Agricultural research has provided, and will continue to provide, substantial returns on investment for New Zealand. The need for ongoing investment in plant research in New Zealand is highlighted by the fact that 43% of our total export earnings are generated from five major plant species. Estimates of the returns from investment in R&D are about $8 for each $1 invested, which even with discounting for the lag between investment and return, has shown a benefit to cost ratio of approximately 3:1. The current level of public and private investment in R&D is well below average among OECD nations, and New Zealand’s R&D environment is unstable, with large shifts in funding leading to loss of key research capabilities. Integrated research teams that have strong industry involvement offer the best conduit for communication between the developers and adopters of new technologies. Identification and support of these teams will improve adoption rates and provide long-term competitive advantages for New Zealand agriculture. Keywords: agricultural research, economic growth, research funding, technology adoption
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The pastoral research carried out on the West Coast of the South Island between 1960 and 2000 could be divided into three categories; nutrient requirements for pasture, pasture establishment and growth and animal performance. Because of the varied fertility of the soil types present, research on nutrient requirement was the largest category. In the 1960’s, requirements for pasture establishment and early growth on pakihi (podzol) soils of lime, phosphorus (P), elemental sulphur (S), potassium (K), copper (Cu) and molybdenum were identified. This work was extended to determine P, S and K maintenance requirements of pakihi, recent alluvial and brown terrace soils in the 1970’s and 1980’s. Elemental S was shown to be the most cost effective S fertiliser under annual rainfall greater than 2000 mm and the tetraphenyl boron (TBK) test was calibrated to measure the supply of nonexchangeable K on recent soils. A series of trials were carried out to determine pasture yield responses to fertiliser nitrogen (N) on recent soils in the early 1970’s. Later work in the mid 1980’s showed that measurement of accumulated soil and air temperature from early spring did not improve the accuracy in prediction of pasture yield responses to N. On the poorly drained, acid and infertile pakihi soils, the interactions between seed coating and lime were measured and the yield advantages of Maku Lotus and Yorkshire fog as alternative pasture species to ryegrass and white clover demonstrated. Rate of pasture growth trials determined the seasonal pattern of pasture production on a range of sites from 1970 to 1995. On recent soils that could not be moled, gravel moling and hump and hollowing substantially increased pasture production during a spring with high rainfall (2000 mm). In the early 1980’s, dairy grazing trials showed that lengthening the grazing rotation during autumn increased winter and spring pasture production. For sheep, preferential grazing of thin ewes from weaning to mating increased overall ovulation rate. The density of sheep dung patches was shown to increase with winter stocking intensity on a pakihi soil. Surveys of dairy farm practice established an association between effectiveness of magnesium (Mg) supplementation of dairy cows and reducing the incidence of metabolic disorders. Many dose response trials established the requirement by dairy calves for selenium (Se), cobalt (Co) and Cu on different West Coast soils. Close contact between West Coast scientists, advisors and farmers ensured that local research information was efficiently communicated with a resulting high level of farmer adoption. Keywords: animal management, fertility, lime, nitrogen, pasture establishment, phosphorus, potassium, soils, South Island, sulphur, trace elements, West Coast
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Beef produced from bulls of dairy origin constitutes a significant component of total production, with up to 700,000 calves reared annually. These calves ae reared on a wide range of artificail rearing systems although once-a-day milk feeding of calves has become the norm in recent years. Successful calf rearing can be achieved by attention to detail and by essentially 'following the recipe'. This paper will outline the 'best practice' calf rearing undertaken at Poukawa and cover the critical areas of calf rearing such as rearing facilities, calf procurement, milk and meal feeding, weaning, post weaning management and animal health. Keywords: animal health, calf rearing, once-a-day feeding, procurement, rearing facilities
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(1214 KB)Much of the value of restoring ecological processes on islands and areas on the mainland lies in answering the question, “how worthwhile is it, in any circumstances, to control invasive weeds and pests?” When the Maungatautari Ecological Island Trust (MEIT) builds a 50 km pest proof fence around Maungatautari, a 3400ha forest-clad mountain in the heart of the Waikato, and then eradicates all the pests, we will travel down a restorative path largely ignorant of how the environment functioned just a thousand years ago, before human settlement. We will learn a lot as we clumsily put the ecological jigsaw puzzle back together again. And of course there will be some missing pieces, for example, the recent extinctions like moa and huia. There will be value in this new knowledge and in the recovered “dawn chorus”, but how do we price it? If we can’t price it, if it has no value, then how do we give the Maungatautari Ecological Island Trust a long life free of begging? The answers begin in what makes the Waikato community seek to restore the mountain to something as close as possible for its “unspoilt” state, i.e. the state it was in before exotic pests and weeds invaded it. We have a sense of natural value lost; a longing for what we know was once there. This is based on knowing just how different our forest ecology was to that of any other country, evolving as it did in the absence of mammals (with the exception of the 2 species of bat). The ecological niche occupied by mammals in other countries, was filled here by the extraordinary array of invertebrates, lizards, frogs and birds. And many of our endemic plants came to be extraordinary as well, partly as a response to the set of animals that evolved.
