- Email: [email protected]
Effect of Lavender Aromatherapy on Acute-Stressed Horses
Journal of Equine Veterinary Science 33 (2013) 67-69
Journal of Equine Veterinary Science journal homepage: www.j-evs.com
Short Communication
Effect of Lavender Aromatherapy on Acute-Stressed Horses Clarence E. Ferguson PhD, Harry F. Kleinman DVM, Justin Browning MS Department of Agricultural Sciences, McNeese State University, Lake Charles, LA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 24 January 2012 Received in revised form 10 April 2012 Accepted 24 April 2012 Available online 6 June 2012
Methods to reduce the effects of acute stress could benefit the equine industry; therefore, the objective of this experiment was to determine whether aromatherapy would hasten the recovery time in acute-stressed horses. A total of seven horses were used in this experiment, using a crossover design where each horse received each treatment 7 days apart. The heart rates (HRs) and respiratory rates (RRs) were recorded for each horse at rest in stalls; then an air horn was blown twice for 15 seconds. The horses were allowed 60 seconds to calm, and then the stressed HRs and RRs were recorded. Control-treated horses were then exposed to humidified air, whereas aromatherapy-treated horses were exposed to humidified air with a 20% mixture of 100% pure lavender essential oil for 15 minutes. Following the 15-minute control or aromatherapy treatment, the recovery HRs and RRs were recorded (15 minutes). There were no statistical differences (P > .05) between the control and aromatherapy treatment for resting HR 33.7 3.6 versus 34.0 3.1 beats per minute (bpm), or change to increased HR in response to the air horn. However, the change in HR, after treatment, was significantly greater (P < .02) after aromatherapy ( 9.25 3.4 bpm) compared with the control treatment (0.29 1.5 bpm). The RR did not differ (P > .05) between the control or aromatherapy treatment groups for the resting RR or change in RR. These results demonstrate that lavender aromatherapy can significantly decrease HR after an acute stress response and signal a shift from the sympathetic nervous control from the parasympathetic system. Ó 2013 Elsevier Inc. All rights reserved.
Keywords: Aromatherapy Lavender Stress Heart rate Horses
1. Introduction Horses evolved on the prairies of North America [1], and there they developed a heightened sense of sight and sound [2]. However, as domesticated work and sport animals, this excitable instinct in horses often causes problems to its health during training, especially when environmental stimuli (e.g., loud noises and novel destinations) causes fear reactions, such as stress, experienced during hauling [3,4]. The repeated pattern of accumulated stressors can also result in chronic stress, which is known to decrease productivity traits in many farm animals [5].
Corresponding author at: Clarence E. Ferguson, PhD, Department of Agricultural Sciences, McNeese State University, Box 92220, Lake Charles, LA. E-mail address: [email protected] (C.E. Ferguson). 0737-0806/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. doi:10.1016/j.jevs.2012.04.014
The use of lavender may be a beneficial treatment to combat the effects of stress experienced by animals during these events, as lavender has been reported to restore calmness in dogs [6] and humans [7,8]. Therefore, this experiment was designed to test the ability of lavender aromatherapy to decrease equine heart rate (HR) and respiratory rate (RR) following induced acute stress, and thereby enhance recovery from stress. 2. Materials and Methods A total of seven mature Quarter Horses with a mean age of 7 years were used in this study and were treated in accordance with McNeese State University Animal Care and Use Committee guidelines. Horses were randomly assigned to treatments so that one-half would receive one lavender treatment first and the other half would receive control treatment first. Following initial treatment, the horse
68
C.E. Ferguson et al. / Journal of Equine Veterinary Science 33 (2013) 67-69
would receive the other treatment w1 week after the first treatment so that each horse received both treatments (crossover design) within a 2-week period. The HRs and RRs were recorded at rest in a stall ( 1 minute) separated from others receiving a different treatment at that time; then the halter and lead rope were removed. All HR and RR recordings were performed under the supervision of a practicing veterinarian. During the time that the initial HRs and RRs were being recorded and before the stressor, horses were assigned a calm score, which was an average of two scores, from 1 to 5 based on the level of calmness observed as several people walked in and out of the stall. A score of 1 reflected a very calm horse not interested in events occurring in the stall, whereas a calm score of 5 represented a very excited horse that was extremely nervous because of the events occurring in the stall. Next, an