Avaliaram-se a hematologia e a bioquímica sérica em equinos de concurso completo de equitação (CCE) em treinamento durante testes de esforço incremental em esteira ergométrica de alta velocidade. Foram utilizados 16 equinos em delineamento experimental inteiramente ao acaso com quatro tratamentos e quatro repetições em esquema de parcelas subdivididas, utilizando-se como fontes de variação nos tratamentos a idade e o histórico de treinamento em CCE. As parcelas foram constituídas pelos testes incrementais realizados nas fases inicial e final do treinamento. As subparcelas foram representadas pelos tempos de avaliação e coletas. Os equinos do grupo experimental novos iniciantes apresentaram valor médio do hematócrito de 43,24%, sendo inferior ao hematócrito do grupo adultos iniciantes, 45,63%, novos experientes, 46,39%, e competidores, 47,74%. Houve diferença (P<0,05) entre os testes físicos realizados nas fases inicial e final do treinamento, com redução na concentração plasmática de glicose, de 112 para 98,88mg/dL, nas concentrações séricas de creatinina, de 1,41 para 1,29mg/dL, e de proteínas totais, de 6,52 para 6,38g/dL, na contagem de monócitos, de 0,54 para 0,48 10³/mm³, e com aumento na concentração plasmática de lactato, de 3,31 para 3,79mmol/L, na concentração sérica de ácido úrico, de 1,44 para 1,77mg/dL, no hematócrito, de 44,19 para 46,90%, na concentração de hemoglobina, de 14,33 para 15,10g/dL, e na contagem de leucócitos totais, de 9,26 para 9,61 10³/mm³. O treinamento dos equinos de CCE aumentou o condicionamento físico dos equinos, com maior capacidade de metabolização do lactato após o exercício e aumento nos valores basais do hematócrito e da concentração de hemoglobina.

No abstract

This study was performed to evaluate the impact of dietary protein levels on nutrient digestibility and water and nitrogen balances in conditioning eventing horses. Twenty-four Brazilian Sport Horses, male and female (8.0 to 15.0 yr; 488 ± 32 kg BW), were used in a randomized design with 4 levels of CP diets: 7.5%, 9.0%, 11.0%, and 13.0%. A digestion assay was performed with partial feces collection over 4 d, followed by 1 d of total urine collection. Data were submitted to regression analysis and adjusted to linear and quadratic models (P < 0.05). No differences were observed in the intake of DM, OM, EE, ADF, and NDF as a function of dietary protein levels. Dry matter intake average was 1.7% of BW. CP and N intake showed a linear increase as a function of increasing protein level in diets. A quadratic response (P < 0.05) was observed on the CP and NDF digestibility coefficients, with the maximum estimated level of digestibility at 11.6% and 11.4% CP in the diet, respectively. There was a linear effect on ADF digestibility coefficients, digestible DM and protein intake, and CP/DE ratio according to dietary protein levels. There was no impact of dietary protein levels on daily water intake, total water intake, or fecal water excretion. Urinary excretion values showed a linear increase in response to increased dietary protein levels, but no impact was observed on water balance, with an average of 8.4 L/d. Nitrogen intake (NI), N absorption (NA), and urinary N increased linearly as a function of increasing dietary protein levels. There was no impact of dietary protein levels on N retention (NR), with an average of 7.5 g N/d. Nitrogen retention as a percentage of NI or NA showed no significant changes in the function of dietary protein levels. There was an impact of dietary protein levels on the digestibility coefficient of CP, NDF, ADF, and digestible protein intake on conditioning eventing horses. The 11.6% CP level in the diet provided an intake of 2.25 g CP/kg BW and 0.37 g N/kg BW, and this intake was the most appropriate for the conditioning of intensely exercised horses, considering the responses related to NI, NA, and the estimated NR to NA ratio. The NDF and ADF responses indicated that dietary fiber was more digested with an increased amount of N in the digestive tract.

This study was designed to evaluate changes on variables in blood, urine and water balance in horses in response to a single dose of electrolyte supplementation. The essay was conducted on a randomised 3×3 Latin Square design repeated over time, with three animals and three treatments: Treatment 1: control group (without supplementation); Treatment 2: supplementation with a medium dose of electrolytes composed of: 0.25 g of NaCl + 0.125 g of KCl + 0.05 g of CaCl + 0.025 g of MgCl per kg of BW; Treatment 3: supplementation with a high dose of electrolytes composed of: 0.625 g of NaCl + 0.3125 g of KCl + 0.125 g of CaCl + 0.0625 g of MgCl per kg of BW, equivalent to 2.5 times the medium dose of supplementation. The electrolytes were supplied through a nasogastric tube 4 h after the morning meal. The diet provided had a forage:concentrate ratio of 70:30, composed of coastcross hay and commercial concentrate, with an estimated consumption of 2% of body weigth (BW). Horses received 116 mg/kg of BW of commercial mineral salt mixed in the concentrate. Samples of blood, urine and digesta were collected over a 12 h period after supplementation for analysis of sodium, potassium, chloride, calcium and magnesium concentration. Water intake and urine output were also measured. Electrolytic supplementation enhanced (P<0.05) the water intake, water retention and urine output. Blood variables were not altered by electrolyte supplementation (P≯0.05). The supplementation also influenced the sodium and chloride excretion in urine (P<0.05). Urine physicochemical characteristics and the concentration of electrolytes excreted with time were significantly altered as a function of the electrolytes supplementation.

This study was carried out to model data of plasma lactate and glucose concentrations, heart rate and haematocrit in eventing horses after incremental speed tests on the field and on a high speed treadmill. The experimental design was a duplicate Latin square, with two tests, on the field and on a treadmill. Eight eventing Brazilian Sport Horses were used, five males and three females, with mean age of 7.4 years old, and average body weight of 479 kg. The protocol for the incremental speed test on the treadmill consisted of 10 minutes of warm up walking and trotting; followed by gallops at initial speed of 5.0 m/s, with increments of 1.0 m/s every minute up to 10.0 m/s. The treadmill inclination was 4% during the gallops. At the end of the test, horses were trotted at 4.0 m/s during 4 minutes, walked at 1.7 m/s during 6 minutes and rested thereafter on the treadmill. The protocol used on the field test consisted of 10 minutes of warm up walking and trotting; followed by 4 steps of one minute at 5.0, 7.0, 8.0 and 10.0 m/s, with 3 minutes intervals of walking recovery between each step. After the test the horses recovered at rest and were monitored during 60 minutes. An exponential regression described the reduction of plasma lactate concentration and heart rate better than a linear regression. The reduction of the haematocrit was better described by a linear regression. It was not possible to adjust plasma glucose concentration during recovery from exercise test on a regression equation because there was no difference (P>0.05) among its mean values.