On the east side of the Southern Alps of the South Island lies the province of Canterbury. Within this province there are five district regions, North, Central, Mid, and South Canterbury (all running from the mountains to the sea and separated by major rivers), and Banks Peninsula. Central and Mid Canterbury are home to the Selwyn and Ashburton District Councils (respectively) and sit side by side in the centre of Canterbury. Selwyn District has a northern boundary with the Waimakariri River, Christchurch City, and Banks Peninsula. Ashburton District has a southern boundary with the Rangitata River. The mighty braided Rakaia River is the dividing boundary between the two districts. Canterbury Regional Council (ECAN), based in Christchurch, has control over environmental issues in the area.
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(77 KB)In 1996, at the annual grassland conference in Oamaru, I presented a paper that examined the economic and productivity trends in New Zealand agriculture over the previous 50 years. At that time, there had been a steady reduction in the real prices received for our agricultural products for the previous 50 years, our animal productivity on sheep and beef farms had remained relatively static over the same period, while dairy cow productivity had been slowly, but steadily rising. The implication for farmers, and agriculture in general, was to reinforce the message that in order to retain profitability, one had to either: • Get bigger, as in scale • Get more productive, as in increased output per animal, or per hectare (while restraining cost of inputs) • Change to a higher value output (eg. chilled meat vs. frozen meat) In fact, over the past 10 years, our farmers, and the agricultural industry, have simultaneously achieved all three. The price received by New Zealand farmers for their lamb has increased 89% since the late 1980s, or 74% after taking away the benefit from exchange rate movements, at a time when the international price for frozen lamb carcases has dropped 12%. Our price for beef has dropped 5% while the international price has dropped 45%, and dairy prices have remained static during a time when butter prices have dropped 37%, all in real terms (Table 1). Crossbred wool, with a 54% drop, and wheat, with a 42% drop, over the same time period, has not feared so well. This is a remarkable achievement for lamb, because of the scale of the price increase, and also for dairy, because it occurred in tandem with a massive (108%) increase in product volume in the same 1990 to 2003 period. Also, we have experienced productivity gains unsurpassed in the history of New Zealand farming, particularly in sheep farming, with lambing percentage increasing 26% and lamb carcass weights 20%, and wool weight per head by 10% since 1990 (Figures 1 and 2). These increases have resulted in total lamb production increasing 10%, despite a 32% decrease in the national sheep flock since 1990. Milksolids per cow has increased 21% over the same time period, as well as a 9% increase in cow stocking rate. At the same time, farms have continued to decrease in number, and increase in scale. The best example of this is in the dairy industry where the average herd size has increased 70% (Figure 3), and there are numerous examples of multiple unit ownership.
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The Canterbury Plains is an area of low rainfall, and large pasture growth responses to irrigation have been demonstrated. As the demand for irrigation water has increased, questions about water allocation impacts on dairy farm production and profit have arisen. This study used farm systems modelling to predict the impacts of water allocation on dairy farming. The model farm was based on a spray irrigated farm, fed from the Rangitata River. A multi-year approach with rainfall, temperature and water supply all affected by weather highlighted both average impacts and the variability in impacts between years. Shifting from dryland to irrigated increased yield and decreased annual variability. A 20% range in water allocated within the four irrigated scenarios gave a 7% range in pasture yield, but there were no differences in annual variability between scenarios in either water supplied or pasture yield. Analysis of simulation results indicated that clusters of poor years and the relationship between dryland and irrigated yields may be important sources of variability for dairy farmers to consider. Interactions between local climate, the seasonal water supply pattern from different irrigation schemes, soil type and irrigation hardware will influence the impacts of restricting water availability on individual farms. The results of this study emphasise the need to consider the role of water storage, climatic patterns, feed storage, use of run-off blocks and the regional balance of water demands as important factors in reducing production variability on-farm and in the region. Keywords: farm systems, pasture yield, Whole Farm Model, yield variability
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(113 KB)Over 60% of the water that is used for irrigation throughout New Zealand is allocated within the Canterbury Region. In 1985 around 150000 hectares of land was irrigated, in 1999 this had more than doubled and the Canterbury Strategic Water Study1 has estimated there is potential in Canterbury to irrigate up to 1000000 hectares. As the demand for water increases the conflicts are likely to increase. These conflicts may be between users, between those who have access to water and those who don’t but would like some, or between existing and potential users and environmental interests. Environment Canterbury has recently notified a major variation to its Natural Resources Regional Plan that includes policies for the management of water, intended to help address the conflicts between the use, development and protection of the regions water resources. This paper and presentation outlines and backgrounds the allocation strategies included in Chapter 5 – Water Quantity and discusses some of the implications for irrigation dependent farming.
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(208 KB)The allocation of water resources between competing demands from agriculture, industry, energy, the environment and urban uses is an increasingly contentious issue in New Zealand. As a result there is a growing interest in the design of policies for better allocating water and policies for promoting the efficient use of water. For many decades governments in Australia have sought to develop and implement policies to promote the optimal allocation and efficient use of water. A wide variety of policies including regulatory, voluntary and market based approaches have been tried and significant modifications and improvement have been made to these policies over time. The experience in Australia has been that the transfer of water between agricultural uses occurs much more slowly than was originally expected. One reason for this is the importance of the reliability of water supply as a key contextual determinant of the feasibility and viability of different agricultural uses of water. While water supplies in NZ may be more reliable than in Australia, reliability can and does change as a result of changes in the rules governing the allocation of water. The experience in Australia with regards to promoting efficient use of water in agriculture is that farmers consider a wide range of needs and contextual factors when making decisions about adopting practices to improve water use efficiency (Armstrong 2004; Kaine & Bewsell 2002a; Burrows et al. 2002). Such decisions involve balancing a complex combination of human, production, environmental, economic and financial components of the farm business (Makeham & Malcolm 1993). Experience in Australia also shows that when they do act, farmers modify the practices or technology to ensure they meet the key needs of their farm business (Armstrong 2002; Kaine & Bewsell 2000a, 2000b, 2001, 2002b). Hence, when regulatory or forced change occurs farmers respond in a wide range of ways – many of which are unpredictable to the policy maker and at least some of which are not consistent with the intention of the regulation. These are deliberate and sensible reactions on the part of farmers given their farm contexts. Consequently, government in NZ needs a sophisticated understanding of farming systems and farm contexts if they are to experience fewer surprises and more successes with their initiatives in water policy. Keywords: farm systems, irrigation, water policy
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The environmental and economic performances of low, medium and high input dairy farming systems were evaluated for model farms within catchments in Waikato, Taranaki Canterbury and Southland. These four catchments, predominantly under dairy landuse, are part of a long term systems study of farm productivity and catchment-specific environmental issues. Within each catchment, environmental and economic performance indicators were derived for model farms by using the farm systems modelling tool UDDER and the OVERSEER™ nutrient budgeting programme. Our analyses indicated that high input systems, currently defined as farms within the top quartile of farm inputs, either as imported feed or fertiliser nitrogen (N), were often the least profitable, as defined by Earnings Before Interest and Tax (EBIT). These high-input systems consistently had the greatest environmental emissions of N and greenhouse gases, and the greatest energy consumption, on a per hectare and a per kg milksolids basis. The most profitable farm input system depended on payout and the catchment under study. Evaluation of the whole-farm system using these modelling tools demonstrated the relatively large contribution that stock wintering made to N emissions from farms within the two South Island catchments. Where reductions in N losses are sought, it would seem prudent to initially target mitigations at this part of the farm system. Keywords: dairy farming, environmental emissions, farm systems modelling, OVERSEER™ nutrient budgets, UDDER farm systems tool
