Vinícius Pimentel Silva

Progresso científico em equideocultura na 1ª década do século XXI

In Brazil, as in other countries, investments in research with horses are related to the objectives of the equine industry in the country. This study aimed to review the current literature with the purpose of assessing the latest scientific and technological development in horses production. Researchers are related to many areas as in production and management, genetics and breeding, nutrition and feeding, reproduction, medicine and surgery, diseases and health protection. There is still research in areas related to equestrian sports, involving equine exercise physiology, riding and training horses and also studies on national and international equine trade. Considering all areas of interest of horse production the largest number of published articles is related to the medicine and surgery and diseases and health. In Animal Science, the largest number of articles is related to nutrition and feeding of horses. However, must be consider that interests of agribusiness, horses breeders associations, governments and society in general, influence the research and consequently the publication of papers about horses.

Feed efficiency in Mangalarga Marchador foals fed diet supplemented with probiotics or phytase

The objective was to assess the effect of probiotic or phytase supplementation on dry matter intake (DMI), average daily gain (ADG) and feed conversion (FC) in 24 Mangalarga Marchador foals (16 males, 8 females), with 241.6 ± 23.2 days of age, and 216.7 ± 27.8 kg of body weight (BW). The study lasted 28 days, the first 23 days for diet and handling adaptation, and the last five days for feces collection. The basal diet consisted of Cynodon pasture and pelleted concentrate (1.2 kg/100 kg BW), as well as water and mineral salt ad libitum. Treatments groups were assigned as follows: basal diet (control); basal diet + 5 g/day of live yeast culture (109 CFU/g of S. cerevisiae); basal diet + 2 g/day of live bacteria (108 CFU/g of B. bifidum, E. faecium, L. acidophilus, L. plantarum) and yeast culture (105 CFU/g of S. cerevisiae); and basal diet + 1250 FTU/day of phytase. Pasture DMI was estimated with an external marker (LIPE™) associated with cecal in situ digestibility of dry matter. All foals were randomized, by replicated, using a 4 × 2 factorial, and results were compared using Student t-test, taking into consideration the effect of initial BW as covariate for the percentage DMI per BW. Among foals, DMI varied from 2.4 to 2.8% BW, with foals supplemented with live bacteria and yeast having lower DMI (total diet and forage). All animals had an ADG of 0.33 kg/day, and foals supplemented with live bacteria and yeast had FC 32.42 to 43.83% lower than foals supplemented with phytase or fed only basal diet. The phytase dose of 205 FTU/kg DM in the basal diet had no effects. Probiotic composed of live bacteria and yeast culture improved feed efficiency of forage and can be used as a nutritional strategy to maintain body condition in foals during the dry season.

Capacidade tamponante, pH e consistência das fezes em equinos submetidos à sobrecarga dietética com amido

This study aimed to evaluate buffer capacity (BC), pH and faeces consistency of horses submitted to dietetic starch overload. Six crossbreed mature horses were submitted to starch overload with gastric infusion of 17.6g starch kg-1 body weight through nasogastric tube. Faecal samples were collected, before and at 4, 8, 12, 16, 20, 24, 28, 32 and 36 hours post-overload, and immediately submitted to evaluation of pH, BC and consistency. The pH data were compared by t student test (P 0.05), with means values varying from 6.09 to 4.46. Based on the model pH = 6.083 - 0.003t - 0.001t2 (R2 = 0.634), faecal pH decreased 0.004 per hour, 0.028 to each four hours and 1.404 at 36 hours after overload, respectively. As pH, faeces BC decreased (P<0.05) in function of the time after overload. Positive relationship was observed (r = 0.65; P<0.0001) between pH and BC of faeces. All horses presented normal consistency faeces (score 3) until eight hours after overload, following by reduction (P<0.05) up to 36 hours. Results demonstrated that starch overload reduce faecal consistency, buffer capacity and pH in horses faeces.

Lactação em éguas da raça Mangalarga Marchador: produção e composição do leite e ganho de peso dos potros lactentes

