 and 1.7 kg/ha/ d). Lucerne produced 11.2 t DM/ha in the open and 7.9 t DM/ha under trees which was 58% and 76% more than cocksfoot in the open and under trees, respectively. However, from September to November, when soil moisture was non-limiting, the lucerne DM production was 36% lower under tree shade than in the open. In comparison, the reduction was only 20% for cocksfoot, which confirms its greater ‘shade tolerance’. The reduced lamb LWG produced from lambs on shaded pastures was attributed to the reduced pre-grazing pasture mass and pasture bulk density, leading to reduced apparent intakes. Crude protein and digestibility values were not influenced by shade, and clover content in cocksfoot pastures were low (<7%). It was concluded that: i) shaded pastures in silvopastoral systems limited animal production compared with open pastures owing to lower DM production rates which lowered pre-grazing pasture mass and reduced bulk density from the etiolated pasture; ii) the suitability of species for silvopastoral systems should be assessed from total plant and animal production and species persistence rather than ‘shade tolerance’, which only examines the relative decline in DM production under shade compared with unshaded situations. Keywords: cocksfoot, Dactylis glomerata, lamb liveweight gain, lucerne, Medicago sativa, pasture production, Pinus radiata, shade tolerance, silvopastoralism
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(614 KB)This paper uses data from an artificial shade trial to compare the impacts of shade duration on pasture production with deciduous and evergreen tree species. Results indicated that light quantity was not the only main limiting factor in understorey pasture yield. At low levels of shade (<40%), pasture relative yields under the nitrogen-fixing tree, Acacia melanoxylon, were greater than relative yields under corresponding levels of artificial shade. We concluded that when comparing tree understorey pasture yields, the variation between tree species was greater than the variation between deciduous and evergreen tree groups. For a deciduous tree species to be effective in mitigating pasture yield during the leaf-free period, they must be leaf-free for longer than 4 months. Additionally, in riparian zone plantings the amount of shading required to reduce water temperatures to desired levels for invertebrate stream life is too high to maintain pasture cover. Selection and management of appropriate tree species to reduce shading intensities is required to maintain adequate understorey pasture yield and density. Further work on deciduous tree species is required to further understand the interactions between understorey pasture yield, duration of shade and tree species. Keywords: Acacia melanoxylon, agroforestry, artificial shade, Eucalyptus nitens, light, Poplar spp.
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(577 KB)Calibration data for the rising plate meter (RPM) collected from four locations and spanning a period of 10 years (1988–1998) were used to develop a pooled standard set of RPM calibrations to be used to estimate herbage mass of dairy pastures across a number of dairying regions. When evaluated in a farmlet study run over a 2-year period, the standard RPM calibration gave similar estimates of average farm cover, pre and postgrazing herbage mass and consumed DM, as herbage mass estimates calculated from RPM measurements calibrated to the local pasture on each assessment day. Compared with visual estimations, the standard RPM calibration underestimated pre-grazing herbage mass, average farm cover and the amount of pasture consumed, and overestimated post-grazing herbage mass. Reasons for these differences are discussed and an alternative approach to using the RPM for on-farm pasture assessment is presented. Standardised, onfarm herbage mass estimates may be possible using the RPM and standard calibrations to calibrate visual estimations prior to visually assessing pasture across the whole farm. Such a standardised pasture assessment method would assist the grazing management of dairy pastures across a number of New Zealand dairying districts. Keywords: average farm cover, dairy-grazing management, pasture growth, post-grazing herbage mass, pre-grazing herbage mass, rising plate meter
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(781 KB)This paper analyses the costs and benefits of planting poplars for erosion control, to determine the economic incentives facing farmers. Using costbenefit analysis over a range of scenarios (e.g., a base scenario, a “most favourable” scenario, and a targeted planting scenario) and underpinning assumptions (e.g., erosion rates, planting densities, stock gross margins), it is found that the private (i.e., on-site) monetary incentives for planting poplars are marginal at best. Even at high expected erosion rates and repair costs, and with harvest values incorporated, the internal rate of return is low (between 5 and 6%). The paper indicates circumstances under which the decision to plant poplars is worthwhile for the farmer. These include circumstances where poplars significantly reduce lamb losses, subsidies are available, or nonmonetary factor are important. Keywords: cost-benefit analysis, erosion, poplars, profit, shelter, sustainability.
