The history of high power fencing shows how this New Zealand idea contributed extensively to the profitability of pastoral farming by improving animal control, pasture utilisation and weed control. The development of electrified fencing is traced wth examples of incidents, starting in America in the thirties where it has improved only slightly, while in New Zealand development started in 1936 to become a world leader thanks to the Phillips (Ruakura) low impedance fence. Examples of its benefits are described by quoting farm profitability competition winners. Power fencing continues to become more sophisticated with items like voltage alarms, shock stops and tumblewheels. Keywords: power fencing, pasture improvement, weed control.
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(60 KB)The Suitability of Grasslands Roa tall fescue (Festura arundinacea Scherb) and Grasslands Maru phalaris (Phalaris aquatica L) for dairying in a grass grub prone environment was evaluated. Pasture growth studies (1961-1984) showed Roa and Maru to produce 16% more drymatter (DM) than ryegrass but the seasonality of growth differed. Roa was more productive in spring and Maru in late-autumn and early winter. The increased tolerance to grass grub and greater DM production suggested that these grasses may be more suitable to dairying than ryegrass. Since 1964 dairy production has been compared from two pasture systems; one comprising 66% Roa/white clover and 33% Maru/white clover and the other a 30 year old ryegrass/white clover pasture, each stocked at 3.7 and 4.3 cows/ha. Results from the farmlet study highlighted the superiority of DM production from Roa and Maru pastures but total milkfat production was similar lrrespecivwe of pasture type or stocking rate. Roa/Maru pastures produced more milkfat in autumn, but this only compensated for less producton over summer. The present work highlights the danger that herbage production data may not accurately predict animal productivity Keywords: Dairy production, ryegrass, pasture production, pasture composition, sodium levels
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(183 KB)The development of a 74 hectare bull beef productlon system is outlined. With pasture development regarded as a high priority techniques used to apply sufficient grazing pressure to change pasture composition are discussed. The combination of stock classes and pasture management changes has allowed a dramatic increase in the proportion of ryegrass and white clover in the sward. Currently a slightly modified one year bull beef system 1s being operated. Spring calves (140) are farmed through to 16-18 months of age and in addition autumn reared calves (60) are taken through to slaughter at 19-20 months. Performance and management objectives are given for this producton system and fhe key factors relating to their practical implementation are discussed.
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(116 KB)A bull-beef system based on buying 8 week old replacement calves and selling bulls at 15-20 months of age was set up prior to the winter of 1983. A commercial venture, it was set up to provide information on calf-to-20-month bull beef systems. Average carcass weights (CW) at slaughter have been 212 kg, 231 kg, 237 kg and 208 kg for the four seasons reported. The margin per ha (sales less replacement costs) in each of those years has been $798, $1380, $875, and $720 respectively. Data collected regularly on average pasture cover and animal livewetght are used to allow management to respond appropriately lo climatic variability, especially through the autumn and winter, and ensure that liveweight (LW) targets are met before summer dry spells. Keywords: pasture cover, target liveweights, profitability
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(98 KB)Volunteer summer-growing paspalum is often present in dairy pastures of northern New Zealand. When paspalum becomes the dominant grass winter/spring pasture production is reduced. This creates management problems on seasonal dairy farms because cow feed requirements and milkfat production are highest in winter/spring. This paper gives data from a current experiment at Ruakura Agricultural Research Station in which Roundup herbicide was used to provide a competitlon-free environment for the overdrilling of cool-season pasture species. Herbicide rates of 6, 4, 2 and 0 l/ha were applied in autumn 1965 before overdrilling a mixture of Ellett ryagrass and Grasslands Kopu white clover. A fifth treatment was the original pasture which was not sprayed or overdrilled. High rates (4-6 I/ha) of Roundup completely elimmated paspalum from the pasture and immediately reduced the white clover to a low proportion (less than 10% of dry matter). The sprayed and overdrilled pastures have remained ryegrass dominant over the duration of the experiment. In 1985 and 1966, winter/spring production from the new ryegrass dominant pastures were significantly better than from the original paspalum dominant pasture. The implications of the noticeable increase in paspalum in the renewed pastures are discussed. Keywords: pasture renewal, pasture renovation, Roundup herbicide, pasture botanical composition, seasonal pasture productlo”.
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(98 KB)Scotch thistle and ragwort are weeds of dairy pastures and are commonly controlled wth broadcast herbicides. Information on the growth habits of populations of these weeds was used to estimate seasonal pasture shading and recovery of populations following herbicide application. These data were then integrated by a Computer model to provlde estimates of the effects of the weeds on milkfat production The economics of using broadcast herbicides for controlling these weeds could then be calculated, taking into account possible harmful effects of some herbicides on pasture clover content. Assuming that lost pasture production is directly proportional to the area covered by weeds, control of Scotch thistle is economic when populations reach one flowering plant per 6 sq m, using MCPB for control in spring. Ragwort is also economic to control but because its control is difficult with pasture-selective herbicides much higher populations can be tolerated. In this work, no account is taken of the poisonous nature of ragwort. Keywords: Scotch thistle. ragwort, MCPB, 2,4-D. weed economics, dairy production. Cirsium vulgare, Senecio jacobaea, dairy model.
