Forage maize for Australian livestock systems.

Abstract

Proc. Aust. Soc. Anim. Prod. Vol. 19 CONTRACT REVIEW FORAGE MAIZE FOR AUSTRALIAN LIVESTOCK SYSTEMS J. B. MORAN Dept of Food and Agriculture, Kyabram Research Institute, Kyabram, Vic. 3620. INTRODUCTION Maize silage is used widely for feeding cattle in Europe and North America but in Australia, the production of forage maize is essentially in its infancy. Forage maize is now the most important arable crop grown in Europe where areas have increased 5-fold over the last 20 years and now total 2.5 million ha. Nearly 3 million ha are grown in the US, while in the USSR over 18 million ha (or 80% the size of Victoria) are sown to forage maize every year. By contrast, less than 10,000 ha is sown in Australia each year. However there has been an upsurge in interest in forage maize over recent years in Australia, particularly for supplementing grazing dairy cows and for lot-feeding beef steers. Forage maize is not a new crop in Australia but in the past our traditional low input/low output livestock systems have relied mainly on grazed pastures. As prices for livestock products rise, the proportion of total production costs devoted to nutrition can be increased. Many producers now look beyond grazed pastures to feed their animals and, for them, forage maize may have a role. Currently the Meat Research Corporation and the Dairy Research and Development Corporation are funding many research and ` on-farm' development projects to assess the role for forage maize in improving animal performance per head and per hectare of grazed pasture. The First Australian Maize Conference was held in southern NSW in 1991 and this led to the formation of the Maize Association of Australia. This industry body will convene regular national conferences which should improve co-ordination of national R and D on maize forage. This review assesses the role and potential for forage maize in Australia and briefly describes some of the projects reported and issues raised in the proceedings of the First Australian Maize Conference (Moran 1991). Summaries of Australian research are also reported by Moran et aZ. (1990) and in the legume contract by Stockdale in these proceedings. BEEF PRODUCTION FROM FORAGE MAIZE A. G. KAISER N.S.W. Dept of Agriculture, Agricultural Research Institute, Wagga Wagga, N.S.W. 2650. Currently the principal users of maize silage for beef production are the feedlots located in NSW and southern Queensland. However with a growing awareness of the potential of the maize crop, its use by other sectors of the beef industry is likely to expand. THE NUTRITIVE VALUE OF FORAGE MAIZE In vivo estimates An important attribute of maize silage is its high energy content. A mean metabolisable energy (ME) content of 10.5 MYkg DM was determined for 26 maize silages in the U.K. (MAFF 1990) while Margan and Moran (1991) reported a value of 10.9 MJ/kg DM for a maize silage produced at Kyabram. Furthermore, Wagga Wagga data indicate that our maize silages can support cattle growth rates similar to those in Europe and North America. For 20 different maize silages, young growing cattle averaged 1.01 kg/day (Kaiser and Piltz, unpublished data). A potential growth rate of 1 kg/day is consistent with a ME content of approximately 10.5 MJ/kg DM. Variability in nutritive value Laboratory studies have shown that forage maize and silages with a predicted ME 2 10 MJ/kg DM can be produced in a wide range of Australian environments (Kaiser et al. 1991), but there is evidence of significant variation. Similar variation has been observed in in vivo studies with sheep, where DM 335 Proc. Aust. Sot. Anim. Prod. Vol. 19 digestibilities varied from 58.9 to 70.5% for 20 maize silages (Kaiser and Piltz, unpublished data). It is apparent from these and overseas studies (Schmidt et al. 1975; MAFF 1990) that maize silage can vary widely in quality. Sources of variation in nutritive value Some progress has been made in determining the sources of variation in digestibility. The effects of maize genotype and crop management have been reviewed recently (Kaiser et al. 1991). Less is known about the influence of environment and climate. For dryland crops, moisture stress is likely to depress digestibility by reducing crop grain content. However, the effect of other climatic factors (e.g. temperature, humidity, solar radiation) on the nutritive value of forage maize in the diverse Australian environment is unknown and should be investigated. Variations in experimental methods have undoubtedly contributed to some of the above differences. In feeding trials, animal performance and forage nutritive value could be depressed by low levels of nitrogen or minerals, poor ensiling technique and aerobic deterioration of the silage during feeding out (Wilkinson 1991). Digestibility could also be influenced by class of animal, level of feeding, silage chop length and failure to use true rather than oven DM content when calculating digestibility values. A large number of analytical procedures have been used to estimate in vitro digestibility and it is difficult to find any consensus in the literature on the most accurate method. Predicting ME content from digestibility also presents problems as the various recommended