The Clean, Green and Ethical Concept in Animal Production

Transcripción

1 Agrociencia (2009) Vol XIII N 3 - Número especial pág The Clean, Green and Ethical Concept in Animal Production Martin, G.B. 1 1 Institute of Agriculture, Faculty of Natural and Agricultural Sciences M082, The University of Western Australia, Crawley 6009, Western Australia, Australia. graeme.martin@uwa.edu.au Summary In response to changes in society and thus the marketplace, animal industries need to become clean, green and ethical (CGE). To be clean, the industries need to minimise the use of drugs, chemicals and exogenous hormones. To be green, the industries need to minimise their impact on the environment. To be ethical, the industries need to avoid practices that compromise animal welfare. Importantly, CGE practices must apply to all participants in the supply chain, from producer to consumer. This paper presents our approach for CGE management of small ruminants on farms in Australia, a context that is directly relevant to the Uruguayan sheep industry because there are so many common aspects in livestock management in the two countries. The major topics are: 1) control of the timing of reproductive events by using socio-sexual signals (the male effect ); 2) focus feeding short periods of nutritional supplementation that are precisely designed for each event in the reproductive process; 3) nutritional pharmacology the possibility of using forages containing bioactive compounds to improve health, efficiency and environmental impact; 4) maximizing offspring survival by a combination of management and nutrition; 5) genetic selection to improve reproductive efficiency and animal heath. These tools involve novel ways of manipulating the endogenous control systems of the animals and many of them can be applied to cattle production systems. Ultimately, CGE management can be cost-effective, increase productivity and, at the same time, greatly improve the image of meat and milk industries in society and the marketplace. Key words: animal ethics, sustainable production, biostimulation, reproduction, nutrition Resumen El Concepto Limpio, Verde y Ético en Producción Animal En respuesta a los cambios en la sociedad y por lo tanto en el mercado, las industrias animales necesitan hacerse limpias, verdes y éticas (LVE). Para ser limpias, las industrias necesitan minimizar el uso de drogas, químicos y hormonas exógenas. Para ser verdes, las industrias necesitan minimizar su impacto en el ambiente. Para ser éticas, las industrias necesitan evitar las prácticas que comprometen al bienestar animal. Es importante que las prácticas LVE apliquen a todos los participantes de la cadena industrial, desde los productores hasta los consumidores. Este artículo presenta nuestra aproximación al manejo LVE de pequeños rumiantes en establecimientos en Australia, un contexto que es directamente relevante para la industria ovina del Uruguay, dado que hay muchos aspectos comunes en el manejo de ganado entre los dos países. Los temas principales son: 1) control del momento de los eventos reproductivos usando señales socio-sexuales (el efecto macho ); 2) alimentación enfocado períodos cortos de suplementación nutricional que son diseñados específicamente para cada evento en el proceso reproductivo; 3) farmacología nutricional la posibilidad de usar forraje que contiene compuestos bioactivos para mejorar la salud, la eficiencia y el impacto ambiental; 4) maximizando la supervivencia de las crías por una combinación de manejo y nutrición; 5) selección genética para mejorar la eficiencia reproductiva y la salud animal. Estas herramientas implican nuevas maneras de manipular el sistema endógeno de control de los animales y, muchos de los mismos pueden ser aplicados a sistemas de producción de ganado. Por último, el manejo LVE puede ser rentable, aumentar la productividad y, al mismo tiempo, mejorar enormemente la imagen de las industrias carniceras y lácteas en la sociedad y el mercado. Palabras clave: ética animal, producción sustentable, bioestimulación, reprodución, nutrición

2 2 Martin, G.B. AGROCIENCIA Introduction In response to changes in society, and thus the marketplace, we have developed a vision for the future of our animal industries in which management practices are clean, green and ethical (CGE): Clean reduced usage, if not elimination, of practices that depend on drugs, chemicals and exogenous hormones; despite the lack of scientific evidence in many cases, the market is a dominant force and often does not always follow logic or evidence; Green minimal damage to the environment, making the industry more sustainable for the long-term. On farms, the most important are ruminant production of greenhouse gases, production of animal waste, and excessive use of fertilisers to generate animal feeds. The need to minimise environmental impact also applies to the allied industries those that participate in the processing of the products from the farm (eg, transport, abattoirs, milk factories); Ethical the obvious focus is the attitude of the industry to animal welfare, a major concern for all industries that are working in sophisticated markets where the consumers expect their products to be derived from animals that have been managed sympathetically. This can be a complex issue because a clean image may involve avoiding the use of antibiotics, perhaps compromising animal welfare. In addition, ethical standards will vary among cultures. Finally, ethical judgement needs to be applied to more than animal management it should include clean and green aspects of the transport, manufacturing and processing sectors. We need look no further than the milk melamine crisis in China to see the potential dangers. In many countries, regulatory authorities have already imposed these conditions on producers, importers and exporters. This has been necessary to overcome resistance in the industry, yet clean, green and ethical need not be difficult or costly. On the contrary, at farm level, CGE management can be developed from a better understanding of the animals and can improve productivity and profitability. Moreover, there is a strong positive aspect in the demand for CGE products from modern, high-priced markets in which consumers have discretionary spending power that widens profit margins. In this paper, we present our approach for CGE management in small ruminants. We will focus on five possible strategies: 1) Control of the timing of reproductive events by using socio-sexual signals (the male effect ) to induce synchronised ovulation in females; 2) Focus feeding - short periods of nutritional supplementation that are precisely timed and specifically designed for each event in the reproductive process; 3) Nutritional pharmacology a term that reflects the possibility of using forages containing bioactive compounds to improve rumen health and efficiency with environmental benefits through the reduction of methane emissions from ruminants; 4) Maximizing offspring survival by a combination of management and nutrition; 5) Genetic selection for fertility, fecundity, behaviour and health. These tools involve novel ways of manipulating the endogenous control systems and production of animals, so the paper will begin with a short review of that topic. Our context may be Australian but is relevant to Uruguayan livestock industries because there are so many aspects in livestock management are common to the two countries. In addition, the CGE concept can be extended to other industries, such as beef cattle. This paper has been developed from others on the topic, particularly: Martin et al., 2004; Martin and Kadokawa 2006; Scaramuzzi and Martin 2008; Martin et al., CGE Reproduction in Small Ruminants The productivity and profitability of our meat and milk industries depend on reproductive performance. For over 100 years, we have been trying to improve reproductive output by developing exogenous hormone regimens, high-level reproductive technology and molecular genetics. We now have some remarkable and effective technologies, but they do not always impress modern consumers and they have little direct, short-term benefit for animal industries in extensive production systems (Martin, 1995; Martin et al., 2004). Our Approach We concentrate on the natural control systems that have evolved in the animals so they can cope with environmental challenges and ensure reproductive success (Martin, 1995). Most important are inputs from the external environmental factors. At brain level, these external inputs ultimately converge with internal inputs and culminate in a final common pathway that controls the secretion of gonadotrophin-releasing hormone (GnRH; Fig. 1). Each input into the control of the reproductive system provides us with an opportunity for management.

3 The Clean, Green and Ethical Concept in Animal Production 3 Socio-Sexual Signals especially pheromones?? Photoperiod Energy Supply Auditory System Olfactory System Vision System Pineal System GnRH Pulsar GnRH? Preoptic-hypothalamic continuum Appetite Control Centres GnRHindependent Mammary gland GnRHdependent LH, FSH Gametes Negative feedback Sex steroids Leptin, Insulin Uterus and Fetoplacental unit Gametogenic Endocrine functions functions Gonad Nutrients, Metabolites and Metabolic hormones Colostrum, Milk Figure 1. Environmental inputs into reproduction operate through a variety of pathways, many of which ultimately affect the «pulsar» (Martin, 1984) that controls the pulsatile secretion of GnRH. Socio-sexual signals are primarily pheromonal (Hawken et al., 2009) and work through the main olfactory system (Delgadillo et al., 2009). Nutritional signals are received at brain level via multiple pathways and affect a range of neural systems that affect the reproductive centres (Blache et al., 2007), but there are also nutritional and metabolic inputs directly into reproductive tissues (Scaramuzzi and Martin, 2008). 1) Control of the timing of reproductive events Three aspects of timing prevent the producers from deciding when their animals will conceive: puberty, seasonal breeding, and postpartum anoestrus. In all three situations, the lack of ovulation is due to lack of GnRH output, so exogenous hormones can be used very effectively to overcome the problem, but they raise issues of danger to human health ( clean ) and pose risks with liberation of sex steroids into environment ( green ) with, for example, the disposal of used intravaginal devices. Expense is also a problem because the treatments are too costly for extensive management systems. Finally, as we shall see below, control of timing is a major impediment for the implementation of focus feeding. For these reasons, we need an efficient, nonpharmacological method for accurately controlling the timing of reproductive events. a) The male effect In sheep and goats, the sudden introduction of novel males can induce ovulation in females that are reproductively quiescent because they are pre-pubertal, out of season, or lactating (review: Ungerfeld, 2007). The male effect can therefore be used to advance puberty, overcome seasonal anoestrus and shorten postpartum anoestrus. Most importantly, the induced ovulations are sufficiently synchronised among a group of females to allow the use of strategies such as AI, focus