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(127 KB)The objective of this study was to measure the effects of giving hay as a supplement to cows grazing at two different daily herbage allowances. Pregnant, non-lactating Friesian cows were allocated to four treatments: low herbage allowance with hay (LA+) or wthout hay (LA); and high allowance with hay (HA+) 01 without hay (HA). Hay was fed at 5 kg DM/cow daily, and the two herbage allowances were 9 or 14 kg DM/cow daily. Supplementing with hay increased total dry matter (DM) intake, but decreased herbage DM intake at both allowances. The decreases in herbage intake were 0.26 and 0.40 kg herbage OM eaten per kg hay DM eaten, at the lower and higher allowances respectively. The corresponding values, expressed as MJ metabolisable energy (ME), were decreases of 0.44 and 0.65 MJME from herbage per MJME eaten as hay. The decreases in herbage intake resulted in increases in residual herbage yield at both allowances. The implications of these results for grazing management during the winter are brlefly discussed. Keywords: supplementary feeding, hay, substitution rate, condition score, dairy cattle.
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(72 KB)The pasture probe, rising plate meter (RPM), ward height and visual assessment methods were compared for the estimation of the herbage mass of dairy pastures. The pasture probe and calibrated visual assessment were slightly more accurate than others. Visual assessment without calibration was less accurate than all other methods. There was little difference between operators of the pasture probe and RPM, but operator variation was large with visual assessment. Variation between calibrations from different days, seasons, and sites was large. Only dead material content was identified to influence this variation. Pooling of calibrations, double sampling procedures, and derivation of different calibration slopes for each day from an equation fitted to calibration data are procedures discussed for the estimation of herbage mass by farmers, advisors and researchers. Wide adoption of methods such as the pasture probe or RPM with “universal” calibrations could reduce inconsistent advice offered to farmers, and can be used with confidence. Keywords: capacitance probe, rising plate meter, visual assessment, ward height, grassland management, pasture composition, pasture assessment.
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(144 KB)The four New Zealand bred white clover cultivars. Tahora, Hula, Pltau and Kopu were evaluated for two years under a high stocking rate in self contained sheep grazed farmlets comparing year round rotational grazing with set stocking. Tahora was clearly superior under set stocking, yielding 50% more than Huia and 140% more than Pitau and Kopu. Under rotational grazing all performed well with only Kopu showing a 20% advantage. An unseasonal early summer drought in the second year showed all cultivars to be highly susceptible to moisture stress at this time under rotational grazing. Large scale death of clover occurred reducing clover content to 2-3% in autumn with no recovery by mid winter. Under set stocking, although severely wilted, all clovers quickly recovered to their former level following rain The management implications are discussed. Keywords: Tahora. Huia, Pitau, Kopu, grazing management, drought, cultivar choice
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(84 KB)Few farmers have firm ideas about the long-term aims of their goat enterprises. Since profit is the primary motive, breeding objectives may change rapidly. Goats are generally a small proportion of total stock numbers and are given preferential grazing. Goat grazing improves pastures by increasing clover content and reducing the number of thistles and weed grasses. Although most farmers feed hay there is no indication this is necessary for high animal performance. The most productive goat management systems on high producing pastures have yet to be defined, especially integration with other livestock dasses. Preliminary data from mixed goat and sheep grazing trials in Canterbury suggest there are benefits in liveweight gain to sheep, but not necessarily to goats by integrating grazing. Areas for future research are considered.
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(61 KB)Two levels of grazing intensity were unposed on pasture during a spring-time pre-treatment period in two years at Massey University’s Dary Cattle Research Unit. The two grazing intensws were lax (L), 2000-2500 kg DMlha residual herbage mass (RHM) and intense (I) 1000-1500 kg DM/ha RHM imposed for 2 grazing rotations. During this period, net herbage accumulation (NHA) on the L swards was approximately twice that on I wards. However, by early summer, NHA was greater on the I than L swards. Subsequently, during the experimental feeding period in early summer, herbage on the I swards contained lower percentages of reproductive tillers, grass stem, and senescent matter, and was of higher digestibllity than herbage on the L wards. Durmg the feedlng period, cows grazing the I wards had greater yields of milk and milk fat than cows on the L wards when offered both generous and restricted daily herbage dry matter allowances. The effect of ward type on dry matter intake (DMI) was dependent on dry matter allowance. However, when a common allowance of leaf was offered, DMI, milk and milk fat yield were not significantly affected by sward type on offer. The results emphasise the importance of maintaining green, leafy swards into late spring and summer in order to maximise milk yield per cow at this time. This was achieved by maintaining a RHM of no more than 1500 kg DMlha throughout spring by imposing sufficiently high stocking rates. Keywords: residual herbage mass, ward characteristics, dry matter allowance, leaf allowance, dry matter intake, milk yield.