equations yield different results and may not even apply to forage maize. For example, at Wagga we have used the MAFF (1975) equation: ME = 0.16 DOMD%, while a more recent equation: ME = 0.18 DOMD% - 1.8 (Australian Agricultural Council 1990), where DOMD is the content of digestible organic matter in the feed, yields results approximately 0.5 MJ/kg DM lower. In both cases, DOMD can be estimated from digestibility of the dry matter or organic matter assuming an ash content of 5%. BEEF PRODUCTION FROM MAIZE SILAGE Maize silage plus supplementary urea and minerals can support growth rates of 1.0 kg/day in both weaner and yearling steers (Moran et aZ. 1990; Kaiser and Piltz unpublished data). Earlier work in South Australia (Hawthorne 1978) yielded lower growth rates (0.6-0.7 kg/day) but these silages were made from immature crops with DM contents of only 23%. Low DM contents can depress silage intake and hence animal performance (Wilkinson 1991). Maize silage-grain finishing diets Many studies have investigated the use of maize silage in finishing diets for steers and it is evident that carcasses and meat of similar quality can be produced on either high grain or high silage rations (Brennan et aZ. 1987). However, increasing grain levels on such diets have yielded variable results. For cattle under 350 kg, responses to additional grain have been disappointing, often not exceeding 1.2 kg/day on high grain diets (e.g. Brennan et al. 1987). With heavier cattle, growth rates up to 1.4 kg/day have been reported on maize silage/high grain diets. In recent Australian studies, the addition of 50% grain to maize silage/urea diets has raised growth rates to 1.2 kg/day (Kaiser, unpublished data; Wales and Moran, unpublished data). Protein levels in finishing diets The low protein content of maize silage can limit liveweight gain and this may account for some of the variation in animal responses to additional grain feeding. Most feeding standards indicate that rapidly growing steers, 300 kg or more liveweight, require no more than ll-12% dietary protein with a rumen degradability of about 90%. Some authors recommend protein levels up to 13.5%, but there are few data to support this higher level, especially once steers have reached 400 kg (Mowat et al. 1977). It is worth noting that soybean meal has been used in most work with maize silage and that few comparisons have been made with protein sources of varying rumen degradability. For younger cattle (150-300 kg), higher protein levels (13-15%) are recommended, especially for animals with high growth potential. For animals above 180 kg liveweight and gaining at 1 kg/day, urea can supply all the supplementary nitrogen for maize silage and UK recommendations are for urea to replace protein meals in maize silage-based finishing rations for steers greater than 250 kg (Wilkinson 1991). It is difficult to ascertain how reliably such North American and European data apply under Australian conditions because of differences in our crops and also the management of our feeder steers. Available evidence suggests that our higher yielding forage maize crops have lower protein contents (5-8%) than those produced overseas (i.e. S-10%). It is also likely that, prior to feedlot finishing, our feeder steers are maintained on lower (and more variable) planes of nutrition than their North American 336 Proc. Aust. Sot. Anim. Prod. Vol. 19 and European counterparts. This could have important implications when formulating finishing diets as their protein requirements could be greater, especially if they are lighter than 450 kg. Mowat et al. (1977) found steers in poorer condition at feedlot entry to require supplemental protein through to heavier liveweights than steers starting in good condition. It is then important to establish the level and type of protein supplements required in maize silage-based diets under Australian conditions to achieve growth rates of at least 1.2 kg/day. Maize silage to supplement grazing cattle Strategic supplementation with maize silage offers a means of finishing steers during periods of low pasture growth and at higher stocking rates. This was recently achieved at Kyabram (Wales et aZ. 1991) where steers given 2.4 kg DM/day of maize silage and grazing annual pastures at 5 steers/ha gained at similar rates to unsupplemented cattle grazing at 2.5 steers/ha. However, it was necessary to feed luceme hay to all steers due to an exceptionally wet winter. In a more recent trial, cattle grazing perennial pastures in autumn at 4 steers/ha and given 0.6 kg DM/day of maize silage gained at 0.80 kg/day compared with 0.59 kg/day for unsupplemented steers grazed at 2.7 steers/ha (Wales and Moran, unpublished data). Clearly, maize silage has considerable potential to supplement steers grazing good quality pasture. THE FUTURE In view of its high yield and nutritive value, utilisation of the maize crop within various sectors of the beef industry should expand. Satisfactory liveweight gain, feed conversion efficiency and carcass and meat quality (Brennan et aZ. 1987) can be achieved on maize silage-based diets. In addition, maize silage feeding does not influenced fat colour on either maize silage/grain (Kaiser and Auldist 1991) or maize silage-pasture systems (Wales