4 4 Martin, G.B. AGROCIENCIA feeding (see below) to improve litter size, fetal programming and neonatal survival. For cattle, there is also strong evidence of a male effect (review: Ungerfeld, 2007) but far more research is needed to explore its potential as a management tool. b) Changing the night-length This could be attractive for small producers because it requires a relatively small investment. There are limits for females because they would begin to cycle over a range of days or even weeks, and farmers with relatively large flocks do not have the facilities to control night lengths. It is a far more attractive proposition for treating males so that their reproductive axis is working at maximum efficiency when they are used for mating or for the male effect (Delgadillo et al., 2002). c) Ultrasound Skilled operators with modern instruments can provide two important types of information (Viñoles et al., 2009b). First, identification of single-bearing and multiple-bearing females allows the use of strategies to manage their specific requirements during pregnancy and after parturition. Second, accurate estimation of fetus age allows the use of precisely timed nutritional supplements during fetal development (see below). This is applicable to cattle as well as small ruminants. 2) Nutrition the concept of Focus feeding For all animal enterprises, there is constant economic pressure to reduce the amount of feed used and then to ensure that the feed available provides the greatest benefit. With this in mind, we can focus on boosting sperm production, maximising potential litter size, programming offspring productivity, and maximizing postnatal survival and development (Fig. 2). For each period of focus feeding, we need to consider both the composition and duration of the diet so they are costeffective for the various enterprises and environments. At any or all of these times, we could use conserved or stored feed or we could shift the entire reproductive process so that the critical periods are aligned with peaks and troughs in the availability of pasture. a) Maximize sperm production Feeding males a supplement for 8 weeks before mating will ensure maximum testicular size and sperm production (review: Martin and Walkden-Brown, 1995). An important issue here is the concept of «fit but not fat» males that are overweight and do not get exercise can perform poorly, even when they have maximum testicular mass (Combrink and Schoeman, 1993). Focus Feeding Periconceptual programming? Ovulation rate Sperm production Embryo survival ŅBloomfield periodó? Fetus and Placenta Š fetal programming???? Colostrum production Postnatal and weaner nutrition Š growth, maturation, puberty Weeks Mating Pregnancy Birth Lactation Wean Male Effect, Short Mating Genetics of Ovulation Rate Fetus age by Ultrasound Birth Environment; Genetics of Lamb Survival Figure 2. A CGE Package for managing reproduction in sheep: periods of focus feeding are used to control the reproductive process, mostly to improve reproductive success. Mild undernutrition during the peri-conceptual period (15% loss of body mass) can cause premature births. To accurately time the periods of feeding, mating must be controlled and brief, or ultrasound must be used to classify the mothers based on the age of their fetuses. Finally, the survival of the new-born must be maximised by a combination of good genetics and good management. Redrawn after Martin et al., 2004.

5 The Clean, Green and Ethical Concept in Animal Production 5 b) Maximize potential litter size (ovulation rate) The upper limit of prolificacy, and thus productivity, is determined by the ovulation rate. For small ruminants, the upper limit is determined genetically and so can be improved through selection, but the expression of that genetic potential is greatly influenced by the nutritional regime before mating (review: Scaramuzzi and Martin, 2008). This is evident from the correlations between body condition and litter size but, more importantly in the context of focussed feeding, there is also an acute effect feeding a supplement for as little as 4 days in the final stages of the oestrous cycle will increase the frequency of twin ovulations by 20-30% (Viñoles et al., 2005; 2009a). The same can be achieved using highquality pasture (Viñoles et al., 2009a). In cattle, ovulation rate is a difficult problem and nutrition and genetics have very little influence. c) Fetal programming the future productivity of the offspring At least three aspects of sheep production are known to be affected by the nutrition of the mother during fetal life (review: Martin et al., 2004): i) initiation and development of secondary follicles in the skin; ii) muscle fibre formation; iii) development of the reproductive axis. d) Colostrum production and survival of the new-born An energy supplement given in the last week of gestation can more than double the amount of colostrum available to lambs at birth (review: Banchero et al., 2006). In addition to the nutritional and immunological benefits, colostrum in the gut improves the lamb s ability to recognise its mother, thus contributing to the establishment of the ewe-lamb bond (Goursaud and Nowak, 1999). The outcome is better neonatal survival (Goodwin and Norton, 2004). 3) Nutritional pharmacology For a ewe, there is little strategic sense in responding to an acute, finely-timed supplement (eg, 500 g lupin grain daily for 3 days during the final 3-6 days of the late luteal phase) by doubling her fecundity with all the risks that are incurred 5 months later. It is difficult to imagine that this is a normal biological response developed during evolution. It therefore seems likely that this type of supplement deceives the reproductive control systems so that they respond in the same way as they would to a sustained period of good nutrition leading to heavy body reserves. This has led us to the concept of nutritional pharmacology (Martin et al., 2008). We have since developed a second aspect to the topic (see below) based on the possibilities of bioactive compounds in forage that might improve health and productivity. a) Energy supplements and down time in reproduction There needs to be a drive to advance the first conception. In addition to increasing the rate of genetic gain by reducing generation interval, early conception will reduce overall methane emissions because females that do not breed continue to produce methane, increasing greenhouse gas production per unit of meat or milk. This magnifies the consequences of delayed puberty and first conception, extended postpartum anoestrus, and offspring mortality. It requires research, development and adoption to overcome farmer scepticism (Kenyon et al., 2004) on factors that delay puberty and cause low fertility in young animals. It is possible that a combination of focus feeding and the male effect is the way forward. b) Bioactive compounds in forage plants Some forage plants add value because they provide bioactive substances in addition to energy and protein. The rumen and its microbial community are a key focus of our attention because rumen fermentation is associated with many inefficiencies and production losses, such as methane production and microbial digestion of valuable dietary protein. Moreover, some gut microbes are associated with enteric diseases and rumen disorders such as lactic acidosis and bloat. Antibiotics have been used widely in farm animals because they can control the microbes responsible for these inefficiencies, diseases and disorders, and they act as growth promoters. This practice has already been banned in Europe. Alternative plants, mainly perennial shrubs, are being investigated for their potential to improve rumen function and gut health, reduce methane production, inhibit helminths, reduce ruminal biohydrogenation and lactic acidosis (see Martin et al., 2009). 4) Maximizing offspring survival A major issue in reproductive efficiency is mother young interactions, particularly in sheep, because of the very high rates of lamb mortality that were typical for the Australian Merino, with the obvious consequences for economics, genetics and ethics. There is little doubt that, in the future, it will be seen as unethical to promote high birth rates if our management systems cannot

