Increasing dietary levels of citral oil on nutrient total tract digestibility, ruminal fermentation, and milk composition in Saanen goats

Abstract

This study was undertaken to evaluate the effects of increasing dietary doses of high purity citral oil on nutrient total tract digestibility, ruminal fermentation, blood metabolites, milk yield and composition, and N utilization in dairy goats. Twenty-four Saanen goats [62±1.4kg of body weight (BW), 75±20days in milk, and 3.0±0.27kg/d of milk yield, at the start of experiment], being eight of them rumen-cannulated, were used in a 4×4 Latin square design experiment with 21-d periods in which the first 14 d were allowed to treatment adaptation. Animals were assigned to the following treatments: control, with no citral supply; and dietary addition of 0.08, 0.16 or 0.24mL of citral oil per kg of BW. Increasing doses of citral oil did not affect dry matter (DM) and nutrient intake, but it linearly decreased neutral detergent fiber total tract digestion in dairy goats. Treatments neither affected ruminal pH nor NH3N, but citral oil linearly increased butyrate proportion in ruminal fluid of goats. Citral oil consumption had a positive quadratic effect on ruminal propionate (mmol/dL and mmol/100mmol) and butyrate (mmol/dL) in goats. Treatments had a negative quadratic effect on ruminal acetate to propionate ratio and acetate proportion. Citral consumption by dairy goats linearly decreased blood urea concentration. Although treatments did not affect milk and fat-corrected milk yield, citral oil linearly decreased milk fat production in goats. Citral had no effect on milk fatty acid profile and N utilization in goats. Citral consumption had no effect on DM and nutrient intake as well as on fat-corrected milk yield, but it may increase ruminal propionate concentration in dairy goats.