Objetivou-se, com este trabalho, avaliar a producao e a composicao do leite de eguas Mangalarga Marchador e o ganho de peso dos potros lactentes. A producao de leite foi avaliada em oito eguas, pelo metodo da pesagem dos potros antes e depois das mamadas, em intervalos de duas horas, em doze observacoes diarias. A partir do somatorio da quantidade de leite produzido nas observacoes, obteve-se a producao diaria de leite. A producao de leite, analisado quanto aos teores de lactose, proteina, gordura e energia, foi avaliada aos 20, 40, 60, 80, 100, 120, 140 e 160 dias da lactacao A producao media de leite variou de 9,95 kg/dia no 40o dia a 7,48 kg/dia no final da lactacao. A producao total de leite estimada foi igual a 1405,56 kg. A producao de leite, expressa em percentual do peso vivo (PV) das eguas, variou entre 2,3% do PV no 20o dia e 1,8% do PV no final da lactacao, sendo similar as quantidades de leite produzidas nos periodos diurno e noturno. Nao foi observado efeito da idade das eguas na producao de leite. O ganho medio diario de peso dos potros ao longo do periodo de amamentacao foi de 0,77 kg, com maiores valores nos meses iniciais do periodo de amamentacao. O leite das eguas apresentou baixas concentracoes de proteina, gordura e energia e altas de lactose, alem de resposta quadratica decrescente, em funcao do periodo da lactacao.

Nutrient digestibility of forage feed determined using mobile bag technique in horses.

This work was carried out to evaluate the nutrient digestibility of forages using mobile bags technique in horses. The forages were lucerne (Medicago sativa), peanut (Arachis pintoi), desmodio (Desmodium ovalifolium), stylo (Stylosanthes guianensis), pigeon pea (Cajanus cajan), lime-yellow pea (Macrotyloma axillare) and coastcross (Cynodon dactylon cv. coastcross). A randomized block design was used with seven treatments (feeds) and five blocks (horses). Five crossbreed horses were used with age ranging from 17 to 27 years and average weight of 350 kg. The assay lasted 12 days, being three days for adaptation to barns, five days for nasogastric insertion of bags and four days for bags collection in feces. The diet of horses was composed of 80% of coastcross hay and 20% of commercial concentrate. During the pre-experimental period of 30 days, the horses were maintained in paddocks feeding the diet. Nylon cloth had 45µ pore size, and bags presented dimensions of 7,5 × 2 cm with 510 mg of DM of forage sample/bag. The nutrient digestibility of forages were calculated through residues inside the bags. The nutrient digestibility of peanut, stylo and lime-yellow pea were high than the other forages, mainly crude protein with values of 91.4, 94.9 and 97.0%, respectively. Fibrous fractions of peanut and lime-yellow pea presented digestibility values of NDF of 72.3 and 65, 2%, and ADF of 70.9 and 59.4%, respectively. Peanut, lime-yellow pea and stylo presented satisfactory nutrient digestibility and had potential to use in diets for horses.

Digestion of carbohydrates of forages in horses

This work was carried out to evaluate the fractions of carbohydrates and estimate the apparent digestibility of these nutrients in two digestion assays with horses. In assay 1, five horses were allotted to a complete randomized blocks design and treatments were seven forages hays, alfalfa (Medicago sativa), peanut forage (Arachis pintoi), desmodio (Desmodium ovalifolium), pigeon pea (Cajanus cajan), lime-yellow pea (Macrotyloma axillare), stylo (Stylosanthes guianensis) e coastcross (Cynodon dactylon), evaluated with the mobile nylon bag technique. In assay 2, four horses were allotted to a 4 × 4 Latin Square design and fed with coastcross hay with four different processed forms with the objective of evaluating whether a reduction of the particle size affected the carbohydrate digestibility. Results showed that horses had high digestion of non-fibrous carbohydrate and hydrolysable carbohydrate and rapidly fermentable carbohydrate fractions of forages. Among the forages analyzed, peanut forage, stylo and lime-yellow pea, presented high nutrient digestibility, and the peanut forage nutrients presented digestibility above 70%, demonstrating potential to be used in diets for horses. The coastcross hay processing in different grinding degrees does not affect the fibrous and non-fibrous carbohydrate fractions digestibility. Analysis of fibrous and non-fibrous carbohydrate fractions is a good indicative of nutritional value of feeds, and could be included in the evaluation of the quality of diets for horses.Neste estudo, foram realizados dois ensaios com os objetivos de avaliar o fracionamento dos carboidratos de alimentos volumosos e estimar a digestibilidade desses nutrientes em dois ensaios de digestao com equinos. No ensaio 1, foram utilizados cinco equinos em delineamento de blocos casualizados, com sete tratamentos - fenos de alfafa (Medicago sativa); amendoim forrageiro (Arachis pintoi); desmodio (Desmodium ovalifolium); guandu (Cajanus cajan); macrotiloma (Macrotyloma axillare); estilosantes (Stylosanthes guianensis); ou coastcross (Cynodon dactylon) - avaliados pela tecnica de sacos de nailon moveis. No ensaio 2, foram utilizados quatro equinos em delineamento quadrado latino 4 × 4, alimentados com feno de coastcross em quatro tipos de moagem com o objetivo de avaliar se a reducao do tamanho de particula interfere na digestibilidade dos carboidratos. Os resultados comprovaram que os equinos possuem alta eficiencia na digestao dos carboidratos nao-fibrosos e de suas fracoes hidrolisaveis e rapidamente fermentaveis. Os fenos de amendoim forrageiro, estilosantess e macrotiloma apresentaram elevada digestibilidade dos carboidratos fibrosos e nao-fibrosos, enquanto a digestibilidade de todos os nutrientes do amendoim forrageiro foi superior a 70%, o que indica potencial para uso desta leguminosa em dietas para equinos. O processamento do feno de coastcross nao influenciou a digestibilidade das fracoes dos carboidratos fibrosos e nao-fibrosos. A analise dos carboidratos fibrosos e nao-fibrosos e um bom indicativo do valor nutricional dos alimentos e pode ser incluida na avaliacao da qualidade de alimentos para equinos.