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(23 KB)Calf rearing is capital intensive, has high risks associated with animal health and is a short term intense activity. It occurs at a time of the year when out-of-season procurement premiums reflect slow processing throughput, rather than the market outlook for beef. In addition, schedules for bobby calves are announced only one week prior to processing which gives the market little time to settle on costs and the margin for calf rearing. This paper looks at viability for rearing and finishing and seeks to define margins for both sectors. This has been calculated using a margin per calf reared to 100 kg and a margin per week for the finisher. Calf rearing is a prescriptive feeding regime in a housed facility, where the performance range is small – i.e calves reach 100 kg liveweight in 12 weeks. By contrast, bull finishing extends over 1 to 2 years, depends on pastures produced in a wide range of climates, topographies and management systems and has a wide range in performance. The major factor impacting on margins in both sectors is the bull schedule. Hence an analysis has been undertaken to look at the impact on both sectors and provide a more equitable basis for establishing the value of the 100 kg calf. The market might not accept the model, but the discussion generated is likely to go some way towards resolving the unsatisfactory status quo position where the decision to rear calves has to be made before 100 kg contract prices are established in the market. Keywords: beef finishing, bobby calves, bull schedule, calf milk replacer, calf rearing, margins, procurement premium, whole milk
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There is a growing shortage of labour within the dairy industry. To address this the industry needs to attract more people and/or reduce the labour requirements on dairy farms. Current milk harvesting techniques contribute to both the labour requirements and the current labour shortage within the industry as the process is labour-intensive and necessitates long and unsociable working hours. Automated milking systems (AMS) have been in operation, albeit on a small scale, on commercial farms in Europe for a decade and may have the potential to address labour issues within the New Zealand dairy industry. A research programme has been established (The Greenfield Project) which aims to determine the feasibility of automated milking under New Zealand dairying conditions. A Fullwoods MERLIN AMS has been installed on a protoype farmlet and is successfully milking a small herd of 41 cows. Progress from the prototype Greenfields system offers considerable potential for implementing AMS in extensive grazing systems. Keywords: automated milking systems, dairy cattle, grazing, labour
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(57 KB)Once-a-day (OAD) milking offers a major opportunity to improve labour output on New Zealand farms. However few full lactation studies have been undertaken to investigate the effect of this strategy on the productivity of the farm system. A trial was established in 2000 to measure the effect of milking frequency and breed in farm systems where stocking rate was adjusted to equalise per hectare feed demand in different herds. There were four treatments: two herds of 35 Friesian and 42 Jersey cows, at 3.5 and 4.2 cows/hectare respectively, were milked OAD for the entire season. Another two herds of 30 Friesian and 36 Jersey cows, at 3.0 and 3.6 cows/ hectare respectively, were milked twice a day. A higher stocking rate was used for the two OAD herds in an attempt to compensate for the effects of the expected decrease in feed eaten. In the Jersey herd, milking OAD resulted in decreased milksolids (MS) yield per cow and per hectare of 22% and 9% respectively. In the Friesians the corresponding decrease was 31% per cow and 19% per hectare. OAD milking resulted in significantly higher protein and milksolids concentrations, and lower lactose concentration. Mean individual somatic cell count was significantly increased by OAD milking, despite the absence of any differences in levels of bacterial infections between herds. The reduction in MS yield per cow and per hectare was smaller for the Jersey herd than the Friesian herd, indicating that the Jersey cow is perhaps better suited to OAD milking. Keywords: farm system, Friesians, Jerseys, milksolids, milk composition, once-a -day milking, somatic cell count
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(56 KB)I am a 30-year-old sharemilker on my parent’s 600 cow developing farm near Blackball on the western side of the Grey Valley. Earlier this year I competed in the National Young Farmer of the Year competition and finished a close third. So what is information? There are two types of information that I use. There is data gathered from my farm to help fine tune the running of the day to day operations on the farm And directional information This is the information that arrives in papers and directs the long-term direction and plans of the farm and farming businesses. Due to the variability in weather on the Coast there is a greater need to monitor and adjust the farming system compared to an area like Canterbury. This was shown last year (2001/02) when the farm was undergoing a rapid period of development and I was under time restraints from increasing the herd size, building a new shed as well as developing the farm. The results of the time pressure was that day to day information gathering was lower resulting in per cow production falling by 11% or around $182 per cow. So what information was lacking that caused this large drop in profit. • Pasture growth rates • Cow condition • Nitrogen requirements • Paddock performance • Milk production • Pre-mating heat detection As scientists and advisers I hear you say that it is the farmer’s responsibility to gather and analyse this information. You have the bigger topics to research and discover, gene marking, improving pasture species, sexing of sperm and ideas that I have not even contemplated yet. This is indeed very valuable research. Where would farming be without the invention of electric fences, artificial breeding and nitrogen research? But my problem is to take a farm with below average production to the top 10% in production with the existing technology and farming principles. I have all the technical information I need at the end of a phone. I can and do ring my consultant, fertiliser rep, vet, neighbour and due to the size and openness of New Zealand science, at present if they do not know I can ring an expert in agronomy, nutrition, soils and receive the answer that I require. I hope that this openness remains as in a time of privatisation and cost cutting it is a true advantage. I feel that for myself the next leap in information is not in the growing of grass or production of milk but in the tools to collect, store and utilise that information. This being tied to a financial benefit to the farming business is the real reason that I farm. Think of the benefits of being able to read pasture cover on a motorbike instantly downloaded, overlaying cow intake with milk production, changes in cow weight, daily soil temperature and predicted nitrogen response. Telling me low producing cows and poor producing paddocks, any potential feed deficits or surpluses. This would be a powerful information tool to use. The majority of this information is already available but until the restraints of time and cost are removed from data gathering and storage, this will not happen.
