Research Projects - Pigs

Proliferative enteritis (PE) is a major disease in the global pig industry.  It is caused by Lawsonia intracellularis and is currently prevented by feeding pigs antibiotics. The project will provide two scientists (APAIs) with training in epidemiology and immunology applicable to livestock industries and biosecurity.

The ultimate aim of the project is to reduce antibiotic use on pig farms to make the pork industry in Australia more globally competitive, and to benefit human health by reducing the risk of amplifying strains of antibiotic-resistant bacteria.

There are three complementary streams of the research plan.  The first stream will provide essential research to maximise the adoption of a commercial vaccine (Enterisol® Ileitis, Boehringer Ingelheim) as an alternative to antibiotics to control PE. Experiments will be undertaken to improve the efficacy of Enterisol® to control PE under Australian pig management systems and to induce immunity to Australian field isolates of Lawsonia intracellularis (LI). In particular, we will:

• measure the protective efficacy and the immune response of vaccinated pigs against Australian LI isolates;
• increase the ability of the vaccine strain of LI to induce an effective immune response in vaccinated pigs by modifying its administration (extending the "antibiotic-free" window);
• identify the antibiotics that do not interfere with the vaccine strain of LI's ability to infect pigs, hence allowing producers to continue to medicate in the face of concurrent disease while they vaccinate against LI;
• establish the feasibility of vaccinating pre-weaning as an alternative to post-weaning as a way of avoiding the inherent post-weaning problems of concurrent medication and ease of administering vaccine through bulk water-delivery systems;
• elucidate immune "markers" of protection to provide the commercial partner, veterinarians and pig producers world-wide with an objective measure of vaccine efficacy.

The second stream will compare the infection dynamics of LI in pigs reared in "traditional" concrete-based housing and in increasingly popular, welfare-friendly, bedded housing, so management strategies can be developed to control PE in these systems, as an adjunct to vaccination.

In this project we will develop systems to minimise the risk of exotic disease occurring in Australia by targeting this sub-population of the pig-rearing community. In particular work will focus on:

• Identification of the locations and practices of peri-urban pig producers
• Improved methods for tracking pig movements
• Mechanisms for health surveillance\
• Improved extension in relation to disease detection and swill feeding.

• An Australian data set demonstrating that gilt progeny reared on sows can perform equally in terms of growth performance to slaughter relative to sow progeny
• Identification of immune and/or nutritional/orexigenic parameters in colostrum and/or milk from sows that are likely to be responsible for providing this subsequent growth performance advantage to their progeny-relative to gilt colostrum and/or milk
• Evidence to support or disprove the hypothesis that any differences in the passive immunity provided to the progeny of sows relative to gilts is the result of a difference in their innate immunity and/or a difference in how they respond to active immune system challenge
• Determination of any differences in the immune response of the progeny themselves to a novel antigenic challenge (tetanus toxoid)

Outcomes from the project will lead to recommendations for on-farm management strategies, commercial opportunities for pharmaceutical and nutrition companies and links into other Pork CRC research (as outlined below).

The outcomes of the second experimental stream will include:

• Determining the importance of PE as a performance limiting factor on farms
• Provide baseline information that would support the decision on whether to vaccinate gilts and/or sows prior to farrowing against PE
• Provide information that would support or disprove the medication of sows around the time of farrowing to reduce the transmission of LI infection to progeny
• Determine if there is a need to vaccinate both gilt and sow progeny against LI infection to prevent PE
• Measure the relative infection rates of gilt and sow progeny as a guide to potential benefits from rearing the two sub-populations separately

Project Deliverables:

1. Early identification of “at-risk” sows for mid- to late-term pregnancy loss during seasonal infertility.
2. Identification of micro-environmental (pen specific) factors that contribute to mid- to late-term pregnancy loss during seasonal infertility.
3. An understanding of the role of oocyte quality during seasonal infertility.
4. Data to support the theory that pheromones are involved in pregnancy loss during seasonal infertility.
5. An understanding of the role of stress and metabolic state of sows as contributors to mid-to-late term pregnancy loss in SI.

To date, most of the research and development work with smallholder farmers and their livestock in low-income countries has been conducted using traditional scientific methods. These methods have a strong focus of output-production (such as the identification of new or improved knowledge or the development of a tangible solution to an identified problem), generally followed a relatively linear sequence of problem identification, resolution and communication, and involved smallholder farmers as participants rather than partners in the research process. This project represents a substantial shift from traditional methodologies. Rather than focusing on the production of outputs, we are specifically seeking to build the capacity of farmers to improve the management, profitability and long-term sustainability of their livestock production systems through continuous improvement in their creativity, decisions, processes, practices and performance. Our work is focused on chicken and pig production systems, which play a key role in household income and nutrition for smallholder families in the Philippines.

LLIP Mission

'Enhancing the wellbeing of smallholder families in western Leyte by increasing the capacity of farmers to continuously improve their pig and chicken production systems to achieve an average of 5% improvements in profit (gross margin), environment (specific KPIs), and energy efficiency (specific KPIs), this year and in the future.'

LLIP Objectives

1. To increase the capacity of participating producers to improve the management, profitability and long-term sustainability of their livestock systems through continuous improvement in their creativity, decisions, processes, practices and performance
2. To improve the contribution of livestock, in a measurable and sustainable way, to the social and economic wellbeing of smallholder families in western Leyte.