The evaluation of practices aimed at reducing levels of piglet mortality
1. The research which is reported here was concerned primarily with factors affecting the stillbirth rate, attempts to reduce the incidence of intrapartum stillbirths and the examination of factors which influence piglet lying behaviour in early postnatal life with a view to recommending a more suitable creep heating arrangement than those that are currently in use. 2. Past work concerning factors during pregnancy, parturition and in the post-partum period which may influence the intrapartum stillbirth rate and the viability of liveborn piglets in the first few days after birth have been reviewed. 3. The first two investigations were undertaken to determine the relationship of sow parity, body condition at the end of gestation and gestation length to litter size and stillbirth rate in the pig. While in the first study, the incidence of stillbirths tended to increase with advancing parity of the sow, in the second study no significant relationship was found between parity and stillbirth rate. 4. The next experiment involved the evaluation of additional vitamin C in the diet of sows for the last 1 to 3 weeks of gestation. 5. In an attempt to improve the efficiency of parturition and reduce the incidence of intrapartum stillbirths, an injection of 5 mg Prostigmin was compared with a control treatment, involving an injection of 2 ml sterile water, injections in both cases being given following the birth of the fourth or fifth piglet. 6. The next experiment was designed to examine piglet lying behaviour in two contrasting farrowing facilities during the first 4-8 hours post partum. Piglets on the unit with front creeps, underfloor heating and sawdust as bedding in the creep spent significantly more of their resting time lying within the confines of the farrowing crate, usually against the udder of the sow, where they were in danger of being overlain, compared with piglets in pens with a side creep, heated by an infra-red lamp and with wood shavings as bedding. Piglets in both situations exhibited a strong natural desire to lie close to the udder of the sow during the first 12 hours after birth, this tendency declining with age. 7. The observations made in the previous study prompted the undertaking of a more detailed investigation to examine the effects of alternative creep heating arrangements at two house temperatures (means of 20.5°C and 13.6°C) on piglet lying behaviour, mortality and growth rate in the neonatal period. The basic creep heating arrangement consisted of a kennel at the front of the pen heated by an infra-red lamp. The intermediate treatment incorporated an infra-red lamp adjacent to the place of birth during parturition, in addition to the basic heated kennel, while the luxury creep heating arrangement was a further extension of the intermediate treatment incorporating an infra-red lamp in each side creep for the first 48 hours after birth. In the first 3 days, piglets used the kennel area for resting more in the cool house than in the warm house (P < 0.001). In the first day of life, the provision of a lamp in each side creep was effective in reducing by half the proportion of time piglets spent lying in the danger area within the confines of the farrowing crate and this was reflected in lower losses from overlying. Piglet mortality to 7 days of age on the three treatments was 20.03, 11.61 and 6.53 per cent in the basic, intermediate and luxury creep heating arrangements, respectively, thus justifying the use of heat lamps adjacent to the place of birth and in the side creeps. Piglet liveweight gains during the first week of life were greater (P < 0.001) in the warm than in the cool house. 8. In the general discussion at the end of the thesis, the research findings reported have been used to provide a sounder basis to recommendations for reducing piglet mortality and improving viability at birth in the commercial situation. In addition, suggestions for future research in this area have been discussed.