# Glucose Injections at Birth, Warmth and Placing at a Nurse Sow Improve the Growth of IUGR Piglets
## 1 Introduction  
Genetic selection towards highly prolific sows has resulted in increased litter sizes, leading to a significantly lower mean birth weight and an increased percentage of small piglets born [1]. This increase in litter size has caused intrauterine crowding and a higher demand for oxygen and nutrients during gestation [2]. Consequently, approximately 30% of neonatal pigs in Denmark suffer from various degrees of intrauterine growth restriction (IUGR) [3, 4]. Intrauterine growth restriction is defined as theimpaired growth and development of the foetus and/or its organs during gestation [5], and because of the brain-sparing effect [6], IUGR piglets can be identified by their unique head shape [3; 7].  
At birth, an initial decrease in rectal temperature is observed in IUGR piglets, and it can take up to 48 h after birth until the normal body temperature of 39 \({}^{\circ}\)C is re-established [8]. To re-establish and maintain the body temperature, newborn piglets rely on glycogen deposits, colostrum intake, and shivering thermogenesis [9]. Intrauterine growth-restricted piglets have a larger surface area to volume ratio than normal piglets and, therefore, exhibit greater heat loss, making them more susceptible to hypothermia [9]. In addition, IUGR piglets exhibit lower hepatic glycogen deposits [4], which, in normal piglets, are depleted approximately 16 h after birth [10]. Therefore, in the first few hours, it is critical for the IUGR piglets to start suckling in order to maintain their body temperature and receive the required energy to survive. Additionally, IUGR piglets have lower rectal temperatures at birth than normal piglets--36.2 vs. 37.5 \({}^{\circ}\)C respectively [11]--and surviving piglets at day seven post-partum were found to have a rectal temperature at birth of 37.7 \({}^{\circ}\)C compared to 36.5 \({}^{\circ}\)C in piglets that died [12]. In addition, it has been estimated that IUGR piglets do not ingest sufficient amounts of colostrum [4], compared to the 200 g colostrum recommended per piglet over the first 24 h to ensure survival during the neonatal phase [13]. Administering both heat and a bolus of colostrum increased rectal temperature by 1 \({}^{\circ}\)C one hour after birth in IUGR piglets, however, the effect disappeared after four hours [14], suggesting that an energy supplementation needs to be given frequently.  
Therefore, the objective of the present study was to investigate the effect of administering IUGR piglets with an energy supplementation three times during the first 24 h after birth, on whole-blood glucose, body weight (BW) gain, and rectal temperatures from birth to day 21 in an on-farm trial. Piglets were placed under a heating lamp for one hour and placed at the same nursing sow suitable for rearing small piglets, to eliminate competition and variability within treatment. We hypothesised that a bolus of porcine colostrum or glucose injection, or both, at birth would have a positive effect on the BW gain, whole-blood glucose levels and rectal temperatures from birth to day 21 in IUGR affected piglets.