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(16 KB)Advances in computer technologies and mathematical modelling have enabled technology providers to develop decision support tools. Studies with farmer groups showed that the value of these tools to farmers may be as much for learning as for decision support. Stockpol was used in one farmer group to support decisions around farm systems design. Quickfeed was developed with another group that were interested in pasture quality, and Bestbreed with a group whose target was lamb growth rate from birth to weaning. The ultimate aim in all three studies was to improve farm profitability. When evaluating the studies, farmers ranked the overall study as being highly effective (72 to 86 %) in achieving the goal of improved profitability yet the value of the models was ranked much lower (40 to 44%). This result may be explained by the perception value relates to hands on use, rather than the learning associated with using the model and interaction with the information encapsulated in the model. Here the learning environment included collecting information to use in the model and comparing the model output with the actual changes that had occurred on farms. In other words, farmers were learning through participation. The value to farmers of computer models or tools may be better measured by their success in improving farm profitability. In these studies, this lay directly in what the farmers learnt and how their behaviour changed as a result of participation in the overall study rather than in continued use of the models per se. This paper discusses this aspect of farmer learning and the benefits of packaging technology in the form of decision support tools. Keywords: computer technologies, decision support, farmer study groups, learning, mathematical modelling, technology providers
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Condition scoring is an easy to use management tool that can assist farmers to monitor their feeding regimes, allowing both better feed and animal management. The relationship between two commonly used condition score systems utilised by New Zealand beef cattle farmers was investigated. Results indicated that there is not a simple relationship between the 0-5 condition score and the 1-10 score system. The relationship varies throughout the year and a single calibration equation should not be used when converting data from one system to the other. Despite this, the use of condition scoring in beef cow herds should be encouraged and operators can use either system, as long as care is taken when interpreting data from publications using different scales. Keywords: beef cows, cattle, condition score, liveweight
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(25 KB)Lignin is the prime factor influencing the digestibility of plant cell wall material. As concentrations of lignin increase, digestibility, intake and animal performance usually decreases. Presented is a simplified acid detergent lignin procedure which has been used to determine lignin concentration from a wide range of forages and also ryegrass at different stages of maturation. Forages used in this study included grasses, legumes, herbs and conserved material, with lignin concentration ranging from 2.02 to 21.1% of the DM. Legumes tended to have higher values than grasses, and ryegrass maturation was not accompanied by increased lignin concentration at 53 days of age. These results will be incorporated into a NIRS method for determining forage quality, and used in a dairy nutrition model to assist in ration formulation for dairy cows. Keywords: analytical method, fibre, forages, lignin
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(47 KB)Lamb behaviour was investigated where varying stocking rates and rearing rank indirectly induced differences in ewe milk production. 24 Romney x Poll Dorset ewes, with either twin or single lambs, were stocked at either 25 or 15 ewes per hectare, three weeks after lambing (2 August ± 1.0 days). Lamb activity (grazing, otherwise active, or inactive) was determined by instantaneous scan sampling at 3-min intervals over 4 hours at 3, 6, 9 and 12 weeks of age. Milk production, estimated by machine milking and lamb live weights were also measured at these ages, on the day prior to observations. Ewes with twin lambs produced slightly more milk than ewes with singles (213 vs. 183 ml per 4 hours, respectively). Ewes on the high stocking rate produced an average of 181 ml milk per 4 hours compared with 216 ml per 4 hours in the low stocking rate group. Twin lambs spent significantly more time grazing than did single lambs (52.3% vs. 41.0% overall, respectively) and lambs on the higher stocking rate spent on average 10% more time grazing, than those stocked less densely. These results suggest that lambs with access to less milk spend more time by grazing, but this does not adequately compensate for the lower milk supply which resulted in reduced lamb growth rates. This raises the possibility of enhancing lamb growth rates prior to weaning by providing high quality, lamb-specific forage to the lamb independently of the ewe. Keywords: ewe milk production, grazing, lamb behaviour, lamb growth rate
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(23 KB)The frequency of measurements to generate pasture growth rate data varies. Commonly measurements are made once weekly or fortnightly and averaged monthly, using a variety of methods. To assess the effect of frequency of measurement on estimates of pasture growth rate, weekly visual assessment of farm pasture cover was compared with the fortnightly and monthly average and also with predictions by a Whole Farm Model. Weekly observed pasture growth rates had large fluctuations but these were removed when the weekly values were averaged monthly. The fluctuations are due to the variety of paddocks assessed, climatic factors, inconsistencies of operators and inherent errors in the technique used. Values calculated by a Whole Farm Model also showed daily variation in pasture growth rate but the fluctuations were not as severe as those in the observed pasture growth rate data because human error of assessment and error in the technique were removed. Observed monthly pasture growth rates were also compared with values calculated by the model. The model closely predicted observed pasture growth rates for most months. To obtain an accurate estimate for monthly growth rates it is better to average a number of assessments. In the field, this could be an average of weekly observations. Because the model calculates rates daily, it can be used to predict pasture growth rates on a more frequent basis (e.g. weekly) to aid feed budgeting. Keywords: dairy farm, herbage mass, model, pasture growth, simulation
