Digestion of fat in calves fed milk replacers prepared by homogenization of low-pressure dispersion.

High-fat (40% of dry matter) milk replacers were fed to calves from 3 to 14 days of age to determine the effect of fat dispersion method on abomasal retention of dietary fat and crude protein and on digestion of fat in upper parts of the gastrointestinal tract. Relative to homogenization, low pressure dispersion of fat into milk replacer resulted in a) much larger rennet clots in the abomasum, b) increased abomasal retention of dietary triglycerides and crude protein, and c) increased triglyceride hydrolysis in the abomasum, duodenum, and upper jejunum at 4 h after feeding. When high-fat diet was fed to postnatal calves, formation of large firm clots was beneficial for promoting a slower release of fat and protein into the duodenum, and digestion of fat was improved in the gastrointestinal tract. Pregastric esterase hydrolysis of dietary triglycerides (tallow, coconut oil) in the abomasum resulted in preferential release of capric, lauric, and myristic fatty acids and a proportionately low release of palmitic and stearic acids.