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(335 KB)Over a 7 year period, two trials were conducted on dry, steep hill country near Waipawa, central Hawkes Bay to examine the effects of combinations of nitrogen (N) and phosphorus (P) fertilisers on sheep and cattle production. Four farmlets were established and balanced so that each contained similar proportions of predominantly north and south facing aspects, and easy (0-200) and steep (>200) slopes. For Trial 1 from 1995 to 1999, the ‘Low P’ farmlets had a soil Olsen P test of 9 ìg/ml, and the ‘High P’ farmlets had a test of 28 ìg/ml (paddock averages). One each of the Low P and of the High P farmlets received N overall in early to mid winter at 30 kg/ha applied in urea fertiliser. The trial was stocked with an initial ratio of about 65:35 sheep (5 year old Romneys) to cattle (18 month old Friesian/Angus). The stocking rate for each farmlet was individually set to fully utilise the expected pasture growth on each farmlet during winter. Standard costs and returns were used for the economic analysis in all years. High soil P status and use of N fertiliser were not economically worthwhile unless ewe numbers were maximised and spring pasture was fully utilised. This was achieved by having farmlets fully stocked with ewes during winter with cattle introduced in early spring to control additional pasture growth. This strategy was particularly successful in a drought year (1998) when N fertiliser allowed a significantly higher ewe stocking rate during winter. The farmlets receiving N fertiliser averaged $148/ha economic net margin compared with $117/ha from those without N fertiliser. In Trial 2, differential application of P (to easy slopes only) and N fertilisers (to steep slopes only) occurred in two of the farmlets. This provided higher economic returns than in Trial 1. The plus-N farmlets averaged $234/ha compared with $184/ha for those without N fertiliser. A major advantage of the differential fertiliser application approach is that the appropriate N or P fertiliser is applied only to areas that will provide the best responses from that type of fertiliser The success of intensified fertiliser use and stocking of dry hill country is dependent on maximising pasture use while reliable soil moisture and pasture growth conditions prevail i.e. early winter- early spring. Outside this period management options must be flexible enough to cope with drying conditions at any time. Keywords: animal production, economic net margin, hill pastures, nitrogen, phosphorus
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(78 KB)There are large differences in pasture growth and composition between aspects in dry hill country (annual rainfall 300-600 mm) in South Island dry hill country that could result in different fertiliser nutrient requirements for the grasses and legumes present. To determine these requirements, small plot mowing trials were carried out on sunny and shady aspects on Glenfoyle Station near Tarras and on Omarama Station over 3 years. At the Glenfoyle sites, nitrogen (N) was applied as urea at an average rate of 0, 15, 30 and 60 kg/ ha/yr and sulphur (S) was applied as gypsum at 0, 10, 20 and 40 kg /ha/yr. At the Omarama sites, N and S were applied at 0, 18, 36 and 71 kg/ha/yr. Soil total N (0.18- 0.33%), sulphate-S (3-5 ìg/g) and organic-S (1.5-3.5 ìg/g) levels were low at all sites. Pasture species on the sunny north-west aspect at Glenfoyle were mainly ryegrass (35% of total pasture content), flatweeds (20%) and subterranean clover (10%) with a predominance of browntop (31%) and white clover (20%) on the shady south-east aspect. There was a total pasture production response from 15-60 kg N/ha/yr (12-20 kg DM/kg N) associated with an increase in ryegrass content in Year 2 on the sunny aspect. On the shady aspect there was a total pasture production response from 30-60 kg N/ha/yr (16-21 kg DM/kg N) associated with an increase in browntop content. Increasing rate of N reduced subterranean clover on the sunny and white clover content on the shady aspect. On the sunny aspect, total pasture production and ryegrass content was increased from the application of 40 kg S/ ha/yr. Pasture composition at Omarama consisted mainly of Danthonia species (41%) and Bromus tectorum (30%) on the sunny north aspect and cocksfoot (39%) and browntop (11%) on the shady south aspect with less than 3% legume content on either aspect. On both aspects, there was a response in pasture production from rates of 18-71 kg N/ha (19-36 kg DM/ kg N) but this was not associated with a consistent response from individual pasture species. There was no response in total pasture production to S. The overall results indicate that high responses to N can be achieved from a range of grass species on both sunny and shady aspects and that soil sulphate-S levels of 3 ìg/g and greater are required for optimal growth of higher fertility responsive pasture species. Keywords: aspect, differential application, dry hill country, grasses, legumes, nitrogen, sulphur
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(293 KB)A dairy farmlet trial carried out in Central Taranaki in 1999/2000 and 2000/2001 examined the effects of calcium (Ca) supplementation (110-180 g/cow of fine limeflour drenched daily between calving in August and mid-mating in December) on serum Ca, incidence of milk fever and milksolids (MS) production at stocking rates of 2.5, 3.2, 3.7 and 4.2 Jersey cows/ha. Pasture Ca contents in spring were around 0.4% in both years and in the marginal to adequate range for dairy cow requirements. However, average blood serum Ca concentrations of 2.4 mmol/l were moderate and only 5% of non-Ca-treated cows occasionally had serum Ca less than 2 mmol/l, within the range for sub-clinical hypocalcaemia. Incidence of clinical milk fever was negligible (0-1%) in milking cows, with no treatment differences. There was no significant effect of Ca supplementation on MS production, although there was a consistent trend (all farmlets in both years) for a small response (3-4%) at the first herd testing. Keywords: calcium supplementation, dairy cow reproduction, dairy cows, hypocalcaemia, milksolids production
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(102 KB)Rates of lime (0, 1.25, 2.5, 5.0, 7.5 and 10 t/ha) were applied to two sites (Wyuna and Routeburn Stations) near Glenorchy in Central Otago. At both these sites initial herbage manganese (Mn) concentrations (780 and 471 mg/kg dry matter (DM) respectively) were above the level (400 mg/kg DM) that has been shown to reduce lamb growth rates. Total pasture production for the three years averaged 3600 kg DM/ha/yr at Wyuna and 8400 kg DM/ha/yr at Routeburn. The application of lime to the predominately browntop (Wyuna = 72%, Routeburn = 46%) pastures in this study, did not result in significant pasture production increases in the first 2 years but in Year 3 there was a significant production increase due to lime at Wyuna (P<0.05). Significant increases in soil pH and calcium and decreases in soil Mn occurred with the application of lime. The lime application also resulted in significantly lower herbage Mn concentrations. One year following lime application at rates of only 2.5 t/ha, herbage Mn concentrations were lowered to below the 400 mg/kg DM animal health threshold at both sites. A relationship between sward dead material content (x) and herbage Mn concentration (y) was established which had different slopes at the two sites (Routeburn y=8.34x + 577; r2 = 0.683, P < 0.001: Wyuna y = 6.8x + 633; r2 = 0.640, P<0.01). This relationship, the slope of which decreased as lime application rates increased, has implications in the interpretation and likely implementation of the results. It would thus appear that improved grazing management which limits the dead material content in the sward would lessen the amount of lime required to lower herbage Mn to below the animal health threshold. Keywords: browntop, dead material, lime application, manganese
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The on-farm milk production, pasture intake and silage intake of cows fed either whole-crop cereal silage or pasture silage as a supplement to pasture was compared in four herds in autumn and two herds in spring during 2002 and 2003. The number of cows per herd ranged from 90 to 270 cows per feeding treatment. Silages were supplemented at rates determined by farmer feed budget. The amount offered ranged from 3 to 6.6 kg DM/cow/ day. Pasture intake estimates ranged from 7.2 to 13.0 kg DM/cow/day. Milksolids (MS) production ranged from 0.93 to 1.61 kg/cow/day in autumn and from 1.33 to 1.98 kg/cow in spring. The feeding of whole-crop cereal silage produced more MS production in two autumn studies compared to feeding pasture silage as a supplement (+0.08 kg/cow/d; P<0.001). Feeding pasture silage produced more MS production in one spring study compared to feeding whole-crop cereal silage as a supplement (+0.06 kg/cow/day; P<0.01). Variations in feed intake and feed nutrient concentrations were the major reasons for variation in milk production changes. The feed quality of whole-crop cereal silages was more variable than pasture silages and low quality was reflected in some palatability and acceptance problems with wholecrop cereal silage. Whole-crop cereal silages fed in 2003 were of more consistent and higher quality than those fed in 2002. Cow live weight gain and body condition score changes reflected the feed intake and feed quality offered to the cows. Whole-crop cereal silages showed potential to equal or better the production gained from supplementing pasture silage when the amount fed was equal and when whole-crop cereal silage quality was high. Keywords: dairy cows, feed intake, feed nutrient concentration, milk constituents, milk production, pasture, pasture silage, whole-crop cereal silage
