Relationship between feed, water intake, and body weight in gestating sows

The aim of the present research was to analyse the relation between the traits feed (FI), water intake (WI), water-to-feed ratio (WFR) and weight of sow (WS) during pregnancy. Data were recorded at the Hohenschulen research farm of the Institute of Animal Breeding and Husbandry of the University of Kiel between April 2007 and June 2008. The sow herd had a size of 90 sows (Large White, German Landrace and their crossbreeds). In total about 8500 observations were available. The average feed, water intake, water-to-feed ratio and weight of sow were 2.9 kg d− 1, 16.7 l d− 1, 5.8 l (kg d)− 1 and 219.1 kg, respectively. Parity class had a significant influence on water and feed intake (p < 0.05). Nulliparous sows had a constant water intake until day 80 of pregnancy. Thereafter water intake increased until the end of pregnancy. Water intake of primiparous sows increased at the beginning and end of pregnancy. The feed intake curves started without variation between sows at the beginning of the observation period. An increase was observed at the end of pregnancy. Weight of sow increased during pregnancy. Nulliparous sows had the highest weight gain and multiparous sows the lowest (39.0 kg and 23.8 kg respectively). Repeatabilities with the fixed regression model varied between 0.56 (FI) and 0.68 (WS). Using random regression the repeatability of feed intake increased continuously over the course of pregnancy from 0.35 to 0.75 indicating that the variance between sows at the beginning was lower than at the end of pregnancy. The repeatabilities of water intake enhanced from 0.57 to 0.75. The correlations between feed and water intake were constant until day 60 of pregnancy. The relationship decreased at the end of pregnancy due to feed adaptation. A negative relationship was found between feed intake and weight of sow but the value increased over the course of pregnancy.