Animal health and sustainable production

Disease management

Infectious diseases have major implications for animal welfare and production efficiency, human health, and food safety and quality. The increasing incidence of diseases such as BSE, TB and brucellosis in cattle has raised considerable concern, both for animal welfare and because of the possibility of infected foods. Mastitis, the most persistent disease in cows, deserves particular attention as it directly impinges on milk quality. Currently, diseases are controlled mainly with vaccines or drugs, but the emergence of antibiotic- and drug-resistant pathogens means disease will continue to be a problem. Moreover, the use of antibiotics will become ever more severely restricted in the future, posing a major challenge for disease management.

Biotechnology should enable us to develop new and improved vaccines for disease prevention. Vaccines have many advantages over drug-based approaches: they are preventive; are cheap and effective; reduce the need to use chemicals and antibiotics (and so avoid the problem of residues); and minimise the risk of resistance developing. Moreover, it is believed that the risks associated with DNA-based vaccines are far less than those associated with conventional vaccines, which use part or all of the pathogenic organism. Not surprisingly, the world market for veterinary vaccines is growing and in Europe is expected to top ?3 billion by 2007, with biotech vaccines accounting for 50% of the total. There is therefore tremendous commercial potential for effective biotech vaccines. Irish vaccine research is well underway, and BioResearch Ireland for example, has already developed some six biotech animal vaccines. Research priorities are to develop:

• New vaccines to control the major animal diseases affecting Irish agriculture
• Rapid and sensitive diagnostic tests (DNA- and antibody-based)for new and existing infectious diseases in farm animals, and capable of early detection of sub-clinical disease
• Molecular-based typing of pathogens (akin to 'genetic fingerprinting') to monitor the spread of disease within and between herds and trace the disease source
• Genetic analysis of animal pathogens, particularly those causing mastitis and those harbouring multiple antibiotic resistance; this will improve our understanding of the factors which cause disease and how best to control it (including the use of anti-microbial peptides as an alternative to antibiotics)
• The use of probiotic bacteria in disease prevention, including the use of unusual fermentable substrates which promote the growth of beneficial organisms in the animal's intestine (prebiotics)

Disease resistance genes

An individual's genetic make-up is important in determining their susceptibility to disease. Thus, one long-term approach to disease management is to select animals with the best gene mix for disease resistance. New gene mapping techniques are greatly improving our knowledge of which genes are important in disease resistance and susceptibility, and this information can now be used to assist breeders to identify the animals from which to breed the next generation. Genetically pin-pointing or finger-printing the desired type of individual means selective breeding can now become faster and more precise. (This new approach to conventional breeding is known as marker-assisted breeding, and is radically different to, and should not be confused with, the creation of genetically modified organisms.) If this approach is incorporated in national breeding programmes it should greatly improve the disease resistance in our national herds. Priorities are:

• Identify the genetic and cellular basis of disease susceptibility and resistance in farm animals for the major diseases affecting Irish agriculture
• Investigate the immunological, molecular and cellular events involved in animal response to disease, in order to identify targets for new diagnostic tests and vaccines
• Identify the key genes that confer a high degree of disease resistance on animals so as to reduce the use of antibiotics in animal production (for example, the lysozyme gene appears to be associated with resistance to mastitis)

Reproductive biotechnology

Animal reproductive biotechnology underpins the 'new genetics', and improving fertility rates will be central to solving the major production and efficiency bottlenecks in the national dairy and beef herds. Genetic improvement in the national dairy herd has already significantly increased the volume of milk produced per cow, but unfortunately this comes with reduced fertility, notably it seems by affecting embryo survival rate. Biotechnology offers a powerful new approach to improve our understanding of the many mechanisms (endocrine, physiological and genetic) involved in embryo loss. This information will be essential in developing strategies to counter embryo loss and enhance cow fertility.

There is tremendous variation in the quality and genetic status of the national beef herd. This could be overcome by more widespread use of superior genetics, notably artificial insemination (AI) with semen from high merit bulls. This is hard to implement, however, because of the difficulty observing oestrus (or 'heat detection'), crucial to timing an insemination, in suckler cows which are less closely watched than dairy cows. Biotechnology offers new approaches to developing effective automated heat detection methods for use in suckler herds.

Finally, sexing of sperm is a long-standing goal of the dairy and beef industries. Separating sperm into X (female) and Y (male) fractions would dramatically improve the efficiency of milk and meat production. Current separation procedures are slow, however, and require expensive equipment and skilled operators. A successful technique would have a world-wide market. Farm animal reproductive research must therefore focus on:

• Qualitative and quantitative determination of the genetic and biochemical aspects of embryo formation, development and viability, and how these are affected by nutrition, production and genetic make-up
• Adapting industrial advances in micro-chip, biosensor and telecommunication applications, together with endocrine and behavioural measurements, to develop an efficient oestrous detection system for Irish beef suckler herds
• Using new biotech approaches to develop a more practical and cost-effective approach to sperm sexing in cattle

Genome analysis for animal improvement

Genome mapping of farm animal species is proceeding apace, and at the current rate complete sequences for the major species should be available within 5-10 years. The focus will then be on identifying the key genes and the other genetic and molecular 'markers' associated with economically important traits such as growth, meat tenderness and flavour in beef; fat and protein synthesis in the mammary gland, and milk composition in dairy cows; ovulation rate in sheep and pigs; and disease resistance and susceptibility. (Functional genomics using miniaturised technologies such as hybridisation micro-assays or DNA chips should prove particularly useful in this regard.)

A major challenge will be to incorporate this new molecular information into conventional animal breeding programmes. Marker-assisted selection, which uses biotech tests to identify the individuals with the desired genetic make-up so that they can be used to breed the next generation, will greatly improve the speed, accuracy and efficiency of breeding programmes, and should for example result in cattle capable of producing more and better quality milk, and leaner, more nutritious meat. Already, scientists have identified specific genes for enzymes which, for example, reduce the levels of undesirable saturated fatty acids in milk and meat. Genome research for animal improvement will therefore focus on:

• Understanding the genetics and biochemistry underlying important production traits, such as meat and milk composition and quality, so as to enhance production efficiency and provide a safe, wholesome product for the consumer
• Identifying which genes are important in animal performance