Effects of urea formaldehyde condensation polymer treatment of flaxseed on ruminal digestion and lactation in dairy cows.

Flaxseed is a potent source of the n-3 fatty acid α-linolenic acid (ALA), yet most ALA is lost during ruminal biohydrogenation when ground flaxseed is fed to ruminants. Heat processing and urea formaldehyde condensation polymer (UFCP) treatment of flaxseed were investigated as possible means of protecting ALA from ruminal degradation. Ground flaxseed (GF), heated ground flaxseed (HGF), or UFCP-treated ground flaxseed (UFCPGF) were incubated for 0, 4, 8, and 12h in 4 ruminally cannulated multiparous lactating Holstein cows. Compared with GF, HGF and UFCPGF decreased ruminal disappearance of dry matter, crude protein, and ALA. Pepsin-digestible protein remaining after 12h of ruminal incubation was greater for UFCPGF and HGF than for GF. Twenty-four lactating Holstein cows (207 ± 37 d in milk, 668 ± 66 kg of body weight, and 1.33 ± 0.56 lactations) were then used in a randomized complete block design experiment with a basal feeding period to assess effects of flaxseed treatment on ALA enrichment of plasma and milk as well as lactational performance. No evidence existed that supplementation of HGF and UFCPGF affected dry matter intake, milk fat content, milk protein content, or energy-corrected milk yield, but UFCPGF marginally decreased milk yield compared with HGF. Plasma concentration of ALA was not affected by treatment. Concentrations of n-3 fatty acids and conjugated linoleic acids in milk fat were increased by UFCPGF relative to HGF, but ALA yield was not affected. Taken together, in situ results suggest that heat-treated flaxseed, with or without UFCP treatment, slowed ruminal disappearance of ALA. Feeding UFCP-treated flaxseed failed to alter ALA content of plasma or milk ALA yield relative to heating alone.

Influence of nonenzymatically browned soybeans on ruminal fermentation and lactational performance of dairy cows.

Four ruminally fistulated Holstein cows were assigned to one of four total mixed rations (TMR) in a 4 x 4 Latin square with 3-wk periods to investigate the effects of added lipid from nonenzymatically browned soybeans or soybean oil on ruminal metabolism and milk fatty acids. All rations contained 50% forage and 1) 4% added lipid from soybean oil, 2) 4 or 6% added lipid from nonenzymatically browned soybeans, or 3) no added lipid (control). The TMR that contained nonenzymatically browned soybeans increased milk C18:2 by 35% compared with the TMR that contained soybean oil. A lactation trial was conducted in which 60 Holstein cows were assigned to one of five TMR from wk 3 to 18 of lactation. The TMR contained 1) 4.5% added lipid from soybean oil, 2) 1.5% added lipid from nonenzymatically browned soybeans and 3% from soybean oil, 3) 3% added lipid from nonenzymatically browned soybeans and 1.5% from soybean oil, 4) 4.5% added lipid from nonenzymatically browned soybeans, and 5) 4.5% added lipid from Ca salts of long-chain fatty acids. Dry matter intake was reduced by 11% for cows fed the TMR containing soybean oil only compared with that for cows fed the other TMR. Milk C18:2 and C18:3 were increased as the inclusion of nonenzymatically browned soybeans in the TMR increased. All percentages of the nonenzymatically browned soybeans fed to cows resulted in fat-corrected milk yields that were similar to those of cows fed the TMR that contained Ca salts of fatty acids.