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(167 KB)Deciding when to harvest sulla (Hedysarum coronarium) can be a compromise between herbage yield and forage nutritive quality. Sulla, which grows up to 1.5 m tall, is tolerant of dry conditions and has been shown to have beneficial effects on ruminant production and health. A trial was conducted at Hamilton, New Zealand, to compare crop yield and nutritive quality of sulla harvested when it reached 30, 45, 60 and 75 cm high (retaining a stubble of 15 cm) over one growing season. Results show harvesting at 75 cm versus 30 cm increased total dry matter (DM) yield by 30%. Increasing harvest height increased total fibre content from 13.1 to 20.1 g/100g DM, (P<0.001) and lowered crude protein concentration from 18.8 to 15.7 g/100g DM, (P<0.001), soluble sugars from 23.1 to 21.5 g/ 100g DM, (P<0.01) and predicted organic matter digestibility from 89 to 82 g/100g DM, (P<0.001). These factors were associated with the decline in proportion of leaf with increasing harvest height from 49.1 to 31.6% of harvested DM. Increased harvest height reduced the concentration of calcium and potassium in the DM by about 10% (P<0.01), however there was a larger reduction in sulphur concentration with increased maturity (P<0.001) from 0.24 to 0.18% of DM (P<0.001). Phosphorous and magnesium concentrations were unaffected. Total condensed tannins (CT) declined from 6.0 to 5.5 % DM with increased harvest height (P<0.001), but all values were within the range regarded as beneficial for animal performance. Concentrations of all nutrients indicated a very good quality forage for sheep and cattle at all harvest heights and harvesting for maximum yield may not compromise quality. These results, although agronomically important, were small and may not produce noticeable effects on animal production. Keywords: condensed tannins, harvest height, Hedysarum coronarium, legume
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(42 KB)Abstract Timing of harvest is the single most important factor affecting the yield and quality of whole-crop cereals used for conserved feed. Changes in dry matter content (%DM) and relationships to herbage quality and maturation are presented for experiments conducted over three seasons beginning in 2001/ 2002. Changes in crop characteristics such as ear moisture, ear fresh weight, ear dry weight and leaf fraction were monitored to determine whether growers could use crop-based measurements in place of whole-crop % DM content to assist withdecision making close to harvest. A preliminary model defined the rate of crop maturation for a range of currently grown cultivars. Linear patterns of dry down occurred with only small variation in drying rate for the duration of grain filling. A model with specific inputs for cultivar, date of awn tip appearance (GS49), and developmental response to thermal time formed the basis of a decision support tool that enables growers and contractors to predict optimum harvest timing for whole-crop cereals. Keywords: silage maturity, supplements, forage, herbage quality
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(41 KB)Recent developments in cereal breeding for forage production have given the potential to greatly increase annual forage dry matter (DM) production. This paper reports on the findings from two cereal forage production trials on irrigated Canterbury land. Trial 1 studied the potential of a range of single and multi-grazed cereal forages over a 9 month period to produce high yields and quality from both grazing and whole-crop silage forage. Trial 2 studied the suitability of different cereal/ legume combinations for green-chop silage grown over a three month summer period. These two cereal forage systems, when combined in a 12 month period, produced in excess of 25 tonnes of high quality forage per hectare, almost double the DM production achieved using current perennial pasture based systems. Trial 1 showed no significant difference in the total DM produced by either single or multi-graze treatments. In Trial 2 pea/cereal combinations produced over 6 t DM/ha. Due to an earlier final harvest the multi-graze system is more easily combined with the summer crop and more likely to produce a lower cost and more sustainable forage system. Animal performance on forage produced in Trial 1 showed that dairy calves can grow well on cereal forages during winter. Keywords: cereal, feed supplements, forage, forage yield, legume, silage
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Site specific data for ryegrass seed crops has been obtained from two precision agriculture projects in Canterbury. Using yield maps and proximal sensors, the temporal and spatial variability within and between crops was quantified. In general, the best ryegrass seed yields were on the medium textured soils within a paddock. The lightest textured parts of a paddock could yield as well or better than these areas, particularly in seasons with cool springs, and in average to dry seasons provided irrigation was optimal. In contrast, heavier textured soils only yielded as well as medium textured soils if they were not overly wet (or cool) early in the season and in very dry years, when irrigation could not meet crop water demands, or in dryland situations. When irrigation was altered on perennial ryegrass by restricting moisture in November, there was greater reduction in seed yield in the lighter textured areas compared to the medium textured areas of a paddock. Extra nitrogen applied in late October improved yields in the medium textured part of the paddock but had a slight negative effect in the lighter areas of the paddock. In a trial using the plant growth regulator, Moddus, application was only beneficial in the medium textured parts of the paddock. Interpretation of ryegrass seed yield maps can be confounded by crop management decisions such as grazing, irrigation and harvest conditions. Late harvesting decreased seed yield so that the effects of soil texture and moisture were less evident. Farmers without this technology can use soil maps, aerial photographs and observation to identify areas of potential difference within a paddock. Targeting soil sampling, plant dry matter, soil moisture and perhaps nutrient analysis to major areas of difference can be useful in developing a zonal management system. Keywords: crop management, precision agriculture, ryegrass seed crops, seed yield maps
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(42 KB)Improving the seed yield potential of new white clover (Trifolium repens L.) cultivars is critical to their commercial viability and to overcoming the increasing pressures from land use change in Canterbury. The genetic control and response to selection was investigated for two seed yield characteristics, inflorescence density (no./m2) and seed yield per inflorescence (g/ inflorescence). Inflorescence density and seed yield per inflorescence were both responsive to selection and acted independent of one another to increase seed yield. Selection for high inflorescence density resulted in 34% higher seed yield than the low inflorescence density selection. This change in seed yield was associated with a 33% higher inflorescence density, while seed yield per inflorescence was unchanged. Similarly, selection for seed yield per inflorescence resulted in a 17% difference in seed yield between the high (HYI) and low (LYI) seed yield per inflorescence selections. This change in seed yield was associated with a 24% higher yield per inflorescence for the HYI selection, while inflorescence density remained unchanged. These results confirm that both mechanisms are under independent genetic control and can be utilized to increase seed yield of new white clover cultivars. Keywords: genetics, inflorescence density, seed production, Trifolium repens, white clover
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(160 KB)Genome maps and DNA markers allow plant breeders to decipher the genetic control of commercially vital quantitative traits. Discovery of the components of these genetic control networks will create opportunities to implement more efficient forage breeding systems. Gene mapping research strategies, using a combination of field trials and DNA-marker data, were used to discover quantitative trait loci (QTL) impacting seed production in white clover (Trifolium repens). Twelve QTL influencing seed yield (SY) or the two component factors inflorescence density (ID) and seed provisioning (SP) were detected using a full-sib gene mapping population in the 2002 trial at Lincoln, New Zealand. Three of these QTL also were detected in the 2003 trial, of which one for ID and one for SP harboured alleles that accounted for up to a 50% change in ID and SP trait value, respectively. Genetic tests for these two alleles were used in a marker-assisted selection (MAS) experiment to identify the plants in the gene mapping population with the highest commercial potential. This initial proof-ofconcept MAS design was successful in identifying the subpopulation with the highest SY value. Implementation of MAS designs will result in increased ability for plant improvement programmes to assure development of commercially successful forage cultivars. Keywords: marker-assisted selection, QTL, seed production, white clover