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(96 KB)Application of the technologies of genetic engineering in the dairy industry will begin within 5 years, probably with the use of bovine somatotropin as a lactation stimulant. There are several other likely developments which may manipulate the animal, the plant or the rumen micro-organism to increase or diversify production or to decrease milking frequency. To take full advantage of increased potential milk production, ways to minimise the seasonality of feed supply must be developed.
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(60 KB)Data indicating changes in the numbers of livestock and farmlng trends for the Waikato/Thames Valley region are presented. These data confirm the dominance of the dairy industry in this region. The expansion of deer (30% per year) and goat (90% per year) farming is shown to be above the national average. Data showing the importance and growth of the equine industry are also presented. Keywords: Pastoral, dairy, sheep, beef, goat, deer, equine.
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(31 KB)The inclusion of Matua prairie grass (Bromus willdenowii Kunth) as a pure sward mto grazing systems involving dairy, bull beef and integrated dairy bull beef systems is investigated using a linear programming model. The ability to test in the model alternative animal production patterns and therefore intake of dry matter throughout the year has allowed definition of the most profitable systems for Matua. The results highlight the need to consider animal production patterns and pasture management objectives which combine to give the best profitability rather than the inflexible animal requirements based on traditional management concepts. Keywords: linear programming
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(59 KB)Thoroughbred production systems are concentrated in the Waikato region on free-draining, high fertility soils utilising perennial pastures based on tyegrass/white clover. The major emphasis is on the production of thoroughbred yearling stock for sale in January, and the mating of breeding stock, from September through until December. As with other pastoral industries in the region, successful pasture management entails matching pasture production with animal requirements. On thoroughbred stud farms, a mixture of different classes of horses and co-grazers. principally cattle, make up the animal requirements. This paper examines the relationship between pasture production and animal requirement on a large-scale thoroughbred stud operation. Data from a typical stud farm near Matamata were used to assess total animal requirements. Pasture production was determined from long-term, local mowing trials. Pastures failed to meet animal requirements on this stud from April through to August, while a surplus of pasture growth occurred from September through until March. Pasture utilisation over the main pasture growing period was estimated to be low. Alternative management options are proposed and discussed. Keywords: thoroughbreds, pasture production, management systems, perennial pastures
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(59 KB)Manawatu dairy farmers have been quick to appreciate the possible benefits of a pasture species that can out-perform conventional ryegrass white clover based pastures. A survey conducted by Grasslands Division, DSIR in 1985 showed knowledge and use of Matua praire grass by dairy farmers in the Wellington province were 70% and 42% respectively, compared with the national figures of 55% and 29% for dairy farmers, and 32% and 9% for non-dairy farmers. When Matua was first released little data was available as to how best to sow the seed, what seed mixes are the most appropriate, how to manage the establishing pasture, and how to get the best from an established pasture. Researchers and pioneering farmers right around the country have by trial and error found the answers to most of these questions. The stimulus to find the answers was always the promise that Matua offered, that of 15 to 30% extra drymatter production compared to standard ryegrass pastures. Not only is there more annual drymatter, but the extra comes at very useful times for the dairyfarmer: winter, early spring and late summer.
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(46 KB)The extent to which propagation of perennial ryegrass from seed can contribute to sward stability and the influence on this of spring pasture management (seedling competition and seed viability and losses was examined in a replicated plot experiment. Under hard grazing in late spring less than 5% of reproductive tillers reached flowering. Where grazing was restricted during reproductive tiller development to allow reseeding, 80-90% of tillers flowered. Subsequent seedling densities were 20-50 times higher and herbage accumulation during late summer-early winter was 33% greater on plots reseeded than those hard grazed in spring. Farm practices such as hard grazing, topping and possibly silage conservation which remove reproductive tillers before flowering will greatly reduce ryegrass reseeding and may contribute to the poor persistence of ryegrass swards under intensive dairy cattle grazing. Keywords: grassland management, propagation, botanical composition, herbage accumulation, soil, seed dynamics.