air horn (Safety-Sport Horn, LPI, Pompano Beach, FL) adjacent to the stall containing the horse was blown twice for 15 seconds (0 minutes). All horses were allowed 60 seconds to calm (for safety purposes) and then were haltered. The stressed HRs and RRs were then recorded (1 minute). Following this, control-treated horses were exposed to humidified air for 15 minutes using a humidifier (Westinghouse, WDD 100 Ultrasonic Humidifier with Aromatherapy, 8½ ounce tank, WestAire Co. LLC, Naperville, IL) by holding the horse’s nostrils in proximity to the released humid air. Horses receiving aromatherapy were treated similarly, but were treated with a humid air produced from a 20% mixture of water and 100% pure lavender (Lavandula augustifolia) essential oil (Plantlife, San Clemente, CA) for 15 minutes. After 15 minutes of treatment, the recovery HR (RHR) and recovery RR (RRR) were recorded. Statistical analysis was performed using PROC MIXED procedures with repeated measures in SAS (SAS Institute, Inc., Gary, NC). The horse’s age, sex, calm score, resting HR, resting RR, stressed HR, stressed RR, RHR, RRR, and their interactions were analyzed using repeated measures of analysis of variance with a Tukey post hoc test. 3. Results There were no statistical differences (P > .05) between the control- and aromatherapy-treated horses for resting HR (33.7 3.6 beats per minute [bpm] versus 34.0 3.1 bpm), stressed HR (38.8 3.9 bpm versus 45.5 5.3 bpm), or RHR (39.1 3.3 bpm versus 36.2 3.8 bpm). Additionally, there were no differences in the change of heart rate from resting to stressed among control-treated (5.1 1.7 bpm) or lavender-treated horses (11.5 4.1 bpm). However, there was a significant decrease in the HR from the stressed HR to RHR in lavender-treated horses ( 9.3 3.4 bpm) compared with control-treated horses (0.28 1.5 bpm) (Table 1). Of the seven horses, four received a calm score of 2 and three received a calm score of 1. These horses were consistent during each trial period. Among horses with a calm score of 2, lavender aromatherapy significantly reduced (P < .0017) HR ( 14.0 4.8 bpm) compared with the same horses during control treatment (0.5 0.5 bpm). There were no statistical differences between controland lavender-treated horses in change of RR from rest to
Table 1 The changes in heart rate, respiratory rate from stressor to end of 15-minute treatment with lavender or humid air, and initial calm score before stressor and treatment Treatment n Change in Heart Change in Respiratory Initial Calm Rate (bpm) Rate (brpm) Score Control Lavender
7 7
0.3 1.5a 9.3 3.4b
0.9 2.6a 3.1 1.5a
1.5 0.2a 1.8 0.3a
a,b Values within a column with differing superscripts are different (P < .05).
stress (0.0 2.8 breaths per min [brpm] vs. 1.9 1.9 brpm) or in the change of RR from stressed to recovery ( 0.9 2.6 brpm vs. 3.1 1.5 brpm) (Table 1). 4. Discussion The results of this experiment demonstrate that 15 minutes of aromatherapy with lavender essential oil can reduce HR in horses. Similar findings have also been reported in dogs [6] and humans [7,8]. Lavender has also been reported to have a sedative effect by reducing the amount of movement in laboratory mice [9] and sheep [10]. When aerosolized lavender breaks down, into two active components: linalool and linalyl acetate, which are responsible for the biological activity of lavender [9]. Herz [11] reported that lavender was capable of restoring control of primary regulation of bodily functions to the parasympathetic nervous system following a “flight or fight” reflex response and may be the mode of action in the horse to reduce HR. The increased sedative effects of lavender among horses with a higher calm score may be the result of these animals deviating further away from baseline HR, which allows for a greater discrepancy between no treatment and lavender. Additionally, one limitation of this study is that the horses used were American rodeo horses, which do not easily become stressed because of an air horn. These horses are accustomed to explosions during the rodeo opening ceremonies. In future experiments, the use of feral horses, yearlings, or foals may likely demonstrate greater changes after lavender aromatherapy. In conclusion, equine practitioners could use lavender aromatherapy to reduce nervousness among horses in the examination area, or for treatment following performance competition to possibly hasten recovery time. However, the use of lavender should be considered only as a short-term solution, as studies in humans report short-term benefits but no differences when evaluated over long-term treatment periods [7]. Acknowledgments The authors thank Dr Delma Porter of the McNeese State University Writing Center for her assistance in proofreading and editing this manuscript. References [1] Janis CM, Damuth J, Theodor JM. The origins and evolution of the North American grassland biome: the story from the hoofed mammals. Palaeogeogr Palaeoclimatol Palaeoecol 2002;177:183-98.