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(197 KB)Seed yields of ryegrass and tall fescue have increased rapidly over the last seven years; the best farm yields are now reaching 3000 kg/ha, up from 2000 kg/ha. These increases are largely due to the adoption of technologies developed from research funded from grower crop levies and effective technology transfer programmes. The key technologies are (1) the adoption of trinexapac ethyl (TE), a plant growth regulator that blocks gibberellic acid biosynthesis and reduces lodging; and (2) new generation triazole and strobilurin fungicides that give improved disease control and extend the period that green leaf area is maintained on crops. Seed yield data from 10 ryegrass and 6 tall fescue trials with TE, and from 13 fungicide trials are presented. The average seed yield increase in tall fescue treated with 200 g TE/ha and ryegrass with 400 g TE/ha was 67% and 50% respectively. In fungicide trials, seed yields in forage perennial ryegrass were increased by 20% and in turf ryegrass by 42%. A survey of growers indicated 95% of ryegrass growers and 100% of tall fescue growers had adopted the use of TE three years after the commercial release of the product. Keywords: fungicides, plant growth regulators, ryegrass, seed yield, strobilurin, tall fescue, triazole, trinexapac
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(118 KB)The viability of the New Zealand herbage seed industry is influenced by national and international factors and changes in consumer requirements. Four main species perennial ryegrass (Lolium perenne), Italian ryegrass (Lolium multiflorum), tall fesuce (Festuca arundinacea) and white clover (Trifolium repens), account for more than 98% of the herbage seed grown in New Zealand. Annual production averages 22000 t, of which 70 to 80% is grass seed with perennial ryegrass (L. perenne) being the largest component. There have also been significant production changes among species with Italian ryegrass (L. multiflorium) in particular increasing in importance, with production doubling between 1999 and 2003. There has been a marked reduction in total area for herbage seed production over the past decade, however, this has been offset, particularly in ryegrass, by higher seed yields per ha. These improvements in seed yield have primarily been achieved through implementation of better management techniques. The increased use of the plant growth regulator trinexapac-ethyl has been very beneficial in grass seed production. There has also been a major shift in New Zealand seed production towards the production of proprietary cultivars. In white clover, for example, proprietary cultivars represented less than 10% of production in 1991 but have increased to 57% in 2003. The rapid uptake of the novel AR1 endophyte technology in proprietary ryegrass cultivars, which has grown from 0% in 2000 to 21% of perennial and hybrid proprietary ryegrass seed produced in 2003, is an excellent example of what can be achieved with an addedvalue product. The future viability of the New Zealand herbage seed industry requires further development of identifiable added value traits associated with the seed. Keywords: AR1 endophyte, plant growth regulators, production statistics, ryegrass, seed production, tall fescue, white clover
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(158 KB)The successful commercialisation of agronomically superior white clover (Trifolium repens) cultivars is dependent on their seed production potential. Field trials were established in 2000 and repeated in 2003 to determine the impact of selection for increased seed yield. The seed yield of the pre-release cultivar (the base population prior to selection for seed yield and cultivar release, representing generation 0) was compared with the field Nucleus generation of the released cultivar (second generation after selection for seed yield, representing generation 2) and the Basic seed generation (the fourth generation after selection for seed yield, representing generation 4), in six recent cultivars (Grasslands Kopu II, Grasslands Challenge, NuSiral, Grasslands Sustain, Grasslands Demand and Grasslands Prestige). The Nucleus and Basic generations had consistently higher seed yield than the pre-release generation for all cultivars. These increases in seed yield were associated with increases in inflorescence density (inflorescences/m2) and to a lesser extent with increased seed yield/inflorescence. Changes were also evident in flowering pattern with four of the six cultivars having a sharper flowering peak following selection. This improved uniformity was also evident through reduced variability in leaf size of the Nucleus generation compared to the pre-release generation. Grasslands Kopu II had the highest seed yields which were associated with moderately high inflorescence density in combination with high seed yield/ inflorescence. The selection strategy used in the final phase of the development of these cultivars has proven successful in increasing seed yield through refining flowering pattern and production while maintaining the morphology and uniformity of the new cultivar. Keywords: cultivars, genetic improvement, seed production, Trifolium repens, white clover
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Large areas of pine forests have been logged and the land sold to farmers for converting to pasture in the South Waikato district. This land use change is expected to continue, given the present commodity prices. A trial was conducted on an ex-forest site at Rotorua to assess the feasibility of converting land from forestry to pastoral agriculture. The establishment of pasture (ryegrass and white clover) on an ex-forest site was successful and results after 4 years indicated there were no major problems with the conversion. An application of 4 t lime/ha lifted soil pH levels into the optimum range of 5.8-6.0 and an annual maintenance dressing of 40 kg phosphorus (P) /ha has more than maintained optimum Olsen P levels of 35-45 μg/ml for pasture growth. It is expected however that commercial sites where post-forest soil P levels were lower than on the Rotorua trial site, would require higher capital P fertiliser input. Soil fauna surveys indicated a recolonisation of some soil macro fauna e.g. earthworms, grass grubs and clover root weevil. Recommendations for converting pines to pasture include removal of stumps and forest debris (where practical), vigorous weed control and the application of nutrients such as phosphate that promote pasture production. Keywords: forestry, soil Olsen phosphorus, soil pH, pasture, Pinus radiata
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(159 KB)Methane (CH4) production from ruminant digestion has a significant impact on the New Zealand greenhouse gas (GHG) inventory and represents a loss of about 10% of metabolisable energy (ME) intake. Previous trials with sheep and cattle have demonstrated significantly lower methane losses per unit feed intake from legumes compared to grass dominant pasture. Most trials have compared forages fed as sole diets but white clover (Trifolium repens) is usually fed with perennial ryegrass (Lolium perenne) as a mixed pasture, as it complements ryegrass for animal production. An indoor feeding trial was conducted in December 2003 with thirty-two Holstein-Friesian dairy cows in mid-lactation to determine effects of increasing proportions of white clover on methane emissions and cow performance. Cows were housed indoors and fed perennial ryegrass with 0, 15, 30 or 60% white clover ad libitum on a dry matter (DM) basis. Increasing proportions of white clover resulted in linear increases in dry matter intakes (DMI) and reductions in methane per kg DM eaten, although the extent to which CH4 production/kg DMI was lowered was less than anticipated from previous measurements from sheep fed white clover as a sole diet. DMI of cows fed 60% white clover was 20.5 vs. 15.6 kg DM/cow/day for 100% perennial ryegrass (P<0.001) with 18.1 vs. 21.7 g CH4/kg DM for the respective treatments. The increased DMI of cows fed increased levels of white clover resulted in a significant but small increase in total daily CH4 emissions. Milk and milksolids yields also increased from 17.6 to 20.4 kg/ cow/day (P<0.001) and 1.32 to 1.52 kg/cow/day (P<0.005) respectively as the proportion of white clover increased from 0 to 60%. Keywords: dairy cow, methane emissions, milk production, perennial ryegrass, white clover
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(101 KB)The potential for water, nutrient and faecal bacteria transport in border-dyke run-off from dairy pasture was monitored within the South Canterbury catchment of Waikakahi during the 2002/2003 milking season. The Waikakahi stream runs lengthways through the catchment and characteristically has mean summer flows approximately four-times that for winter (2002; 1850 l/s vs 450 l/s, respectively). This extra flow is assumed to be fed largely from irrigation run-off and drainage. Three borders of a flood-irrigated dairy paddock in the upper part of the catchment, located on Temuka gley soils, were directed off to a collection weir over which seven irrigation events were recorded for runoff volume, Escherichia coli (E. coli) and phosphorus (P) and nitrogen (N) concentrations. Irrigation volume loss from the Waikakahi field site was, on average, 50% of total inflow and considerably higher than the accepted recommended maximum in Australia of 10%. However, it was accepted that this represented a possible “worst-case” scenario. Run-off totalled 2600 m3/ha over the first six events with the large volume at least partly attributed to insufficient infiltration into the soil due to the low hydraulic conductivity of the Temuka soils. Irrigation volumes entering the catchment were generally sufficient to supply 90-100 mm depth of water across the area but border gradients appear too steep to allow sufficient infiltration before the water ran to the end of the border. Re-grading borders to allow for the