The effects of some essential oils on milk yield, milk composition and methane production in goat

The objective of this study was to evaluate 6 essential oils/EO?s (garlic, thyme, clove, orange peel, mint and cinnamon) on in vitro digestibility, milk yield, milk composition and methane emission in goat. The first in-vitro test was arranged to determine three optimum EO?s and doses (100, 200, 300 ppm). 3 determined EO?s (clove (CO), cinnamon (CIN), and orange peel (PO) essential oils) at doses 300 ppm were used for the 2nd in-vitro test and two in-vivo test. The second in-vitro test was arranged to evaluated 3 combination of EO?s (COPO, COCIN and POCIN) with in-vitro Hohenheim gas test method (HGT) and Daisy incubator true digestibility test (ANKOM Tech.). The combination (300 ppm or 1.8 g/d doses) also was evaluated at first in-vivo test for in vivo CH4 production and in-vivo apparent digestibility (IVAD) used open respiratory chamber system (MARS system, Sable®). The second in-vivo test used on 120 German Fawn x Hair first backcross (B1) dairy goats determining for effect of the combination on milk yield (MY) and quality. The 1st in vitro test resulted highest level in-vitro methane reduction potential (MRP,%) 72.83% at PO 300 ppm after 6 h incubation, while CO 300 ppm had highest in vitro true digestibility of dry matter (IVTDDM) 81.41% after 30 hour incubation. CIN had high value both of MRP level and IVTDDM (48.91 and 79,12 %). Combination of CO, CIN and PO in 2nd in vitro test increased MRP but there was no interaction affect both of in vitro MRP and IVTDDM. The first in vivo test resulted that all combination reduced in vivo CH4 production but did not increase nutrient intake. There was no affect of all combination on milk yield (MY) and milk composition but all of combination had in vivo MRP in same average (27.18 to 28.80%). Oral infusion only CO, CIN or PO had better values of all of test than combination because of strong antimicrobial of eugenol (CO), cinnamaldehyde and thymol (CIN) and limonene (PO). In conclusion, CO, CIN and PO at doses 300 ppm or infusion, 1.8 g/day, could be used as goat feed additive for reduce methane emission but no negative effect on goat performance (milk yield, milk composition and live weight change). There was no advantage for combine CO, CIN and PO at doses 300 ppm or infusion 1.8/day under feeding condition with 60/40 concentrate/roughage ratio with relatively low yielding goats.