The animal production sector has undergone remarkable changes during the last decades. Ongoing progress in breeding through selection towards higher growth rates and improved reproductive traits has resulted in increased performance and productivity in modern livestock operations (Walters, 2006).
These achievements have caused an increase in the numbers of animals kept and in the overall consumption of animal products worldwide. Since 1950, the global per capita meat consumption, for example, has nearly doubled and this trend is expected to continue, especially in Asian, Latin American and some African countries.
The overall increase in animal performance and productivity has also been driven by improved management techniques and feeding strategies, in line with an intensification of production methods in many regions of the world. In recent years, breeding goals have increasingly shifted towards additional, however less heritable,
parameters: meat quality, lifetime production of sows and resistance against diseases have become important goals in today’s breeding programs.
However, it is currently debated if, in the near future, the increase in animal performance is going to reach a maximum point due to physiological limits. Moreover, it can be questioned whether the genetic potential of modern livestock breeds is already completely exploited in practice. Albeit the genetic potential is a major factor determining livestock performance, it cannot be seen independently from other factors such as feed ingredients, feeding regime, stocking density, hygienic conditions and overall health status. As illustrated in Figure 1, these factors have to be optimized in order to exploit the full potential of animal performance.Figure 1 Factors affecting performance and health status of livestock
Since feedstuffs usually represent the largest portion of the total production input in livestock operations, adequate feeding management has a substantial impact to increase the overall productivity of animal production. It has been recognized that voluntary feed intake is one of the most important factors restraining maximum performance in different categories of livestock. In breeding sows, for example, feed intake in lactation largely determines the sow’s milk production. This, in turn, has a significant impact on the transfer of nutrient from the sow to the piglets, thus affecting growth rates and health status of the litter. Therefore, realization of high feed intakes is regarded as one major precondition for high performance levels in modern livestock breeds.
With the worldwide emergence of biotechnology in many industries, there are new and highly efficient methods available to further push forward the breeding progress. However, introduction and implementation of such new technologies will largely depend upon the acceptance of consumers. New breeding and production goals will more and more have to focus on actual consumers’ demands. There is not only an increasing demand for high-quality foodstuffs, but also for environmentally-sound production techniques and animal welfare. At the same time, however, the highly competitive market conditions call for low prices for animal products, thus driving the trend towards a continuous reduction in production costs. Moreover, the frequent emergence of zoonotic diseases such as Bovine Spongiform Encephalopathy (BSE), swine fever or avian influenza has put massive pressure on the animal production sector as well as on public authorities.
High-performing animals, reared under intensive production conditions, which are characterized by high stocking densities, tend to be susceptible to several diseases (Goddeeris, 2005). Such diseases may be caused by invasion of pathogens into livestock operations, alteration of feeding regimens, or harsh changes in ambient conditions (temperature or humidity), just to mention some possible elicitors. Thus, a stable health status, based on a healthy gut, is mandatory to secure animal health and performance. However, the gut environment of animals is a highly complex ecosystem in which physiological, dietary and environmental factors interact among each other in a sensitive manner.
The routine use of in-feed antibiotics in livestock feeding has created growing public concern regarding bacterial resistances and residues in animal products such as meat, eggs and milk (Domig, 2005). Although these issues are subject to controversial discussions among experts worldwide, the European Union finally implemented the ban of all Antibiotic Growth Promoters (AGPs) in January 2006. It is expected that the removal of AGPs is likely to create additional microbial pressure on the farms, which might result in lower growth rates and poorer feed conversion. Moreover, spreading of pathogenic germs might even cause an increase in the incidence of foodborne diseases in humans (Cervantes, 2006).
Adequate management of gut health by nutritional means is supposed to be one of the main targets in modern livestock nutrition. There is a general consent about the urgent need for alternative approaches to maintain animal health and performance levels, thus securing food safety. But what are the principal measures to fulfill this need? Furthermore, is it possible to replace AGPs through implementation of natural and safe concepts? On the one hand, there is room for improvement with respect to management practices.
Excellent hygienic conditions and adequate disinfection programs are prerequisites for control of pathogens not only on the farms, but also in the slaughter and processing facilities. On the other hand, tremendous efforts have been undertaken by researchers and the feed industry to develop effective feeding strategies in order to maintain health status and performance levels. There is an overwhelming number of alternative products available at the market. However, scientific reports regarding their efficacy are not always conclusive. The use of Natural Growth Promoters (NGPsTM), including acidifiers, probiotics and phytogenics, is regarded as key strategy to support gut health, to counteract pathogenic germs and to optimize digestive functions (Steiner, 2006). Depending on individual farm conditions, suitable combinations of different NGPsTM have proven efficacious in substituting AGPs.
It remains to be seen if AGPs will be phased out in other regions, including America and Asia, as well. Decisions will most likely depend on the European experience in the forthcoming years following the ban. Developments of performance parameters, microbial status, presence and spreading of pathogens in the livestock operations as well as incidence of food-borne diseases in the human sector have to be monitored carefully in the near future.References
Cervantes, H. (2006) Banning antibiotic growth promoters: Learning from the European experience. Poultry International, June 2006, 10–14.
Domig, K.J. (2005) Antibiotikaresistenz und der Einsatz von Antibiotika in der Tierernährung. 4. BOKU-Symposium Tierernährung: Tierernährung ohne Antibiotische Leistungsförderer. Vienna, Austria, pp.1–8.
Goddeeris, B.M. (2005) Crosstalk between nutrition and immunity. Proceedings of the Society of Nutrition and Physiology 14, pp. 15–20.
Steiner, T. (2006) Managing Gut Health – Natural Growth Promoters as a Key to Animal Performance. Nottingham University Press, Nottingham, United Kingdom.
Walters, R. (2006) Exploiting genetic potential with feed. International Pig Topics 21 (5), 13–15.Participants of the panel discussion are international experts in the field of animal nutrition:"How far can we go in improving animal performance?"
Prof. Dr. Maximilian Schuh - Veterinary University of Vienna, Austria
Prof. Dr. Roger Busch - University of Munich, Germany
Prof. Dr. Seksom Attamangkune - Director of Suwanvajokkasikit Animal Research and Development Institute
(SARDI), Kasetsart University, Thailand
Dr. Shelly McKee - Department of Poultry Science, Auburn University, USA