The parameters that affect the interaction between grazing animals and pas- ture characteristics are summarized in Fig. 8.11 (Baumontet al., 2000). The suc- cess of this model is largely dependent on the shepherd’s understanding of forage heterogeneity and its influence on animal foraging strategies. A model of a shepherded circuit viewed as a sequence of patches characterized by different degrees of forage palatability and abundance, named the ‘menu model’, is described in Fig. 8.12. The aim of this model is to improve animal intake, allow- ing a high use of abundant but not highly palatable plants and also protecting the highly palatable but rare resources. Such a circuit has a moderation patch (M), with plants abundant but not highly palatable, at the beginning (Fig. 8.12), in order to reduce the appetite of the flock. Successively, an appetite promotion patch (A), with highly palatable but less abundant plants, is offered, to stimulate a low appetite. After that, a target patch with medium plant abundance and palatability is used as a main course (MC) for the bulk of the meal.
When goats start to lose interest in this patch, a booster patch (B) can be offered to increase their appetite. A booster patch may have either very low palat- ability and medium abundance or high palatability and low abundance. After that, animals can be moved to another target patch, with slightly better instantaneous palatability and abundance than the MC, considered as the second course (SC)
– Instantaneous palatability +
– Relative abundance +
M: Moderation A: Appetite promotion MC: Main course B: Booster SC: Second course D: Dessert M
MC
SC
D
B
A B Target patches
Fig. 8.12. The menu model: a grazing circuit with an ordered sequence of offered patches during one main meal, whose objective is to constantly increase the animal’s eating motivation on resources of medium or low quality. (Adapted from Meuretet al., 1995.)
of the diet. At the end of the circuit, when animals are already full, a dessert patch (D) with high forage availability and palatability can be used to reduce the risk of over-grazing.
The application of this model requires frequent pasture modifications by the shepherd and adaptation to local conditions. In order to reduce human work, several strategies that stimulate goat circulation in the shrubland could be used.
For example, the placement of fences, gates, shadow points, watering points and mineral licks in strategic areas of the pasture could force the animals to use cer- tain areas. Moreover, the introduction of some grass sward, even in a small area, or the increase of natural herbaceous plants in some areas of the shrubland may affect animal distribution and dietary selection. In fact, use of grasses at the vege- tative stage increases shrub intake by goats (Leclerc, 1984), and a high level of degradable protein in the herbage can counteract the negative effects of tannins on ruminal environment (Landau et al., 2000). Grazing management should also take into consideration grazing time, especially during warm seasons, when high temperatures reduce grazing activity of goats during the day. In these peri- ods, goats should be allowed to pasture preferably in early morning or late eve- ning, when they usually eat more woody and shrubby species (Leclerc, 1984).
If goats are supplemented, the level and the composition of the feed additives modify their feeding behaviour. The use of ‘alternative’ supplements, rich in highly digestible fibres (e.g. sugarbeet pulp and soybean hulls) and N (urea), adminis- tered to goats in small amounts twice a day before access to the shrubland, can increase pasture intake (Meuretet al., 1994; Ben Salemet al., 2000b).
Grazing management of goats in Mediterranean shrublands could also deal with the use of biological control of shrubby vegetation as an alternative to mechanical and chemical methods, since shrub encroachment is not a rare phe- nomenon in these areas. In fact, in Mediterranean grasslands of northern Greece, shrub encroachment was a consequence of reduced grazing by goats and aban- donment of traditional management practices, such as shrub use for fuelwood and charcoal (Zarovaliet al., 2007).
Due to their diet diversity, high resistance to plant toxins and anti-nutritive factors and their morpho-physiological characteristics, goats can eat plants that are less palatable and/or not attainable for other animals (Hart, 2001). Most of these plants (e.g.Rubusspp.,Rosaspp.,Euphorbiaspp.,Smilaxspp. andRubia spp.), if not managed effectively, tend to spread over the pasture and form some
‘non-grazeable patches’, thus increasing the risk of wildfires. Goats preferentially eat flowers and seeds of immature weeds, such as Silybum and Cardus spp.
(Yiakoulaki and Papanastasis, 2003), reducing their spread and perpetuation (Allan and Holst, 1996).