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(151 KB)Clover cultivars grown with ryegrass were compared in an establishment year under dairy cow grazing. There was no difference in total annual productton but summer production was greater with Pawera red clover and with Kopu or Pitau white clovers. Clovers differed little in the proportion of nitrogen fixed, except during summer when values were highest for Pawera. Pawera was less prone to nematode attack than white clover cultivars but was more susceptible to clover rot. Resident clovers and high buried seed levels (e.g., 11-91 kg/ha) made introduction of new clover cultivars difficult. Sown clovers established best (50-70% of total clover plants) when drilled into soil treated with dicamba and glyphosate. Keywords: white clover, red clover, nematodes. nitrogen fixation, pasture renovation
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(94 KB)Soil chemical fertility, pasture composition and pasture production data were collected for seven ‘microsites’ within two farmlets at Massey University’s No. 1 sheep farm. Palmerston North. The two farmlets had been maintained for twenty years at stocking rates of 26 and 16 su/ha, and were found to have gradients (presumed to result from sheep grazing and camping behaviour) of increasing soil fertility away from a road and towards a shelterbelt. Microsites were placed along these gradients to include contrasting fertility levels for the two stocking rates. Mean values for soil pH, Olsen P and ‘quicktest’ K tiller density for the various pasture species and pasture production at each of the seven microsites are presented. A microsite where Olsen P = 109 was barley grass dominant and produced 10.5 t DM/ha/year. For other microsites ryegrass tillers per m2 increased with P and stocking rate; and white clover and sweet vernal growing points/tillers per m2 decreased with increasing P. Production ranged from 9.9 t DM/ha/year where Olsen P = 14 to 19.1 t DM/ha/year with different seasonal timing where Olsen P = 66.
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(98 KB)The microcomputer has sigmficant potential for enhancing farm deciston making in grazing management. The avallability of pasture models in conjunction with feed planning software makes it possible to calculate pasture production characteristics of dllferent areas on the farm. With this Information, and with performance monitoring, each unit can be put to best use as part of the total farm area. With a knowledge of limiting factors production can be increased, or the utilization of resources improved. Implementation of this innovation must occur within the framework of the information system for each farm. An example is given from the Waikato where this informatlon has been used successfully to improve stocking rates and grazing management on the farm. Advantages and limitations of microcomputer technology for implementing these systems are discussed. Keywords: Microcomputers, models, decision making aids, pasture production
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(56 KB)Diversification in agriculture has seen the establishment of new enterprises such as deer farming. While still a small industry in absolute terms the deer industry is growing rapidly. The utilisation in situ of pasture by deer is discussed in relation to their feed requirements for two types of farming viz. weaner production and a 15 month venison stag operation. Seasonal feed requirements are poorly aligned with average pasture growth with both types of farmmg being characterised by surplus spring pasture and a deficit during summer and autumn. The primary constraint to increased on-farm production is the summer deficit. It is suggested that alternative pasture species with improved summer growth charatieristics be examined. It is also argued that earlier calving and the use of larger terminal sires could ease the pressure on summer pature and more closely align feed requirements of deer with pasture growth. Keywords: Farmed deer, red deer, pasture growth. pasture intake, feed requirements, calving date, terminal sire.
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(62 KB)Plant enzymes can be electrophoretically separated and identified by specific staining. Resulting banding patterns can enable the identification of enzyme genotypes for individual plants. The ability to identify banding patterns for particular enzymes has a number of applications. Three examples are documented here: i) Identifying clones, e.g. Trifolium hybrids, ii) Identifying hybrid progeny, e.g. subterranean clover (T. wbterraneum L.). and iii) Distinguishing cultivars on the basis of population allele frequency, e.g. perennial ryegrass (Lolium perenne L.) cultivars Ellett. Grasslands Nui and Grasslands Ruanui. Keywords: Isozymes, pasture plants, enzyme genotypes.
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(86 KB)Improved pasture species, irrigation and nitrogen fertilizer options for increasing pasture growth rate during inter and Summer have been evaluated in growth rate and annual production of young Friesian bulls. Effective increases in Summer pasture production have been obtained from the use of irrigation, Pawera red clover, Matua prairie grass and particularly a combination of irrigation and Matua, Nitrogen fertilizer, Matua and carryover effects of irrigation have increased cool Season pasture growth rates. Liveweight gains reflect these increases except on Matua pastures where poor growth rate of calves occurs durmg summer. The negative effects of the different pasture treatments on Spring liveweight gain are attributed partly to the effects of compensatory growth in bulls but also to treatment effects which reduce pasture growth rate during this season. For this reason the most effective gains are made by 15-18 month old bulls during summer. Pasture species and pasture mixtures react differently to applications of irrigation and nitrogen fertilizer. The most appropriate Strategies and combinations are discussed
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(118 KB)Four separate experiments evaluating Grasslands Puna chicory (Cichorium intybus) are reported. Three of these experiments used animals to measure the quality while the fourth looked at establishment and persistence on summer dry areas in Southland. Liveweight gains both with calves and lambs were higher with Puna than could be expected with conventional pastures. In an autumn trial lambs grazing Puna grew over 70 g/head/day faster than those grazing rape. Grasslands Puna established and persisted when sown in pasture mixtures in Southland. Production was maintaned at a high level after three years of rotational grazing. Keywords: Cichorium intybus; pasture quality; herbage allowance; animal performance
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(115 KB)Through recent advances in molecular and reproductive biology selected genes from one animal or species can be inserted into another animal’s genome to produce a ‘transgenic’ animal. Striking increases have been achieved in the rate of growth of mice containing additional copies of the rat growth hormone gene. Such results raised the possibility of using similar techniques to modify the expression of existing genes and introduce novel gene(s) into domestic livestock for improved productivity. The introduction of multiple copies of the growth hormone genes into pig embryos has resulted in live births of pigs that grew 10-20X larger and reached market weight three weeks earlier than litter-mates. The introduced genes were passed from generation to generation. In sheep cysteine supplementation into the abomasum produced at 10.20% increase in wool growth rate. Genes responsible for cysteine biosynthesis have been isolated from yeast, and a modified gene suitable for expression in sheep produced. By engineering the cysteine biosynthetic pathway into the sheep genome there is scope to considerably increase wool production. Keywords: gene transfer, transgenesis. recombinant DNA, embryo manipulation.