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(70 KB)Several New Zealand studies suggest that pastoral land use causes appreciable water quality degradation particularly in lowland streams. The water quality of eight NZ lowland streams, three near Morrinsville in the Waikato Region and five south of Hokitika in Westland, was sampled monthly for 13 months. Three of the five Westland streams are spring-fed streams on dairy-farmed alluvial plains of large rivers, and have high and steady flows and visually clear water, contrasting with two nearby reference streams in forested land which are more flow-variable and have humic-stained water. The catchments of the three Waikato streams, with the exception of a forested headwater area, are intensively grazed, mostly by dairy cows. Median conductivity, phosphorus and nitrogen concentrations, and (to a lesser extent) faecal contamination (as indicated by Escherichia coli concentrations), were all elevated in streams draining dairy pasture, often exceeding water quality guidelines. The most intensively-farmed Waikato stream (Toenepi Stream) has very high concentrations of nutrients and fairly high faecal contamination. At the other extreme, Dunlop Creek (Westland) has very low concentrations of nutrients and faecal contamination, consistent with its minimally-disturbed native forest catchment. The optical variables: humic concentration, turbidity and (inversely related) visual water clarity, show less of a pattern with land use across stream sites, apparently because of the influence of other factors, such as soil characteristics. The area-specific yields of streams in Westland dairy land were comparable with those in the Toenepi Stream, reflecting high rainfall driving runoff and leaching in Westland. However, the concentrations of contaminants mobilised by dairy farming were generally higher in Waikato than in Westland because of dilution in high water flows in the latter region. The water quality degradation of streams draining dairy land will need to be addressed by the dairy industry. Keywords: dairying, faecal contamination, nitrogen, nutrients, phosphorus, turbidity, water quality
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(66 KB)The wet, warm West Coast climate favours tree production and pastures. Much of the land remains in indigenous forest under the control of Government agencies. In the more accessible parts of this land, and in land held under private ownership, we explore the feasibility of “farming” two examples of native biodiversity. Sphagnum moss production varies with location and differences in meso- and micro-climate. A climate model was used to predict where future sustainable sphagnum development may occur; i.e. within farming systems in the areas with the fastest growth rates. At its simplest and cheapest, this may involve flooding unimproved land and managing the moss. Another alternative could involve integration of moss production in the wet “hollow” of “hump and hollow” pasture systems. The West Coast retains several unique populations of kiwis and other indigenous birds. We advocate the future role of private enterprise (i.e. landholders) in protecting kiwi and, in the longer-term, the local communities profiting from ecotourism centred on them. Keywords: climate modelling, eco-tourism, kiwi, sphagnum moss
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(52 KB)Giant buttercup (Ranunculus acris L.) is estimated to cost the New Zealand dairy industry $118 million annually in lost milksolid production opportunity through the exclusion of palatable pasture species. Historical reliance by dairy farmers on annual or biennial applications of the ‘phenoxy’ herbicides MCPA and MCPB, has led to the widespread evolution of phenoxy-herbicide-resistant populations of the weed. The newer herbicides, thifensulfuron methyl and flumetsulam are now being used against giant buttercup, although thifensuluron, like MCPA, can cause clover damage and as a result may promote the growth of giant buttercup populations. In this paper we review the history of giant buttercup management on New Zealand dairy farms and the science that led to the discovery of the herbicide resistance. We also attempt to define a path toward sustainable ecologically-based management of this weed based upon an improved understanding of its population dynamics and the use of a pasture-selective mycoherbicide utilizing the naturally-occurring fungus, Sclerotinia sclerotiorum. Keywords: dairy pasture, economics, giant buttercup, herbicide resistance, mycoherbicide, opportunity cost, population dynamics, Ranunculus acris, weed
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(37 KB)Perennial ryegrass pastures in New Zealand are usually established from seed naturally infected with the wildtype endophyte. New pastures can now be sown with perennial ryegrass that has no endophyte or has been infected with a new endophyte. Cows can contaminate pastures by consuming ryegrass seed infected with the wild-type endophyte on old pastures, and transferring the seed in their dung onto new pastures. A quarantine period before grazing new pastures may allow cows to eliminate wild-type endophyte-infected perennial ryegrass seed from their digestive tract, preventing contamination from this source. A trial was run at Dexcel, Hamilton, to define an appropriate quarantine period. Cows grazed wild-type (high endophyte) ryegrass pastures containing seedheads for 4 days before grazing Lotus corniculatus (quarantine pasture) for a further 4 days. This procedure was repeated five times from November 2000 to April 2001. Dung samples were collected daily after shifting cows off high endophyte ryegrass. Pastures contained viable ryegrass seed on seedheads from December to April, and ryegrass seedlings germinated in dung samples collected from January to April. Viable endophyte-infected perennial ryegrass seed was present in dung for 2 days after removal from the seed source, with 0.8% of the seed eaten remaining viable. Ryegrass seed endophyte viability was reduced from 100% to 40% after passage through the digestive tract of the cows. It is recommended that cows do not graze endophyte-free pastures or those sown with ryegrass containing a new endophyte for at least 2 days after grazing high endophyte ryegrass pastures containing ryegrass seedheads. Keywords: dairy cows, dung, perennial ryegrass, ryegrass endophyte, seedheads, seed transfer
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(43 KB)A combination of mowing and grazing by sheep has been shown to successfully control Californian thistle (Cirsium arvense) in small plot and paddock scale trials. Between 1994 and 2000 the technique was applied to 15 paddocks on nine farms in Otago, Southland and Mid- Canterbury. Thistle-infested pastures were mown as low as possible, usually in December after weaning. Thistles at this time were up to 1m tall at the mid to late bud stage. Mobs of at least 350 ewes/ha were introduced at mowing or a day or two before, with all mown herbage eaten within 3 days. Pastures were re-grazed with this or similar sized mobs at approximately threeweek intervals to remove re-growth thistles which had emerged since the previous grazing and before their spines hardened. Each grazing forced the plant’s root system to produce a new crop of aerial shoots and this ultimately used up the root reserves causing the thistles to die. The farmers involved were responsible for implementing recommendations on mob size, time and length of grazing. Three or four repeat grazings markedly reduced thistle numbers the following summer, resulting in almost complete elimination by autumn in year two after the programme was repeated. With fewer grazings in year one, control took longer. The grazing regime had no apparent effect on ewe health and resulted in improved pasture quality. Keywords: Californian thistles, mob size, repeat grazing, thistle numbers