6 6 Martin, G.B. AGROCIENCIA ensure that the new-born can survive and prosper. The use of focus feeding to improve colostrum production has been described above. There is also a great need for better management practices at the time of birth we need to provide a calm environment, and shelter, feed and water close to the birth site. This will increase the amount of time the mother spends at the birth site and therefore improve the development of the motheryoung bond (Nowak, 1996). 5) Genetic selection for fertility, fecundity, behaviour and health For the past 15 years, we have used genetic selection for temperament to produce two experimental lines: calm and nervous. Early on, this project suggested that calm ewes are better mothers than nervous ewes (Murphy et al., 1994). There is also scope for selection of lamb survival as a trait itself as means of reducing neonatal mortality (see Sawalha et al., 2007). The temperament project extends to other stress-affected aspects of the production process: reproduction, growth rate, immune function, milk yield, meat quality. In all of areas, better temperament is expected to improve productivity while giving our industries an ethical quality (D. Blache, Pers. Comm. 2009). Because of increasing resistance of parasites to pharmacological treatments, there is also interest in developing parasite-resistant sheep. For example, selection for the resistance to gastro-intestinal nematodes has been quite successful (Karlsson and Greeff, 2006). Conclusions Understanding the reproductive responses of animals to environmental factors, such as nutrition, socio-sexual signals and stressors, can help us develop natural systems as replacements for exogenous hormones and drugs for controlling and improving the productivity of our sheep and goats. In addition, we can easily genetically improve our animals (eg, ovulation rate, lamb survival, parasite resistance) to greatly improve many aspects of their productivity. The use of such CGE tools in the management of our animals can be costeffective and improve profits, at the same time greatly improving the image of our industries in society and the marketplace. All we need is a little more research and development. References Banchero, G.E.; Perez Clariget, R.; Bencini, R.; Lindsay, D.R.; Milton, J.T.B. and Martin, G.B Endocrine and metabolic factors involved in the effect of nutrition on the production of colostrum in female sheep. Reprod. Nutr. Develop. 46: Blache, D.; Chagas, L.M. and Martin, G.B Nutritional inputs into the reproductive neuroendocrine control system a multidimensional perspective. In: Reproduction in Domestic Ruminants VI. Edited by Juengel, J.I., Murray, J.F. and Smith, M.F. Nottingham University Press, Nottingham, UK. pp Combrink, G.C. and Schoeman, S.J The influence of exercising rams on the lambing performance of a Merino flock. S. Afr. J. Anim. Sci. 23: Delgadillo, J.A.; Flores, J.A.; Véliz, F.G.; Hernández, H.F.; Duarte, G.; Vielma, J.; Poindron, P., Chemineau, P. and Malpaux, B Induction of sexual activity of lactating anovulatory female goats using male goats treated only with artificial long days. J. Anim. Sci. 80: Delgadillo, J.A.; Gelez, H.; Ungerfeld, R.; Hawken, P.A.R. and Martin, G.B The male effect in sheep and goats revisiting the dogmas. Behav. Brain Res. 200, Goodwin, N. and Norton, B.W Improving doe nutrition immediately prior to kidding increases kid survival. Anim. Prod. Aust. 25: 233. Goursaud, A.P. and Nowak, R Colostrum mediates the development of mother preference by the new born lamb. Physiol. Behav. 67: Hawken, P.A.R.; Esmaili, T.; Scanlan, V.; Blache, D. and Martin, G.B Can audio-visual or visual stimuli from a prospective mate stimulate a reproductive neuroendocrine response in sheep? Animal 3: Karlsson, L.J.E. and Greeff, J.C Selection response in faecal worm egg count in the Rylington Merino worm resistant flock. Aust. J. Exp. Agric. 46: Kenyon, P.R.; Morris, S.T.; Perkins, N.R. and West, D.M Hogget mating use in New Zealand - a survey. Proc. N.Z. Soc. Anim. Prod. 64: Martin, G.B Factors affecting the secretion of luteinizing hormone in the ewe. Biol. Rev. 59: Martin, G.B Reproductive research on farm animals for Australia some long-distance goals. Reprod. Fertil. Dev. 7: Martin, G.B. and Walkden-Brown, S.W Nutritional influences on reproduction in mature male sheep and goats. J. Reprod. Fertil. Suppl. 49: Martin, G.B.; Milton, J.T.B.; Davidson, R.H.; Banchero Hunzicker, G.E.; Lindsay, D.R. and Blache, D Natural methods of increasing reproductive efficiency in sheep and goats. Anim. Reprod. Sci :

7 The Clean, Green and Ethical Concept in Animal Production 7 Martin, G.B. and Kadokawa, H «Clean, green and ethical» animal production. Case study: reproductive efficiency in small ruminants. J. Reprod. Develop. 52: Martin, G.B.; Blache, D. and Williams, I.H Chapter 10: The costs of reproduction. In: Resource allocation theory applied to farm animals. Edited by Rauw, W.M. CABI Publishing; Oxford, UK. pp Martin, G.B.; Durmic, Z.; Kenyon, P.R. and Vercoe, P.E Landcorp Farming Limited Lecture: Clean, green and ethical animal reproduction: extension to sheep and dairy systems in New Zealand. Proc. N.Z. Soc. Anim. Prod. 69: Murphy, P.M.; Purvis, I.W.; Lindsay, D.R.; Le Neindre, P.; Orgeur, P. and Poindron, P Measures of temperament are highly repeatable in Merino sheep and some are related to maternal behaviour. Anim. Prod. Aust. 20, Nowak, R Neonatal survival: contributions from behavioural studies in sheep. Appl. Anim. Behav. Sci. 49, Sawalha, R.M.; Conington, J.; Brotherstone, S. and Villanueva, B Analyses of lamb survival of Scottish Blackface sheep. Animal 1, Scaramuzzi, R.J. and Martin, G.B The importance of interactions among nutrition, seasonality and sociosexual factors in the development of hormone-free methods for controlling fertility. Reprod. Dom. Anim. 43 Suppl. 2, Ungerfeld, R Socio-sexual signalling and gonadal function: Opportunities for reproductive management in domestic ruminants. In: Reproduction in Domestic Ruminants VI. Edited by Juengel, J.I., Murray, J.F. and Smith, M.F. Nottingham University Press, Nottingham, UK. pp Viñoles, C.; Forsberg, M.; Martin, G.B.; Cajarville, C.; Repetto, J. and Meikle, A Short-term nutritional supplementation of ewes in low body condition affects follicle development due to an increase in glucose and metabolic hormones. Reproduction 129, Viñoles, C.; Meikle, A. and Martin, G.B. 2009a. Short-term nutritional treatments grazing legumes or feeding concentrates increase prolificacy in Corriedale ewes. Anim. Reprod. Sci. 113, Viñoles, C.; Gonzalez-Bulnes, A.; Martin, G.B.; Sales, F. and Sale, S. 2009b. Chapter 11: Small Ruminants. In: Practical Atlas of Ruminant and Camelid Reproductive Ultrasonography. Edited by Des Côteaux, L., Gnemmi, G. and Colloto, J. Wiley-Blackwell, Ames, Iowa, USA. In press.

8 8 Agrociencia (2009) Vol XIII N 3 - Número especial pág AGROCIENCIA Adaptability is Sustainability Provenza, F. D. 1 1 Department of Wildland Resources, Utah State University Logan E. mail: fred.provenza@usu.edu Summary The availability of fossil fuels will likely decline dramatically during the first half of the twenty-first century, and the deficits probably will not be alleviated by alternative sources of energy. This seeming catastrophe will create opportunities for communities to benefit from foods produced locally in ways that nurture relationships among soil, water, plants, herbivores and people to sustain their collective well beings. Agriculture will be much more at the heart of communities, but by necessity it will no longer be so dependent on fossils to fuel machinery or fertilizers, herbicides and insecticides to grow and protect plants in monocultures, antibiotics and anthelmintics to maintain the health of herbivores, or nutritional supplements and pharmaceuticals to sustain humans. Rather, from soils and plants to herbivores and people we will have to learn what it means to be locally adapted to the landscapes we inhabit. In the process, plants will become more important as nutrition centers and pharmacies, their vast arrays of primary (nutrients) and secondary (pharmaceuticals) compounds useful in nutrition and health. There also will be a need, as in times past before our heavy reliance on fossil fuels, to produce livestock in easy-care systems that match seasonally available forages with production needs, and that match animals anatomically, physiologically and behaviorally to local landscapes. This will mean reducing inputs of fossil fuels to increase profitability by 1) matching animal needs to forage resources, 2) selecting for animals that are adapted anatomically, physiologically, and behaviorally to local environments, 3) culling animals unable to reproduce with minimal help from humans, and 4) creating grazing systems that enhance the well-being of soils, plants, herbivores and people. Key words: adaptation, change, forages, fossil fuels, learning, livestock, people Resumen Adaptabilidad es Sustentabilidad La disponibilidad de combustible fósiles declinará probablemente dramáticamente durante la primera mitad del siglo veintiuno, y su déficit no será aliviado por fuentes alternativas de energía. Esta catástrofe aparente creará oportunidades para las comunidades de beneficiarse de alimentos producidos localmente y de forma que nutre las relaciones entre el suelo, el agua, las plantas, los herbívoros y la gente para sostener su bienestar colectivo. La agricultura estará mucho más en el corazón de las comunidades, pero por necesidad no será más tan dependiente de combustibles fósiles para maquinaria o fertilizantes, herbicidas e insecticidas para cultivar y proteger plantas en monocultivos, antibióticos y antihelmínticos para mantener la salud de los herbívoros, o suplementos nutritivos y farmacéuticos para sostener humanos. Mejor dicho, del suelo y las plantas a herbívoros y gente tendremos que aprender lo que significa estar localmente adaptado a los paisajes en que vivimos. En el proceso, las plantas serán cada vez más importante como centros de nutrición y como farmacias, siendo su plétora de componentes primarios (nutrientes) y secundarios (farmacéuticos) útil en la nutrición y la salud. También habrá necesidad, como en tiempos pasados, antes de nuestra pesada dependencia de combustibles fósiles, de producir ganado en sistemas de fácil cuidado que armonicen los forrajes estacionalmente disponibles con las necesidades de producción, y que armonicen a los animales anatómica, fisiológica y comportamentalmente a los paisajes locales. Esto implicará reducir el uso de combustibles fósiles para aumentar la rentabilidad al 1) adecuar las necesidades animales a los recursos forrajeros, 2) seleccionar animales que están adaptados anatómica, fisiológica, y