et al. 1991). Two major issues which need to be addressed are firstly, management strategies to produce high yielding crops and high nutritive value silages and secondly, diet formulation (especially protein) to achieve high growth rates (in excess of 1.2 kg/day) in steers on maize silage/grain diets. DAIRY PRODUCTION FROM FORAGE MAIZE IN QUEENSLAND T. M. DAVISON, R. 2: COWAN and D. V KERR Queensland Dept of Primary Industries, Mutdapilly Research Station, Ipswich, Qld 4305. The potential for maize silage in dairy feeding systems in northern Australia has been recognised for many years. Forage maize is well suited to major sub-tropical dairying areas, particularly where irrigation is used, and where farmers have a tradition of cropping. Milk yield in nearly all situations is well below cow potential and the production of large amounts of maize silage should substantially increase farm productivity. Furthermore, this extra milk attracts a stable and relatively attractive price. Why then has adoption been slow? The adoption of other technologies, such as irrigation, temperate pasture and nitrogen fertiliser, has been much more rapid. We believe farmers see maize silage as changing their whole way of life, that it is introducing a new system of production. It is not sufficient to point to advantages in some aspects, such as forage yield or effects on milk quality, but we need to provide data on how the system as a whole works. The financial restraints and returns, the replacement of grazed pasture or crop, feeding out and supplementation are some of the more important aspects which need to be linked together in giving advice. ON-FARM PRODUCTIVITY Because the use of maize silage stimulates a large number of changes in a farming system, it is not possible to obtain realistic estimates of productivity increases from small, isolated studies. We have developed a computer model based on time series analysis and using historical records of individual farms. This model can predict production if a major change in management had not been made. This value is, in effect, a control to compare with present production. Comparisons of these 2 values then give an estimate of change in production due to the use of maize silage. It is necessary that no other major changes in management occur during the period of study, in our case from 5 to 10 years. Three farms in south-east Queensland were studied, with an individual model being developed for each farm. In each case, there was substantial seasonal variation but a consistent increase in milk production, ranging from 21 000 to 150 000 L/farm.year. In addition to increases in production, there 337 Proc. Aust. Sot. Anim. Prod. Vol. I9 have been substantial changes in the pattern of milk output with the introduction of silage (Kerr et al. 199 1). Milk output during autumn and winter, periods when yields had previously been low, increased twofold compared with increases of about 20% during spring and summer. Another method of assessing the effects of maize silage on farm productivity is to compare those farms utilising this resource to those without. Several factors contribute to differences between these groups, but such comparisons are useful in describing the types of farms which have been successful in incorporating maize silage. For example among suppliers to the South Coast and Warwick Co-operative dairy factory in Queensland, 4 farms have consistently used large quantities of conserved maize, either as silage or haylage. They have larger herd sizes, higher milk production/cow and hence greater total outputs of milk than the average farm (Cowan et al. 1991). CASH FLOW Many farmers recognise the nutritional qualities of maize silage and the high yields obtained. However, it is clear that adoption will not be universal. Major concerns include: alternative technology may be easier, e.g. fertiliser on pasture, paddocks are out of production for up to 6 months while maize is being grown and harvested, machinery and equipment costs are relatively high, and organising labour at harvest time. Taking these 4 points together, farms which are not developed to their potential under grazing should not be modified to include maize silage. There is alternative technology available to increase their milk yields profitably, the costs for machinery are very low and there is no disruption to the farm routine. By contrast, farms which have developed to their potential under grazing have no alternative technology, but they often have a high cash flow and the versatility to remove an area from grazing without major disruption. Also the investment in machinery is a smaller proportion of turnover than it is in less developed farms. Consequently we see maize silage fitting a continuum of technology, where pasture development proceeds towards its potential before maize silage becomes relevant. Once relevant, maize silage is able to sustain continued increases in milk output. The cost of maize silage was obtained by surveying 4 farms using maize silage (Kerr unpublished data). Capital costs in the first year varied from $A6000 to $22 000. The cost of growing and ensiling the crop varied from $15 to $22/t of fresh silage. The total cost, including depreciation on machinery, was from 6 to 