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(30 KB)A trial was carried out at Dexcel in Hamilton to investigate the effects of silage supplementation of grazing dairy cows post-peak lactation. Forage mixtures used in the four week trial were based on previous trial results and information from in vitro and in sacco incubations. Sulla and maize silages were used to supplement pasture and to meet minimum requirements for protein. Five groups of ten cows were grazed on a restricted daily allowance of 18 kg dry matter (DM) pasture/cow to simulate a summer pasture deficit, and four groups received sulla silage (S) or maize silage (M) alone or in mixtures of 25M:15S or 15M:25S to make up 40% of total DM intake. A sixth group was given an unrestricted (38 kg DM/cow/day) pasture allowance. The pasture was of high nutritive value and not typical of usual summer conditions, which limited the effects of supplementation in the trial. The restricted pasture allowance resulted in a low level of substitution (0.29) when the silages were fed and substantially increased feed intakes. Although differences in cow responses to the silage mixtures were minor, liveweight and milk production were improved relative to restricted pasture allowance but not for cows given 38 kg pasture DM/ day. The low level of substitution demonstrated the impact of the restricted pasture allowance on cow performance. In sacco data show highest DM degradation rate (k, h-1) when cows were fed pasture with sulla silage (0.08); diets with a high proportion of maize silage were degraded slowly (P<0.01). Supplementation with sulla may increase digestion rate and rumen clearance and reduce the effect of fibre in ryegrass diets. Keywords: dairy cows, maize, pasture, silage, sulla
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(29 KB)The potential of caucasian clover (Trifolium ambiguum M. Bieb.) to produce high quality forage and to establish in on-farm conditions was tested in southern New Zealand. Caucasian clover was established alone and after one year the plots were oversown with ryegrass, in November. After a further 6-month establishment period, dry matter (DM) yield and botanical composition were measured over the following two years. A 2 x 2 factorial design tested the effects of early or late flowering ryegrass and frequent (2 weeks in spring, 4 weeks in summer and autumn and twice during winter) or infrequent (4 weeks in spring, 6 weeks in summer and autumn, and once in winter) defoliation. Plots defoliated frequently produced less dry matter than infrequently defoliated plots (13260 and 16180 kg DM/ha respectively in year 1 and 9980 and 12250 kg DM/ha respectively in year 2, P<0.01) and had a lower percentage of caucasian clover (62 and 68% respectively in year 1, P<0.05; 50 and 56% respectively in year 2, P<0.05). Ryegrass flowering date had no effect on total, seasonal or compositional yields. On-farm experimentation investigated establishment methods, included direct drilling, pasture to pasture and following a brassica crop. Caucasian clover was sown alone at 4 kg/ha coated seed (Prillcote®) with 375 kg/ha drilling superphosphate (0-9-0-11) in November 2000. Four rates of nitrogen (0, 25, 50 and 100 kg/ha urea (46% N)) were applied in February, after emergence. Plant numbers were lowest in the direct drilled paddocks, intermediate in the pasture to pasture sowings and greatest following a brassica crop (3.5, 6.5 and 10.6 plants/m2 respectively, P<0.05). Rhizome length, taproot length and taproot weight were not significantly affected by either establishment method or nitrogen fertiliser. Competition from weeds, especially grasses, was the biggest single factor influencing plant number. Though caucasian clover has the potential to produce large amounts of high quality herbage, establishment problems restrict its’ use. Keywords: defoliation, establishment, fertiliser, growth, methods, Trifolium ambiguum
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(66 KB)Forages suitable for supplementing pasture-fed dairy cows over summer-autumn must provide adequate dry matter (DM) and increase milk yield above that produced by cows grazing normal ryegrass/white clover pasture, without compromising milk composition. A trial was conducted in January-February 2001 to compare the benefits obtained from feeding four types of silage. There were two silages that contained condensed tannins (CT) (birdsfoot trefoil (Lotus corniculatus) and sulla (Hedysarum coronarium)), maize silage or traditional ryegrass-dominant pasture silage, all fed at 5 kg DM/cow/d with restricted pasture. Cows on the restricted pasture (control) treatment and those fed the silage treatments were offered an allowance of 25 kg DM pasture/cow/d, while the full pasture cows were offered 50 kg DM pasture/cow/d. Silage supplementation, regardless of silage type, increased both total dry matter intake (DMI) and milk production compared with the restricted pasture treatment. Cows on the Lotus silage supplement, and the full pasture treatment had significantly higher milk yields than the other silage-supplemented cows, all of which had similar milk yields. For the Lotus silage treatment, the high milk yield was probably due to a combination of the higher nutritive value of the silage, and to the action of CT, because the total DMI of the cows on the Lotus silage was the same as that of cows on the pasture silage and maize silage. The high milk yield of the full pasture treatment was mainly a result of the cows having a significantly higher total DMI than cows on all the other treatments. This trial has demonstrated the potential benefit of silage supplementation, particularly with Lotus silage, for increased milksolids yield in summerautumn when low pasture growth rates and quality may otherwise limit production. Keywords: condensed tannins, dairy cows, Lotus, maize, milksolids, ryegrass, silage, sulla, supplementation
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(34 KB)Beef cattle production in Uruguay is limited by heifer mating age when grazing natural pastures. Lotus pedunculatus cv. Grasslands Maku is a forage species that was recently introduced to Uruguayan farming systems, with high potential to improve herbage production in acid and low fertility soils. This paper provides information about winter and spring performance of Hereford x Angus heifers grazing an improved Lotus pedunculatus cv. Grasslands Maku pasture when fed at different pasture allowances. Four pasture allowances (3, 5, 10 and 16 kg DM/100 kg animal liveweight/day) from June 30 to October 9 (P1) followed by one pasture allowance of 9 kg DM/100 kg animal liveweight/day from October 9 to November 28 (P2), were assigned to 9 months old Hereford x Angus heifers weighing 129 kg. Measurements included herbage mass, botanical composition, pasture growth rate, sward height and animal liveweight. Liveweight gains were evaluated using a repeated measurement model in time. Pasture mass decreased from 4000 kg DM/ha to 1100, 1050, 1350 and 2000 kg DM/ha for the herbage allowances of 3, 5, 10 and 16% respectively during P1. Legume content at the end of P1 was 550, 400, 700 and 700 kg DM/ha for 