Fatty acid intake alters growth and immunity in milk-fed calves.

The aim of the present study was to determine the effect of supplementing milk replacer (MR) with NeoTec4 (Provimi North America, Brookville, OH), a commercially available blend of butyric acid, coconut oil, and flax oil, on calf growth, efficiency, and indices of immune function. In trial 1a, 48 male Holstein calves were fed either a control MR that contained only animal fat or the same MR with NeoTec4 (treatment) along with free-choice starter. The MR (28.7% crude protein, 15.6% fat) was fed at an average of 1 kg of dry matter (DM)/d. In trial 1b, weaned calves from trial 1a were all fed dry starter for 28 d without NeoTec4 (phase 1), and then half the calves were fed NeoTec4 for 28 d (phase 2). In trial 2, 40 male Holstein calves were fed a control MR with lard, coconut oil, and soy lecithin or the same MR supplemented with NeoTec4 (treatment). The MR (22.8% crude protein, 18.9% fat) was fed at an average of 1 kg of DM/d; no starter was fed. In trial 1a, NeoTec4 improved average daily gain, feed intake, and feed efficiency, reduced the number of days that calves experienced scours, and reduced the medical treatments for clostridium sickness. In trials 1a and 2, NeoTec4 altered the inflammatory response to vaccination with Pasteurella at 5 wk of age and to challenge with Salmonella toxin at less than 2 wk of age (fed NeoTec4 for 6 d), as observed by reduced hyperthermia and hypophagia, and altered the tumor necrosis factor-α response. In addition, NeoTec4 enhanced the response in IL-4 and globular protein estimates postchallenge and enhanced titers for bovine viral diarrhea and respiratory parainfluenza-3. Postchallenge serum concentrations of albumin were lower and urea nitrogen concentrations were greater in control calves than in calves fed NeoTec4. In trial 1b, performance did not differ during the first 28 d when no calves received NeoTec4, but calves receiving NeoTec4 in the second 28 d had greater average daily gain and feed efficiency. We conclude that supplementation of MR with NeoTec4 alters some immune and inflammatory responses, including increasing titers to bovine viral diarrhea and respiratory parainfluenza-3 vaccinations, reduces scours, reduces medical treatments for clostridium sickness, and improves growth rates and feed efficiency.