9 Adaptability is Sustainability 9 comportamentalmente a los ambientes locales, 3) refugar animales que no son capaces de reproducirse sin la intervención del hombre, y 4) crear sistemas de pastoreo que aumentarán el bienestar de los suelos, las plantas, los herbívoros y la gente. Palabras clave: Adaptación, cambio, forrajes, combustibles fósiles, aprendizaje, ganado, gente Introduction Sustainability is first and foremost about ongoing adaptation in ever changing environments. What might that mean in the twenty-first century? Many now argue that the availability of fossil fuels will decline considerably in the first half of the twenty-first century, and that the massive deficits will not be alleviated, even with all of the alternative sources of energy (e.g., Kunstler, 2005; Rubin, 2009). This seeming catastrophe will create opportunities as life changes from urban to rural, and the communities that emerge come to rely on foods produced locally, due to our inability to transport goods over the vast distances we currently do nationally and internationally. Agriculture will be much more at the heart of these communities than it is nowadays, but its lifeblood will not be fossils to fuel machinery or fertilizers, herbicides, and insecticides to grow and protect plants in monocultures, antibiotics and anthelmintics to maintain the health of herbivores, or nutritional supplements and pharmaceuticals to sustain the wellbeing of humans. Rather, from soils and plants to herbivores and people we will learn once again what it means to be locally adapted. We will of necessity nurture relationships among soil, water, plants, herbivores and people in ways that sustain the production, health and well-being of ecosystems and that make farming profitable and enjoyable. Plants will be used more as nutrition centers and pharmacies, their vast arrays of primary (nutrients) and secondary (pharmaceuticals) compounds useful in nutrition and health. Nature provides the creatures of this earth with a full range of benefits, including the nutrition and health of plants, herbivores, or people, without many of the costs we sustain nowadays due to our heavy reliance on fossil-fuel intensive fertilizers, herbicides, insecticides and antibiotics. Animals will need to be locally adapted to the landscapes where they will live from conception to consumption. If we continue to use ruminants as a source of food, there will be increased demand for livestock production from pastures and rangelands, as it requires only one third to one half the fossil fuel to produce a pound of beef from range as opposed to feedlots. We will again be required to produce ruminants on forages, as nature has done for millennia. There will be a need, as in times past before our heavy reliance on fossil fuels, to produce livestock in systems that match seasonally available forages with production needs, and that match animals anatomically, physiologically and behaviorally to landscapes. To take advantage of these benefits, we must learn to make the most efficient use of what nature provides when she provides it. Selecting for locally adapted animals Fossil fuels have enabled people and many of the wild and domesticated species of plants and animals that interact with us to exceed the carrying capacities of landscapes. In the process, people and the agriculture upon which we all rely have become dependent upon fossil fuels to power farm equipment (oil), synthesize nitrogen fertilizer (natural gas), and transport goods (oil) (Pollan, 2006). Low oil prices made it feasible to use high-input harvested forages and feed grains. At some point in the not-too-distant future, rising prices for oil and natural gas and demands for ethanol will increase grain prices to the point where it will no longer be feasible to finish animals on grain in feedlots. While they were meant to do the opposite, fossil-fuel-intensive practices have increased costs and adversely affected the environment during the latter half of the twentieth century. Cutting Costs by Mimicking Natural Processes Grassroots efforts in agriculture now emphasize cutting costs to maximize profits, and many people are developing management philosophies and practices based upon natural processes (Howell, 2008). They graze animals in ways that mimic natural grazing systems to sustain soils and plants. They retain only animals that can survive on what nature provides, without additional forage inputs, by selecting for locally-adapted animals and by culling animals unable to reproduce without help from humans. That makes sense ecologically and economically. It also makes sense behaviorally: behavior links ecology and economy by creating a match between what animals need and what is on hand.

10 10 Provenza, F. D. AGROCIENCIA While understanding animal adaptations to landscapes has always been an important aspect of the nutritional ecology of ruminants (Demment and Van Soest, 1985; Hofmann, 1988), until recently land managers have not attempted to put these ideas into practice. Instead, many people involved in academia, agribusiness, and livestock production have emphasized production at the expense of profit, without linking animals ecologically to the landscapes they inhabit. Thus, animals have been selected with nutritional demands that exceeded the capacity of the forage resource to meet their needs. This problem has been exacerbated by performance testing bulls and rams in confinement on concentrate rations, which likely has selected for animals that perform well in feedlots, but are not well adapted to finishing on pastures and rangelands. Nor have we appreciated that ongoing adaptation by wild and domestic herbivores involves a continuous dialogue among genes and behavior in ever-changing social and biophysical environments. Soil, plants, animals and the continents they inhabit change constantly. Even in the short span of time since the last glaciations (roughly 20,000 years), changes in climate have drastically altered physical environments and the species of plants and animals that inhabit those environs (Pielou, 1991). Rather than adapting to these changes, we have attempted with massive inputs of fossil fuels to eradicate «invasive» species of plants and animals. What would we have done when the species we now consider «native» were «invading» after the last glaciations? Likewise, we have attempted at great cost economically and ecologically to change landscapes to suit domestic animals, rather than considering how animals must continually adapt to the ever-changing availability of foods and habitats. With cattle and sheep in particular, we have attempted in vain with massive mechanical and chemical inputs to convert landscapes dominated by shrubs to grass to fit our conception of livestock as grazers, rather than selecting among and within breeds of livestock for individuals that can use the plants that exist on landscapes. While we often consider cattle to be grass eaters and sheep to be forb eaters, they can thrive under a wide range of conditions, including shrub-dominated areas in the arid southwest U.S., provided they have been selected anatomically, physiologically and behaviorally to survive on their own in the landscapes they inhabit (Provenza and Balph, 1990). We must take advantage of the marvelous variation within breeds to select for individuals able to perform efficiently on poor quality forages high in secondary compounds common in arid environments (Provenza and Balph, 1990; Provenza et al., 1992, 2003). In arid areas, that means selecting for animals of smaller frame size that better match the seasonal availability and diversity of forage supplies, and selecting for animals able to consume the diverse arrays of secondary compounds found in various species of plants now «invading» landscapes. Smaller frame sizes reduce the amount of food that must be consumed, which enables animals to better mix various plant species thereby allowing them to cope with the chemical and physical defenses abundant in plants that inhabit arid environments (Provenza, 2003b). Historically, people have selected for animals of uniformly large frame sizes and body compositions, enabled in arid areas by supplemental forages, as well as for meat flavor made homogeneous by finishing animals on high-grain diets. With the decline in fossil fuels, that will change as animals are produced and consumed locally, and as consumers acquire preferences for the flavors of animals produced from plants grown on local soils (Johns, 1994). Matching animal needs to seasonally available forage supplies also means mothers will have offspring when forage quality is highest in late spring or early summer, rather than when plants are mature and dormant in the middle of winter. Wild ruminants have adapted these reproductive behaviors to ensure they have ample nutrients during late gestation and early lactation, times when their needs are greatest. They must rely only on what nature provides each year, as living on fossil fuels is not an option. In the case of cattle (and sheep), the advantages of having offspring in synchrony with nature occur because 1) feed and labor costs are reduced by 70%, 2) most (90%) calves are born in the first 30 days of the calving season, without feeding any hay, and 3) more total pounds of calves are weaned, that are worth more per pound (Kit Pharo, www. PharoCattle.com). At Home on the Range: Learning to Adapt from Mother Since the dawn of the Age of Genetics, we have been taught that genes are destiny, and while genes certainly influence the expression of behaviors, it is just as true that behaviors influence the expression of genes. In that sense, genes learn from the environment (Lipton, 2005).

