This study investigated the interaction of stocking density and feed availability on short-term behavioral responses of dairy cattle. Multiparous (n = 48) and primiparous (n = 20) lactating Holstein cows were assigned to 1 of 4 pens (n = 17 cows/pen). Pens were balanced for parity (2.3 ± 1.1; mean ± SD), DIM (121 ± 38), and milk production (47 ± 8 kg/d). Treatments were assigned to pens in a 4 × 4 Latin square with 14-d periods using a 2 × 2 factorial arrangement. Two stocking densities (STKD; 100 or 142% of stalls and headlocks) and 2 levels of feed access (FA; no restriction, NR and 5 h restriction from 19 to 24 h post-feeding, R, resulted in 4 treatments: (1) 100NR, (2) 100R, (3) 142NR, and (4) 142R. Pen intake was measured on d 8–14 of each period. Time spent lying, feeding, and ruminating were measured using 10-min scan sampling for 72-h from d 8–10 of each period. Data were analyzed using a mixed model in JMP with pen as the experiment unit. Overstocking decreased daily lying time. Overstocking tended, and R decreased, daily feeding time. Intake (25.8 kg/cow/d, SEM = 0.3) did not differ (P > 0.10). While STKD did not alter total rumination time, overstocking decreased rumination within the free-stall, implying a shift in location of rumination. Feeding and rumination times were shifted with R, increasing feeding and decreasing rumination 0 to 8 h post-feed delivery while decreasing feeding and increasing rumination 17 to 24 h post-feed delivery. In response to reduce feed access, cows altered their feeding and rumination patterns to maintain total chewing activity. An additive effect of overstocking and feed access was not evident in these behaviors. Table 1.

Item	100%			142%		SEM	P-value
	NR	R		NR	R		STKD	FA	STKD × FA
Lying time, min/d	784	786		761	752	13	0.02	0.68	0.55
Feeding time
Daily total, min/d	230	222		227	219	6	0.08	<0.01	0.96
0-8 h post-feeding, min	87	98		83	95	3	0.18	<0.01	0.85
17-24 h post-feeding, min	60	39		61	41	2	0.41	<0.01	0.73
Rumination time
Daily total, min/d	510	524		519	517	9	0.90	0.43	0.31
0-8 h post-feeding, min	162	155		163	152	3	0.73	<0.01	0.33
17-24 h post-feeding, min	185	200		189	199	5	0.77	0.02	0.50
Rumination in freestall
% total rumination	85.0	84.4		80.0	78.2	1.4	<0.01	0.18	0.53