Management and nutritional strategies to improve the postnatal performance of light weight pigs

Aims and objectives:

To develop treatments for light pigs that will enable them to decrease the deficit in their growth. In order to propose appropriate treatments for these pigs, a protocol is needed to identify the reasons that might have contributed to the delay in growth and whether pigs would be able to benefit from remedial measures.

Objectives

1. To conduct a detailed epidemiological study to identify the risk factors which contribute towards the light-pig syndrome (and associated pen variability).
2. Depending on the risk factors identified above, to develop treatments that would be appropriate for the stage of growth of the lighter pigs. Such treatments may be both nutritional and environmental ones.
3. To identify whether these treatments benefit light pigs at different stages of their production life (i.e. weaner, grower and finisher stages).
4. To conduct a large scale experiment in commercial facilities to investigate the feasibility and accrued benefits of the proposed treatments on light pigs, under commercial husbandry conditions

Summary of findings:

During the production period from birth to slaughter there are some pigs that grow markedly slower, despite conditions that seem to support the rapid growth of their contemporaries. This reduction in growth inevitably leads to weight variation within a group and results in system inefficiencies. The aim of this thesis was to identify risk factors involved in poor growth and to develop management and nutritional treatments to enable light pigs to maximise their growth at different stages of production.

Risk factor analysis for a large dataset showed that, in particular, low birth and weaning weight result in poor growth to finishing. Some light pigs do, however, have the capacity to compensate for low weight at earlier stages of production. Preweaning intervention 

demonstrated that low birth weight pigs cross fostered into litters with similar weight littermates had a significantly higher weaning weight than those in mixed litters with heavier pigs; however the provision of supplementary milk to such litters had no further beneficial effect. A post weaning feeding regime formulated for low birth weight pigs, with a higher nutrient specification diet based on more digestible ingredients, not only showed improved performance to 10 weeks of age, but also enabled low birth weight pigs to meet the BW of heavier birth weight pigs. In contrast, a high specification diet (higher in amino acid: energy content) had no effect on the growth of low birth weight pigs when offered from 9 weeks of age, suggesting a critical window for intervention.

Overall, the crucial stages of postnatal growth for light pigs have been identified, and preweaning and early post weaning treatments have been developed. These not only improve the performance of low birth weight pigs but also allow them to catch up with heavier birth weight pigs.