11 Adaptability is Sustainability 11 An important form of this discourse, termed predictive adaptive responses (PAR), refers to responses that are 1) induced by the environment early in life, 2) cause changes neurologically, morphologically, physiologically and behaviorally, and 3) confer survival advantages when the environment of rearing matches the environment where a young animal then lives (Gluckman et al., 2005). Predictive adaptive responses act via developmental plasticity early in life to modify the phenotype so it matches the environment of rearing, which is expected to be inhabited later in life. To the degree that PAR responses become fixed, there is some degree of risk of a mismatch between what has been expressed and what is actually needed to survive in an environment. Provided that environments do not change too quickly or radically relative to the lifespan of the individual, risk is low and gene expression helps ensure a match between a generation of organisms and the environment where they are born and reared. If, however, the fetus predicts its future reproductive environment incorrectly, either due to failure of appropriate transduction of the state of the environment from mother to fetus or because the environment changes radically from that predicted, the fetus will have increased risk of poor performance and disease. This is often the case as domestic and wild animals moved from familiar to unfamiliar environments suffer more than locally adapted animals from malnutrition, ingestion of poisonous plants and predation (Provenza and Balph, 1990; Provenza et al., 1992; Davis and Stamps, 2004). This disparity also occurs commonly when domestic animals are moved from rangelands to feedlots where the foods, social and physical environments all differ radically from what they have learned. These mismatches do not occur when animals are conceived, born, reared and die in familiar social and biophysical haunts. Given our pre-disposition to consider behaviors as fixed genetically, we have neither been aware nor appreciated the significance of predictive adaptive responses in humans (Gluckman et al., 2005) or in herbivores (Provenza, 1995b; Provenza et al., 2003). Nonetheless, experiences in utero and early in life cause a suite of changes involving gene expression, neurological, morphological, and physiological processes that affect behavior (e.g., Schlichting and Pigliucci, 1998; Lewontin, 2000; LeDoux, 2002; Moore, 2002; Dufty et al., 2002; Provenza and Villalba, 2006; Doidge, 2007). Learning from mother begins early in life as flavors of foods mother eats are transferred to her offspring in utero and in her milk, thus preparing the developing fetus for forages it will encounter after birth. The fetal taste system is fully functional during the last trimester of gestation, and flavors in mother s diet influence food preference of her offspring (Simitzis et al., 2008). For instance, the flavors of onion and garlic are transferred in utero and in milk, which increases the likelihood young animals will eat onion and garlic when they begin to forage (Nolte et al., 1992; Nolte and Provenza, 1992a,b). As offspring begin to forage, they further learn what to eat and where to go by following mother (Mirza and Provenza, 1990, 1992; Thorhallsdottir et al., 1990; Howery et al., 1998). Lambs fed nutritious foods like wheat with their mothers for as little as 1 hour/day for 5 days eat more wheat than lambs exposed to wheat without their mothers. Even 3 years later, with no additional exposure to wheat, intake of wheat is nearly 10 times higher if lambs are exposed to wheat with their mothers than if inexperienced lambs are exposed alone or not exposed at all (Green et al., 1984). Crossfostering studies show that young goats eat markedly more high-tannin browse if their mother eats high-tannin browse (Tzack et al., 2009). Young herbivores also learn motor skills needed to harvest grasses, forbs, and shrubs, all forages with different architectures (Flores et al., 1989a,b; Ortega-Reyes and Provenza, 1993a,b), they acquire preferences for foods (sheep - Nolte and Provenza, 1992a,b; Squibb et al., 1990; goats - Biquand and Biquand-Guyot, 1992), and their bodies adapt to using particular foods (Ortega Reyes et al., 1992; Distel et al., 1994, 1996). For instance, lambs exposed to saltbush in utero grow faster and handle a salt load better than lambs from mothers on pasture; they excrete salt more rapidly, drink less water, and maintain higher intake when eating saltbush (Chadwick et al., 2009a,b,c). Livestock also eat more of poor-quality forages they have learned to eat early in life with their mothers. Goats reared from 1 to 4 months of age with their mothers on blackbrush-dominated rangeland ate over 2.5 times more blackbrush than did goats naive to blackbrush. Moreover, experienced goats consumed 30% more blackbrush than inexperienced goats when allowed to choose between the poorly nutritious blackbrush and alfalfa pellets (Distel and Provenza, 1991). Likewise, intake and animal performance differed markedly during a 3-year study when cows 5 years of age were fed straw

12 12 Provenza, F. D. AGROCIENCIA as a major part of their diet from December to May (Wiedmeier et al., 2002). Half of the cows ate straw for 2 months as calves, whereas the other half had never seen straw. Throughout the study, experienced cows ate more straw, maintained better body weight and condition, produced more milk, and bred back sooner than cows not exposed to straw. Linking soil, plants, herbivores and people The health of landscapes depends on interrelationships among soils, plants, herbivores and people. Nearly 50 years ago, in a book titled Soils, Grass and Cancer, Andre Voisin (1959) highlighted these connections and warned that people, in our attempts to produce food for a burgeoning world population, have forgotten that our bodies come from the soil. To Voisin, it seemed that the rise of the artificial fertilizer industry has caused people to become so reliant on its products that we have forgotten our intimate relationship with the soil as nature made it, and that our adulterations of the soil from which we arise may be sealing our destiny as a species on earth. Though this quandary is little more than a century old, its progression has been geometric in the increase of diseases in plants, animals and humans due to overuse of artificial fertilizers applied to plants grown in monoculture. Conversely, soil developed naturally and rich in organic matter and nutrients provide the basis for health in plants, herbivores and people. Importantly, people can use grazing by livestock to generate soils rich in organic matter and nutrients and diverse in plants. Large herds of animals grazing at high stock densities for short periods of time add to soils organic matter and nutrients from feces and urine and the trampling of plants (McNaughton, 1984; Bryant et al., 1991, Savory and Butterfield, 1999, Augustine et al., 2003; Gerrish, 2004; Howell, 2008). Thus, herbivores can build healthy soils and increase the palatability of plants by providing conditions conducive for plants to grow rather than defend with excessive levels of chemical defenses. High stock densities also encourage herbivores to «mix the best with the rest» rather than to «eat the best and leave the rest» which can help to maintain plant diversity and prevent directional shifts in vegetation to landscapes dominated by one or only a few species of plants high in secondary compounds (Provenza et al., 2003; Provenza, 2003a,b). The Value of Plant Diversity Natural landscapes are diverse mixes of plants that occur in patches reflecting history of use in concert with particular soil, precipitation and temperature regimes. For plants, diversity is the rule for species, phenologies, growth forms and biochemistries. Regarding the latter, plants are nutrition centers and pharmacies with vast arrays of primary (nutrients) and secondary (pharmaceuticals) compounds useful in animal nutrition and health (Craig, 1999; Engel, 2002; Crozier et al., 2006). Eating a diverse array of foods is fundamental for nutrition and health. Given appropriate mixtures of plants, cattle, sheep and goats eat more and perform better when they are offered plants that contain secondary compounds (Provenza et al., 2007). Variety is so important bodies have built-in mechanisms that ensure animals satiate on foods eaten in a meal, which guarantees animals eat a variety of foods and forage in different locations (Provenza, 1995a, 1996; Bailey and Provenza, 2007). Variety enables animals to reap the benefits of ingesting various primary and secondary compounds and it also enables individuality. Bodies have the nutritional wisdom necessary to meet needs for energy, protein and various minerals (Provenza and Villalba, 2006), and to self-medicate (Villalba and Provenza, 2007). Offering animals choices in confinement, on pastures and rangelands allows each individual to meet its needs for nutrients and to regulate its intake of secondary compounds by mixing foods in ways that work for that individual (Provenza, 2003a; Provenza et al., 2003). Thus, variety not only enables individuality, it also greatly increases the likelihood of providing cells with the vast arrays of primary and secondary compounds essential for their nutrition and health. The Roles of Secondary Compounds in Nutrition and Health We know much about the roles of primary compounds in nutrition, but we are just beginning to appreciate the nutritional and pharmaceutical values of nature s pharmacy, the secondary compounds. All plants produce secondary compounds, even the plants we grow in our gardens, but until recently people thought secondary compounds were waste products of plant metabolism. Over the years, researchers came to understand the roles of nutrients such as nitrogen, phosphorus and potassium in plant nutrition, but they had no idea why these other compounds occurred in plants. We have learned much in the past 30 years about the roles of secondary compounds in the health of plants, including functions as diverse as attracting pollinators and seed