3, 5, 10 and 16% of total pasture mass respectively. Herbage mass increased by 328 kg DM/ha per cm sward height (P<0.01, r2= 0.69, n=240). Mean pasture growth rate in P1 was 21 kg DM/ha/day, being promoted by intensive grazing. In P2, mean pasture growth rate was 58 kg DM/day, increasing when laxly grazed in the previous period (P1). During P1, herbage allowance explained 77% (P<0.001) of liveweight gain, with significant differences (P<0.05) between all treatments (0.20, 0.36, 0.57 and 0.70 kg/heifer/day for allowances of 3, 5, 10 and 16 kg DM/100 kg liveweight/day respectively). In P2, liveweight gains were inversely correlated to the liveweight gains achieved in P1 (1.03, 0.96, 0.85 and 0.76 kg/heifer/day for P1 allowances of 3, 5, 10 and 16 kg DM/100 kg liveweight/day respectively). Feed planning in P1 produced a range of differences of liveweight of 51 kg/heifer and that reduced to 38 kg/heifer in P2. During P1, daily liveweight gains and production/ha were maximized at 16 and 3% of herbage allowance respectively. Keywords: beef heifer growth, herbage allowance, Lotus pedunculatus cv. Grasslands Maku
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(40 KB)Dry matter (DM) production and crude protein (CP%) of sheep urine patches in a grazed cocksfoot pasture (28 day rotation with 21±1 days regrowth) were measured at Lincoln University from September 1999 to May 2001. Also, the DM response from artificial urine patches was measured over time. The rate of nitrogen (N) applied per hectare in an individual urine patch was 173 kg N/ha in autumn compared with 448 kg N/ha in spring. This stimulated a maximum difference in DM production between urine patches and controls over a 21 day period of 1970 kg DM/ha in spring (October). Smaller differences were measured in summer (380 kg DM/ha) and winter (370 kg DM/ha). The maximum difference in CP% was also in spring being 27.0% for urine patches and 18.7% for controls. DM production differences were attributed to differences in net leaf photosynthetic rate, which ranged from 23.5 in spring to 4.5 mol CO2 m-2 s-1in summer. Leaf photosynthetic rate was limited solely by N supply in spring, by soil moisture (mean soil volumetric water content in the top 500 mm < 20%) and leaf N content (< 3 %N) in summer and mainly by low temperatures (< 9 ºC) but also N supply in winter. The low temperature in winter also meant the duration of urine patch response was 133 days compared with 105 days in spring and 77 days in summer. In a second experiment, the DM response of cocksfoot to synthetic urine (300 kg N/ha) and irrigation was examined in ungrazed areas (four 60-day regrowth periods and one 110-day winter regrowth). From these treatments, the maximum annual DM production for cocksfoot with irrigation and N was 28.6 t DM/ha/yr compared with 9.2 t DM/ha/yr for the control. The addition of irrigation alone yielded 13.0 t DM/ha/yr compared with N alone at 23.5 t DM/ha/yr. To overcome the N stress in cocksfoot pastures a combination of applied N in spring, tap rooted perennial legumes in summer and annual clovers in winter is recommended. Keywords: clover, cocksfoot, crude protein, Dactylis glomerata, leaf photosynthesis, nitrogen, pasture production, potential yield, urine patches
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Pasture damage from insect pests is an increasing concern with rising forage value and biosecurity breaches. At the same time options for traditional chemical control of pests are becoming limited. Biological control of insect pests is important in limiting pest damage, with toxin-producing endophytes, parasitoids and insect diseases the key components limiting insect pest populations and damage in pastures. We are proposing a bioprotection strategy for pasture pest management that maximises the benefit of biocontrol and changes the emphasis from curative to preventative action in the protection of pastures from damaging pests. Keywords: bioprotection, biological control, insect pests, pest management
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(32 KB)At a time of increasing and changing trade and tourism, biosecurity is becoming a major issue. New Zealand’s pastoral ecosystems are uniquely vulnerable to invading pests and weeds and, in many regions, pastures are being used more intensively than ever. This in turn is making pest impacts more severe. Other factors causing increasing concern about biosecurity include climate change and public concern about existing pest management strategies. Weed problems are increasing in some marginal areas where there has been destocking. This contribution further discusses the need for contingency planning for biosecurity threats, particularly with reference to keeping weed and pest organisms out of this country at the border. In relation to this, funding issues for research are discussed and with this, the need for the government and sectors to clearly delineate areas of responsibility. This raises issues about the shortcomings of simplistic userpays models and the ongoing conundrum of whether and how the perpetrators and/or the ‘beneficiaries’ of pest management research should pay after biosecurity failure. Keywords: biosecurity, border control, eradication, funding, pests, pest management
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(30 KB)In spite of ragwort flea beetle (RFB) being present on a Dannevirke dairy farm, pastures were sprayed each winter to reduce ragwort density and limit the risk of ragwort poisoning of stock. The trial on this farm from June 1999 – October 2001, aimed to determine whether herbicide (H) impacted on RFB and how H and RFB each impacted on ragwort growth and persistence. RFBfree areas were created by spraying with insecticide (I). Effects of ragwort on animal health are also reported. High ester 2,4-D (H) boom-sprayed once only, in June 1999, killed most ragwort plants and reduced RFB larvae densities to low levels before the plants died. Once new ragwort established in treatment H, the plants became infested with RFB larvae. RFB larvae were suppressed by I resulting in ragwort density declining more slowly than in treatments where RFB were not suppressed. Insecticide treatments were stopped after 15 months and, at 24 months, ragwort could not be found within the trial area. Ragwort control was attributed to the cessation of herbicide spraying allowing the RFB population to reach a sufficient density to kill both small and large ragwort plants. Sub-clinical ragwort poisoning was found in livers of culled cows that had grazed on ragwort-dense pastures. Keywords: animal health, biological control, Longitarsus jacobaeae, pyrrolizidine alkaloids, ragwort, ragwort flea beetle, Senecio jacobaea
