Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: March 20, 2003
Publication Date: June 20, 2003
Citation: Soder, K.J., Sanderson, M.A., Muller, L.D., Stack, J.L. 2003. Effect of forage diversity on intake and productivity of grazing lactating dairy cows [abstract]. Joint Abstracts of the American Dairy Science and Society of Animal Science. 86(Suppl. 1):93. Technical Abstract: A study was designed to determine the effects of forage diversity on intake and productivity of grazing lactating dairy cows. Sixteen lactating Holstein cows (100 DIM, 634 kg BW, 4 ruminally cannulated) were assigned to four 4x4 Latin squares with 21-d periods. The four pasture treatments were: (2SP) Orchardgrass/white clover; (3SP) 2SP + chicory; (6SP) 3SP + tall fescue, perennial ryegrass, and birdsfoot trefoil; and (9SP) 6SP + red clover, alfalfa, and bluegrass. Pasture allowance was 25 kg DM/cow/d. Cows were fed a 13% CP corn-based concentrate (1 kg/4 kg milk) in two equal feedings after milking. Pasture DMI was measured using Cr2O3 as a fecal marker. Pasture CP was highest for the 3SP mix. The 2SP mix had the highest NDF and lowest IVDMD. DMI, milk yield, milk fat and protein, and rumen NH3-N were not affected by treatment. Milk urea N increased on the most complex mix (9SP). Rumen pH and VFA tended to be higher for the 2SP mix. Acetate:propionate decreased with increasing level of pasture diversity. Level of forage diversity did not have a major impact on DMI or productivity of grazing dairy cows. However, forage production and carrying capacity were greater on the complex mixtures than on the 2SP mix.