8 cents/kg DM. These values compare favourably with those used for many grazed forages as shown in Table 1. Table 1. Major forage types in Queensland, their potential milk production (L/ha) and cost (mean and range) in terms of milk produced (c/L) (Davison 1990) FEEDING SYSTEMS INCORPORATING FORAGE MAIZE Maize silage is deficient in protein and several minerals essential for milking cows. Minerals can be readily added as a supplement, usually in the grain-based concentrate given to cows, but the source of protein is critical. The most efficient source is grazed legume. A number of farms in Queensland have used the combination of grazing clover or luceme at night and feeding maize silage during the day. This offers a number of advantages including efficient use of grazed pasture, a supply of protein to complement maize silage, the opportunity to feed large amounts of maize silage and to reduce heat 338 Proc. Aust. Sot. Anim. Prod. Vol. I9 stress during hot weather. This system largely involves the provision of shade though there is now interest in the use of sprinklers. Urea is often used to increase the protein content of maize silage. Urea is usually added at ensiling although similar responses have been obtained when included with the silage at feeding. We have also observed responses to the inclusion of sodium bicarbonate in very wet diets. Where maize silage and irrigated pasture were the major dietary components, sodium bicarbonate increased yields of both milk and milk fat. Increasing the productivity of grazed forages will continue to boost milk output on the majority of northern Australian dairy farms. However the integration of maize silage into feeding systems is relevant to a steadily increasing number of farms where the potential under grazing is close to being reahsed. We would expect maize silage to be seen as a means of increasing total productivity and stabilising output. Herds will graze for approximately half the day then feed from a trough during the remaining time. Key characteristics of this system will be high milk production per cow and high total farm output of milk. DAIRY PRODUCTION FROM FORAGE MAIZE ON IRRIGATED FARMS IN NORTHERN VICTORIA AND THE RIVERINA J. L. I? LAWSON Dept of Food and Agriculture, Kyabram Research Institute, Kyabram, Vie. 3620. Maize silage has the potential to significantly increase the productivity of irrigated dairy farms in northern Victoria and the Riverina by allowing farmers to increase stocking rates and hence grazing pressures. It is, however, but one of many options for intensification competing for scarce farm resources. Therefore it is important for its adoption that on-farm limitations are identified, and that we identify how and where it can be used to maximise benefits to the dairy farmer. Much of the past Australian research has concentrated on the growing, storing and feeding maize silage in conjunction with high quality legume pastures. These and overseas studies have clearly identified a potential for maize silage to improve milk production in Australia. However this potential cannot be fully realised until the technology has been further developed and proven effective on-farm in our environment. Farmers are traditionally cautious in adopting new technology. This combined with their scarce financial resources, has resulted in a relatively slow rate of adoption of feeding maize silage. The issue of slow rates of adoption and the need to develop practical farming systems integrating maize silage is currently being investigated through a dairy industry funded Maize Development Project at Kyabram. It was established following consultation between Victorian government research and extension officers, local dairy farmers and private consultants. The project involves a multi-disciplinary team of dairy nutritionists, pasture specialists, dairy extension officers and producers. Dairy farmers are involved at all levels of the development process extending from the organisational level through to invaluable field-based feedback. The aim of the project is to identify on-farm limitations to the feeding of maize fodder and to assist dairy farmers currently feeding maize silage to use it more effectively. This is being attempted through maize feeding discussion groups, a quarterly newsletter (Maize Team News) and on-farm monitoring. The project not only complements past and current research but is likely to influence future research priorities. ON-FARM LIMITATIONS Barriers identified to date include the capital investment required, the extra workload and the need to more precisely balance the total diet of grazing cows, particularly those grazing mixed pastures. Cost competitiveness with alternative intensification options also has a major impact on the use of maize onfarm. Capital investment The capital investment needed to feed maize is the first and most obvious barrier to adoption. Although many dairy farmers recognise the need to improve productivity, they believe that this should be by the lowest cost system possible. They are often deterred from feeding maize silage by the need to purchase a front-end loader ($2500) and feedout wagon ($2000 to $16 000) and to construct storage 339 Proc. Aust. Sot. Anim. Prod. Vol. 19 bunkers ($500 to $5000) and a feedpad ($5000), the latter to avoid excessive wastage. Earle (1991) has, however, shown that reducing total farm costs does not necessarily lower the unit cost of production. Once farmers invest in a system, there are economies of scale. Therefore when feeding maize silage, farmers should not dabble but do it properly. Furthermore, these investments can be utilised for other farm operations, such as storing pasture silage in the bunkers and feeding out pasture hay or silage on the feedpad. The maize feeding discussion groups provide a useful forum for farmers to discuss issues relating to capital investment and for the transfer of some very handy tips as a result of other' experiences. s Newsletter articles also provide technical advice on bunker and feedpad designs. Labour input Undeniably feeding maize silage involves more work then simply feeding pasture or grain in the dairy. A well designed farm with storage bunkers close to the feed area, all weather access and reliable equipment will considerably reduce time spent feeding out maize silage. It is not uncommon for farmers to require only 30 to 45 min to feed their 150- to 200-cow herd each day. Nutritional knowledge Probably the greatest barrier to adoption is the variable on-farm milk responses to maize silage feeding. All too often the comment is made that the cows liked the maize and ` well on it' but for did , very little, if any, extra milk. Farmers expect additional milk through feeding supplements. Consequently poor milk responses have generated considerable disillusionment amongst farmers. These poor on-farm milk responses can generally be attributed to the nutritional limitations of feeding maize silage to cows grazing mixed grass-clover pastures of variable protein content. Research at Kyabram (Stockdale and Beavis 1988) has shown improved milk responses when feeding maize silage in conjunction with Persian clover (21% protein) pastures than on mixed 75% ryegrass-25% white clover (16% protein) pastures. Pasture protein per se therefore has a big effect on milk responses to maize silage (68% protein). The situation is further complicated by the fact that maize silage is generally fed during autumn when pasture protein levels are at their lowest. Protein deficiency can be further exaggerated if the silage is fed together with a low protein cereal grain. To overcome variable milk responses, farmers need a better understanding of cow nutrient requirements at different stages of lactation and, more importantly, how to provide them from their available feed supplies. Unfortunately a history of an almost complete reliance on pasture-based production systems often means that such skills are lacking. Only recently have farmers begun to feed supplements, namely grain (and now maize silage) to their milking herds. As more and more pasture (a relatively well balanced feed) is replaced by supplements, there is a greater need to ensure that the herd' diet is nutritionally balanced. This places increasing demands on managerial skills and often s requires a whole new way of thinking. Consequently within the discussion groups and in the newsletter, a great deal of attention is given to the fundamentals of dairy nutrition and feed quality. Balancing the diet One major difficulty encountered when calculating total diets for grazing cows is knowing the quantity and quality of grazed pasture. The project is assessing methods to overcome this limitation. Pasture metres are used in the discussion groups to estimate pasture intake (kg DM actually eaten). Harvesting pasture quadrats (pre and post grazing) for protein and energy analyses helps farmers to more accurately estimate pasture quality. The level of supplement fed is relatively easy to determine while its quality can be obtained using commercial feed testing services. Feedback to date has been very encouraging with more farmers now aware of the importance of total dietary protein. Many farmers are experimenting with feeding more protein during periods of maize silage feeding by grazing cows on subclover pastures or supplementing them with subclover silage, high protein grains or pellets. Some are also incorporating urea into their maize silage. ON-FARM MONITORING One important aspect of the project has been the information collected from 5 monitor farms across the northern Victorian irrigation area. Total feed inputs and milk production were recorded on each farm over 1 full week in spring (October), summer (January-February), autumn (April) and winter (June) during the 1990-91 lactation. Daily pasture allocation and intakes have been calculated from pre and post grazing pasture yields, paddock area and herd size. From data on intake and quality of pasture and supplements, together with changes in pasture protein due to grazing, dietary protein can be calculated. The monitoring is providing valuable on-farm data to help understand how farmers are integrating maize silage into their particular farming system. To date, 2 aspects that stand out as having a major 340 Proc. Aust. Sot. Anim. Prod. Vol. 19 impact on its efficiency on-farm available pasture. firstly, the quality of feedstuffs secondly, the utilisation of Feed quality The dramatic effect of feed quality on milk responses to feeding