1225 Effect of variability in lighting and temperature environments for mature gilts housed in gestation crates on measures of reproduction and animal well-being 1 D. C. Canaday,* J. L. Salak-Johnson,* A. M. Visconti,* X. Wang†, K. Bhalerao†, and R. V. Knox* 2 *Department of Animal Sciences and †Department of Agricultural and Biological Engineering, University of Illinois, Urbana-Champaign 61801 ABSTRACT: The effects of room temperature and light intensity before breeding and into early gestation were evaluated on the reproductive performance and well-being of gilts housed individually in crates. In eight replicates, estrus was synchronized in mature gilts (n = 198) and after last feeding of Matrix were randomly assigned to a room temperature of 15°C (COLD), 21°C (NEUTRAL), or 30°C (HOT) and a light intensity of 11 (DIM) or 433 (BRIGHT) lx. Estrous detection was performed daily and gilts inseminated twice. Blood samples were collected before and after breeding for determination of immune measures and cortisol concentrations. Gilt ADFI, BW, and body temperature were measured. On d 30 postbreeding, gilts were slaughtered to recover reproductive tracts to evaluate pregnancy and litter characteristics. There were no temperature × light intensity interactions for any response variable. Reproductive measures of follicle development, expression of estrus, ovulation rate, pregnancy rate (83.2%), litter size (14.3 ± 0.5), and fetal measures were not affected by temperature or lighting (P > 0.10). Gilts in COLD (37.6°C) had a lower (P < 0.05) rectal temperature than those in NEUTRAL (38.2°C) and HOT (38.6 ± 0.04°C). Both BW gain and final BW were greater (P < 0.0001) for gilts kept in HOT than those in NEUTRAL or COLD environments. Cortisol was greater (P < 0.01) for gilts kept in COLD compared with those kept in the HOT room. Gilts housed in the HOT environment made more postural changes (P < 0.05) than did those kept in either COLD or NEUTRAL temperatures. Gilts kept in the HOT temperature spent more total time lying and more time lying ventrally compared with those gilts housed in the NEUTRAL or COLD rooms. Total white blood cells and the percentage of neutrophils as well as neutrophil-to-lymphocyte ratio were all influenced (P < 0.05) by temperature but there was no effect (P > 0.10) of light or interaction with temperature on other immune cells or measures. These results indicate that temperatures in the range of 15 to 30°C or light intensity at 11 to 433 lx do not impact reproduction during the follicular phase and into early gestation for mature gilts housed in gestation crates. However, room temperature does impact physiological, behavioral, and immune responses of mature gilts and should be considered as a potential factor that may influence gilt well-being during the first 30 d postbreeding. Key words: fertility, gestation crate, gilts, lighting, temperature, well-being © 2013 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2013.91:1225–1236 doi:10.2527/jas2012-5733 1 The authors gratefully acknowledge funding support from the Illinois Council on Funding for Agriculture Research (C-FAR) and wish to thank the University of Illinois swine research staff (R. Wischover, S. Hughes, R. Allen, B. Fischer, G. Bressner, and D. Bidner) for their assistance in animal and facility design and management. This work could not have been completed without the help from these Animal Science students: J. Taibl, A. DeDecker, C. Skees, N. Sloter, S. Breen, B. Yantis, K. Spencer, M. Hopgood, J. Ringwelski, and J. Sanders. Our thanks in building plans and maintenance to S. Ford and A. Lenkaitis from Agricultural and Biological Engineering and to S. Hester of Polar Refrigeration, Heating, and Cooling Inc. Lastly, our sincere thanks to J. Jones of Calihan Pork Processors Inc., in Peoria, IL, for allowing us to collect reproductive tracts from our experimental animals. 2 Corresponding author: rknox@illinois.edu Received August 7, 2012. Accepted December 9, 2012. INTRODUCTION Unexplained reproductive failure is common in swine breeding herds and could be related to variation in environmental factors such as temperature and light intensity. High temperatures have been shown to affect puberty (Flowers et al., 1989), litter size, pregnancy rate (Edwards et al., 1968; Omtvedt et al., 1971), feed intake, body temperature, plasma cortisol concentration, and immune function (Abilay et al., 1975; Oki and Atkinson, 2004). Light intensity has Published December 2, 2014