A cinnamaldehyde feed additive improved feed use-efficiency in lactating dairy cows

Dietary supplementation of essential oils (EO) may increase milk yield and feed use-efficiency in Holstein cattle. A study was conducted to determine the effect of EO feed additives in dairy cattle productivity. The hypothesis was that compared with cinnamaldehyde feed additive supplementation, the supplementation with an additive containing a blend of cinnamaldehyde and garlic oil would improve feed use-efficiency in lactating dairy cattle. Forty-eight lactating Holstein cows (34 multiparous, days in milk (DIM) 118 +/- 31.1, and 14 primiparous, DIM 134 +/- 38.8) were enroled and randomly assigned to one of three treatments for 8 weeks: 1) control diet (CTRL; no EO supplementation; n = 16), 2) supplementation with cinnamaldehyde (CIN; 600 mg of a prototype to provide 125 mg of cinnamaldehyde; Novus International Inc., St. Charles, MO; n = 16), or 3) supplementation with essential oil blend (EOB; Next Enhance (R) CGO feed additive, Novus International Inc., St. Charles, MO; to provide 125 mg of cinnamaldehyde and 10 mg of garlic oil; n = 16). Cows were housed in a free-stall barn and the diet was offered as total mixed ration (TMR) formulated with 36% forage and 64% concentrate. The TMR was fed individually and EO additives were top-dressed. Production data were collected and analyzed using the Mixed procedure of SAS (version 9.4) where the fixed effects of treatment, time (i.e., week or day, as repeated measurements), and all possible interactions were included in the model. Compared with CTRL, CIN and EOB decreased (P < 0.05) dry matter intake (DMI, 30.1, 28.2, and 29.6 kg/day respectively). Yields of milk, fat, protein and lactose, and percentage of fat, protein and lactose were not affected by treatments. Compared with CTRL, CIN and EOB decreased (P < 0.05) milk urea nitrogen (MUN) concentrations (11.8, 10.9 and 11.4 mg/dL, respectively). Compared with CTRL, EOB reduced (P < 0.05) somatic cell count (126 and 84 x 103 cells/mL, respectively). Body weight, body condition score, and plasma free fatty acid concentrations were not affected by treatments. Compared with CTRL and EOB, CIN increased (P < 0.05) energy-corrected milk yield (ECM) to DMI ratio (1.63, 1.64 and 1.68, respectively). Moreover, there was a tendency (P < 0.10) for EOB and CIN treatments to increase milk yield to DMI ratio. Compared with CTRL, CIN elicited an increase (P < 0.05) in the conversion efficiency of dietary nitrogen into milk protein (28.1 and 28.7%, respectively). In our study, CIN supplemen-tation increased nitrogen use-efficiency to sustain synthesis of ECM. Therefore, dietary supplementation of cinnamaldehyde may be used to improve nitrogen metabolism and increase feed use-efficiency in lactating dairy cows.