13 Adaptability is Sustainability 13 dispersers, helping plants recover from injury, protecting plants from ultraviolet radiation, and defending plants against diseases, pathogens and herbivores (Rosenthal and Janzen, 1979; Rosenthal and Berenbaum, 1992). At the same time we were learning of the value of secondary compounds, we were reducing their concentrations through selection to maximize yields of crops and pastures that were inevitably more susceptible to environmental hardships. In their stead, we resorted to fossil fuel-based fertilizers, herbicides and insecticides to grow and protect plants in monocultures, antibiotics and anthelmintics to maintain the health of herbivores, and nutritional supplements and pharmaceuticals to sustain the wellbeing of humans. Such systems corrupt the health of soils, plants, herbivores and humans and gradually degrade the economic and environmental health of landscapes. Ironically, we are now attempting to genetically engineer specific compounds with similar beneficial functions back into plants. Instead, we should be asking how and why nature grows plants in diverse mixtures with remarkable arrays of secondary compounds, and reconstructing pastures and grazing lands with assorted species that together enhance soil fertility, provide benefits of secondary compounds, and that vary in time of production, depths of rooting, and contrasting uses of water and nutrients (Provenza et al., 2007). For people, the biochemical composition of the meals we eat has become more uniform as the variety of foods in our diets has declined, and we no longer experience the benefits of eating an array of plant-derived secondary metabolites (Craig, 1999; Engel, 2002). With ready access to processed foods high in sugar, carbohydrates, fat and salt, young people no longer acquire preferences for «unpalatable» foods as they lack the traditional cultural foundations to guide their selection of foods high in secondary compounds (Johns, 1994). Conversely, hunter-gatherers who have maintained their traditional diets have far less cancer, heart disease, diabetes and osteoporosis than people who forage on fast foods, and it is not because hunter-gatherers die before these ills can develop (Logan and Dixon, 1994; Johns, 1994, Engel, 2002). Issues of diet mixing and secondary compounds are just as relevant for the nutrition and health of herbivores. While we have much to learn about plant mixtures and interactions among primary and secondary compounds, it is becoming increasingly clear that offering animals a variety of foods that not only meet their needs for nutrients, but that also provide a variety of secondary compounds, can enhance nutrition and health. As case in point, tannins are increasingly recognized as compounds important in health and nutrition, though historically they were thought by agriculturalists and ecologists alike to adversely affect herbivores. Eating plants high in tannins is a way for herbivores to reduce internal parasites (Min and Hart, 2003), and tannins alleviate bloat by binding to proteins in the rumen (Waghorn, 1990). By making the protein unavailable for digestion and absorption until it reaches the more acidic abomasum, tannins also enhance nutrition by providing high-quality protein to the small intestines (Barry et al., 2001). This high-quality-protein-bypass effect enhances immune responses and increases resistance to gastrointestinal nematodes (Niezen et al., 2002; Min et al., 2004a,b). The resulting increase in essential and branched-chain amino acids improves reproduction efficiency in sheep (Min et al., 2001). Tannins in the diet are a natural way to reduce methane emission in ruminants (Woodward et al., 2004), which is an important issue regarding ongoing efforts to diminish the influence of livestock on global warming. Finally, tannins eaten in modest amounts by herbivores can improve the color and quality of meat for human consumption (Priolo et al., 2005, 2008; Luciano et al., 2008). More generally, diverse assortments of secondary compounds in the diets of herbivores are likely to influence the flavor, color, and quality of meat, milk, and cheese for human consumption in ways that are positive, but as yet mostly unknown (Carpino et al., 2004a,b; Vasta et al., 2008a,b). Diet Sequencing and Complementarities among Secondary Compounds While complementarities among secondary compounds are an important but little understood area of plant-herbivore interactions, even less is known about how the sequences of eating plants with different compounds affects foraging, though they appear to be critical. Sheep eat much more food with terpenes when they first eat food with tannins (Mote et al., 2008). These findings are consistent with landscape-level studies that show ewes with a high preference for sagebrush, a shrub high in terpenes, also consume more bitterbrush, a shrub high in tannins, compared with ewes that have a lower preference for sagebrush (Seefeldt, 2005). While further studies are required to assess how sequence affects food consumption, these data indicate there is a strong effect. Likewise, cattle steadily decrease time eating endophyte-infected tall fescue when they first graze tall

14 14 Provenza, F. D. AGROCIENCIA fescue alone for 30 minutes followed by trefoil, alfalfa, or alfalfa-trefoil combination for 60 minutes (Lyman et al., 2009). Conversely, when the sequence is reversed, cattle forage actively on trefoil, alfalfa, or trefoil-alfalfa combination and then forage actively on fescue throughout the 90-minute meal. These patterns of foraging are similar with high-alkaloid reed canarygrass (Lyman et al., 2009). Sequence of ingestion thus greatly influences intake of alkaloid-containing grasses by cattle. Our research thus suggests eating tannin- and saponin-containing forages increases intake and may reduce fescue toxicity, which highlights the potential major impact of plant diversity generally and biochemical complementarities specifically. If legumes high in tannins and saponins can offset the negative effects of the alkaloids in tall fescue, the economic impact for beef producers coping with fescue toxicosis will be enormous. More generally, other toxic plant problems worldwide may benefit from similar research and applications of biochemical diversity. While this research is promising and suggestive of the importance of the interactions between forages with different secondary compounds, we are only beginning to understand the complexities involved in diet sequencing based on a limited number of forages and compounds. Conclusions What does it mean to be locally adapted to a landscape? It means reducing inputs of fossil fuels to increase profitability by 1) matching animal needs to forage resources, 2) selecting for locally adapted animals anatomically, physiologically, and behaviorally, 3) culling animals unable to reproduce without help from humans, and 4) creating grazing systems that enhance the well-being of soils, plants, herbivores and people. In essence, it means getting by with what nature provides. She gets her energy from the sun, she works with what she has on hand, and she provides a range of benefits (nutrition and health for plants, herbivores and people) without the costs (fertilizers, herbicides, insecticides, antibiotics and anthelmintics) of fossilfuels (Provenza et al., 2007). That makes sense even at today s prices for fossil fuels, and it will make more sense as the availability of oil and natural gas diminishes over the next 35 to 40 years, not only for people in agriculture, but for societies who want clean air, abundant water and healthful foods. Acknowledgements This work was supported by grants from the Utah Agricultural Experiment Station and the Agriculture and Food Research Initiative (AFRI), USDA. References Augustine, D.J.; McNaughton, S.J. and Frank, D.A Feedbacks between soil nutrients and large herbivores in a managed savanna ecosystem. Ecological Applications 13: Bailey, D.W. and Provenza, F.D Mechanisms determining large herbivore distribution. In press in F. van Langevelde and H.T.T. Prins (eds.) Resource Ecology Spatial and Temporal Dynamics of Foraging. Wageningen University Resource Ecology Group & Frontis, Wageningen. Barry, T.N.; McNeill, D.M. and McNabb, W.C Plant secondary compounds: their impact on nutritive value and upon animal production. Pages in Proc. XIX Int. Grass. Conf., Sao Paulo, Brazil. Biquand, S. and Biquand-Guyot, V The influence of peers, lineage and environment on food selection of the criollo goat (Capra hircus). Appl. Anim. Behav. Sci. 34: Bryant, J.P.; Provenza, F.D.; Pastor, J.; Reichardt, P.B.; Clausen, T.P. and DuToit, J.T Interactions between woody plants and browsing mammals mediated by secondary metabolites. Ann. Rev. Ecol. Syst. 22: Carpino, S.; Home, J.; Melilli, C.; Licitra, G.; Barbano, D.M. and Van Soest, P.J. 2004a. Contribution of native pasture to the sensory properties of Ragusano cheese. J. Dairy Sci. 87: Carpino, S.; Mallia, S.; La Terra, S.; Melilli, C.; Licitra, G.; Acree, T.E.; Barbano, D.M. and Van Soest, P.J. 2004b. Composition and aroma compounds of Ragusano cheese: Native Pasture and Total Mixed Rations. J. Dairy Sci. 87: Chadwick M.A.; Vercoe, P.V.; Williams, I.H. and Revell, D.K. 2009a. Programming sheep production on saltbrush: adaptations of offspring from ewes that consumed high amounts of salt during pregnancy and early lactation. Anim. Prod. Sci. 49: Chadwick M.A.; Vercoe, P.V.; Williams, I.H. and Revell, D.K. 2009b. Dietary exposure of pregnant ewes to salt dictates how their offspring respond to salt. Physiol. Behav. 97:437:445. Chadwick M.A.; Vercoe, P.V.; Williams, I.H. and Revell, D.K. 2009c. Feeding pregnant ewes a high-salt diet or saltbrush suppresses their offspring s postnatal rennin activity. Animal in press.

