A study using 4 ruminally cannulated Holstein cows was conducted to evaluate the degradability of maize silage and alfalfa haylage prepared by different processing methods. Maize silage (20-mm length) and alfalfa haylage (40-mm length) were either wet (MSW; AHW) or air-dried (MSD; AHD). Air-dried silage and haylage were also ground to pass through a 2.5-mm screen (MSG; AHG). Samples were incubated in the rumen for 2, 6, 12, 24, 36, 48, and 72 h. Cows were fed ad libitum with free access to water. Treatment MSW had a lower acid detergent fiber (ADF) degradability at 2 h (P < 0.05) compared with air-dried samples (MSD and MSG). Processing methods had significant effects (P < 0.05) on NDF degradability at 72 h, ADF degradability at 36, 48, and 72 h, and ruminal degradable ADF. All of the highest values were observed in AHG treatment (Table 1). Based on this study, processing methods of drying and grinding should be taken into consideration when evaluating nutritive values of forages. Table1. Degradabilities of NDF and ADF in differently processed maize silage and alfalfa haylage incubated in situ¹

Item	Maize silage			P-value	Alfalfa haylage			P-value
MSW	MSD	MSG	AHW	AHD	AHG
NDF
2 h	13.72	16.68	14.48	0.31	24.62	27.76	27.81	0.30
36 h	40.96	41.91	39.91	0.94	50.79	46.23	51.89	0.27
48 h	43.40	42.69	40.80	0.80	51.08	52.75	55.96	0.18
72 h	48.58	55.20	47.31	0.28	53.68b	56.54ab	59.42a	0.03
RDNDF	31.16	34.18	29.81	0.39	41.96	42.82	44.57	0.31
ADF
2 h	12.16b	14.58ab	16.17a	0.09	20.61	21.50	23.91	0.54
36 h	41.54	41.39	51.57	0.22	41.71ab	39.26b	46.68a	0.04
48 h	44.54	45.21	43.30	0.97	46.19b	47.66b	53.10a	0.03
72 h	50.06	54.43	50.95	0.68	49.20b	51.75b	57.05a	<0.01
RDADF	31.41	33.14	33.04	0.85	35.75b	36.62b	40.04a	0.04

^a,bMeans with different superscript letters with the same row represent a significant difference between treatments (P < 0.05). ¹MSW = wet maize silage, MSD = air-dried maize silage, MSG = air-dried ground maize silage, AHW = wet alfalfa haylage, AHD = air-dried alfalfa haylage, AHG = air-dried ground alfalfa haylage, RDNDF = ruminally degradable NDF, RDADF = ruminally degradable ADF.