The use of goats associated or not with other methods for shrub and/or weed control is a management practice that has started to gain attention in the USA and Australia. A balanced utilization of shrub and/or weed-invaded areas by mixed grazing ruminants (goats, sheep, cattle, horses) associated with addi- tional practices, such as shrub cutting for fuelwood or prescribed burning, may be particularly helpful. However, to increase the effectiveness of weed control by grazing, further research is needed on stocking rate, season and duration of graz- ing, effects on animal performance and cost of application of this practice.
References
Allan, C.J. and Holst, P.J. (1996) The ecological role of the goat in maintaining pasture and range. In: Proceedings of the VI International Conference on Goats. Interna- tional Academic Publishers, Beijing, China, pp. 427–435.
Ammar, H., López, S. and González, J.S. (2005) Assessment of the digestibility of some Mediterranean shrubs byin vitrotechniques.Animal Feed Science and Technology 119, 323–331.
Baumont, R., Prache, S., Meuret, M. and Morand-Fehr, P. (2000) How forage characteristics influence behaviour and intake in small ruminants: a review.Livestock Production Science64, 15–28.
Ben Salem, H., Nefzaoui, A. and Abdouli, H. (1994) Palatability of shrubs and fodder trees measured on sheep and dromedaries: 1. Methodological approach.Animal Feed Science and Technology46, 143–153.
Ben Salem, H., Nefzaoui, A. and Ben Salem, L. (1999) Sheep and goat preferences for fodder shrubs. Relationship with the nutritive characteristics.Options Méditerranéennes 52, 155–159.
Ben Salem, H., Nefzaoui, A., Ben Salem, L. and Tisserand, J.L. (2000a) Deactivation of condensed tannins inAcacia cyanofillaLindl foliage by polyethylene glycol in feed blocks. Effect on feed intake, diet digestibility, nitrogen balance, microbial synthesis and growth by sheep.Livestock Production Science64, 51–60.
Ben Salem, H., Nefzaoui, A. and Ben Salem, L. (2000b) Supplementing range goats in central Tunisia with feed blocks or a mixture ofOpuntia ficus indicavar.inermisand Atriplex nummularia. Effects on behavioural activities and growth. In:Proceedings of the VII International Conference on Goats, Tours, France. Institut de l’Elevage and Institut National de la Recherche Agronomique, Paris, pp. 988–989.
Ben Salem, H., Ben Salem, L., Nefzaoui, A. and Ben Saïd, M.S. (2003) Effect of PEG and olive cake feed blocks supply on feed intake, digestion, and health of goats given kermes oak (Quercus cocciferaL.) foliage.Animal Feed Science and Technology110, 45–59.
Boubaker, A., Kayouli, C., Buldgen, A. and Boukary, A. (2004) Chemical and biological characterisation of some woody species browsed by goats in the North-West of Tunisia.
Options Méditerranéennes59, 147–151.
Cabiddu, A., Decandia, M., Sitzia, M. and Molle, G. (2000) A note on the chemical com- position and tannin content of some Mediterranean shrubs browsed by Sarda goats.
Options Méditerranéennes52, 175–178.
Cannas, A., Pes, A., Mancuso, R., Vodret, B. and Nudda, A. (1998) Effect of dietary energy and protein concentration on the concentration of milk urea nitrogen in dairy ewes.Journal of Dairy Science81, 499–508.
Congiu, F., Dattilo, M. and Serra, A. (1978) Indagine preliminare sulla composizione chimica e sul valore nutritivo delle principali essenze arbustive presenti in Sardegna.
Zootecnia e Nutrizione Animale4, 433–441.
Cooper, S.M., Owen-Smith, N. and Bryant, J.P. (1988) Foliage acceptability to browsing ruminants in relation to seasonal changes in the leaf chemistry of woody plants in a South African savanna.Oecologia75, 336–342.
Daget, P. and Poissonet, J. (1969) Analyse Phytologique des Prairies. Application Agronomique. Document No. 48. Centre National de la Recherche Scientifique– Centre d’Etudes Phytosociologiques et Ecologiques Louis Emberger, Montpellier, France.
Decandia, M., Molle, G., Sitzia, M., Ruiu, P.A., Pampiro, F., Pintus, A. and Kababya, D.
(1997a) Feeding behaviour of goats browsing on a Mediterranean shrubland.