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(586 KB)An on-farm demonstration of the effects of a higher stocking rate (expressed as cows per hectare), supported by purchased maize silage, was conducted on a commercial Waikato dairy farm that was split into two farmlets. Milk from each farmlet was collected into separate vats. This paper reports on two seasons of comparison between: 1. A 57-ha farmlet with 185 Friesian cows stocked at 3.25 cows per ha, representing the farm’s previous management (Control -LS) and; 2. A 51-ha farmlet with 185 Friesian cows stocked at 3.6 cows per ha, supported by the purchase of 430 kg DM per cow of maize silage (Treatment -HS) The comparison aimed to demonstrate that higher stocking rates, supported by purchased maize silage, would increase total pasture utilisation and increase profit per hectare. Milksolids production for the HS farmlet was 105 and 99 kg per ha higher than LS in years one and two with Economic Farm Surplus per ha increasing by $113–$375 per ha (depending on payout). The comparison highlighted the difficulty of determining stocking rate on a cows-per-ha basis for a farm with unknown pasture production. In effect, the comparison was between two herds stocked at a similar level relative to total feed supply, with both herds being limited by total feed supply. This study also demonstrated practical management issues involved for farmers who are adding purchased feed into their systems. Being a commercial dairy farm meant this split herd demonstration could not be subjected to strict scientific protocols, as the commercial objectives of the farmers had to be met. The limitations and advantages of this type of on-farm demonstration are discussed. Keywords: economic farm surplus, maize silage, milksolids production per ha, on-farm demonstration, split-herd comparison, stocking rate
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(582 KB)Over the past 5 years, the emu industry has had forced upon it the need to adjust its practices to conditions determined by the meat, oil and hide markets, rather than the inflated prices enjoyed in the honeymoon years when emu breeders were exploiting a highly inflated bird market. The cost of economically raising birds to the slaughter stage is now the major challenge. The use of a forage crop to reduce feeding costs, the single largest cost to raising emu, was trialled in the Franklin County through funding from AGMARDT. Chicory, plantain, white and red clover were sown and rotationally grazed by emu. Emu on this forage crop also received a half ration of grain-based meal pellets (Forage-birds). This was compared with grazing emu on existing pasture and a full ration of meal pellets (Control-birds). The estimated savings per bird averaged $35.50 (excl. GST), or 24%, for the Forage-birds. For two of the three farms, the average saving per bird exceeded $44.00 or 30%, owing to lower costs of establishment for the forage crop and less extra meal feeding during summer/autumn drought and winter cold. Costs were recalculated to allow for economies of scale, and average savings then increased to 34%. It is expected that greater savings, 40% or more, may be achieved through better preparation of the seedbed giving a better establishment of the sown forage species, if more favourable weather conditions prevail when the species are establishing, and through greater experience. However, it requires more land per bird and more watchful management in terms of seasonal change affecting the crop. Meat quality ratings were all within acceptable levels, while fat from Forage-birds was yellow and Control-birds white. There were indications that fat from Forage-birds was healthier for humans through a better linoleic:linolenic fatty acid ratio and a better polyunsaturated:saturated fatty acid ratio than fat from Control-birds. At slaughter, differences in liveweight and meat quality between farms, and between birds, indicated the importance of correct slaughter and transport procedures to minimise stress. Birds from the forage group were more placid. Keywords: chicory, Cichorum intybus, clover, cost:benefit, Dromaius novaehollandiae, emu, fat, Plantago lanceolota, plantain, Trifolium pratense, Trifolium repens
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(570 KB)This paper reviews the use of maize silage in pastoral dairying systems in New Zealand. The evolution of dairying systems to make profitable use of maize silage and other supplementary feeds has occurred during the last decade in conjunction with an increased use of maize silage. When used within recommended levels of feeding, maize silage provides a low cost source of starch and fibre which complements pasture well for much of the year. Balancing dietary deficiencies in protein, minerals, and in some cases fibre, will optimise milksolids production at high levels of maize silage supplementation. Targets for good quality maize silage include a dry matter content of 2835%, an energy content of 10.8 MJME/ kgDM, a protein content of 78%, and a pH of 3.8 to 4.5. Opportunities for further productivity gains exist through further intensification of dairying systems using high-yielding crops. Keywords: dairy cow, feed quality, maize silage, nutrition
