How Much Energy Vaquejada Horses Spend in a Field Simulation Test?

SIMPLE SUMMARY: Vaquejada is an important Brazilian equine discipline characterized by high-intensity and short-duration exercise that should influence the energetic cost for athletic horses. The aim of this study was to analyse this effect by a vaquejada simulation test (VST), in order to evaluate energy expenditure (EE), transport cost (COT) and metabolic energy requirement (Pmet) in horses. Eight Quarter Horses were evaluated in a VST composed of three races (130–150 m each) with a 5-min interval between them. All horses used an integrated heart rate (HR) and GPS monitoring system (V800, Polar Electro, Lake Success, NY, USA) to calculate the energetic index (EE, COT and Pmet). Furthermore, blood samples were collected for lactate analysis at rest, immediately after the first, second and third race and after 30 min of recovery. The results highlight that pull horses (PH) had higher EE and COT, while helper horses (HH) had higher Pmet. Although practicing the same sport, PH and EE must be considered different athletes by veterinarians, owners and all practitioners of this specific sport. ABSTRACT: Vaquejada is a high-intensity and short-duration exercise in which helper horses (HH) are responsible to keep a bull running in a line while pull horses (PH) work to put the bull down after 100 m of running. The purpose of this study was to quantify and compare energy expenditures (EE), transport costs (COT) and metabolic energy requirements (Pmet) of horses used in Vaquejada. Thus, eight Quarter Horses, in randomly formed pairs, performed a vaquejada simulation test (VST), which consisted of three races on a sand track (130–150 m), with a 5-min interval between them. All horses used an integrated heart rate (HR) and GPS monitoring system (V800, Polar Electro) and, from these data, EE, COT and Pmet were calculated using the formulas: EE (J/kg/min) = 0.0566 × HR(1.9955), COT = (HR-35)/kg/m × 10(3) and Pmet = (HR-35)/min/kg. Blood samples were collected for lactate analysis at rest, immediately after the first, second and third race and after 30 min of recovery. Data obtained were submitted to one-way ANOVA and Tukey tests (p ≤ 0.05). In VST, HH had higher EE and higher HR at trot; while PH presented higher EE and HR at canter. Finally, considering total VST, PH had higher EE and COT, while HH had higher Pmet. Lactate was higher in PH. Despite practicing the same sport, PH and HH should be considered distinct athletes, and these must be considered to set up appropriate physical and nutritional programs, which will lead to better performance and guarantees of well-being.