C.E. Ferguson et al. / Journal of Equine Veterinary Science 33 (2013) 67-69 [2] Saslow CA. Understanding the perceptual world of horses. Appl Anim Behav Sci 2002;78:209-24. [3] Cregier SE. Reducing equine hauling stress: a review. J Equine Vet Sci 1982;2:186-98. [4] Waran NK, Cuddeford D. Effects of loading and transport on the heart rate and behavior of horses. Appl Anim Behav Sci 1995; 43:71-81. [5] Grandin T. Review: reducing handling stress improves productivity and welfare. Prof Anim Sci 1998;14:1-10. [6] Komiya M, Sugiyama A, Tanabe K, Uchino T, Takeuchi T. Evaluation of the effect of topical application of lavender oil on autonomic nerve activity in dogs. Am J Vet Res 2009;70:764-9. [7] Kuroda K, Inoue N, Ito Y, Kubota K, Sugimoto A, Kaduda T, et al. Sedative effects of the jasmine tea odor and R-(-)-linalool, one of its
[8]
[9]
[10]
[11]
69
major odor components, on autonomic nerve activity and mood states. Eur J Appl Physiology 2005;95:107-14. Chien LW, Ceng SL, Chi FL. The effect of lavender aromatherapy on autonomic nervous system in midlife women with insomnia. Evid Based Complement Alternat Med 2012;2012:740813. Buchbauer G, Jirovetz L, Jäger W, Dietrich H, Plank C. Aromatherapy: evidence for sedative effects of the essential oil of lavender after inhalation. Z Naturforsch C 1991;46:1067-72. Hawken P, Fiol C, Blache DB. Behavioral reactivity to psychosocial stress determines the effects of lavender oil on anxiety in sheep. J Anim Sci 2011;89(E-Suppl 1):10. Herz RS. Aromatherapy facts and fiction: a scientific analysis of olfactory effects on mood, physiology and behavior. International J Neurosci 2007;119:263-90.
Journal of Equine Veterinary Science journal homepage: www.j-evs.com
Short Communication
Effect of Lavender Aromatherapy on Acute-Stressed Horses Clarence E. Ferguson PhD, Harry F. Kleinman DVM, Justin Browning MS Department of Agricultural Sciences, McNeese State University, Lake Charles, LA
a r t i c l e i n f o
a b s t r a c t
Article history: Received 24 January 2012 Received in revised form 10 April 2012 Accepted 24 April 2012 Available online 6 June 2012
Methods to reduce the effects of acute stress could benefit the equine industry; therefore, the objective of this experiment was to determine whether aromatherapy would hasten the recovery time in acute-stressed horses. A total of seven horses were used in this experiment, using a crossover design where each horse received each treatment 7 days apart. The heart rates (HRs) and respiratory rates (RRs) were recorded for each horse at rest in stalls; then an air horn was blown twice for 15 seconds. The horses were allowed 60 seconds to calm, and then the stressed HRs and RRs were recorded. Control-treated horses were then exposed to humidified air, whereas aromatherapy-treated horses were exposed to humidified air with a 20% mixture of 100% pure lavender essential oil for 15 minutes. Following the 15-minute control or aromatherapy treatment, the recovery HRs and RRs were recorded (15 minutes). There were no statistical differences (P > .05) between the control and aromatherapy treatment for resting HR 33.7 3.6 versus 34.0 3.1 beats per minute (bpm), or change to increased HR in response to the air horn. However, the change in HR, after treatment, was significantly greater (P < .02) after aromatherapy ( 9.25 3.4 bpm) compared with the control treatment (0.29 1.5 bpm). The RR did not differ (P > .05) between the control or aromatherapy treatment groups for the resting RR or change in RR. These results demonstrate that lavender aromatherapy can significantly decrease HR after an acute stress response and signal a shift from the sympathetic nervous control from the parasympathetic system. Ó 2013 Elsevier Inc. All rights reserved.