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(204 KB)A mechanistic model was developed to identify biological processes responsible for differences in reproductive tillering between ‘Ellett’ and ‘Grasslands Ruanui’ perennial ryegrass cultivars. In the model, a field perennial ryegrass tiller population was represented with six compartments: vegetative, emerging reproductive, mature reproductive and dead tillers (three compartments). The biological processes driving the transfer of tillers from one compartment to another were: conversion of vegetative tillers to reproductive tillers, maturation of emerging reproductive tillers, senescence of mature reproductive tillers, and death of reproductive tillers due to grazing. The model was used to analyse data from Waikato dairy pastures. This enabled some of the effects of irrigation, nitrogen, cultivar and season (weather) on the biological processes to be identified. During spring and early summer, the proportion of reproductive tillers in ‘Ellett’ pastures was always higher than in ‘Grasslands Ruanui’, regardless of treatment and year. The model explained this difference by a higher conversion rate of ‘Ellett’ vegetative tillers to reproductive tillers, and suggested that conversion rate is the key process determining reproductive development in perennial ryegrass. Opportunities to control reproductive tillering are discussed. Keywords: flowering, Lolium perenne, perennial ryegrass, reproductive development
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(641 KB)The N2 fixation ability of caucasian clover was compared with that of white clover in irrigated ryegrass pastures over years 2 and 3 of a grazing experiment, using the 15N enrichment technique. ‘Endura’ caucasian clover was inoculated with the specific Rhizobium strain ICC148. The N concentration in clover herbage and the proportion of clover N derived from N2 fixation (PN) were similar for both clovers at averages of 4.6%N and 50–60% respectively over the 2 years. The amount of N2 fixed per hectare was directly related to the amount of clover dry matter (DM) produced by the two clover species. Caucasian clover produced four times the DM yield of white clover in year 2 (5400 cf. 1450 kg DM/ha) and four times the amount of N2 fixed in herbage (136 cf. 36 kg N/ ha). In year 3, caucasian clover produced 50% more clover DM (3450 cf. 2370 kg DM/ha) and N2 fixed (98 cf. 66 kg N/ha) than white clover. The increased N input from caucasian clover increased grass %N and N uptake from soil in caucasian clover pastures resulting in higher total pasture production compared with white clover pastures (15.7 cf. 14.2 t DM/ha) by year 3. In this study, caucasian clover demonstrated greater potential than white clover to meet the N demands of high-yielding perennial ryegrass in an intensive pastoral system. Keywords: clover content, Lolium perenne, nitrogen fixation, pasture production, Trifolium ambiguum, T. repens
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(579 KB)Perennial ryegrass (Lolium perenne) cultivars adapted to New Zealand conditions are bred by several scientifically equipped New Zealand interests. New cultivars are evaluated in a network of trials organised by the New Zealand Plant Breeding and Research Association. This paper presents data from 17 trials completed throughout New Zealand since 1991. Data were analysed for each trial and then in a multi-site analysis enabling comparison of estimated cultivar means, over all New Zealand trials, North Island trials and Canterbury trials. New cultivars released to the market yielded on average 6% more herbage annually, and 9% in summer, than cultivars available before 1991. Other cultivars were evaluated but showed no yield advantage and have not been commercially released. Point analysis of plots in the final season of trials indicated that recently released cultivars maintain ground cover at least as well as the older ones. Limited data for rust infection indicated that the oldest cultivars are the most severely affected. Keywords: cultivar evaluation, endophyte, NZPBRA, pasture plant breeding, perennial ryegrass
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(868 KB)Herbage mass and rising plate meter (RPM) height was estimated using the RPM as part of a farmlet trial, at No. 2 Dairy, Dexcel Hamilton. Herbage mass estimations were collected over a 3-year period, from pre- and post-grazing and weekly farm walk estimates. The aim of the study was to determine how appropriate the RPM was for use on New Zealand dairy farms. The RPM gives reliable information using 50 readings per paddock for paddock selection, grazing residual, and average herbage mass between 1000 and 4000 kg DM/ha. There was a tendency however, for the RPM to underestimate herbage mass when compared with visual estimates. The RPM is limited in its estimation of herbage mass above 4000 kg DM/ha and cannot be relied upon to give useful results for dry matter intake and net herbage accumulation (particularly with weekly farm walk data). As long as RPM limits are observed, overall results show that the RPM is an inexpensive tool to aid in farm monitoring and decision making. Keywords: dairy farming, grazing residual, herbage mass, rising plate meter, RPM height
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(643 KB)Poplar (Populus spp.) trees are planted on pastoral hill country throughout New Zealand, primarily for soil conservation. The effect of wide-spaced trees (16–100/ha) aged 8–15 years on understorey pasture growth, botanical composition, and microenvironmental characteristics, was determined at Pohangina (1997–2000) and Lawrence (1998– 2000) in the lower North and South Islands, respectively. Relative to environments without trees, at Lawrence pasture growth (13 100 kg dry matter (DM)/ha/yr) was reduced by 20% and 34% on north and south sides of trees, respectively. At Pohangina (7915 kg DM/ha/yr), trees had less influence (7% and 14% reduction) on understorey pasture growth. There were also strong seasonal effects at both sites, corresponding to when the trees were foliated. Swards at each site comprised 81–93% grass. At Lawrence, swards had similar botanical composition beneath and beyond trees. Swards on the north side of trees at Pohangina comprised relatively high grass and low legume content compared with those on the south side and in the open. Compared with open pasture, areas beneath young poplars received up to 24% less rainfall and 31% less solar irradiance, and soil water content (0–200 mm depth) was up to 33% lower in summer and autumn. At intermediate soil water contents (0.25–0.35 m3/m3), the profile of soil water content around trees during drying was frequently U-shaped, being lowest beneath the stem and increasing with distance away from the tree. Likely reasons for the pasture responses and variation in tree-pasture interactions between sites are discussed. The results will be used to model changes in tree-pasture interactions over time. Keywords: agroforestry, poplar, Populus, silvopastoralism, soil conservation, soil water, treepasture interactions