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16 16 Provenza, F. D. AGROCIENCIA Moore, D.S The Dependent Gene: The Fallacy of «Nature vs. Nurture.» Henry Holt and Company, New York, NY. Mote, T.; Villalba, J.J. and Provenza, F.D Foraging sequence influences the ability of lambs to consume foods containing tannins and terpenes. Appl. Anim. Behav. Sci. 113: Niezen, J.H.; Charleston, W.A.G.; Robertson, H.A.; Shelton, D.; Waghorn, G.C. and Green, R The effect of feeding sulla (Hedysarum coronarium) or lucerne (Medicago sativa) on lamb parasite burdens and development of immunity to gastrointestinal nematodes. Vet. Parasit. 105: Nolte, D.L.; Provenza, F.D.; Callan, R. and Panter, K.E Garlic in the ovine fetal environment. Physiol. Behav. 52: Nolte, D.L. and Provenza, F.D. 1992a. Food preferences in lambs after exposure to flavors in milk. Appl. Anim. Behav. Sci. 32: Nolte, D.L. and Provenza, F.D. 1992b. Food preferences in lambs after exposure to flavors in solid foods. Appl. Anim. Behav. Sci. 32: Ortega Reyes, L.; Provenza, F.D.; Parker, C.F. and Hatfield, P.G Drylot performance and ruminal papillae development of lambs exposed to a high concentrate diet while nursing. Small Rum. Res. 7: Ortega-Reyes, L. and Provenza, F.D. 1993a. Amount of experience and age affect the development of foraging skills of goats browsing blackbrush (Coleogyne ramosissima). Appl. Anim. Behav. Sci. 36: Ortega-Reyes, L. and Provenza, F.D. 1993b. Experience with blackbrush affects ingestion of shrub live oak by goats. J. Anim. Sci. 71: Pielou, E.C After the Ice Age: The Return of Life to Glaciated North America. The University of Chicago Press, Chicago, IL. Pollan, M The Omnivores Dilemma: A Natural History of Four Meals. The Penguin Press, New York, NY. Priolo, A.; Bella, M.; Lanza, M.; Galofaro, V.; Biondi, L.; Barbagallo, D.; Ben Salem, H. and Pennisi, P Carcass and meat quality of lambs fed fresh sulla (Hedysarum coronarium L.) with or without polyethylene glycol or concentrate. Small Rum. Res. 59: Priolo, A.; Vasta, V.; Fasone, V.; Lanza, C.M.; Scerra, M.; Biondi, L.; Bella, M. and Whittington, F.M Meat odour and flavour and indloes concentration in ruminal fluid and adipose tissue of lambs fed green herbage or concentrates with or without tannins. Animal in press. Provenza, F.D. 1995a. Postingestive feedback as an elementary determinant of food preference and intake in ruminants. J. Range Manage. 48:2-17. Provenza, F.D. 1995b. Tracking variable environments: There is more than one kind of memory. J. Chem. Ecol. 21: Provenza, F.D Acquired aversions as the basis for varied diets of ruminants foraging on rangelands. J. Anim. Sci. 74: Provenza, F.D. 2003a. Foraging Behavior: Managing to Survive in a World of Change. Utah State Univ., Logan. Provenza, F.D. 2003b. Twenty-five years of paradox in plantherbivore interactions and «sustainable» grazing management. Rangelands 25:4-15. Provenza, F.D. and Balph, D.F Applicability of five diet-selection models to various foraging challenges ruminants encounters. Pages in R.N. Hughes (Ed.), Behavioural Mechanisms of Food Selection. NATO ASI Series G: Ecological Sciences, Vol. 20. Springer-Verlag, Berlin. Heildelberg, Germany. Provenza, F.D. and Villalba, J.J Foraging in domestic vertebrates: Linking the internal and external milieu. Pages in V.L. Bels (ed.) Feeding in Domestic Vertebrates: From Structure to Function. CABI Publ., Oxfordshire, UK. Provenza, F.D.; Pfister, J.A. and Cheney, C.D Mechanisms of learning in diet selection with reference to phytotoxicosis in herbivores. J. Range Manage. 45: Provenza, F.D.; Villalba, J.J.; Dziba, L.E.; Atwood, S.B. and Banner, R.E Linking herbivore experience, varied diets, and plant biochemical diversity. Small Rum. Res. 49: Provenza, F.D.; Villalba, J.J.; Haskell, J.H.; MacAdam, J.A.; Griggs, T.C. and Wiedmeier, R.D The value to herbivores of plant physical and chemical diversity in time and space. Crop Sci. 47: Rosenthal, G.A. and Janzen, D.H. (eds.) Herbivores: Their Interaction with Secondary Plant Metabolites. Academic Press, New York, NY. Rosenthal, G.A. and Berenbaum, M.R. (eds.) Herbivores: Their Interactions with Secondary Plant Metabolites. Second Ed. Academic Press, New York, NY. Rubin, J Why Your World is About to Get a Whole Lot Smaller. Random House, New York, NY. Savory, A. and Butterfield, J Holistic Management: A New Framework for Decision-Making. Second Edition, Island Press, Covalo, Calif. Schlichting, C.D. and Pigliucci, M Phenotypic Evolution: A Reaction Norm Perspective. Sinauer Publications, Sinauer, MA. Seefeldt, S.S Consequences of selecting Ramboulliet ewes for Mountain Big Sagebrush (Artemisia tridentata ssp. vaseyana) dietary preference. Rangeland Ecol. Manage. 58: Simitzis, P.E.; Deligeorgis, S.G.; Bizelis, J.A. and Fegeros, K Feeding preferences in lambs influenced by prenatal flavour exposure. Physiol. Behav. 93: Squibb, R.C.; Provenza, F.D. and Balph, D.F Effect of age of exposure on consumption of a shrub by sheep. J. Anim. Sci. 68:

17 Adaptability is Sustainability 17 Thorhallsdottir, A.G.; Provenza, F.D. and Balph, D.F Ability of lambs to learn about novel foods while observing or participating with social models. Appl. Anim. Behav. Sci. 25: Tzack, A.G.; Ungar, E.D.; Landau, S.Y.; Perevolotsky, A.; Muklada, H. and Walker, J.W Breed and maternal effects on the intake of tannin-rich browse by juvenile goats (Capra hircus). Appl. Anim. Behav. Sci. 119: Vasta, V.; Nudda, A.; Cannas, A.; Lanza, M. and Priolo, A. 2008a. Alternative feed resources and their effects on the quality of meat and milk from small ruminants. Anim. Feed Sci. Tech. 147: Vasta, V.; Harinder Makkar, H.P.S.; Mele, M. and Priolo, A. 2008b. Ruminal biohydrogenation as affected by tannins in vitro. Brit. J. Nutr. In press. Villalba, J.J. and Provenza, F.D Self-medication and homeostatic endeavor in herbivores: learning about the benefits of nature s pharmacy. Animal 1: Voisin, A Soil, Grass and Cancer. Philosophical Library, Inc. New York, NY. Waghorn, G. C Beneficial effects of low concentrations of condensed tannins in forages fed to ruminants. P137 in D.E. Akin, L.G. Ljungdahl, J.R. Wilson, and P.J. Harris. (ed.) Microbial and Plant Opportunities to Improve Lignocellulose Utilization by Ruminants. Elsevier Sci. Publ., New York, NY. Wiedmeier, R.D.; Provenza, F.D. and Burritt, E.A Exposure to ammoniated wheat straw as suckling calves improves performance of mature beef cows wintered on ammoniated wheat straw. J. Anim. Sci. 80: Woodward, S.L.; Waghorn, G.C. and Laboyrie, P.G Condensed tannins in birdsfoot trefoil (Lotus corniculatus) reduce methane emissions from dairy cows. Proceedings of the New Zealand Society of Animal Production 64:

18 18 Agrociencia (2009) Vol XIII N 3 - Número especial pág AGROCIENCIA Ecofisiología de Sistemas Pastoriles: Aplicaciones para su Sustentabilidad Nabinger, C. 1 ; de Faccio Carvalho, P.C. 1 Departamento de Plantas Forrajeras y Agrometeorología, UFRGS. Correo electrónico: nabinger@ufrgs.br Resumen Solo en las últimas décadas se empieza a tomar conciencia de los riesgos de los efectos de la explotación desmedida de los recursos naturales y sus consecuencias sobre el ambiente y la calidad de vida en la planeta. En el caso de las pasturas naturales, su conservación depende de la agregación del valor de otros servicios prestados que normalmente no son considerados. La preservación y calidad del agua, de los suelos, del paisaje, de los aspectos culturales y otros no son valorados, quedando únicamente la renta originada de la venta de los productos animales como remuneración al productor. Y esa renta es baja pues el manejo a que están sometidas esas pasturas no les permite expresar su potencial productivo. Eso fue consecuencia de un abordaje equivocado por parte de la investigación, que solo recientemente ha adoptado una postura más analítico y explicativa de los procesos conducentes a la producción de forraje y al comportamiento de los animales en pastoreo, en sustitución al abordaje tradicional productivista. La aplicación de conocimientos generados sobre la morfogénesis de las distintas especies vegetales que componen la pastura y de los conocimientos sobre como esa morfogénesis afecta la estructura del pasto y sus consecuencias sobre el comportamiento ingestivo y el desempeño del animal en pastoreo, es la única forma de originar recomendaciones de manejo que lleven al aumento de producción y de renta sin comprometer el ecosistema y agregando otros valores que talvez un día sean efectivamente reconocidos y repasados al productor. El presente artículo propone una revisión de los aspectos de ecofisiología de forrajeras y del comportamiento ingestivo del animal, centrada en pasturas naturales, la presentación de un modelo conceptual de funcionamiento de la pastura y algunas aplicaciones que han resultado en aumento de producción animal y de renta al productor, con mejoras en algunos indicadores de sustentabilidad del ecosistema. Palabras clave: oferta de forraje, diferimiento, modelaje, comportamiento ingestivo, estructura del pasto; morfogénesis Summary Ecophysiology of Pastoral Systems: Aplications for Sustainability Only during the last decades a conscience is being formed about the risks of the effects of unlimited exploitation of the natural resources and its consequences for the environment and the quality of life on the planet. In the case of native pastures, their conservation depends on the added value of other services, which are usually not taken into consideration. Preservation and quality of water, soil, and landscape, of cultural and other aspects are not valued; leaving only the profits generated form the sales of animals to the farmer. This profit is low because the management of the pastures do not allow them to express their productive potential. This is due to a wrong approach of research, which only recently has adopted a more analytical and explicative standpoint toward the processes leading to the production of forage and the behaviour of animals on pasture, substituting the traditional productive approach. The application of knowledge generated on morphogenesis of the different plant species, which compose the pasture, and the knowledge on how this morphogenesis affects the structure of the pasture and its consequences for ingestive behaviour and animal performance on pasture, is the only way to generate recommendations for management, which will lead to increases in production and profit without compromising the ecosystem, adding other values, which maybe one day will be sufficiently known by the farmer. This paper revises aspects of ecophysiology of