slower infiltration rates of heavy texture soils is suggested. Concentrations of P, N and E. coli in irrigation run-off were consistently higher than the acceptable critical limits for water quality and even with in-stream dilution, would continue to exceed water standards. Total-P and dissolved reactive phosphorus (DRP) concentrations in nonfertiliser affected run-off (first six events) were high at ~0.8 mg and 0.6 mg P/l, respectively. Total phosphorus and nitrogen losses over the seven events totalled 3.4 and 2.0 kg/ha, respectively. The source of most P appears to be from high soil P levels (soil Olsen P levels >45 ìg/ ml), indicating the importance of ensuring soil Olsen P values remain within the agronomic target range (20-30 ìg/ml). The presence of fertiliser and timing of application, and days between irrigation and last grazing, were also important determinants of nutrient concentrations inirrigation run-off. Flow obstructions within the headrace channel were linked to differences in volumes entering individual borders and also caused unintended inflow from irrigation of the adjacent set of borders. Improving the smoothness of the headrace channel is required to achieve more even watering. A number of other contributing factors that may lead to excessive irrigation run-off were also noted. In this particular set in the first instance, inflow times needed shortening to reduce water loss. Reducing the volume of irrigation run-off overall entering the stream remains the chief means of reducing nutrient and faecal bacteria contaminant loadings and improving water quality. Keywords: border-dyke irrigation, dairy pasture, faecal bacteria, nitrogen, phosphorus
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(228 KB)Grazing of winter forage crops can cause extensive
compaction of soils that may reduce re-growth of crops
and lead to large emissions of nitrous oxide (N2O). A
field trial was undertaken to investigate the effects of
cattle grazing at three soil moisture contents on N2O
emissions and dry matter (DM) production of a winter
forage crop established by intensive (IT), minimum
(MT), or no tillage (NT) practices. A multi-grazing triticale
(cv. Doubletake) was sown in the main tillage plots in
March 2003. In June, the tillage plots (three replicates)
were each divided into six split plots and additional
treatments were imposed: simulated treading (+/-); soil
moisture at treading (< field capacity (FC); FC; and >FC);
and urine (+/-). Tillage practice and soil moisture content
at treading affected soil compaction. The greatest increase
in surface soil (0-7.5 cm) bulk density occurred in IT
plots treaded at >FC. Treading wet soil greatly increased
(up to 8 times) the amount of N2O emitted. The highest
cumulative N2O emissions were from IT (14.9 kg N/ha)
and MT (12.7 kg N/ha) urine-applied plots treaded at
>FC. There was no difference in N2O emitted from
treaded
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(188 KB)
A best management protocol for growing a turnip crop was developed from published information and provided to dairy farmers intending to grow the crop. On the basis of information returned by farmers in the 2002/2003 and 2003/2004 growing seasons, the validity of the assumptions underlying the protocol were tested. Many of the returned forms were incomplete and could not be used in the analysis. Adherence to the protocol was variable as farmers interpreted the prescriptive protocol differently and applied components of the protocol as they saw fit on their property. Protocol directions for nitrogen application, soil phosphorus content and sowing rate were applied the most uniformly, providing little variation for testing the impact of these factors. Farmers who applied post-emergence herbicide and insecticide as prescribed achieved a higher (P<0.01) turnip yield (on average 12.5 t DM/ha) than those that did not (average 10.9 t DM/ha). Most of this extra yield (1.3 t of the 1.6 t DM/ha) was the result of elevated leaf yields (P<0.01) though the leaf:bulb ratio was not significantly affected by following the protocol. We cautiously conclude that following the protocol will be beneficial to farmers. The caution is based on the fact that the results reported did not originate from a controlled experiment, but from a survey where differences in factors such as farming ability and cropping experience were not adequately accounted for between treatments. Keywords: dairy farming, farmer survey, herbicide, insecticide, summer feed gap, turnip
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(71 KB)In New Zealand dairy systems, cows usually lose condition in early lactation, when their feed demand is high, to buffer milksolids (MS) production. Condition score (CS) at calving is influenced by drying-off date and CS at drying-off. In late-March, two groups of cows with average CS 4.5 were dried off early and offered normal (13 kg DM/cow/day) and high (26 kg DM/cow/day) pasture feeding allowances. Another group of average CS 4.5 was offered 26 kg DM/cow/ day and dried-off late (mid-May). Two more groups with average CS 5.1 were offered normal (26 kg DM/ cow/day) and high (52 kg DM/cow/day) allowances and also dried-off late. From late-March to mid-May, dry cows fed at the high level gained about twice as much condition as normally fed dry cows (+1.5 vs +0.7 CS). The late dried-off cows at initial CS 4.5 and 5.1 had a gain in CS (0.3 units) or maintained condition respectively under normal feeding, but gained 0.4 CS under high feeding. In late lactation, there was no significant difference in MS production (P<0.05) from high compared to normal feeding at CS 5.1, but the high fed cows produced significantly more MS than the normally fed cows at CS 4.5. In the next lactation, from calving in late-August to late-October, there was a trend for both early and late dried-off cows that had been fed at a high level in the preceding late lactation to produce more MS than those that had been normally fed (1.93 vs 1.79 kg MS/cow/day averaged across both CS groups). Drying-off date had a significant effect on MS production in early lactation (early drying-off 1.93 kg MS/cow/day vs late drying-off 1.76 kg MS/cow/day) for cows with initial CS 4.5. There was a strong relationship between CS at calving and MS production in early lactation, with 1 extra CS at calving equivalent to 0.19 kg of extra MS/day. Changes in cow body fat content during late lactation corresponded closely to changes in CS (52 kg body fat/CS unit). The results suggest that where autumn feed is limited, there is little difference in the efficiency of pasture use between normal autumn feeding of late dried-off fatter cows to allow higher autumn feeding of early dried-off thinner cows (5.0 kg MS/kg DM), compared with normal autumn feeding of early dried-off thinner cows to allow higher autumn feeding of late dried-off fatter cows (4.7 kg MS/kg DM) Keywords: cow body fat content, cow condition score, dairy cows, drying-off date, feeding level, milksolids production
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(91 KB)A study was conducted on seasonally dry hill pastures near Waipawa, central Hawkes Bay, over a two year period to investigate how the application of nitrogen (N) fertiliser changed the pasture chemical and species composition and if animals subsequently preferentially grazed that pasture. In Year 1 the short term effects of N fertiliser (30 kg N/ha) was evaluated on both north and south facing slopes after the pasture was spelled for about 12 to 25 days only after N fertiliser application. This period did not allow sufficient time for pasture dry matter (DM) responses to develop. In Year 2, using the same trial sites, the pasture was allowed to develop DM response differences of 500 kg/ha or more following N fertiliser application before animals commenced grazing. On each occasion, grazing observations were made during a 5 hour period following stock introduction to spelled pasture. Herbage mass per plot was measured prior to, and at the end of the grazing period, and the amounts of pasture utilised per plot calculated. In Year 1 there were three separate measurements and grazing observations. The first was in mid winter on pasture with a high dead matter and near zero clover content and overall low quality. N fertiliser had no effect on chemical composition. In the second and third observations in late July and September respectively, when more clover and less dead matter was present, N and crude protein (CP) concentrations were both enhanced by earlier N fertiliser application. Similarly in 2003 when herbage mass responses were allowed to accumulate following N fertiliser application, the pasture N, phosphorus, potassium and CP levels all increased and soluble sugars and starch levels decreased. These effects were more pronounced in the pasture from the south than from the north aspect. In Year 1 there were no differences between Nfertilised and non-fertilised plots in mean grazing intensity (ewes/100m2), or in the amounts of pasture DM utilised during grazing. In Year 2, grazing intensities and the amounts of pasture utilised, were higher where pasture mass was significantly higher as a result of N fertiliser application. The results suggested that where significantly greater pasture DM responses are allowed to occur, the subsequent grazing intensities will also be greater compared with grazing intensities on associatedpasture. It is likely that the differences in pasture chemical composition induced by application of N fertiliser at 30 kg /ha were insufficient to cause any difference in grazing behaviour by ewes. Higher N fertiliser rates may be required to induce such chemical changes and grazing preferences as observed in other studies. Keywords: grazing intensity, nitrogen fertiliser, pasture quality, pasture species