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(619 KB)The decimation of white clover in Waikato and Bay of Plenty pastures owing to the invasion clover root weevil (CRW) initiated an extensive screening of legume germplasm to identify plant material that could survive and remain productive under high CRW pressure. A total of 50 000 plants from 275 lines and six species, were planted on seven commercial farms and evaluated for tolerance/ resistance to CRW under conventional farming practices. Plant productivity and level of CRW damage were both highest on white clover. Significant CRW damage was also observed on red clover and caucasian clover, but not on birdsfoot trefoil, lotus major or lucerne. However, the productivity under stock grazing of the latter three species was not sufficient to consider them suitable alternatives to white clover. Within the white clover lines there was encouraging variability in the level of CRW damage, and in the ratio of damage to shoot production. While root damage is of greater importance than shoot damage, the latter reflects CRW activity and egg deposition and is a good indicator of likely larval development and root damage. Factors such as farm type (dairy farms versus dry stock farms) had some influence on shoot production, but very little influence on CRW damage. Climatic conditions appeared to have strong influences on clover shoot production and CRW damage, with dry conditions from late spring to early autumn having a particularly suppressive effect on CRW damage and CRW population growth. Top performing lines have been selected from this screening and are currently being evaluated in more detail under high CRW pressure. Keywords: clover, clover root weevil, plant screening, Sitona lepidus, tolerance, Trifolium repens
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(563 KB)Poplars and willows planted on farms for soil conservation and shelter are also potential sources of supplementary forage. The objective of this paper is to provide information that assists in the estimation of the value of poplar and willow forage. The quantity of forage in trees and branches was measured and non-destructive methods for estimating forage yield were evaluated. The edible forage dry matter (DM) of 5–10-year-old trees ranged from 2–22 kg DM/tree. The edible forage yield of poplar and willow branches with a basal diameter (BD) up to 100 mm was shown to be estimated from kg DM = 0.04 BD – 0.6. The nutritive values of poplars and willows were found to be similar, but the concentration of condensed tannins was usually higher in willows. Tree bark was found to have sufficient nutritive value to be stripped from trees for its feed value by livestock. Cattle were observed to be able to browse willows to a height of 2m and to eat stems with a diameter from 2.7 to 7 mm. Keywords: browse estimation, condensed tannins, nutritive value, poplar, supplements, willow
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(590 KB)
Three on-farm experiments were undertaken to examine the comparative performance of Friesian and selected Jersey x Friesian bulls in intensive bull beef systems. In Experiment 1, Friesian, ¼ Jersey/¾ Friesian and ½ Jersey/½ Friesian bulls were sourced as 4-day-old calves, reared together and farmed commercially through until slaughter at 29 months of age. When slaughtered at the same age, Friesian bulls averaged 290 kg carcass weight, with ¼ Jersey and ½ Jersey bulls averaging 289 and 271 kg, respectively. There was considerable variation in animal performance within the breed types, with the top 50% of the ½ Jersey bulls averaging 553 kg liveweight and the bottom 50% of the Friesian bulls averaging 522 kg at 29 months of age. In Experiment 2, 31 rising 2-year-old Friesian type bulls (436 kg) and 32 rising 2-year-old Jersey x type bulls (423 kg) were each allocated to two lanes of a Technosystem and stocked at 1828 kg liveweight/ha. Between May and November, Friesian type bulls produced 2.5% more beef liveweight per hectare than the Jersey x bulls (816 vs 796 kg of liveweight/ha). In Experiment 3, 43 rising 1-year-old Friesian type (199 kg) and 46 rising 1-year-old Jersey x bulls (185 kg) were each allocated to two lanes of a Technosystem and stocked at 1016 kg liveweight/ ha. Between June and December, Jersey x type bulls produced 1% more liveweight/ha than the Friesian type bulls (1151 vs 1141 kg of liveweight/ ha). The Friesian type bulls outperformed the Jersey x type bulls on a per head basis. Nevertheless there were a number of high performing Jersey x type bulls, suggesting that coat colour is not a suitable means of identifying better or poorer performing bulls. When Friesian type and Jersey x type bulls were stocked at a similar liveweight per hectare, there was little difference in terms of total output of beef per hectare. Since bulls are bought and sold on a liveweight basis, Jersey x type bulls can be as profitable as Friesian type bulls provided the purchase price is discounted to reflect the fact that more of them will be slaughtered in lower paying weight ranges. Our calculations indicate that on present prices, this discount for selected Jersey x type bulls could be as little as $11 per head to offset reductions in carcass value. Current discounts for Jersey x type bulls are well in excess of this and may reflect the difficulties in re-selling Jersey x type bulls and perceived behavioural problems with these bulls. Keywords: bull beef, Friesian, Jersey, per head, per hectare