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(42 KB)Vegetation surveys were carried out on 10 Central Districts and two northern racetracks. Tracks could be allotted to three groups according to the type of turf cover. classified mainly on the relative importance of ryegrass (Lolium species), Poa (Poa trivialis), browntop (Agrostis capillaris) and white clover (Trifolium repens): Type 1 (3 tracks) had swards consisting of about half Poa, one quarter ryegrass and 20% white clover; Type 2 (2 tracks) had about 30% ryegrass and Poa with substantial browntop, and Type 3 (7 tracks) had higher ryegrass contents (44.75%), intermediate Poa and little browntop. Unlike ryegrass, Poa is very intolerant of heavy wear, and therefore should be unwelcome on racetracks. Data gathered here indicate Poa presence is encouraged by high phosphate applications while ryegrass is stimulated by potassium applications and lower cutting heights. Appropriate fertiliser applications and lower cutting heights should move the botanical composition towards higher ryegrass contents. Keywords: ryegrass, Poa trivialis, browntop, white clover, fertilisers, mowing
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(129 KB)A bloat survey of 312 North Island dairy farms carried out in spring 1986 by Ruakura staff showed that farms with moderate to severe bloat tended to have larger herds, higher stocking rates, a greater proportion of clover in pastures and higher soil potassium, levels (Carruthers et al. 1987). However, these 4 factors together accounted for only 22% of the variation in bloat severity between farms. In an attempt to highlight further factors important in bloat, a comparison was made of nil and severe bloat farms in South Auckland-Waikato.
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(37 KB)Swards that had been either set stocked (SS) or rotationally grazed (RG) for five years were sampled monthly over two years by removing turves. The uncut white clover plants were then washed out, classified by branching structure (lst, 2nd, 3rd, 4th order) and then dissected into stolon and leaf before drying and weighing Under both managements stolon dry weight per plant and branching structure of the population each indicated a strong seasonal shift from larger plant size during summer, autumn and winter (February, 109 mg stolon DW/plant, 7% of population 1st branching order) to a preponderance of smaller plants in spring (October, 41 mg stolon DW/plant, 30% of population 1st branching order). Grazing management affected stolon DW per plant (means. RG 106 mg. SS 53 mg) but had little effect on branching structure. However, in spring, under RG management proportions of 1st branching order plants in the population were higher for a longer period than under SS management. The simpler structure of plants in spring is thought to increase the vulnerability of the white clover population to adverse conditions at this time. While RG management allowed white clover to better utilize favourable growth conditions, it also increased the susceptibility of the population to large declines during stress periods; SS management reduced the potential for growth, but enhanced stability during stress periods. Hence where environmental conditions are unpredictable SS rather than RG management will favour retention of white clover in the sward. The seasonal and grazing management effects reported are likely to occur across a wide range of environments. Keywords: Trifolium repens, individual plants, plant size, seasonal variation, branching.
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(122 KB)Resistance of perennial ryegrass plants regenerated from tissue culture (somaclones) to crown rust (Puccinia coronata) was assessed in growth cabinet/glasshouse experiments. Somaclones regenerated from callus cultures initiated from the vegetative tissue of three different somaclonal parent plants were tested for resistance to crown rust collected from Palmerston North and Linwln. Most plants tested were highty resistant and their leaves developed small pale yellow flecks but showed little or no sporulation. However, a few large pustules did develop on leaves of some of the somaclones. Screening experiments with rust cultures initiated from each of three single pustules showed that somaclones varied in their reaction to crown rust. Within each group of somadones derived from a particular parent some were more susceptible. and some more resistant, than the parental genotype. Two of the somaclones obtained from one of the parent plants had very fine leaves similar to those of turf perennial ryegrass plants. Somactoning may provide an efficient technique for plant breeders to improve the crown rust resistance of both pasture and turf perennial ryegrasses. Keyword% Puccinia coronata, Lolium perenne, somaclones. tissue cutture, plant breeding, plant diseases.