In:Book of Abstracts of the 48th Annual Meeting of the European Association for Animal Production, Wien, Austria. Abstract S3.13, p. 293.
Decandia, M., Sitzia, M., Molle, G., Fois, N. and Fois, G. (1997b) Effect of weather condi- tions on browsing behaviour of goats in Mediterranean shrubland. In:Proceedings of the International Workshop on ‘Ecological Basis of Livestock Grazing in Mediterranean Ecosystems’, Thessaloniki, Greece. European Commission of Science, Research and Development, Brussels, pp. 227–230.
Decandia, M., Molle, G., Ligios, S. and Scanu, G. (1999) Effect of different levels of polyethylene glycol on the nutritional value ofPistacia lentiscusL. fed to goats.
In: Proceedings of the XIII ASPA Congress, Piacenza, Italy. Franco Angeli s.r.l., Milan, Italy, pp. 384–386.
Decandia, M., Sitzia, M., Cabiddu, A., Kababya, D. and Molle, G. (2000a) The use of polyethylene glycol to reduce the anti-nutritional effects of tannins in goats fed woody species.Small Ruminant Research38, 157–164.
Decandia, M., Molle, G., Sitzia, M., Cabiddu, A., Ruiu, P.A., Pampiro, F. and Pintus, A.
(2000b) Responses to an antitannic supplementation by browsing goats. In:Pro- ceedings of the VII International Conference on Goats, Tours, France. Institut de l’Elevage and Institut National de la Recherche Agronomique, Paris, pp. 71–73.
Decandia, M., Molle, G., Sitzia, M., Cabiddu, A., Pampiro, F. and Ruiu, P.A. (2004a) Feeding behaviour of dairy goats supplemented with polyethylene glycol browsing on bushland with different herbage cover.Options Méditerranéennes59, 29–33.
Decandia, M., Cabiddu, A., Sitzia, M. and Molle, G. (2004b) Gestione delle risorse alimentari nell’allevamento estensivo di caprini nelle regioni del Mediterraneo.
Informatore Zootecnico18, 176–196.
Decandia, M., Pinna, G., Cabiddu, A. and Molle, G. (2005a) Intake by lactating goats browsing on Mediterranean shrubland. In:Proceedings of the XX International Grassland Congress, Dublin. Wageningen Academic Publishers, Wageningen, The Netherlands, p. 540.
Decandia, M., Cabiddu, A., Molle, G., Branca, A., Epifani, G., Pintus, S., Tavera, F., Piredda, G., Pinna, G. and Addis, M. (2005b) Effect of different feeding systems on fatty acid composition and volatile compound content in goat milk. 11th Seminar of the FAO–CIHEAM Sub-Network on Sheep and Goat Nutrition, Catania, Italy.
Options Méditerranéennes, in press.
Dominique, M.F., Dellow, D.W. and Barry, T.N. (1991) Voluntary intake and rumen digestion of a low-quality roughage by goats and sheep.Journal of Agricultural Science117, 117–120.
Dumont, B., Meuret, M. and Prud’hon, M. (1995) Direct observation of biting for studying grazing behavior of goats and llamas on garrigue rangelands. Small Ruminant Research16, 27–35.
Fedele, V., Pizzillo, M., Claps, S., Morand-Fehr, P. and Rubino, R. (1993) Grazing behav- iour and diet selection of goats on native pasture in Southern Italy.Small Ruminant Research11, 305–322.
Gilboa, N. (1996) The negative effects of tannins and its neutralization in livestock. PhD thesis, The Hebrew University of Jerusalem, Jerusalem.
Gilboa, N., Perevolotsky, A., Landau, S., Nitsan, Z. and Silanikove, N. (2000) Increasing productivity in goats grazing Mediterranean woodland and scrubland by supple- mentation of polyethylene glycol.Small Ruminant Research38, 183–190.
Hadjipanayiotou, M. (1986) Studies on the response of lactating Damascus goats to dietary protein.Journal of Animal Physiology and Animal Nutrition57, 41–52.
Hadjipanayiotou, M. and Antoniou, T. (1983) A comparison of rumen fermentation pat- terns in sheep and goats given a variety of diets.Journal of the Science of Food and Agriculture34, 1319–1322.