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(570 KB)On-farm milk production and ancillary information was monitored for spring-calving cows grazing high (HT) and low toxin (LT) pastures in Northland over three seasons from spring 1997 to autumn 2000. Two groups of 16 second-calving Holstein-Friesian cows, balanced for calving date and production worth, grazed HT or LT ryegrass pastures from October 1997 to May 1998. Milk production was monitored for 10 consecutive days each month culminating with a herd test. The LT group out-produced the HT group for each measurement period from December, and over the whole season, produced 20% more milk solids. The HT group had significantly higher serum lysergol levels and correspondingly lower prolactin levels than the LT group. As pasture quality was similar it was suggested that the differences in milk production were most likely due to differences in intake. At the start of the 1998–1999 season 25% of the farm was in low endophyte ryegrass or in ryegrass with the AR1 endophyte. The farm and herd were split so that milk production from HT and LT farmlets could be monitored. Milk from each group was collected into separate tanks and all cows were ‘herd-tested’ 4-weekly. Despite twothirds of the LT farmlet being conserved for silage, which resulted in a severe feed shortage that necessitated supplements being fed-out on this farmlet from January, the LT group out-produced the HT group by 5% per cow and by 10% per hectare for the season from October to late May. In the 1999–2000 season, the farm and herd split was 29% LT and 71% HT. The objective was changed to one of maximising production from each system and this required changes in management. The LT system was managed to encourage clover-dominance from mid-spring and this was achieved by lengthening the rotation out to 6 weeks and then reducing it back to 3.5 weeks by leaving higher residuals and conserving <10% of the surplus. In contrast, a fast rotation (2.5 to 3 week) was used for the HT system and surplus feed was conserved. The LT pastures contained considerably more clover than the HT pastures. The only differences in pasture quality were in the November–December period when protein and soluble carbohydrate levels were higher in LT than HT pastures. The LT system out-produced the HT system by 8% per cow and by 12% per hectare. Issues surrounding the establishment and maintenance of LT pastures are discussed. Keywords: dairy cows, endophyte toxins, milk production, Northland, ryegrass
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(602 KB)Milk production by Jersey cows grazing a common allowance of irrigated or non-irrigated pastures over four summers (1997–2000) is described. The pastures were: (1) high-endophyte perennial ryegrass–white clover (2) tall fescue, phalaris, cocksfoot, white clover, red clover (3) same as (2) plus paspalum (4) endophyte-free ryegrass, timothy, white clover, red clover and (5) existing high-endophyte ryegrass–white clover. Irrigation improved milksolids yield by 5% over 4 years, with inconsistent effects on milk composition, no effects on pasture in vitro digestibility and nitrogen content, and usually no effect on pasture botanical composition. In 1997, cows on (1) produced the lowest milksolid (MS) yields. Cows grazing ryegrass–white clover (1 and 5) produced less than those on tall fescue-based pastures (2 and 3) (0.74 vs 0.86 kg MS/cow/day) in 1998, and the yields of cows on ryegrass/timothy-based pastures (4) were best (0.96 kg MS/cow/day). The same trends in milksolids yield occurred in 1999, except for cows on (1) which were similar to (4). Cows on existing pasture often produced the lowest milksolid yields. Trends in milksolids production over the 4 years reflected trends in total clover (red + white) contents. Keywords: cocksfoot, dairy cows, grazing, pasture quality, perennial ryegrass, persistence, phalaris, red clover, tall fescue, timothy, triple mix, volunteer ryegrass, white clover
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(582 KB)Two years of results from a 10 farmlet, farm systems trial (ending May 2001) are presented. The trial was designed to determine the efficiency and profitability of milksolids production when annual drymatter intake/cow and subsequent milksolids production/cow is increased within a whole farm system. Operating within the trial were five levels of feed intake and two farm management systems. The data presented show that with increasing kg liveweight/tonne of drymatter/ha, there was an increase in efficiency of pasture utilisation but a decrease in per cow efficiency. Extremes in increasing kg liveweight/tonne of drymatter were inclined to decrease the Economic Farm Surplus. Keywords: allowance, dairying, efficiency, milksolids, model
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(584 KB)A group of 12 farmers managing a total of 8845 ha in the West Waikato Region of the North Island, conducted a project to understand and overcome poor livestock performance during the summer– autumn period. Pastures and livestock were monitored to measure the impact of the conditions. Metabolisable energy (ME) of pasture averaged 9.0, 9.8 and 9.3 mega joules per kg of dry matter over the 3 years of study and elevated levels of pasture toxins were consistently found from mid- January to the end of May. To counter these conditions, farmers adopted varying strategies including pasture management and alternative feeding (silage and forage crops). A computerbased tool that enabled the user to make livestock feeding decisions based on the pasture cover, the ME of the pasture, and the quantity and ME of a feed supplement was developed. Farmers were able to reduce the proportion of damaged livers in lambs from 60 to 40% of the flock, which was against the district trend. When the right strategies were implemented, lamb and cattle liveweight gains increased from 52 to 146 g/day and 0.34 to 0.5 kg/day respectively. On average, ewe reproductive performance also improved during the period from 2.4 to 2.8% of lambs scanned/kg ewe body weight. The project emphasised to farmers that their resident pastures did not meet the needs of a high performing livestock production system and that alternative feeding strategies were required if higher performance was to be achieved. Keywords: Androvax, livestock feeding, metabolisable energy, pasture toxins, zinc