maize silage observed in the monitoring reinforces the importance of balancing diets for protein as well as energy. There is a wide range of supplements fed throughout the year and their quality and ability to meet herd requirements are receiving close attention. The ability of grazing cows to select diets higher in quality than those available is of particular interest. Pasture utilisation For efficient use of supplements, it is essential that the pasture is well utilised and that substitution of the supplement for pasture is minimised. Pasture utilisation is calculated from the amount of pasture eaten as a proportion of that on offer. This must also take into account the pasture too close to ground level for effective grazing. Pasture utilisation on the monitor farms averaged 60% which is similar to that recorded on other dairy farms in northern Victoria; an efficient level is 70% or better. Utilisation is influenced by stocking rate, season and the level of supplementation. Utilisation was measured on 1 farm in spring to be 81% with cows producing 22 L milk/day and fed no supplements. At the same time, supplements were fed on a second monitor farm which recorded only 54% pasture utilisation and milk yields of 21.8 L/day milk. Clearly pasture, the cheapest feed resource, was being wasted on the second farm. In autumn, both farms fed maize silage and had 70% utilised pasture. CONCLUSIONS It is too early to draw final conclusions, but it appears that protein in the total diet and pasture utilisation are likely to be problem areas when feeding maize silage on farm. Aspects such as these are central to the successful integration of maize silage into dairy operations in irrigated southern Australia. DEVELOPING A FUTURE FOR FORAGE MAIZE J. B. MORAN Dept of Food and Agriculture, Kyabram Research Institute, Kyabram, Vie. 3620. Basic research into the successful integration of maize silage into Australian pasture-based dairy and beef systems has still to be done. For example, at Kyabram we are currently measuring milk production and rumen metabolism in dairy cows fed white clover-based pastures together with maize silage and additional energy and protein supplements. We are also determining optimum levels of maize silage to feed during different seasons for year-round, pasture-based beef production. Furthermore, our on-farm dairy project has identified the importance of farmers being able to describe pasture quality more accurately to optimise levels of maize silage feeding to grazing cows. Other Kyabram scientists are developing lower cost systems for growing forage maize to help overcome one of the greatest limitations to its acceptance by the cattle industry, namely high production costs. Contract grown forage maize is available in certain areas, such as in the beef feedlots regions of southern Queensland and northern NSW and in the irrigated dairying areas in northern Victoria. Although more expensive than ` home grown' maize, it allows producers to concentrate on their livestock rather than to diversify into cropping. In Davison' paper in this contract, the total cost in s Queensland, including depreciation of machinery, for maize silage was $60-80/t DM while in Victoria, Donohue (1991) costs forage maize (in the bunker) at $81/t DM, including the opportunity cost of lost pasture production. In contrast, Earle (199 1) quotes a purchase price of $70/t DM for the standing crop plus an additional $40-50/t DM for harvesting and cartage, making a total of $110-120/t DM to get maize into the buyer' silage bunker. The purchase price of contract grown maize forage will vary with s the returns from other cash crops but it should reflect the costs of alternative supplements as well as the supply and demand for maize greenchop in the area. Whether it is cheaper for small dairy farms to grow or purchase their forage maize requirements depends on many factors, such as the size of their operation, the number of labour units, the seasonality of their milk production, the availability of contract growers and of most importance, the cost of the 341 Proc. Aust. Sot. Anim. Prod. Vol. I9 purchased forage maize and other feedstuffs. The availability of contractors to sow and harvest the crop could well be the deciding factor. Unfortunately contractors will not commit themselves to buying specialist machinery without being assured of customers and potential new growers often don' start t because there are no suitable contractors in their area. The above papers highlight some of the pitfalls faced by farmers wanting to feed forage maize prior to more effectively utilising their cheapest feed, namely their pastures, and also trying to ` it on the do cheap' Optimum stocking rates will vary in different regions depending on whether the dairy farm is . supplying ` quota' milk, the climatic constraints and the pasture species. However to minimise pasture substitution, farms should be well stocked. Grazing management for beef cattle is less precise than for dairy cows and hence pasture substitution would be more of an issue, although in most cases an unrecognised one. These papers also show the short lead time between much of the industry supported research and its application by producers. What took decades to develop in