19 Ecofisiología de sistemas pastoriles 19 forage and the ingestive behaviour of the animals, concentrating on native pastures; presents a conceptual model of the functioning of pasture; and some applications that have resulted in an increase in animal production and profits to the farmer, along with improvement of some indicators of sustainability of the ecosystem. Key words: forage allowance, deferrement, modeling, ingestive behavior, sward structure, morphogenesis Introducción Los ecosistemas pastoriles son los más grandes ecosistemas del mundo (40.5 % del área terrestre sin considerar la Groenlandia y Antártica). Millones de productores rurales dependen de los mismos, que además, son esenciales para la protección del ambiente y la conservación in situ de recursos genéticos. A pesar de su importancia económica y ambiental, su preservación y adecuada utilización ha recibido relativamente poca atención por parte de los ambientalistas y de los gobiernos, los cuales ven la ganadería a pasto mucho más como un problema que como parte esencial para la conservación y preservación de su biodiversidad. Según Heindenreich (2009) el reconocimiento de Valor Económico Total de los bienes y servicios proveídos por las pasturas naturales es inexistente. Ese valor total debe considerar: (a) valor del uso directo sin conversión de la pastura (pastoralismo de subsistencia, recursos genéticos bio-medicinales, recreación activa); (b) valores socio-culturales de no uso (salud física y mental, valores estéticos, heredabilidad cultural, valor espiritual, conocimientos ecológicos tradicionales, recreación pasiva, etc.); (c) valor indirecto de los servicios ecológicos (calidad de los suelos, filtración y almacenado de agua, secuestro de carbono y calidad del aire, etc.). En consecuencia, se observa un creciente aumento de la presión sobre las pasturas naturales tanto vía conversión para otras actividades agrícolas (granos, pasturas cultivadas y silvicultura) como vía utilización de cargas animales excesivas. La incorporación de estos valores en las tomas de decisiones (individuales los ganaderos, o colectivos los responsables por las políticas públicas) sería fundamental para garantizar la conservación y protección de ese ecosistema. Si esos valores no son considerados en su totalidad no se tendrá nunca una visión completa de los beneficios para el ser humano y las decisiones continuarán a ser tomadas de la forma actual, o sea únicamente por valoración de la renta directa de la venta de los productos animales generados, llevando al actual incremento exponencial de la degradación de esos ambientes. Si bien es necesario considerar todos los aspectos de valoración antes mencionadas, la presente discusión se centralizará en la cuestión más inmediata, a nuestro entender, que es el valor de uso directo en la producción animal, una vez que afecta de forma mas impactante las decisiones del ganadero y puede ser el primer paso para el convencimiento de los mismos (y por que no, también de los gestores públicos) sobre las potencialidades no exploradas o mal exploradas que presentan las pasturas naturales. Y las bases para el logro de los objetivos de producción y conservación están en la comprensión de las bases ecofisiológicas del crecimiento de las plantas y del comportamiento ingestivo de los animales. Rol de la ecofisiología y ecología del pastoreo en el uso de las pasturas Por muchas décadas la investigación en pasturas permanentes estuvo focalizada en la descripción florística o simplemente en la producción de forraje. El enfoque era esencialmente productivista. Una postura más analítico-explicativa, donde se pretende no simplemente cuantificar un potencial productivo del pasto pero sí entender su funcionamiento y los procesos que determinarán o no la realización de aquel potencial es reciente. Esa nueva concepción busca conocer el origen de los procesos, insertados en leyes mayores de funcionamiento del ecosistema, de forma que los resultados sean reproducibles en cualquier otra condición que no sean aquellas en las cuales fueron generados. En las plantas forrajeras los atributos morfogenéticos determinan la arquitectura de la planta y afectan la accesibilidad de los animales al forraje. La morfología de las plantas individuales, a su vez, afecta la estructura y funcionamiento de las poblaciones y comunidades, determinando las interacciones competitivas entre las especies y entre individuos de una misma especie. El pastoreo altera esas relaciones competitivas al defoliar diferencialmente a las distintas especies, modificando la expresión de los mecanismos de rebrote, a favor de unas y en detrimento de otras. Esto acarrea a su vez, cambios en la composición botánica que pueden afec-

20 20 Nabinger, C.; de Faccio Carvalho, P.C. AGROCIENCIA tar la cantidad, calidad y estacionalidad de la producción de la pastura y, por consiguiente, la producción animal. Por lo tanto, la implementación de estrategias de manejo debe contemplar tanto las características morfogenéticas de las plantas dominantes en la pastura como también la respuesta del comportamiento ingestivo de los animales. El conocimiento analítico del proceso de construcción de la producción de pasto (Nabinger, 1997; Nabinger e Pontes, 2001) y del proceso de cosecha de forraje en pastoreo (Carvalho et al., 1999; Carvalho et al., 2000; Carvalho et al., 2009) son fundamentales para avanzar en la comprensión de las relaciones causa-efecto entre plantas y animales. Esa es la única forma de proponer bases de manejo sólidas y extrapolables a cualquier condición. Esa manera de abordar el problema forrajero necesita una mejor conceptualización y comprensión de la interacción suelo-clima-planta-animal. La Figura 1 representa un modelo conceptual para entender estas relaciones y tiene por base los modelos propuestos por Lemaire y Chapman (1996), Cruz y Boval (2000) y Freitas (2003). Ese modelo considera las condiciones del medio (temperatura, agua, radiación solar, fertilización, etc.) y de manejo (frecuencia y intensidad de defoliación) afectando la morfogénesis, que a su vez altera las características estructurales del pasto, determinando el comportamiento ingestivo de los animales en pastoreo. Tales interacciones son complejas y dinámicas, influenciadas por la defoliación, principal conexión pasto-animal. Las variables del comportamiento ingestivo son dependientes de las características estructurales del pasto, las cuales afectan el desempeño individual del animal. Las características morfogénicas, a su vez, determinan la capacidad de soporte de la pastura. Más importantes son las tasas de surgimiento, de elongación y la longevidad de la hoja, más animales pueden ser alimentados por área con una oferta de forraje óptima, o sea, mayor capacidad de soporte tendrá el pasto. Conocer las respuestas de las distintas plantas forrajeras a las variables ambientales no controlables es el primer paso para definir su potencial productivo. Eso presupone una etapa en donde los factores controlables (agua y nutrientes) estén disponibles en niveles óptimos. De esa forma se podrá modelizar las respuestas morfogenéticas (tasa de elongación de la hoja, tasa de elongación del macollo o estolón y longevidad de la hoja) de diferentes genotipos a variaciones en las condiciones de temperatura, radiación solar y fotoperíodo para explicar las variaciones en la velocidad de acumulación de forraje, la cual debe dictar el ritmo de utilización por los animales. Pero esas variables también determinan la formación del índice de área foliar (IAF) en conjunto con las variables estructurales de la planta (número de hojas vivas por macollo, densidad de PRODUCCIÓN ANIMAL POR ÁREA Animales por Producción Elongación de la hoja Elongacion Surgimiento de hojas Duración CARACT. MORFOGENICAS Carga animal Desempeño Tamaño de la Densidad de Hojas Calidade IAF MASA DE FORRAJE Y CARACTERÍSTICAS ESTRUTURALES Frecuencia y intensidad de la defoliación Comportam. Profundidad del bocado Tasa de bocado Búsqueda y apreensión Tiempo de pastoreo Figura 1. Modelo conceptual de las relaciones suelo-clima-planta-animal.