The management of the lightweight piglets from modern pig systems

Abstract

The management of lightweight pigs that have resulted from increases in sow prolificacy are a major challenge for modern pig systems. The overall aim of this thesis was to develop intervention strategies that improve the performance of light piglets without penalising heavy piglets, with the pre- and immediate post-weaning period being the most critical windows for intervention. In the first experiment (Chapter 2) creation of litter uniformity pre-weaning optimized the performance of piglets born lightweight, with long term benefits up to slaughter; heavy piglets on the other hand were penalized by this strategy. Despite heavy piglet efforts to compensate for insufficient milk intake by increasing creep feed intake, this was insufficient for achieving similar growths to heavy piglets kept in mixed litters. That being said, piglets born heavy ate high amounts of creep feed whereas piglets born light hardly consumed any creep feed. In Chapter 3, it shown that irrespective of birth weight mid parity sows were identified as best foster sows. Their piglets were weaned heavy, whilst having eaten high amounts of creep feed. Second parity sows also weaned heavy piglets, but due to piglet low creep feed intake they were unable to maintain this weight advantage post-weaning. Despite the high creep feed intake of primiparous sow reared piglets, these piglets were weaned light and remained light postweaning. Lightweight piglets did not seem to benefit from an amino acid enriched post-weaning starter regime (Chapter 4). Although birth weight is still commonly used as indicator for identifying runt piglets, not all light piglets are destined to remain light. In fact, piglet shape at birth such as, length and head circumferences in relation to birth weight, seemed better predictors of postnatal growth. Chapter 5 evaluated the effect of weaning age, weaning weight and an increased allowance of nursery diets on the performance of piglets through 5 months of age. The results suggested that an enhanced allowance of the nursery diets was beneficial, but that delayed weaning may yield long term benefits for piglets weaned lightweight. The data from this thesis provide novel information and implications for the management of lightweight piglets. Some lightweight piglets are able to improve their post-natal performance and creating the optimal environment such as litter uniformity, rearing them by mid parity sows and weaning later will be beneficial to them.