Keywords: Aromatherapy Lavender Stress Heart rate Horses
1. Introduction Horses evolved on the prairies of North America [1], and there they developed a heightened sense of sight and sound [2]. However, as domesticated work and sport animals, this excitable instinct in horses often causes problems to its health during training, especially when environmental stimuli (e.g., loud noises and novel destinations) causes fear reactions, such as stress, experienced during hauling [3,4]. The repeated pattern of accumulated stressors can also result in chronic stress, which is known to decrease productivity traits in many farm animals [5].
Corresponding author at: Clarence E. Ferguson, PhD, Department of Agricultural Sciences, McNeese State University, Box 92220, Lake Charles, LA. E-mail address: [email protected] (C.E. Ferguson). 0737-0806/$ - see front matter Ó 2013 Elsevier Inc. All rights reserved. doi:10.1016/j.jevs.2012.04.014
The use of lavender may be a beneficial treatment to combat the effects of stress experienced by animals during these events, as lavender has been reported to restore calmness in dogs [6] and humans [7,8]. Therefore, this experiment was designed to test the ability of lavender aromatherapy to decrease equine heart rate (HR) and respiratory rate (RR) following induced acute stress, and thereby enhance recovery from stress. 2. Materials and Methods A total of seven mature Quarter Horses with a mean age of 7 years were used in this study and were treated in accordance with McNeese State University Animal Care and Use Committee guidelines. Horses were randomly assigned to treatments so that one-half would receive one lavender treatment first and the other half would receive control treatment first. Following initial treatment, the horse
68
C.E. Ferguson et al. / Journal of Equine Veterinary Science 33 (2013) 67-69
would receive the other treatment w1 week after the first treatment so that each horse received both treatments (crossover design) within a 2-week period. The HRs and RRs were recorded at rest in a stall ( 1 minute) separated from others receiving a different treatment at that time; then the halter and lead rope were removed. All HR and RR recordings were performed under the supervision of a practicing veterinarian. During the time that the initial HRs and RRs were being recorded and before the stressor, horses were assigned a calm score, which was an average of two scores, from 1 to 5 based on the level of calmness observed as several people walked in and out of the stall. A score of 1 reflected a very calm horse not interested in events occurring in the stall, whereas a calm score of 5 represented a very excited horse that was extremely nervous because of the events occurring in the stall. Next, an air horn (Safety-Sport Horn, LPI, Pompano Beach, FL) adjacent to the stall containing the horse was blown twice for 15 seconds (0 minutes). All horses were allowed 60 seconds to calm (for safety purposes) and then were haltered. The stressed HRs and RRs were then recorded (1 minute). Following this, control-treated horses were exposed to humidified air for 15 minutes using a humidifier (Westinghouse, WDD 100 Ultrasonic Humidifier with Aromatherapy, 8½ ounce tank, WestAire Co. LLC, Naperville, IL) by holding the horse’s nostrils in proximity to the released humid air. Horses receiving aromatherapy were treated similarly, but were treated with a humid air produced from a 20% mixture of water and 100% pure lavender (Lavandula augustifolia) essential oil (Plantlife, San Clemente, CA) for 15 minutes. After 15 minutes of treatment, the recovery HR (RHR) and recovery RR (RRR) were recorded. Statistical analysis was performed using PROC MIXED procedures with repeated measures in SAS (SAS Institute, Inc., Gary, NC). The horse’s age, sex, calm score, resting HR, resting RR, stressed HR, stressed RR, RHR, RRR, and their interactions were analyzed using repeated measures of analysis of variance with a Tukey post hoc test. 3. Results There were no statistical differences (P > .05) between the control- and aromatherapy-treated horses for resting HR (33.7 3.6 beats per minute [bpm] versus 34.0 3.1 bpm), stressed HR (38.8 3.9 bpm versus 45.5 5.3 bpm), or RHR (39.1 3.3 bpm versus 36.2 3.8 bpm). Additionally, there were no differences in the change of heart rate from resting to stressed among control-treated (5.1 1.7 bpm) or lavender-treated horses (11.5 4.1 bpm). However, there was a significant decrease in the HR from the stressed HR to RHR in lavender-treated horses ( 9.3 3.4 bpm) compared with control-treated horses (0.28 1.5 bpm) (Table 1). Of the seven horses, four received a calm score of 2 and three received a calm score of 1. These horses were consistent during each trial period. Among horses with a calm score of 2, lavender aromatherapy significantly reduced (P < .0017) HR ( 14.0 4.8 bpm) compared with the same horses during control treatment (0.5 0.5 bpm). There were no statistical differences between controland lavender-treated horses in change of RR from rest to
Table 1 The changes in heart rate, respiratory rate from stressor to end of 15-minute treatment with lavender or humid air, and initial calm score before stressor and treatment Treatment n Change in Heart Change in Respiratory Initial Calm Rate (bpm) Rate (brpm) Score Control Lavender
7 7
0.3 1.5a 9.3 3.4b
0.9 2.6a 3.1 1.5a
1.5 0.2a 1.8 0.3a
a,b Values within a column with differing superscripts are different (P < .05).