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(82 KB)This paper describes the development of a forage selection decision tool. The project was carried out in conjunction with Meat and Wool New Zealand and farmer mentor groups in Manawatu, Canterbury and Southland. The model uses a multi-criteria technique called Electre III which helps rank the characteristics of forages relative to environmental conditions and farmers objectives. The approach allows farmers to rank and compare suitable species and cultivars. The decision tool provides advice on appropriate seed mixes and specific information on establishment and management. In addition the model was structured to allow farmers to discover limitations to their environment or management systems through a process called ‘back-chaining’. An example of this is where a farmer queries the model to discover what conditions prevented a forage from being selected. Demonstrations of the Forage Master to a range of farmer groups nationwide has provided excellent feedback on the value of the decision tool, firstly for aiding on-farm decision making and secondly, benefits associated with the information provided in the help links. Keywords: computer model, cultivars, forage, forage selection, multiple criteria, pasture species
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(179 KB)Decision tree models were applied to predict annual and seasonal pasture production and investigate the interactions between pasture production and environmental and management factors in the North Island hill country. The results showed that spring rainfall was the most important factor influencing annual pasture production, while hill slope was the most important factor influencing spring and winter production. Summer and autumn rainfall were the most important factors influencing summer and autumn production respectively. The decision tree models for annual, spring, summer, autumn and winter pasture production correctly predicted 82%, 71%, 90%, 88% and 90 % of cases in the model validation. By integrating with a geographic information system (GIS), the outputs of these decision tree models can be used as a tool for pasture management in assessing the impacts of alternative phosphorus fertiliser application strategies, or potential climate change, such as summer drought on hill pasture production. This can assist farmers in making decisions such as setting stocking rate and assessing feed supply. Keywords: data mining, decision tree, GIS, hill slope, rainfall
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(204 KB)Uptake of cobalt (Co) and copper (Cu) by ryegrass/ white clover based dairy pasture from autumn spray applications of cobalt sulphate (CoSO4) copper sulphate (CuSO4) and Cu chelate was measured at a site near Woodlands in Southland. The rates of application were 0, 12.6, 25.2, 50.5 g Co/ha (0, 60, 120 and 240 g CoSO4/ ha), and 0, 0.25, 0.5 and 1 kg Cu/ha. The concentration of Co in herbage was significantly increased initially by the two highest application rates (P<0.001). However, only the highest application rate of 50.5 g Co/ha (240g CoSO4/ha) gave increased herbage Co concentrations for the full 41 day duration of this study. In contrast the concentration of Cu in herbage at all rates of application for both forms was significantly higher (P<0.001) than that of the control even after 41 days, with the lowest rate of the sulphate form having concentrations similar to the highest rate of the chelate form. The herbage Cu concentrations from the treated plots, immediately following the application, exceeded 100 mg Cu/kg dry matter (DM) for all application rates and forms and dropped steadily until day 27 at which time they were in the range of 20-90 mg Cu/kg DM. Cu concentration remained relatively static from day 27 until the end of measurement at day 41. These levels should be sufficient to supply animal requirements, resulting in liver Cu levels which could remain adequate for the critical winter period. Hence when applied in liquid form, rates of Cu application lower than previously recommended may be sufficient. Despite this, care must still be taken in the first 5-10 days following application to avoid Cu toxicity to grazing animals. Keywords: copper chelate, cobalt sulphate, copper sulphate, pasture cobalt content, pasture copper content
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(173 KB)The Dexcel “Feed4Profit” extension programme was established in 2001 to help dairy farmers increase their profitability through improved feeding systems. Managing for high pasture quality can result in increased milksolids production and profit. Dairy farmers learning needs around management of pasture quality were assessed at eight discussion groups throughout New Zealand. The farmers defined pasture quality more in visual than nutritional terms. They believed that it was dependent on soil fertility, quality and pasture cover and pasture composition. They grouped management into three main headings: day-today, periodic (spring and autumn – winter) and longterm. Day-to-day management included stocking rate, adequate pre- and post- grazing covers, round length, and use of inputs. Management during the spring included monitoring, harvesting supplements and topping. Autumn – winter management included regressing, weed control and minimizing pugging damage. Long-term management techniques included adequate soil fertility, drainage, selection of the appropriate breed of cow, and managing for persistence. Farmers identified that they needed to improve in their analysis and use of pasture quality information, management of different pasture species, management of surplus, low quality and low quantity pasture, and estimation of pasture quantity. The outcomes that the farmers wanted from their use of an extension package were increased pasture and land utilization, increased productivity and profitability. This research was used to develop an extension package around maintaining high pasture quality. A reference team of farmers and rural professionals guided the process. Their feedback resulted in a poster, rather than a booklet, being produced by the Feed4Profit team. Keywords: dairy farmers, dairy management, extension, learning needs, milksolids, pasture quality, profit
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(61 KB)This paper outlines findings for three experiments on the AgResearch Invermay deer farm that quantified soil and water quality via fence-line pacing and wallowing, and water quality in streams draining the farm. Five weeks after winter grazing (28 hinds/ha), fence-line pacing decreased soil macroporosity and saturated hydraulic conductivity, and increased suspended sediment (SS; 0.226 g/100ml), total phosphorus (P) (TP; 2.0 mg/l), mainly as particulate P (up to 90% of TP), and E. coli (3.52 log10 cfu/100ml) concentrations in a simulated overland flow 1 day after grazing had stopped compared to soils from the rest of the paddock (0.148 g/100ml, 0.86 mg/l and 2.86 log10/100ml). Six weeks following a first simulated rainfall event, and without interim grazing, concentrations in the second simulated event had decreased but losses of P, especially in fence-line paced soils, were still high and above recommended limits for surface water quality (TP = 0.033 mg/l). A survey of visible erosion in 6 deer paddocks with topography (2- 10o) yielded a mean erosion rate of 1.08 t/ha/yr (range, 0.41-2.01 t/ha/yr), 43% associated with fence-lines, troughs or gateways and 57% associated with wallows. Data from three waterways indicated that mean values for two sites that drain 100% deer farmed land, exceeded current lowland surface water limits for dissolved (0.01 mg/l) and TP (0.033 mg/l) and ammoniacal-nitrogen (N) (0.021 mg N/l). Limits for E. coli (126 E. coli/100ml) and nitrate-N (0.444 mg N/l) were also exceeded at another site, which drained a wallow. All guideline values were exceeded during storm flow when ephemeral streams, commonly draining wallows, were flowing to permanent waterways. However, loads of P, N and SS were below average for mixed-grazing pasture catchments in New Zealand. This was attributed to a dry year (rainfall <20% of normal), which suggests management targeting fence-line pacing and wallowing should mitigate bad effects on water quality from deer farmed catchments in average or wet years. Keywords: E. coli, nitrogen, nutrient load, phosphorus, suspended sediment
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(208 KB)Four hundred and eighty East Friesian composite (50% East Friesian, 25% Poll Dorset, 25% Texel) or Romney ewes were assigned to either a conventional lambing (March) group or a year-round lambing group. The trial began in January 2003 and the year-round system aims to have ewes lambing every 73 days. In the year-round system approximately a third of the ewes were synchronised and joined with mixed age rams of their respective breed for a 21 day period on 13 January, 27 March, 8 June, 21 August and 1 November. This results in each ewe having the opportunity to lamb five times in a three-year period. The conventionally bred ewes were joined with rams on 27 March for 2 cycles of breeding. Results after year one indicate the number of lambs born and weaned per ewe lambing was similar for East Friesian ewes in the year-round and conventional lambing groups. However Romney ewes reared less lambs (1.22 vs 1.41, P<0.05) than East Friesian composite ewes in the conventional system. Pregnancy rates at scanning were higher in East Friesian composite than Romney ewes in the year-round system (0.75 vs 0.65, P<0.05) but there were no differences between the two breeds in the conventional system. Lamb birth weights were heavier in the conventional system than the year-round system (5.1 ± 0.1 kg vs 4.2 ± 0.1 kg and 4.8 ± 0.1 kg vs 4.1 ± 0.1 kg for East Friesian and Romney ewes respectively). Lambs born in June were significantly lighter than lambs born in August or November in the all year-round system. Lamb growth rates and weaning weights of lambs born to East Friesian composite dams were heavier than lambs born to Romney dam in both systems. The major constraint that appears to be limiting high performance in the year-round system is the low pregnancy rates in the non-breeding season (i.e. August to January). Based on year one data it can be concluded that income from lamb sales in the year-round system can match or better (in the case of East Friesian composite ewes) a conventional March lambing system without any premiums for the out-of-season lambs and is likely to be further improved if pregnancy rates can be improved. Keywords: lamb growth, lamb production, number of lambs born, year-round lambing