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(566 KB)
Biotechnology will play an essential role in the economic future of New Zealand and in maintaining the global competitiveness of our forage-based primary production. The genomics era has added a new dimension to cultivar development, with marker-assisted selection allowing more precise genome modifications during plant breeding, and plant transformation providing more direct and novel routes to cultivar improvement. The biggest impact will be the ability of researchers to consider genetic pathways and networks rather than working on “single gene fixes”. Integral to functional genomics are the rapidly developing fields of proteomics and metanomics – all these skills are needed to make a complete biotechnology package. Genetics and plant breeding have made a huge contribution toward forage crop performance in pasture-based systems, and biotechnology will provide future innovations and opportunities. Several research groups worldwide are developing comprehensive genetic maps of white clover and perennial ryegrass and are linking these to functional analysis of sequence databases to identify agronomically important genes. For this approach to capture its full value, researchers will need to fully integrate functional genomics with genetics, biochemistry, plant biology, agronomy and farm system management. Strong mapping, gene discovery, functional genomics and transformation capabilities will allow high-throughput analysis of gene function and application in new cultivars, using marker-assisted breeding or in transgenic lines. These tools provide an exciting opportunity to tackle some of the challenges faced in optimising pasture-based farming systems. Keywords: biotechnology, functional genomics, gene discovery, marker-assisted selection, perennial ryegrass, plant breeding, transgenic, white clover
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(534 KB)To measure the impact of biological control of Argentine stem weevil, Listronotus bonariensis (ASW) by Microctonus hyperodae in dairy pasture, a research site was established in the autumn of 1997 on a dairy farm near Lincoln, where the parasitoid had been present since 1994. Existing pasture was killed with glyphosate and four ryegrass cultivar treatments consisting of three perennial (Nui, Embassy, Vedette) and one hybrid mixture (Marsden/Greenstone), each containing either low or high levels of Neotyphodium lolii endophyte, were sown by direct drilling. A third main plot treatment was low endophyte plus insecticide. Between 1997 and 1999, seasonal pasture production was measured in all plots. Herbage composition was also measured in all plots for the first 2 years but only in the Nui treatments in 1999. ASW adult and larval densities, larval damage to ryegrass, parasitism by M. hyperodae and ryegrass tiller density were measured on Nui plots in spring and again in summer, coinciding with periods of peak ASW egg laying and larval development. Between 1997 and 2000, ASW adult densities in Nui were highest in the first summer (26 January 1998) following establishment. Thereafter, densities did not rise above c. 60 ASW/m2. Densities of adults, larvae, levels of larval damage to ryegrass, and parasitism by M. hyperodae were significantly higher in summer than spring (P<0.001) but with the exception of larval damage, there were no significant differences between the low and high endophyte Nui. There were no significant differences in herbage production among the low endophyte, high endophyte, and low endophyte plus insecticide treatments for any of the ryegrass cultivar treatments. The ryegrass component of the pasture showed a similar rate of decline over time for all Nui treatments. Over a 20-month period, average levels of endophyte in the high endophyte Nui plots increased from 35 to 46%. Conversely, average levels in the lowendophyte Nui plots, remained at c. 5%. The lack of any significant differences in herbage production and the relatively stable endophyte levels are discussed in relation to the ASW population data and M. hyperodae parasitism rates obtained from the Nui plots. Keywords: Argentine stem weevil, biological control, dairy pasture, endophyte, Lolium perenne, Microctonus hyperodae, ryegrass cultivars
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(618 KB)The use of biotechnology, in the form of gene mapping, marker-assisted selection (MAS), and map-based cloning can increase breeding efficiency and the array of traits amenable to selection. The increased efficiency is achieved by combining conventional glasshouse and field evaluations with DNA marker-based selection for superior genes; thereby maximising genetic gain from selection and/or improving traits with low heritability which are not amenable to improvement by conventional breeding alone. Implementation of MAS also reduces costs by permitting selection of superior plants at an early developmental stage or in the absence of the pathogen or pest. Robust genetic linkage maps are the basic requirement for identifying the genes controlling agronomically significant traits, and subsequent implementation of MAS. Recent advances in biotechnology have developed high-throughput, gene-targeted marker systems that allow rapid development of comprehensive genome maps and MAS programmes. Core linkage maps based on multiple DNA marker technologies are being developed for two of New Zealand’s most important forage genomes, white clover (Trifolium repens) and perennial ryegrass (Lolium perenne). Markers from these maps will be used to: a) identify genes controlling simple and complex traits, b) implement targeted MAS strategies, c) transfer novel traits from related species into elite forage cultivars via crosshybridisation, d) clone genes to be inserted directly into elite cultivars, e) provide DNA fingerprints for variety identification, and f) identify putative heterotic groups for hybrid cultivar development. Keywords: DNA markers, EST, gene mapping, linkage, Lolium perenne, marker-assisted selection, Trifolium repens