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(58 KB)Weeds are part of any land based production system and need to be managed appropriately to minimise their negative impact on economic returns. Too frequently herbicides are used routinely to cure the weed problem without examining the underlying cause of the problem. Routine herbicide use poses risks to the environment and damages New Zealand’s ‘Clean and Green’ image, therefore alternative weed management strategies need to be considered. In pasture based systems, ensuring that the forage species are in prime condition all year round is the method of choice to reduce weed problems to sub-economic levels. Forage grasses are very competitive, so much so that they often prevent significant contributions from companion species like white clover. In an experiment Californian thistle was grown in pasture maintained at two different height ranges. Maintaining a longer pasture significantly reduced Californian thistle shoot production, while not affecting total forage production. It is concluded that maintaining longer pasture residuals not only slightly increased pasture production, it also minimised weed problems and should therefore be the choice weed control strategy for pastoral farmers, wherever possible. Keywords: Californian thistle, grazing, pasture management, weed management
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Agriculture contributes about 60% of New Zealand’s total greenhouse gas emissions. Management practices for reducing these emissions will be required to meet our future international commitments. This paper presents estimates of two practical on-farm measures for reducing total greenhouse gas emissions from an average dairy farm on the West Coast of the South Island of New Zealand: 1) the incorporation of cereal silage into the diet, and 2) the strategic use of a stand-off pad in winter. Total calculated greenhouse gas emissions were reduced by about 14% if fertiliser N-boosted pasture was replaced with bought-in cereal silage grown off-farm. The estimated reduction in emissions was due to reductions in nitrous oxide and carbon dioxide emissions, whereas methane emissions were not significantly affected by this management practice. Reduced methane emissions required an increase in per animal production and a corresponding decrease in stocking rate. The use of a stand-off pad during winter did not significantly affect total greenhouse gas emissions using current inventory calculations. However, recent research suggests that it may reduce emissions by 3 to 8%, when accounting for the seasonal variation in N2O emissions and reduced fertiliser N requirements due to reduced pasture damage. A preliminary assessment of the economic implications of the cereal silage option suggested the cost of using cereal silage is likely to be higher than any savings that could be accrued from carbon credits obtained from reducing greenhouse gas emissions. However, the costs associated with building and using a stand-off pad are likely to be off-set against a potential increase in pasture production, and carbon credits obtained from a reduction in greenhouse gas emission would represent a net cost saving. Keywords: carbon dioxide, cereal silage, dairying, methane, mitigation options, nitrous oxide, stand-off pad
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(43 KB)The New Zealand government has indicated that it will ratify the Kyoto Protocol, which means that legally binding targets will be set for reducing greenhouse gas (GHG) emissions. In “preferred” policies to achieve these targets, the agricultural sector will not be taxed directly but is expected to contribute to research leading to methane mitigation. A wide range of possibilities other than reducing livestock numbers exist for lowering livestock methane emissions: increasing the efficiency of animal production, exploiting betweenanimal variation; anti-methanogenic feed additives; dietary manipulation, including pasture composition modification; immunisation; and, manipulation of the rumen microbial ecosystem. Reduction in methane will not only have global environmental benefits, but also, as methane represents a loss of about 6% of an animal’s energy intake, any reduction should be reflected in increased animal productivity per unit of intake. It should be possible to deliver a win/win situation with respect to methane reduction and increased productivity. Keywords: climate change, inventory, methane, mitigation, ruminants
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(31 KB)Methane production has been measured from lambs fed contrasting forages. This work has been driven by the need to reduce greenhouse gas emissions from agriculture and to determine energy losses to methane from contrasting diets. Young ram lambs were fed either fresh ryegrass/white clover pasture, lucerne (also pelleted lucerne), sulla, chicory, red clover, Lotus pedunculatus (lotus) and mixtures of sulla and lucerne, sulla and chicory and chicory with red clover. The effects of condensed tannin (CT) in lotus on methane production were also measured. The trials were carried out indoors with sheep held in metabolism crates to enable an accurate measurement of intake and digestibility as well as methane production. Principal findings were a two-fold range in emissions from 11.5g CH4/kg dry matter intake (DMI) with lotus to 25.7g CH4/kg DMI with pasture and a 16% reduction in methane production due to the CT in lotus. This range in emissions from good quality forages represents a loss of about 7-11% of metabolisable energy and presents a clear direction for future research to better utilise the feeding value of pastures and reduce greenhouse gas (GHG) emissions from agriculture. High quality perennial forages should be used where practical, and researchers need to identify plant parameters responsible for the variation in methane emissions. Research must focus on rapid passage of digesta through the rumen of grazing animals and will involve manipulation of the fibre content of grasses. Introduction of CT into diets is a likely target to reduce methane production. Improving the rapidly digestible constituents of forages is another opportunity, but difficult to target. Keywords: condensed tannins, forage quality, forages, greenhouse gases, methane emissions, sheep
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(36 KB)Ecologically sustainable pastures remain the base of New Zealand’s competitive advantage in livestock production, but while modest but steady productivity gains from pasture plant breeding have been documented, these appear to be difficult to convert to livestock production, and pasture production is perceived as up against a ceiling. This paper discusses the contribution of pasture plant breeding, focusing on the ryegrasses, and to a lesser extent on white clover. Heritable variation is evident in the basic components of herbage growth and herbage quality. However, changes to individual traits are not reflected in improved integrated field performance. More precise information is required on how factors interact. New breeding technologies will allow integrated improvement of interacting factors. Evaluation trials and modelling should be managed to provide feed-back identifying the specific requirements of future high-performing systems. Keywords: New Zealand, plant breeding, ryegrass, white clover
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(59 KB)
