title: Mating behavior increases workload of the heart in Thoroughbred stallions.
abstract: To evaluate the influence of mating behavior on cardiac function, changes in heart rate (HR), electrocardiogram (ECG), hematocrit (Hct) and serum concentration of alpha-atrial natriuretic peptide (alpha-ANP) were evaluated in 10 clinically sound Thoroughbred stallions before and after mating behavior. The stallions were submitted twice to experimental pseudomating in the same month in 2009 and 2010. Measurements and blood samples were collected at a stable before mating (baseline) and at a covering yard before and after mating. ECG was recorded by a Holter-ECG system. Arrhythmias were detected in 5 stallions before or after mating behavior. Minimum HR (HRmin), maximum HR (HRmax) and HR recorded when the stallions entered into yard (HRent) and ejaculated (HRejc) were 34.2 ± 3.7, 168.9 ± 14.2, 141.8 ± 35.3 and 142.6 ± 27.3 beats/min, respectively. Time from entrance into the yard to ejaculation (mating time; MT) ranged from 30 to 2,103 sec and was highly correlated with HRent (r=-0.82) and the time required for attaining HRmax after entrance into the yard (dT HRmax) (r=0.87). Hct and serum alpha-ANP concentration significantly increased after ejaculation (60.0 ± 3.2%, P<0.0001, and 1.54 ± 0.61 ng/ml, P=0.0353) compared with the baselines values (46.9 ± 4.4%, 1.40 ± 0.60 ng/ml). HRent and Hct were significantly higher in the stallions with an MT of less than 5 min (n=5) compared with those (n=5) with an MT of more than 5 min (P=0.0324 and P=0.0082). Mating behavior increases the workload of the heart in Thoroughbred stallions.
authors: Kyushu Stallion Station, The Japan Bloodhorse Breeders' Association, Kagoshima 899-8313, Japan. hatazoe@jbba.jp
authors: Takashi
authors: T
authors: Hatazoe
authors: Chikara
authors: C
authors: Kubota
authors: Makoto
authors: M
authors: Fujiki
authors: Kazuhiro
authors: K
authors: Misumi
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology / Q000662:veterinary; D009320:Atrial Natriuretic Factor / Q000097:blood; D004562:Electrocardiography / Q000662:veterinary; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006400:Hematocrit / Q000662:veterinary; D006736:Horses / Q000502:physiology*; D006801:Humans; D008297:Male; D012044:Regression Analysis; D012726:Sexual Behavior, Animal / Q000502:physiology*
chemical_list: D009320:Atrial Natriuretic Factor