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(568 KB)Traceability requirements for market access, food safety and disease control are a key issue in the meat industry. Traceability also offers new opportunities for market-lead product improvement and genetic selection. DNA technology has recently provided a solution to the problem of tracing meat cuts from overseas markets back to the New Zealand processor’s carcass record and the farm of origin. The DNA system involves storing a sample of every carcass processed, and using forensic DNA matching to identify the ensuing meat cuts. While the system has solved one aspect of traceability, significant challenges remain to provide cost effective meat traceability for market assurance and product improvement. Keywords: animal welfare, consumers, DNA, market access, traceability
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(566 KB)
AR1 is a new fungal endophyte that is being released in perennial ryegrass to New Zealand farmers. This endophyte lacks the mammalian toxins, ergovaline and lolitrem B, but produces peramine which provides resistance to a major ryegrass pest, Argentine stem weevil (Listronotus bonariensis). Black beetle (Heteronychus arator) is another important pest of ryegrass in northern areas of New Zealand. Adults are selective feeders, and avoid feeding on ryegrass infected with wildtype endophyte. A limited supply of suitable food greatly reduces their reproductive capacity. Laboratory and field investigations were therefore carried out to evaluate the degree of resistance to black beetle provided by AR1. Assessments of adult black beetle feeding were made on two field trials planted in autumn 1999. In both trials, adult feeding was significantly higher on ryegrass infected with AR1 than on ryegrass with wild-type but also significantly lower on AR1 than on endophyte-free ryegrass. In a pot trial conducted in summer, black beetle adult damage to 4-week-old AR1-infected ryegrass was no different from damage to endophyte-free plants. However in 6-month-old plants, damage to AR1 plants was significantly less than to endophyte-free plants and was similar to damage levels on wild-type plants. A further pot trial showed that beetles overwintering on AR1 ryegrass had a higher reproductive capacity than those overwintering on wild-type infected ryegrass. In February 2001, two field trials planted the previous June were sampled for black beetle larvae. Black beetle presence was significantly higher on endophyte-free plots than on wild-type plots, with presence on AR1 intermediate between these treatments. Ryegrass infected with AR1, although showing a degree of resistance to black beetle compared with endophyte-free ryegrass, is more susceptible to damage than wild-type, particularly in its first year of planting. Limited data indicate that older AR1 swards may have similar resistance to that of the wild-type but further research is needed to clarify the effect of stand maturity on black beetle damage to ryegrass infected with this new endophyte. Keywords: AR1, black beetle, endophyte, Heteronychus, Listronotus, Neotyphodium, ryegrass
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(565 KB)Sheep and laboratory trials have been undertaken to evaluate the potential value of Dorycnium rectum (Erect Dorycnium) for controlling gastrointestinal parasites. This perennial shrub grows to 3–4 m and can be cut or used as a browse forage. The leaves contain condensed tannin (CT) at about 20% of the dry matter (DM). Sheep were fed D. rectum to determine its digestibility and the effects of CT upon digestion. DM digestibility was 59.6% and increased to 63.6% (P<0.05) when the effects of CT were removed, with comparable values of 23.6% and 73.6% for nitrogen (N) digestibility. Condensed tannin was extracted from D. rectum to evaluate its in vitro effects on egg hatching and larval development of the gastrointestinal parasites Trichostrongylus colubriformis and Ostertagia circumcincta. Very low concentrations (200 μg/ml) reduced egg hatching and virtually halted maturation to the infective third larval (L3) stage. Although the CT in D. rectum reduced its nutritive value for sheep when fed as a sole diet, the inhibition of larval development in vitro suggests a possible role for disrupting the cycle of reinfection in grazing sheep. Keywords: condensed tannins, digestibility, Dorycnium rectum, intestinal parasites, sheep
