Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 7/25/2002
Publication Date: N/A
Technical Abstract: Fifteen Holstein cows averaging 256 DIM were blocked by parity and DIM and randomly assigned to 5 squares in a 3x3 Latin square trial and fed TMR containing (DM basis): 40% control alfalfa silage (CAS), 20% corn silage, 33% high moisture corn, 6% soybean meal (18% CP); 40% ammonium tetraformate-treated alfalfa silage (TAS), 20% corn silage, 33% high moisture corn, 6% soybean meal (18% CP); or 54% red clover silage (RCS), 6% dried molasses, 33% high moisture corn, and 6% soybean meal (16% CP). All diets contained 33% NDF and 38 to 40% NFC. Hay-crop silages differed (P < 0.01) in NPN and ADIN (% of total N): 49 and 4% (CAS); 45 and 4% (TAS); and 28 and 17% (RCS). Periods were 4-wk long; data were collected during the last 2-wk of each period and analyzed using proc mixed in SAS. Means separated using a protected LSD (a = 0.05) are reported below. Replacing CAS with TAS (with lower NPN) increased DMI, yield of milk, FCM, protein, and SNF, and DM- and N-efficiency. Replacing CAS with RCS (with lower NPN but higher ADIN) also increased DMI and N-efficiency but did not increase yield. Replacing CAS or TAS with RCS lowered MUN and milk NPN, increased apparent digestibility, and diverted N excretion from urine to feces.