The objective of the study was to determine the effect of nursery stocking density (STOCK) and feeder space (FS) on gilt estrous traits. Composite Landrace × Large White PIC gilts (n = 230) were weaned at 37 d of age and 9.6 kg. Gilts were randomly assigned to a nursery STOCK of 0.42 or 0.21 m² and a FS of 14.35 or 7.175 cm per pig in a 2 × 2 factorial arrangement. After 33 d in the nursery, gilts were moved to the finisher weighing 23.7 kg. In the finisher, gilts were remixed and housed 15 per pen (0.84 m² per pig). Starting at 181 d of age, gilts were penned daily with a mature boar for 7 min and estrous symptoms recorded. At 188 d of age, gilts were allotted 7 min of fence-line boar contact daily until breeding. Measurements of gilt reproductive performance included: whether or not a gilt reached puberty (Pubertal), age at puberty, puberty weight, vulva width at puberty (Vulva_Width1), length of estrus at puberty (LOE1), vulva width at second estrous (Vulva_Width2), and length of estrus at second estrous (LOE2).Data were analyzed in SAS using PROC MIXED for continuous traits and PROC GLIMMIX for the categorical trait Pubertal. Fixed effects included STOCK, FS, the interaction between STOCK and FS, nursery room and age at first boar exposure. Stocking density and FS LSMEAN estimates for gilt estrous traits are shown in Table 1. Length of estrus at puberty tended (P = 0.08) to be greater for pigs stocked at 0.21 m² when compared with 0.42 m² (1.74 vs. 1.57 d). Yet no other estrous characteristics were affected by STOCK or FS (P ≤ 0.22). Results suggest nursery STOCK and FS have little effect on subsequent gilt estrous characteristics. Table 1. Effect of nursery stocking density and feeder space on subsequent gilt estrous characteristics

Trait	Stocking density, m2				Feeder space, cm/pig
0.42	0.21	SE	14.35	7.175	SE
Pubertal, %	79.4	74.5	4.0		78.7	75.3	4.0
Age at puberty	203.5	202.5	2.7		203.9	202.1	2.7
Puberty weight, kg	138.1	135.7	5.4		136.7	137.1	5.4
Vulva_Width1, cm	38.6	37.7	0.72		38.3	38.1	0.72
LOE1, d	1.57	1.74	0.10		1.65	1.65	0.10
Vulva_Width2, cm	38.2	38.4	1.11		37.9	38.6	1.10
LOE2, d	1.89	1.90	0.15		1.94	1.85	0.15