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(596 KB)An experiment was conducted at Dexcel, Hamilton from September 1999 to April 2001 to evaluate how pre-sowing pasture management and establishment method influenced the contamination of a newly sown AR1 endophyte-infected ryegrass dairy pasture with ryegrass infected with the wild endophyte (Neotyphodium lolii). Contamination level was estimated by counting the number of volunteer ryegrass plants between drill rows and by analysing bulk ryegrass samples for lolitrem B concentration. Hay, silage, grazed, grazed/topped and a turnip crop as pre-sowing managements generated large differences in viable ryegrass seed density (2555, 747, 348, 391 and 25 seeds/m2, respectively) on the soil surface after natural reseeding in March 2000. Measurements on 20 November 2000 showed the spray/cultivation and double-spray/fallow establishment methods were effective in reducing contamination with volunteer ryegrass plants (8 and 34 plants/m2, respectively), in contrast to drilling AR1 endophyte- infected ryegrass seed into hard-grazed existing pasture (581 plants/m2). On 14 March 2001, lolitrem B levels were lower in the spray/ cultivated and double-spray/fallow treatments compared to the hard-grazed treatment (0.3, 0.5, 1.1 μg/g, respectively). Information is also presented on sown plant density of AR1 endophyteinfected ryegrass. Keywords: AR1 endophyte, cultivation, glyphosate, Lolium perenne, natural reseeding, Neotyphodium lolii
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(670 KB)There is awareness and a growing interest amongst sheep and beef farmers towards the potential opportunity that low-chemical and organic markets offer. However, the ability to supply to these specifications is seriously constrained by a general lack of information among livestock producers of the practicalities of conversion to a low-chemical or organic supply system. This paper reports on a recently completed study that examined the knowledge gaps among livestock producers with an interest in further investigating low-chemical or organic production. The challenges confronting the producer are substantial if the opportunities that low-chemical natural and organic markets offer to the sector is to be realised. It is not a get-rich-quick option, and will require a medium to long-term planning and investment horizon. There is considerable ignorance, and hence confusion about the challenges and the conversion process. The study emphasised the importance of conversion planning, including the need for a pre-conversion period on most properties. Developing decision rules for managing at-risk livestock forms an integral part of the conversion plan as they ensure preservation of the production base, maintenance of high animal health and welfare standards, and management of risk. Contrary to popular belief, conversion to organic supply does not have to result in a cessation in the expansion of the production base or a loss in the performance of the current production base. An integral part of the conversion planning process is the continued development of the farm operation’s production base. Keywords: conversion planning, decision rules, livestock farming, low-chemical, organic
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(556 KB)
This paper reviews the key factors that have led to the widespread adoption of maize silage in North Island and Canterbury dairying systems and explores current maize silage feeding strategies. Maize silage has proven to be a cost effective supplementary feed that allows farmers to achieve higher MS/ha production. The worldwide significance of maize ensures a large plant breeding and research input that has resulted in significant ongoing genetic gains. Current maize feeding systems are based around systems quantified and described by research at Waimate West Demonstration Farm. A number of new technologies using maize silage are being investigated. These centre on manipulating the feed value of the silage through both plant breeding mechanisms and harvest-management strategies. Keywords: maize silage, supplementary feed
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(590 KB)This paper describes the concept of using Linear Programming (resource allocation modelling) to better understand and manage any pastoral system and to question the assumptions made of best practice given the limited knowledge available. Results from a case farm are presented to show typical outputs. Keywords: beef, dairy, modelling, resource allocation, sheep, sustainability
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(550 KB)An upper limit to productivity of perennial ryegrass–white clover pastures in New Zealand at about 15 t DM/ha per year has been identified as a constraint to future increases in productivity. With potential yields of 26.6 t DM/ha per year from temperate grasses and 45 t DM/ha per year from maize at mid-latitudes, the challenge for New Zealand dairy farming systems is to achieve greater than 15 t DM/ha per year without imposing additional production or environmental costs. Given these constraints a major switch to crops is not feasible because those that produce more than pasture, e.g., maize, have insufficient crude protein to support lactation. Theoretically, a farm area allocation to 78% perennial ryegrass–white clover and 22% maize-winter oats could provide 23.3 t DM/ha per year at a crude protein content of 16%. This is greater than the 20 t DM/ha per year upper limit of irrigated perennial ryegrass–white clover. Incremental yield improvements of grasses and clovers by traditional plant breeding are low (1.5% per year), and difficult to capture. Future plant breeding gains are more likely to come from increased plant stress tolerance. Improved pasture monitoring to allow timely removal of constraints, will enable potential yields to be achieved. Biotechnology offers the possibility of improving the potential yield of net photosynthesis by 20% either through the transfer of genes from a C4 plant (e.g., maize) or a C3 plant (e.g., perennial ryegrass), or use of the major photosynthetic enzymes, rubisco, from a thermophilic alga. Biotechnology is also providing new knowledge about the control of plant development and response to stresses. The application of this knowledge may allow dairy farmers to achieve another 5 t DM/ha per year from perennial ryegrass–white clover pastures. Keywords: biotechnology, dairy, perennial ryegrass, photosynthesis, white clover, yield limitation
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(636 KB)
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