Effects of feeding formate-treated alfalfa silage or red clover silage on the production of lactating dairy cows.
In trial 1, 15 Holsteins were fed 3 total mixed rations (TMR) with 33% neutral detergent fiber in 3 x 3 Latin squares (28-d periods). Two TMR contained (dry matter basis): 40% control alfalfa silage (CAS) or 40% ammonium tetraformate-treated alfalfa silage (TAS), 20% corn silage (CS), 33% high-moisture shelled corn (HMSC), 6% solvent soybean meal (SSBM), and 18% crude protein (CP); the third TMR contained 54% red clover silage (RCS), 6% dried molasses, 33% HMSC, 6% SSBM, and 16.3% CP. Silages differed in nonprotein N (NPN) and acid detergent insoluble N (ADIN; % of total N): 50 and 4% (CAS); 45 and 3% (TAS); 27 and 8% (RCS). Replacing CAS with TAS increased intake, yields of milk, fat-corrected milk, protein, and solids-not-fat, and apparent dry matter and N efficiency. Replacing CAS with RCS increased intake and N efficiency but not milk yield. Replacing CAS or TAS with RCS lowered milk urea N, increased apparent nutrient digestibility, and diverted N excretion from urine to feces. In trial 2, 24 Holsteins (8 ruminally cannulated) were fed 4 TMR in 4 x 4 Latin squares (28-d periods). Diets included the CAS, TAS, and RCS (RCS1) fed in trial 1 plus an immature RCS (RCS2; 29% NPN, 4% ADIN). The CAS, TAS, and RCS2 diets contained 36% HMSC and 3% SSBM and the RCS1 diet contained 31% HMSC and 9% SSBM. All TMR had 50% legume silage, 10% CS, 27% neutral detergent fiber, and 17 to 18% CP. Little difference was observed between cows fed CAS and TAS. Intakes of DM and yields of milk, fat-corrected milk, fat, protein, lactose, and solids-not-fat, and milk fat and protein content were greater on alfalfa silage vs. RCS. Blood urea N, milk urea N, ruminal ammonia, and total urinary N excretion were reduced on RCS, suggesting better N utilization on the lower NPN silage. Apparent N efficiency tended to be higher for cows fed RCS but there was no difference when N efficiency was expressed as kilograms of milk yield per kilogram of total N excreted.
Broderick
G A
GA
Agricultural Research Service, USDA US Dairy Forage Research Center, 1925 Linden Drive West, Madison 53706, USA. gbroderi@wisc.edu
Brito
A F
AF
Olmos Colmenero
J J
JJ
D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004063:Digestion / Q000187:drug effects / Q000502:physiology; D005243:Feces / Q000737:chemistry; D005260:Female; D005561:Formates / Q000008:administration & dosage*; D006863:Hydrogen-Ion Concentration; D007774:Lactation / Q000502:physiology*; D000455:Medicago sativa / Q000737:chemistry / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis; D011897:Random Allocation; D012417:Rumen / Q000737:chemistry / Q000378:metabolism; D012820:Silage / Q000032:analysis; D013997:Time Factors; D029921:Trifolium / Q000737:chemistry / Q000378:metabolism*
D005561:Formates; C030544:formic acid; D009584:Nitrogen