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(77 KB)
This paper reports a field experiment and a farm survey, which aimed to find out if there is evidence that elevated herbage crude protein (CP):sugar levels have negative effects on dairy cow performance. Differences in herbage CP levels were induced by using nitrogen (+N) or withholding (-N) applied as fertiliser urea for two groups of 20 dairy cows in early lactation (August to November 2003). Cows fed urea-fertilised herbage had elevated milk urea levels (-N = 5.4 mmol/l, +N = 8.3 mmol/l, P<0.001). A feed conversion efficiency (FCE) index was calculated as the ratio between theoretical daily metabolic energy (ME) requirement based on measured live weight and milksolids (MS) production data, and the observed mean daily ME intake over a 74 day observation period. Using this index, the apparent FCE was approximately 10% lower for the +N than for the –N group of cows. A survey of 16 farms indicated an association between elevated milk urea and decreased MS production per cow per day, consistent with the experimental result. It is concluded that although fertiliser urea does appear to reduce FCE, urea use can still be a viable strategy to improve the overall performance of a dairy farm system. Keywords: dairy cow performance, feed conversion efficiency, fertiliser urea, metabolisable energy, milksolids production
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(82 KB)Increasing the total lipid concentration and modifying the fatty acid profile in forage may increase energy intake and productivity of animals and improve the attributes of meat and milk for human health. To predict the outcome of modifying these traits in ryegrass, 3 groups of weaned lambs (n=15 per treatment) grazed ryegrass (4% total lipid) and received twice-daily oral doses of oil at 0, 28 or 56 ml/day. The oil consisted of a blend of 75% linseed oil (high in linolenic acid) and 25% sunflower oil (high in linoleic acid). For the 2 groups receiving oil the total dietary lipid concentration was increased to simulate ryegrass having medium (6%) or high (8%) total lipid. Average daily liveweight gain (238 g/day) and carcass weight (16.9 kg) were not significantly affected by lipid concentration in the diet. However, lambs eating the simulated high-lipid ryegrass ate 16% less dry matter (1285 vs 1530 g/d, P=0.07) but had 33% higher feed conversion efficiency (85 vs 64 g carcass gain/kg intake, P<0.05) than control lambs. Blood plasma and carcass meat from lambs given oils contained lower concentrations of short chain, saturated fatty acids and higher concentrations of poly-unsaturated fatty acids. These simulated changes to ryegrass indicate that modifying the lipid concentration and fatty acid profile in ryegrass could have a feed-sparing effect and improve the human-health attributes of meat from lambs finished during the spring. Keywords: average daily liveweight gain, dry matter intake, feed conversion efficiency, forage lipid, ryegrass
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(110 KB)This study looked at ewe effects on the number of lambs reared (litter size and mortality) and lamb 12 week weight (birth weight and growth rate). Over six years, data was collected on 5571 lambs born to around 3390 Romney (R), Finn cross Romney (F x R), East Friesian cross Romney (EF x R) and Poll Dorset cross Romney (PD x R) ewes. Ewe live weights were recorded pre-lambing and 12 weeks post-lambing. Lambs were weighed at birth and 12 weeks post-lambing. Ewe effects played a significant role in affecting the productivity of the system and many effects were cumulative. Over six years, the lambing percentage (lambs born/ewes lambing) was 165 %. Two tooth ewes had lower lambing percentages than the mixed age ewes (155 vs 170 %). Lambing percentages were 186 % for F x R, 171 % for the EF x R, 155 % for the PD x R and 153 % for the R ewes. Birth weights ranged from 1 kg to 9.8 kg, with a mean of 4.8 kg. Lambs born to F x R ewes (4.28 kg) were significantly lighter at birth than those born to PD x R ewes (5.34 kg). On average, 5 % of lambs were dead at tagging and 11 % of all lambs born were not present at 12 wks of age. The relationship between birth weight and mortality differed to previously published New Zealand reports with high survival rates in the present study over a wide range of birth weights from 3 to 9 kg. It is likely that changes in management practices (improved nutrition, heavier ewes, and selection for easy care lambing) may have contributed to the reduced mortality rates in the heavier lambs in the present study. Ewe genotype modified the effect of birth rank on birth weight and mortality. The average penalty for each additional lamb was smaller for the progeny of the EF x R and F x R ewes (0.85 and 0.88 kg, respectively) than for the progeny of the R and PD x R ewes (1.09 and 1.17 kg, respectively). Triplets born to R ewes had significantly lower survival rates than the other lambs. Heavier birth weights are likely to result in heavier lambs at 12 weeks of age that can be sold earlier. Keywords: birth rank, birth weight, ewe breed, lamb growth, lamb survival
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(96 KB)Supplementing magnesium (Mg) to dairy cows is widely practised in New Zealand herds. Various methods are used including drenching, pasture dusting, water trough treatment and adding to hay/silage. Following hypomagnesaemia problems on a Northland farm, a capital input of 124 kg /ha of magnesium oxide (MgO) was applied in April 2000 followed by annual maintenance rates of 25-30 kg Mg/ha (all as MgO). Soil, pasture and animal samples were taken regularly over a 3 year period and in the second year, on-farm management practices were detailed along with climatic conditions. Results indicated a very good lift in soil quick test Mg (from 16 to 29) with treated pasture averaging 0.21-0.25 % Mg. In the first year blood serum Mg levels of the cows (10 sampled on 4 occasions) were all close to optimum at 0.90 mmol/l but in the second year (10 sampled on 6 occasions), there were occasions when levels were lower and in some cases at or below the critical level (0.62 mmol/l). When farm management practices and climatic conditions were documented in 2001, there were instances when other feedstuffs low in Mg were fed as a high proportion of the diet leading to less Mg intake than from treated pasture alone. Also very wet conditions from August through to November led to much pugging damage and presumably poor pasture utilisation and lowered Mg intake. Although increased soil and herbage Mg status is useful as a background for maintaining animal performance, there will be times when other Mg supplementation will be necessary. In the Northland case this occurred in the second year after capital Mg fertiliser had been applied. In separate field trials in Northland and Rotorua, kieserite (magnesium sulphate) was shown to be a quicker acting Mg fertiliser than Mg. The trials indicated that 25 kg Mg/ha as kieserite generally gave a significant short term lift in pasture Mg status. If the cost was comparable a “little and often” philosophy of Mg fertiliser application may be a better alternative to a capital plus maintenance approach allowing pasture Mg to be boosted more quickly at critical periods of the year. Keywords: dairy cows, kieserite, magnesium fertiliser, magnesium oxide, magnesium supplementation
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(143 KB)Sheep diets are likely to be deficient in sodium (Na) if pasture contains less than 0.04% Na (lambs and maintenance) or 0.05% Na for ewe flushing and lactation. Herbage from four species was sampled in autumn 2002 from 12 sites on a transect south of the Rakaia River from the coast to 110 km inland. All species had >0.10 % Na near the coast but browntop and cocksfoot declined to < 0.10% Na at 10 km and 20 km inland respectively. White clover and ryegrass declined to about 0.10% Na at 40 km and 80 km respectively. In autumn 2003, soil and herbage samples were collected from 8 farms over a range of distances from the coast. Soil quick test (QT) Na from the 8 farms had a strong negative correlation with distance from the sea. Soil QT Na was <5 at 40 km inland and declined to 2 at Mt Grand in the Upper Clutha basin 150 km from the east coast. The herbs, plantain and chicory, had highest concentrations of Na at both high and low soil QT Na. Ryegrass and white clover had moderate Na content at high soil Na but ryegrass appeared to be less sensitive to low soil Na. Although cocksfoot is classified as a natrophile and it had high herbage Na% at high soil Na, it was sensitive to low soil Na. The very low soil QT Na of 2 at Mt Grand resulted in all species except plantain and chicory having <0.04% Na in their herbage. Merino ewes and lambs, which were present when coarse salt (NaCl) was spread at rates ranging from 50 to 300 kg/ha, were strongly attracted to +NaCl plots on south-facing Mt Grand pastures. In two days the sheep grazing and trampling increased bare ground from 25% before salt was spread to between 40 and 63%. It was concluded that natrophobic species grown on inland soils with soil QT Na <5 are likely to be deficient for sheep; all species except plantain and chicory will produce deficient herbage (<0.04%) if soil QT Na is 2 or less and lactating Merino ewes grazing Na deficient pasture will be strongly attracted to areas where coarse salt is spread. The increase in % bare ground resulting from sheep seeking salt may provide a tool for enhancing the establishment of pasture seeds broadcast on to hill country. Keywords: grazing behaviour, natrophile, natrophobe, pasture sodium, sheep pastures, sodium deficiency, soil sodium