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(83 KB)The quantities of pasture utilised on New Zealand’s predominantly pastoral dairy farms can be indirectly estimated from calculating the feed requirements of livestock on the farm and adjusting the total quantities consumed for feed purchased from off the farm. This method provides a logical and quantitative framework for analysing between farm differences in productivity and pasture utilisation. The calculations require information regarding the number, breed and categories of stock farmed; the total production of milk or milkiat; the quantities of crops, hay and silage grown and/or conserved; and the quantities of purchased feeds consumed. Reliable tables of feed requirements are available for use in such calculations. This method has been used to examine data collected in surveys of town supply and seasonal supply farms in Manawatu and South Auckland by Massey University and Lincoln College, respectively. Comparisons between districts are unreliable because the surveys were conducted in different seasons and by different sampling methods. However, the differences between farm types were similar within districts and indicated lower stocking rates and milkfat production per hectare on town supply farms. There was a large reliance on the use of home grown pasture on all farms, but town supply farms used higher proportions of crops, hay and silage than did seasonal supply farms. A wide range existed between farms in the quantities of home grown feed consumed per hectare (4.9-18.0 tonnes DM/ha on town supply farms and 6.7-17.1 tonnes DfvVha on seasonal supply farms). This method of analysis. together with estimates of potential pasture production, may help to identity situations in which increases in pasture utilisation may be capable of increasing farm productivity. Keywords: town supply, seasonal supply, grazing, Conservation, supplements, farm productivity
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(78 KB)The effect of withholding superphosphate fertiliser for up to fwo years on grazed day pasture in Taranaki has been assessed in plot trials. Three sites of different initial soil test phosphate (Olsen P) level were used, viz. 16, 34 and 60. Seasonal or annual dry matter yields, seasonal distribution of pasture growth, Olsen P. botanical Composltlon and herbage P content were in general, not significantly affected by withholding superphosphate. A farmlet grazing trial has shown that withholding superphosphate for 18 months did not reduce dairy production in the first season. Farmers could make large short-term cost savings by withholding superphosphate fertiliser, without affecting dairy producton. Keywords: pasture production, seasonal distribution, botanical composition, dairy production
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(142 KB)Waikato dary pastures were developed through large inputs of superphosphate and potassium chloride. Many farmers have continued to apply similarly large amounts of fertiliser in post-development situations. Trials to study the effects on the production of dairy pastures to restricting or stopping fertiliser application were started in 1978 and have continued to the present. The tria1s were conducted on 6 commercial dairy farms throughout the Waikato region selected for high milkfat production and past fertiliser applications. Each trlal included 3 fertiliser treatments: 1000, 500 and 0 kg fertiliser (30% potassic superphosphate)/ha/year. Pasture production was estimated through a trimming technique designed to cause minimal interference with management and use of the experimental paddock by the farmer and in later years through calibrated visual assessments and electronic probe readings of pasture dry matter. Pastures receiving 500 kg fertiliser/ha/year produced on average 2.5% less over an 8 year period than pastures receiving 1,000 kg fertiliser. Applying no fertiliser caused a slow reduction in pasture production in 3 of the trials but an immediate reduction of more than 10% in the other three trials. The latter effect could be partly explained by low soil test levels and high stocking rate. Keywords: Yellow-brown loams, gley soils, maintenance fertiliser, phosphorus, potassium.
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(83 KB)The present strategy for achieving our production goals consists of growing more total annual DM especially over the critical winter and spring periods. To this end we are undersowing older pastures with high-producing species and converting the extra growth into milkfat, using high quality cows over a 280- to 300-day lactation period. Calving date has been moving earlier to capitalise on the higher winter growth rates recorded from the newer pastures. The choice of renewal method will continue to be made according to the amount of paspalum present in the older pastures with spray being used if the paspalum content exceeds 10%. Glyphosate will also continue to be used if new clover cultivars are included in the seed mixture of the new pastures. Maize silage will continue to be grown, or purchased, to fill feed deficit periods while it is profitable to do so. However, our experience to date, has been that undersowing, even if it has to be repeated annually, is presently the cheapest form of providing additional feed for the cows. Even assuming that the best managements are practised to produce high quality pastures for the lactating cows, I believe that the breeders of new pasture cultivars must place more emphasis on palatibility and digestibility, to enable tomorrow’s farmers to achieve still higher milkfat yields (profitably) from fewer and fewer, genetically superior cows. Should these plants perform and persist under the current management abuses to which present-day pastures are subjected, then we are well on the way to a profitable future.
