Table 4.

Responsiveness of 1-day-old broiler chickens to vaccination with the K2p170 vaccine by spray.

Days post-exposurea	Rale soundb			Mean ciliostasis scoresc			Histopathologic lesion scoresd
	Control	Inoculated		Control	Inoculated		Upper trachea			Lower trachea			Lung			Kidney
		H120	K2p170		H120	K2p170	Control	Inoculated		Control	Inoculated		Control	Inoculated		Control	Inoculated
								H120	K2p170		H120	K2p170		H120	K2p170		H120	K2p170
Day 4	0/5	3/5	3/5	0.15	0.04	0.00	0.05	0.31	0.95	0	0	0.10	0.40	0.40	0.80	0	0	0
Day 8	0/5	3/5	3/5	0.06	3.04	2.66	0.05	2.30	2.65	0.10	2.05	0.90	0.40	0.40	0.90	0	0	0.10
Day 11	0/5	1/5	1/5	0.14	2.02	1.78	0.20	2.35	1.85	0	1.10	1.10	0	0.20	0.20	0	0	0
Day 14	0/5	0/5	0/5	0.12	1.82	1.14	0.10	1.80	1.65	0	1.75	0.70	0.30	0.50	0.10	0	0	0

^aOne-day-old broiler chicks were inoculated with IBV (10^4.5EID₅₀/bird) by coarse spray.

^bOn days 4, 8, 11, and 14 post-vaccination, birds were checked individually for tracheal rales (a sound emanating from the bronchi, also detected by vibrations when holding a chick).

^cOn days 4, 8, 11, and 14 post-vaccination, tracheas were removed from five chickens in each group (the same animals used for histological sampling). Ten trachea rings per chick were prepared (three upper, four middle, and three lower trachea rings). The rings were examined under low-power magnification and ciliary activity was scored as follows: 0, no ciliostasis; 1, 25% ciliostasis; 2, 50% ciliostasis; 3, 75% ciliostasis; 4, 100% ciliostasis.

^dHistopathology of the trachea, lung, and kidney at 4 days post-challenge with IBV was reported as histopathologic lesion scores.