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(138 KB)
Drawing on practical farming experience and on-farm observations, plus a range of trials from both published and unpublished sources, the authors have compared the relative benefits of mixed species pastures (MSP), also known as mixed herb leys, with traditional ryegrass white clover pastures. This collection of data, demonstrates production advantages using MSP, with lower weed and pest problems, leading to economic benefits and therefore contributing to more sustainable pastoral systems. Keywords: animal production, endophyte, Festuca arundinacea, financial return, grassgrub, internal parasites, Lolium perenne, thistles
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(83 KB)Caucasian clover has specific rhizobial requirements, and inoculation with a recommended strain is essential for nodulation and symbiotic N2 fixation. However, these rhizobia form nodules on white clover which do not fix nitrogen i.e. are ineffective. At the Nelson NZGA conference, Elliot and co-workers cautioned that caucasian clover rhizobia may over time reduce N2 fixation by white clover in New Zealand pastures. We have shown that high populations of caucasian clover rhizobia build up in the soil under swards of caucasian clover with numbers ranging from 103 to 106/g soil. A field trial was established on a site containing a naturalised population of rhizobia nodulating white clover (105 rhizobia/g soil). Treatments were imposed by mixing caucasian clover rhizobia into the soil, so that they made up 0, 50% or 99% of the clover rhizobia population. The trial was then sown with uninoculated white clover seed. The planned levels of caucasian clover rhizobia were present after 1 month and there was only a small decline in numbers up to 22 months after sowing. White clover rhizobia increased over the first 14 months at least 10-fold, to 106/g soil, even in the presence of caucasian clover rhizobia. There were no significant effects on white clover forage yield or on the calculated amount of N2 fixed, even when soil populations of caucasian clover rhizobia made up 99% of the population of clover rhizobia at sowing. This lack of effect could be explained by the small percentage (up to 5%) of nodules on white clover formed by caucasian clover rhizobia. There is no doubt that high populations of caucasian clover rhizobia will develop in New Zealand soils with the increased use of caucasian clover and its associated rhizobia, but the presence of these rhizobia did not reduce symbiotic N2 fixation of white clover in this field experiment. Keywords: caucasian clover, competition, nitrogen fixation, nodulation, rhizobia, Trifolium ambiguum, Trifolium repens, white clover
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(182 KB)The nutritional benefits of condensed tannin (CT) in forages such as Lotus are known but difficulties with establishment, herbage production and persistence in a pasture have hindered farmer uptake of this valuable legume. A sheep grazing experiment was established to investigate the effects of growing three Lotus corniculatus (Grasslands Goldie, G46 and Creeping) and two L. pedunculatus (Grasslands Maku and Grasslands Trojan) cultivars with or without Grasslands Advance tall fescue (Schedonorus phoenix syn. Festuca arundinacea) and with or without white clover (Trifolium repens) under infrequent (8-weekly) grazing. Without grass, the content of L. corniculatus and L. pedunculatus in the swards was 85% and 60% respectively by year 3. Adding white clover reduced the Lotus content in the swards by 20%. With tall fescue, the L. corniculatus cultivars increased from 6 to 34% between the summer of year 2 and year 3. In contrast, the L. pedunculatus cultivars remained at very low 1- 2% levels in the summer of both years. Inclusion of white clover did not further reduce Lotus content in the tall fescue swards. While there was no significant difference in content and yield between L. corniculatus cultivars, there was a consistent trend for Goldie to produce more herbage. Goldie had the potential to produce 2 t dry matter (DM)/ ha/year in a mixed pasture with tall fescue under infrequent grazing. Creeping L. corniculatus contained higher CT levels than Goldie (3.5 cf.1.1% of herbage DM respectively) and is thus potentially able to provide greater amounts of CT in a pasture. Trojan and Maku L. pedunculatus had similar plant density and herbage productivity. The experiment will be monitored further to determine the long-term persistence of these Lotus cultivars in a mixed pasture. Keywords: condensed tannins, infrequent grazing, legume composition, Lotus corniculatus, L. pedunculatus, tall fescue, white clover
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(170 KB)The quality and quantity of production from irrigated lucerne, chicory and red clover swards were compared over six years (30 November 1996 30 June 2002) on a Wakanui silt loam at Lincoln University. Mean annual yields from lucerne swards (21 t DM/ha) were 3.9 t/ha greater than chicory and red clover over five perennial regrowth seasons. Sown species gave 100% of dry matter (DM) production in the first regrowth season, but by the fifth season sown species gave 65, 55 and 0% of DM production for chicory, lucerne and red clover respectively. Utilised herbage had a similar metabolisable energy (ME) content for all three species (10.9 11.6 MJ/ kg/DM). The crude protein (CP) content of utilised herbage was also similar for lucerne and red clover (0.25-0.29 g/g DM), but chicory had a lower CP content (0.18 g/g DM). This combined with utilisation data to show lucerne swards provided 30% greater annual CP and ME intake for grazing stock than either chicory or red clover. This demonstrated the greater potential of lucerne to improve livestock production from high value land. Changes in lucerne herbage quality were also analysed within regrowth cycles to examine the influence of the time of grazing on CP and ME intake. The fraction of palatable lucerne herbage decreased linearly from 100% at 700 kg/ha standing DM to 57% at 4300 kg/ha standing DM. The CP and ME contents of the palatable fraction of lucerne herbage were always higher than the post grazing residual. This highlights the selective grazing of the stock, which consumed 80% of total CP and 70% of total ME for a crop of 4300 kg/ha standing DM. This grazing preference shows that delaying defoliation will not reduce potential stock production, unless stock are forced to consume the low quality stem in standing herbage. Keywords: Cichorium intybus, crude protein, herbage utilisation, Medicago sativa, metabolisable energy, pasture persistence, Trifolium pratense
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(170 KB)Cultivars of Lolium perenne with high concentrations of water soluble carbohydrates (WSC) are seen as desirable for the reduction of nitrogen losses and greenhouse gases (notably N2O) produced from grazing by livestock, as well as offering some opportunities for increasing meat and milk production. These benefits have been shown consistently in the UK, but here we report a series of investigations which suggest the high sugar grass (HSG) trait may not be so consistently or readily expressed in field conditions in New Zealand. First, the cultivars AberDart (HSG) and Fennema (control) were grown in paddocks in the Manawatu (Aorangi) and studied from July 2001 to October 2002. Total WSC levels in the harvestable component (leaf snips) increased during spring in both cultivars, but the differences between the HSG and control were smaller than seen in the UK and were only marginally significant (P = 0.063). Likewise, no consistent differences in WSC in leaf blades were found in a second trial, grown this time in pots outdoors, where water and nutrients were more controlled. This second trial included not just AberDart, but the original HSG, AberDove, which had been the focus of many successful trials in the UK. An analysis of the environmental factors that might be relevant to the expression of the quality trait ‘high sugar’, and of possible differences between UK and NZ climates and trials, led us to a third series of experiments, conducted in NZ, in controlled environment chambers. Total WSC became substantially greater (> 2fold) in all three cultivars when grown at 10oC (day and night) than at 20oC but only at 10 oC did one HSG, AberDove, show a small, but significantly greater WSC, than Fennema (P < 0.05). However, significantly higher levels of WSC (P < 0.05) were expressed in leaf blades of both AberDart and AberDove, compared to Fennema, when grown at temperatures of 20oC day / 10oC night (14h day), and especially (68% and 46% respectively) when this followed a period of cold (10 weeks at 5oC) and short days. Our findings suggest that low temperatures, either low night temperatures, or previous periods of sustained cold (<10oC), may be necessary for expressing a sustained higher WSC trait in the harvestable components of Lolium perenne. Keywords: High Sugar Grasses, greenhouse gases, perennial ryegrass, water soluble carbohydrates
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