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(86 KB)The effect on bloat of increasmg the concentration of Na in herbage was investigated in two experiments at Ruakura. NaCl fertiliser applied at 190-200 kg/ha to pastures containing ryegrass and white clover increased the concentration of Na by two to three times. This resulted in K:Na ratios of 7 to 15 in fertilised herbage compared with 18 to 40 in unfertilised herbage in subsequent spring and autumn periods. Bloat was assessed using cows of high susceptibility to bloat. Under conditions when only moderate bloat was observed, the incidence and severity of bloat on NaCl fertlized areas was similar to or higher than that on unfertilised areas in all seasons. These data do not support suggestions that lowering the K:Na ratlo through use of NaCl fertiliser will control or eliminate bloat. Keywords: NaCl, survey, dairy cows, ryegrass, white clover.
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(42 KB)Six grazing treatments, consisting of an intensity comparison (hard, medium and lax) at a 14.day regrowth interval, and a frequency comparison (regrowth intervals of 7, 14, 21 and 26 days) at the medium intensity, were imposed over 12 weeks during spring (treatment period). Subsequent pasture performance was assessed over a further 12 weeks during summer (post-treatment period). By the end of the treatment period two groups of wards were apparent. Compared with the other wards. Lax and Medium swards at regrowth intervals of 21 and 26 days were characterised by greater total, green, ryegrass reproductive stem and dead herbage mass and lower proportion of leaf. During the post-treatment period reproductive stem senesced and these wards contained greater levels of dead herbage. These swards also had lower leaf accumulation during the treatment period, though leaf accumulation was lower only on lax grazed swards during the post-treatment period. On high-fertility, ryegrass-dominant pastures hard grazing was not required to maintain pasture quality, as this occurred also under the medium grazing intensity (residual sward height 6-6 cm) provided the interval between grazing was 14 days or less (pregrazing ward height of 20 cm). It may be expected that herbage intake and animal performance on lax and infrequently (21 and 26 days) grazed swards would be reduced because of both lower leaf accumulation and greater dead herbage mass especially over the summer. Keywords: Pasture quality, ward characterisics, grazing frequency, grazing intensity, leaf accumulation, herbage mass.
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(126 KB)The performance of Kopu white clover was compared with that ot Huia and Pitau under intensive dairy grazing management at Taupo and the Manawatu. Sampling included both dry matter production and detailed white clover stolon and leaf measurements. These trials have shown that there are significant advantages to be gained from the use of Kopu over both Huia and Pitau. in rotationally grazed cattle swards, particularly during autumn and winter. At the Taupe site where Kopu was sown with high endophyte perennial ryegrass, seasonal white clover yields from Kopu were 120% greater than from Huia in autumn and 160% in winter. At the Manawatu site with Matua prairie grass as the grass component, the advantage of Kopu over Pitau was 105% in autumn, increasing lo 150% by winter. These results are discussed in relation to the significance of Kopu to dairy farming in the central and southern North Wand region. Keywords: rotationally grazed swards. cool season activity, erect habit, dairy pasture, intensive dairying
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(78 KB)Because of the growing number of pasture cultivars used in NZ and the difficulty of reliably separating cultivars of the same species by morphological characters, seed protein banding patterns have become a useful supplementary means of cultivar identification for the purposes of seed certification and plant variety rights applications. Sodium dodecylsufphate polyacrylamide gel electrophoresis of proteins extracted from ground seed samples produces distinctive patterns of bands representing seed storage proteins of different molecular weights. The procedure can be carried out in two days using viable or dead seed, and the results are not affected by site and season of growth. Although individual seeds of outbreeding species such as perennial ryegrass and white clover produce different banding patterns, the combined population representing the cultivar remains constant unless there has been genetic shift during seed multiplication. Speckes for whrch this procedure is being successfully used include the ryegrasses and fescues, browntop, cocksfoot, bromes, red and white clovers, subterranean clover, serradella and lotus. Even cultrvars as closely related as Nui and Ellett ryegrasses and Huia and Pitau white clovers can be separated by careful work. Because of minor technical differences between runs, all cultivars to be compared must be run on the same gel. Keywords: Seed certification, Plant variety rights, sodium dodecylsulphate polyacrylamide gel electrophoresis.
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(234 KB)I’m actively farming in the Koputaroa District north of Levin, on soil types consisting of loam, silt loam, peat and sand flats, broken by ridges, on 460 hectares in five separate blocks, all freehold. As well, 120 hectares in two blocks are leased nearby. Due to neighbouring farm purchases in the past 12 years, decisions affecting stock sales and purchases have sometimes been made to accommodate financial arrangements. Approximately 1,800 bulls are farmed, with approximately 1,200 killed per year usually as 2 or 2 1/2 year olds. 400 cows are milked in one herd as well, with most calves reared as replacements for either the dairy or beef operation. Two married men, living on the farms, handle the cows and help with dehorning and some drenching, if required. Hay feeding, if necessary, is also shared if large quantities are fed during floods or wet spells. I tend to run the bulls myself although some casual labour is available if required. Most of the effort, from the three of us, is concentrated on stock work. New fencing, draining, thistle spraying and top dressing are contracted.