Hart, S.P. (2001) Recent perspectives in using goats for vegetation management in the USA.Journal of Dairy Science84(E Suppl.), E170–E176.
Howe, J.C. and Barry, T.N. (1988) Voluntary intake and digestion of gorse (Ulex europeus) by goats and sheep.Journal of Agricultural Science111, 107–114.
Jones, W.T. and Mangan, J.L. (1977) Complexes of the condensed tannins of sainfoin (Onobrychis viciaefolia Scop) with fraction 1 leaf protein and submaxillary mucoprotein and their reversal by PEG and pH.Journal of the Science of Food and Agriculture28, 126–136.
Kababya, D. (1994) Grazing behavior and nutrition of goats in Mediterranean woodland.
Masters thesis, Faculty of Agriculture of the Hebrew University of Jerusalem, Jerusalem.
Kababya, D., Perevolotsky, A., Bruckental, I. and Landau, S. (1998) Selection of diets by dual-purpose Mamber goats in Mediterranean woodland.Journal of Agricultural Science131, 221–228.
Koukoura, Z. (1988) Composition of kermes oak browse as affected by shade and stage of maturity.Animal Feed Science and Technology21, 1–9.
Kumar, S. and Vaithiyanathan, S. (1990) Occurrence, nutritional significance and effect on animal productivity of tannins in tree leaves.Animal Feed Science and Technology 30, 21–38.
Landau, S., Vecht, J. and Perevolotsky, A. (1993) Effects of two levels of concentrate supplementation on milk production of dairy goats browsing Mediterranean scrub- land.Small Ruminant Research11, 227–237.
Landau, S., Provenza, F. and Silanikove, N. (2000) Feeding behaviour and utilization of vegetation by goats under extensive systems. In:Proceedings of the VII International Conference on Goats, Tours, France. Institut de l’Elevage and Institut National de la Recherche Agronomique, Paris, pp. 47–52.
Leclerc, B. (1984) Utilisation du maquis corse par des caprins et des ovins.Acta Ecologica, Ecologia Applicata5, 383–406.
Le Houérou, H.N. (1981) Impact of man and his animals on Mediterranean vegetation.
In: Di Castri, F., Goodall, D.W. and Specht, R.L. (eds) Mediterranean-type Shrublands.Ecosystems of the World, Vol. 11. Elsevier, Amsterdam, pp. 479–521.
Le Houérou, H.N. (1993a) Environmental aspects of fodder trees and shrubs plantation in the Mediterranean basin. In: Papanastasis, V. (ed.)Fodder Trees and Shrubs in the Mediterranean Production Systems: Objectives and Expected Results of the EC Research Contract. Agriculture, Agrimed Research Programme EUR 14459 EN.
Commission of the European Communities, Brussels, pp. 11–34.
Le Houérou, H.N. (1993b) Grazing lands of the Mediterranean basin. In: Coupland, R.T.
(ed.)Natural Grassland.Ecosystems of the World, Vol. 8. Elsevier Science, Amsterdam, pp. 171–196.
Liakos, L.G., Papanastasis, V.P. and Tsiouvaras, C.N. (1980) Contribution to the conver- sion of kermes oak bushlands to grasslands and comparison of their production with improved bushlands in Greece.Dasiki Erevna1, 97–141.
Makkar, H.P.S., Blummel, M. and Becker, K. (1997) In vitrorumen apparent and true digestibilities of tannin-rich forages.Animal Feed Science and Technology67, 245–251.
Meuret, M. (1989) Feuillages fromages et flux ingérés. Thesis in Agronomic Sciences, Gembloux, Belgium. Institut National de la Recherche Agronomique–Sciences pour l’Action et le Développement, Avignon, France, p. 229.
Meuret, M. (1996) Organizing a grazing route to motivate intake on coarse resources.
Annales de Zootechnie45(Suppl.), 87–88.
Meuret, M. and Bruchou, C. (1994) Modélisation de l’ingestion selon la diversité des choix alimentaires réalisés par la chèvre au paturage sur parcours. Rencontres Recherches Ruminants1, 225–228.
Meuret, M., Lasseur, J., Molénat, G. and de Simiane, M. (1994) Un complément pour stimuler l’appétit.Reussir-Patre416, 23–26.