Sheep and cattle have difficulty satisfying their preference for white clover when it’s proportion in pastures is low. We tested the hypothesis that they prefer clover because it has a higher concentration of nitrogen (N), and expected that they would reduce their preference for clover (increase their preference for grass) when grass had a higher concentration of N. In two experiments, mature sheep and growing cattle were offered choices between grass, having either a high or a low concentration of N, and white clover, growing as adjacent pure swards. To test the specific role of N in preference they were also offered each grass alone (sheep only) and a choice between the high and low N grass. Sheep and cattle preferred clover (75% of time grazing on clover and 25% on grass), but this preference was not affected by the concentration of N in the grass. They preferred the grass with a high concentration of N to that with a low concentration. Sheep and cattle detect differences in the N concentration of food items, but alter their grazing behaviour (express a preference) only when it does not affect dry matter intake or the proportion of clover in their diet. We conclude that N is not the reason why animals prefer white clover. Manipulating the N concentration in grass will not cause the switch in preference required for animals to easily satisfy their preference from typical mixed species pastures that are grass-dominant and have a low proportion of clover. Keywords: cattle, diet selection, food preference, grazing behaviour, nitrogen, sheep
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(31 KB)The Kuriwao Farm Action group has followed a process of continued monitoring and evaluation to improve sheep production. Involvement in this project has given the farmers meaningful information for all members to use as part of their decision making. As a group they have evaluated options such as pasture cultivars and renovation strategies, sheep genetics, chemical topping and hogget mating. The benefit to all members has been faster progress and less costly mistakes. Many new technologies such as scanning, improved pasture species, chemical topping and improved animal genetics and nutrition are now standard practice on these properties. The farmers made bigger gains in the last five years as the impact of new sheep genetics and crossbreeding combined with a greater understanding of the importance of ewe nutrition in both lamb numbers and growth. The original objectives of the project were to improve lambing percentage, pasture performance and lamb growth. On average, lambing percentage improved by 2% per year for the last nine years (and 3% per year since 1996). Average lamb growth rate lifted by 8.6g/d/year (5% per year). Keywords: genetics, learning, nutrition, pasture improvement, pasture production, sheep production
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(47 KB)Milking cows in mid-season gave a 12.8% increase in milk yield when drenched with NaCl where herbage sodium (Na) levels were deficient (<0.05%), whereas at a herbage Na level of 0.10% in February, there was no milk yield response to salt supplementation. Dairy heifers growing at 1.0-1.6 kg liveweight gain/head/day at a herbage Na level of 0.05% and ad libitum pasture did not benefit from salt supplementation using salt blocks. An application of 100 kg NaCl/ha salt to pasture maintained Na levels in pasture for 5 months but in severely deficient situations up to 180 kg/ha may be required. Dusting pastures with salt or a salt/MgO combination prior to calving resulted in elevated herbage Na and magnesium (Mg) status from the dust adhering to the grass for up to 5 days after application. Mixing the two products improved handling and reduced the drift of dust when applied to the paddock. There is a range of methods for supplementing animals with sodium, all of which have their place, depending on the type of livestock enterprise. Keywords: dairy cows, dairy heifers, pasture, salt blocks, salt dusting, sodium
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(85 KB)Autumn sowing on 4 February (SD1) and 31 March (SD2) 2000 was used to compare the establishment success of white and caucasian clovers sown with 0, 3, 6 or 12 kg seed/ha of perennial ryegrass. Total dry matter (DM) production from sowing to 3 October 2000 averaged 5770 and 3470 kg DM/ha for the two sowing dates, respectively. Clover species did not affect herbage production in monocultures which averaged 2610 kg DM/ha. The total DM increase from the addition of ryegrass was 87, 109 and 114% for 3, 6 and 12 kg/ha, respectively. On 3 October 2000, white clover content averaged 15% when sown with 3-12 kg/ha ryegrass on SD1 but less than 2% for SD2. Caucasian clover never exceeded 9% in either sowing and weed content was 2% when ryegrass was included for SD1 but 18% for SD2. A complimentary controlled environment study examined seedling development and growth of the three species. For each species the leaf appearance interval (phyllochron) in days differed across temperatures but was constant in thermal time at 94ºCd for white clover, 109ºCd for caucasian clover and 101ºCd for ryegrass. Axillary leaves and tillers of ryegrass first appeared after 375ºCd compared with 439ºCd for axillary leaves of white clover and 532ºCd for stolon initials. No secondary leaf development or rhizome initiation was detected in caucasian clover up to 774ºCd. At this time ryegrass seedling shoots were 635 mg/plant compared with 167 and 184 mg/plant for white and caucasian clovers, respectively. Thus, the success of ryegrass seedlings during autumn pasture establishment was explained by its high relative growth rate, and rapid onset of axillary leaf and tiller development compared with white and particularly caucasian clovers. Successful caucasian clover establishment is most likely to occur in the absence of either ryegrass or white clover. Keywords: axillary shoots, Lolium perenne, pasture establishment, phyllochron, sowing date, sowing rate, thermal time, Trifolium ambiguum, Trifolium repens
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(77 KB)There has been a marked increase in the use of cereals for supplementary grazing and silage for the developing dairy industry in the South Island. Cereals provide high energy supplement in autumn/winter or can be used as a high fibre source in spring. Variation in yield potential in cultivar trials in Canterbury was assessed for autumn and spring-sown crops. The aim was to produce high quality cereal feeds with good yield potential by examining the variation among species and cultivar selections in well managed trials. Single-bite crops sown in early autumn in Canterbury provide up to 5.5 t/ha herbage DM yield with at least 17.5 % protein, 12% total soluble carbohydrate including starch (TSC) and metabolisable energy (ME) of 11.3 MJ/kg in mid-June. Multiple graze types (eg. Doubletake triticale) with similar winter productivity and quality to single-bite crops produced an additional 13.5 t/ha biomass for a silage crop. At ensiling, this cultivar had 9.3 MJ/kg ME with mean 19.5% total soluble carbohydrates. Spring-sown cereals for silage produced up to 20 t/ha. Harvest timing was a significant factor in the wide range in quality of herbage for ensiling. Cultivar means ranged from 7.0 - 12.8% DM for protein, 8.7- 31.6% DM for TSC and 8.3-10.5 MJ/kg DM for ME. More mature herbage had reduced organic matter digestibility and higher TSC but reduced ensilability at DM content in excess of 40%. Keywords: dairying, fibre, forage, herbage quality, metabolisable energy, near infrared reflectance spectroscopy, supplements
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