stress (0.0 2.8 breaths per min [brpm] vs. 1.9 1.9 brpm) or in the change of RR from stressed to recovery ( 0.9 2.6 brpm vs. 3.1 1.5 brpm) (Table 1). 4. Discussion The results of this experiment demonstrate that 15 minutes of aromatherapy with lavender essential oil can reduce HR in horses. Similar findings have also been reported in dogs [6] and humans [7,8]. Lavender has also been reported to have a sedative effect by reducing the amount of movement in laboratory mice [9] and sheep [10]. When aerosolized lavender breaks down, into two active components: linalool and linalyl acetate, which are responsible for the biological activity of lavender [9]. Herz [11] reported that lavender was capable of restoring control of primary regulation of bodily functions to the parasympathetic nervous system following a “flight or fight” reflex response and may be the mode of action in the horse to reduce HR. The increased sedative effects of lavender among horses with a higher calm score may be the result of these animals deviating further away from baseline HR, which allows for a greater discrepancy between no treatment and lavender. Additionally, one limitation of this study is that the horses used were American rodeo horses, which do not easily become stressed because of an air horn. These horses are accustomed to explosions during the rodeo opening ceremonies. In future experiments, the use of feral horses, yearlings, or foals may likely demonstrate greater changes after lavender aromatherapy. In conclusion, equine practitioners could use lavender aromatherapy to reduce nervousness among horses in the examination area, or for treatment following performance competition to possibly hasten recovery time. However, the use of lavender should be considered only as a short-term solution, as studies in humans report short-term benefits but no differences when evaluated over long-term treatment periods [7]. Acknowledgments The authors thank Dr Delma Porter of the McNeese State University Writing Center for her assistance in proofreading and editing this manuscript. References [1] Janis CM, Damuth J, Theodor JM. The origins and evolution of the North American grassland biome: the story from the hoofed mammals. Palaeogeogr Palaeoclimatol Palaeoecol 2002;177:183-98.
C.E. Ferguson et al. / Journal of Equine Veterinary Science 33 (2013) 67-69 [2] Saslow CA. Understanding the perceptual world of horses. Appl Anim Behav Sci 2002;78:209-24. [3] Cregier SE. Reducing equine hauling stress: a review. J Equine Vet Sci 1982;2:186-98. [4] Waran NK, Cuddeford D. Effects of loading and transport on the heart rate and behavior of horses. Appl Anim Behav Sci 1995; 43:71-81. [5] Grandin T. Review: reducing handling stress improves productivity and welfare. Prof Anim Sci 1998;14:1-10. [6] Komiya M, Sugiyama A, Tanabe K, Uchino T, Takeuchi T. Evaluation of the effect of topical application of lavender oil on autonomic nerve activity in dogs. Am J Vet Res 2009;70:764-9. [7] Kuroda K, Inoue N, Ito Y, Kubota K, Sugimoto A, Kaduda T, et al. Sedative effects of the jasmine tea odor and R-(-)-linalool, one of its
[8]
[9]
[10]
[11]
69
major odor components, on autonomic nerve activity and mood states. Eur J Appl Physiology 2005;95:107-14. Chien LW, Ceng SL, Chi FL. The effect of lavender aromatherapy on autonomic nervous system in midlife women with insomnia. Evid Based Complement Alternat Med 2012;2012:740813. Buchbauer G, Jirovetz L, Jäger W, Dietrich H, Plank C. Aromatherapy: evidence for sedative effects of the essential oil of lavender after inhalation. Z Naturforsch C 1991;46:1067-72. Hawken P, Fiol C, Blache DB. Behavioral reactivity to psychosocial stress determines the effects of lavender oil on anxiety in sheep. J Anim Sci 2011;89(E-Suppl 1):10. Herz RS. Aromatherapy facts and fiction: a scientific analysis of olfactory effects on mood, physiology and behavior. International J Neurosci 2007;119:263-90.