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(38 KB)Cell culture and genetic engineering techniques can be used to develop improved pasture plants. To utilise these methods we have developed procedures for regenerating plants from tissue cultures of perennial ryegrass and white clover. In both, the plant genotype influences regeneration capacity. There was significant genetic variation among regenerated perennial ryegrass plants in a wide range of characteristics. Most of the regenerants were resIstant to crown rust and this trait was highly heritable. This rust resistance is being used to breed a new ryegrass cultivar. A system for introducing cloned genes into white clover is described. This capability is bemg used to incorporate genes with the potential to improve nutritional quality and pest resistance. Other possibilities for engineering genetic improvements in white clover, genes conferring herbicide tolerance and resistance to white clover mosaic virus, are briefly outlined. Keywords: Lolium perenne, Trifolium repens, cell culture, somaclonal variation, crown rust resistance, transformation, cloned genes, nutritional quality, proteinase inhibitors, Bt toxins, pest resistance, WCMV viral cross-protection, herbicide tolerance, Agrobacterium, Bacillus thuringenisis.
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(100 KB)Tissue culture was used in an attempt to obtain a fertile perennial ryegrass x tall fescue hybrid. Regenerated hybrid plants were found to be morphologically variable and contain extensive chromosome rearrangements. Spontaneous chromosome doubling had occurred as well as chromosome elimination. though no fertile hybrid plants have been obtained to date. Keywords: somaclonal variation, Lolium perenne, Festuca arundinacea, intergeneric hybrids
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(117 KB)To assist farmers and their advisers in becoming familiar with the many different varieties of Italian ryegrass currently available, this paper compares morphological, physiological and biochemical characteristics of Concord, Ceres Progrow, Lemtal (Belgium), Grasslands Tama, Grasslands Paroa, Grasslands Moata, Te Puna, Te Rahu, Bradley, Rakaia and also Grasslands Manawa, a hybrid cultivar which behaves as a persistent Italian ryegrass. In trials at Palmerston North in 1966/67, Moata stood out for its size in comparison to all other lines. Rakaia and Progrow from the South Island were short-lived and early heading, went directly to head after spring sowing and had large heads and many florets per spikelet, despite small size of leaves and plants. By contrast, Concord and Te Rahu from North Island dairy pastures were persistent, later heading and large in both vegetative and reproductive characteristics. All the varieties based on NZ material were quicker to germinate than any of the cultivars bred from overseas material, and, except Bradley, contained Acremonium endophyte. Keywords: Lolium multiflorum Lam., crown rust, germination, vernalisation, electrophoresis, seed protem banding, vegetative and reproductive characteristics, Acremonium endophyte.
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(417 KB)A glasshouse study investigated the dry matter response of Grasslands Kopu and Grasslands Tahora white clover, cultivars of differing origins and morphologies, to three phosphate fertilizers, monocalcium phosphate (MCP), partially acidulated phosphate rock (PAPR) and a reactive phosphate rock, North Carolina phosphate rock (NCPR), of differing water solubility. Kopu responded more rapldly and reached Its maximum dry matter yield at a lower phosphorus (P) level than Tahora when MCP and NCPR were the P fertilizers. With PAPR as the P fertilizer, their response was similar. The shoot dry matter response by Kopu to all three P sources was reflected more in leaf weight and size than leaf number or stolon length. In contrast Tahora responded to added P by increasing leaf number and stolon length to a much greater extent than Kopu. Keywords: Trifolium repens, monocalcium phosphate, partially acidulated phosphate rock, reactive phosphate rock.
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(106 KB)Comparisons were made between three winter grazing management systems based on different pasture growth rate predictions. Management systems were chosen to restrict ewes to their budgeted intakes while at the same time reaching a target of 1500 kg DM/ha average pasture cover at lambing. Two of the three farmlets failed to meet their planned objectives. Changes in average pasture mver were frequently the result of an interaction between pasture growth rate and herbage intake. It was concluded that rotation length alone gave insufficient control over the management system and for a farmer to be able to make appropriate adjustments a minimum level of monitoring would be to estimate animal intake rate and average pasture cover.
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(93 KB)Present economics dictate New Zealand dairy farmers either increase producton or reduce expenditure to maintain net farm income. Costs associated with present feed conservation practices,are high and so cheaper alternatives for bridging a winter feed deficit are considered. Making no conservation would mean generating additional feed energy by foregoing some milkfat production. Lower cow conversion ratios of milkfat from pasture in late lactation means it is more economic to create additional feed at the end of the season by drying-off earlier rather than calving later. Utilising additional cow liveweight as a store of energy has high metabolic inefficiencies. At today’s prices, grazing cows off to overcome the deficit is the most economic and practical solution. Economically, alternatives to traditional supplement systems requre a massive reduction of capital farm machinery to be viable. Management strategies, both to control the spring feed surplus and to increase average farm herbage masses in early winter without loss of growth or quality, need to be developed.
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