Applied Animal Behaviour Science 144 (2013) 116–120 Contents lists available at SciVerse ScienceDirect Applied Animal Behaviour Science journa l h o me pag e: www.elsevier.com/locate/applanim The effects of the light regimen imposed during lactation on the performance and behaviour of sows and their litters Panagiotis E. Simitzis a,∗ , Dimitrios Veis a , Nikos Demiris b , Maria A. Charismiadou a , Anna Ayoutanti a , Stelios G. Deligeorgis a a Department of Animal Breeding and Husbandry, Faculty of Animal Science and Aquaculture, Agricultural University of Athens, Greece b Department of Statistics, Athens University of Economics and Business, Greece a r t i c l e i n f o Article history: Accepted 22 January 2013 Available online 20 February 2013 Keywords: Photoperiod Piglets’ performance Sow posture Nursing Farrowing a b s t r a c t The objective of the present study was to highlight the possible effects of an extended photoperiod throughout lactation on the performance and behaviour of sows and their piglets. Sows were randomly assigned to two light regimens: (1) standard (n = 12) consisting of 8 h of light (0700–1500) daily from day 111 of gestation until day 28 of lactation, and (2) extended (n = 12) consisting of 20 h of light (0700–0300) from day 111 of gestation until day 28 of lactation (weaning). Piglets were weighed on days 2 and 28 and average feed intake was measured. Behaviour was recorded for a continuous 24 h period on days 6, 10, 15, 17 and 19. A backtest was also carried out at the 28th day of lactation. The increase of the daily light throughout lactation seems to have a beneficial impact on litter growth during lactation (P < 0.001). During the backtest, piglets of the extended photoperiod group exhibited more escape attempts compared to that of the standard pho- toperiod group (P < 0.001). An increase in daily photoperiod from 8 to 20 h light also appears to positively influence piglet activity and creep feed intake, without affecting sow activity, the mean duration of nursing and the mean interval between two consecutive nursings. Finally, sow posture appears to significantly influence piglet activity; when the sow was standing the number of piglets that were also standing was greater compared to the other sow postures (sitting or lying) (P < 0.001). As it is concluded, light regimen could be manip- ulated as a tool to improve piglets’ growth performance during lactation. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The pre-weaning piglet mortality continues to be a major welfare and economic concern in pig productive systems, despite the technological advances and devel- opments in pig production and management during the last decades. It is well recognized in practice that many factors such as breed, season of birth, sow parity, age of sow, farmer behaviour, birth weight, farming conditions, sow health status and behaviour influence piglet mortality ∗ Corresponding author at: Iera Odos, 118 55 Athens, Greece. Tel.: +30 2105294449; fax: +30 2105294442. E-mail address: pansimitzis@aua.gr (P.E. Simitzis). (Edwards, 2002; Pedersen et al., 2006; Weber et al., 2009). The highest preweaning mortality rates occur within the first 3 days after birth because of problems with adapta- tion and development (Tuchscherer et al., 2000). Newborn piglets are very sensitive and two of the most important causes of death are crushing and savaging by the dam. The use of an extended photoperiod (24 h instead of 8 h of daily light) during farrowing can reduce the number of gilts that fatally savage their piglets (Harris and Gonyou, 2003). Changes in photoperiodic regimen during gestation or farrowing could be used as a tool with the intention to positively modify sow and piglets behaviour and improve their performance (Harris and Gonyou, 2003; Marby et al., 1983, 1982). Manipulation of photoperiod might provide an effective way of enhancing the efficiency of production 0168-1591/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.applanim.2013.01.014