Passage kinetics of digesta in horses fed with coastcross hay ground to different degrees

This study was conducted to evaluate the kinetics, physicochemical characteristics and particle size of digesta in the right ventral colon (RVC) of horses fed coastcross hay ground to different degrees. Four horses fitted with cannulae in the RVC were used and were fed the following forms of hay: long, chopped, ground to 5 mm and ground to 3 mm. A Latin Square 4x4 study design was used. Each experimental period included 10 days for diet adaptation, four days for feces collection and one day for digesta collection. The kinetics of the particulate and solute phases of digesta were evaluated based on the mean retention time (MRT), passage rate (k) and transit time (TT) using two external markers: Cr-NDF and Co-EDTA. The TT of solid phase digesta was 3 hours longer (P 0.05) in k or MRT in either the liquid or solid phase of digesta as a function of the different degrees of hay grinding. However, the liquid phase of digesta presented a higher k than the solid phase, with values of 3.28 and 2.73 h-1 being obtained, respectively. The smallest particle size and the lowest neutral detergent fiber contents in colon digesta were observed when hay ground to 3 mm was offered, leading to values of 0.51 mm and 53.46%, respectively. Grinding the hay increased the transit time of the liquid phase in the digestive tract of the horses, whereas no change in the kinetics of the solid phase digesta was observed. The grinding of hay reduced the NDF and the average particle size in the right ventral colon.

The impact of dietary protein levels on nutrient digestibility and water and nitrogen balances in eventing horses

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.

In situ caecal degradation of roughages in horses

Objetivou-se avaliar a degradacao da materia seca (MS), fibra em detergente neutro (FDN) e proteina bruta de alimentos volumosos pela tecnica da digestao cecal in situ em equinos. Avaliaram-se as forrageiras: feno de alfafa (Medicago sativa), amendoim forrageiro (Arachis pintoi cv. Amarillo), desmodio (Desmodium ovalifolium), estilosantes (Stylosanthes guianensis cv. Mineirao), guandu (Cajanus cajan), macrotiloma (Macrotyloma axillare) e feno de coastcross (Cynodon dactylon cv. coastcross). O ensaio teve duracao de 35 dias e foi realizado em delineamento inteiramente casualizado com sete alimentos e tres repeticoes. Utilizou-se uma egua fistulada no ceco, alimentada com dieta composta por feno de coastcross (80%) e concentrado (20%), fornecida quatro vezes ao dia em quantidade equivalente a 2% do peso vivo. No ceco, foram inseridos 3 a 4 sacos de nailon de porosidade 45 μ de 6,5 × 20 cm, contendo 5,2 g de MS/saco, nos tempos de 2, 4, 6, 8, 12, 24 e 48 horas de incubacao. Os parâmetros de degradacao da MS de todos os volumosos foram significativos. Nao houve ajuste no modelo de degradacao da PB e FDN do guandu. O amendoim, estilosantes e macrotiloma apresentaram maior fracao potencialmente degradavel da MS, com valores de 53, 46,5 e 40%, respectivamente, e os maiores valores da fracao soluvel de 20, 21, 28,6%, alem de elevadas taxas de degradacao (10,36, 20,26 e 14,8%h-1). Nestes alimentos, tambem foram observadas as maiores taxas de degradacao da FDN (9,1 e 11,3, 11,2%h-1), das fracoes potencialmente degradaveis (55, 51,8 e 47,2%) e as mais altas taxas de degradacao da PB em 48 horas de incubacao (87, 95, 94,8%, respectivamente). O amendoim forrageiro, o estilosantes e o macrotiloma apresentam potencial de uso nas dietas para equinos.

Blood and urinary variables in horses supplemented with electrolytes

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 commercia...