RESUMO: O objetivo deste estudo foi avaliar o ajuste dos modelos Brody, Logístico e Platô de resposta quadrática aos dados de perímetros torácico e de canela em equinos Mangalarga Marchador obtidos pelo método transversal, a fim de selecionar o melhor modelo e predizer sobre o crescimento e a maturidade de machos e fêmeas desta raça. Foram utilizados dados de 230 equinos de seis a 176 meses de idade que foram divididos por sexo e em 16 classes de idade. Os modelos estudados foram comparados segundo os avaliadores de qualidade: coeficiente de determinação ajustado ( R adj 2) e desvio padrão residual (DPR), utilizando-se o software estatístico R. Os perímetros torácicos obtidos pelos modelos variaram de 172,06 a 181,50 cm (Brody), 172,51 a 181,89 cm (Logístico) e 183,09 a 177,67 cm (Platô) para fêmeas e machos, respectivamente. Para o perímetro de canela os valores variaram de 18,18 a 19,33 cm (Brody), 18,11 a 19,41 cm (Logístico) e 18,70 a 19,40 cm (Platô) para fêmeas e machos, respectivamente. O modelo logístico é mais indicado para expressar o crescimento em perímetro torácico de machos e fêmeas da raça Mangalarga Marchador. Já para a variável perímetro de canela, o modelo mais indicado para os machos foi o modelo Logístico e para as fêmeas o modelo de Brody.

ABSTRACT: This study evaluated the suitability of the Brody, logistic, and quadratic response plateau models to describe chest and cannon girth data obtained cross-sectionally in Mangalarga Marchador horses, in order to select the best model and predict the growth and maturity of males and females of this breed. Data were collected from 230 horses aged 6 to 176 months, divided by sex and age (16 age classes). The studied models were compared according to each quality evaluator by computing the adjusted coefficient of determination ( R adj 2) and residual standard deviation (RSD) with R statistical software. The chest girths obtained by the models ranged from 172.06 (males) to 181.50 cm (females) (Brody), 172.51 (males) to 181.89 cm (females) (logistic), and 177.67 (males) to 183.09 cm (females) (plateau). For cannon girth, the values were 18.18 (females) to 19.33 cm (males) (Brody), 18.11 (females) to 19.41 cm (males) (logistic), and 18.70 (females) to 19.40 cm (males) (plateau). The logistic model was best suited to describe the growth in chest girth of male and female Mangalarga Marchador horses. For cannon girth growth, the model best suited for males was the logistic model, and the one best suited for females was the Brody model.

ABSTRACT The objective of this study was to evaluate the accuracy of the following six body weight (BW) estimation methods in Campolina (CAM) horses: A - weight tape placed at three different positions on the animal’s thorax; B - Crevat and Quetelet’s formula; C - Hall’s formula; D - Hintz and Griffiths’s table; E - Santos’s table; and F - Cintra’s formula. A total of 380 CAM horses were separated according to sex, age class, and gestational stage and evaluated. To determine their accuracy, weights measured on a scale and weight estimates of the six methods were compared by paired t-test, mean prediction error (MPE), and coefficient of determination (R2), using R software. The predictive capacity of method F was lower in the 6-12 months age class, so this formula is not indicated. The BW was overestimated compared with the actual weight by methods A (with weight tape placed in position 3) and B and underestimated by method C. Methods D and E accurately estimated BW of CAM horses. Correction factors are required to accurately estimate BW in this breed using methods B and C. Method A with the weight tape placed in position 2 is the most accurate for predicting BW, including pregnant female horses, and can, therefore, be considered the most suitable method for estimating BW of CAM horses.

RESUMO: O objetivo deste estudo foi avaliar os modelos logístico e platô de resposta quadrática na descrição do crescimento de equinos da raça Mangalarga Marchador identificando o que melhor descreve o crescimento das variáveis altura de cernelha e comprimento corporal. Foram utilizados dados de 230 equinos de 6 a 176 meses de idade que foram divididos por sexo e em 16 classes de idade. Toda a parte computacional envolvida foi realizada utilizando-se o software estatístico R. O modelo logístico foi o mais indicado para expressar o crescimento em altura na cernelha e comprimento corporal de machos e fêmeas da raça Mangalarga Marchador. Foi criada uma tabela de valores referência para estas medidas ao longo da idade com base no intervalo de confiança dos parâmetros deste modelo. Estimativas das alturas de cernelha adultas obtidas pelo modelo logístico variaram de 144 a 154 cm nos machos e de 143 a 151 cm para fêmeas. Já em comprimento corporal os valores adultos variaram de 146 a 156 cm nos machos e 143 a 156 cm para fêmeas. As fêmeas apresentam maior precocidade do que os machos para atingir a estabilidade em ambas variáveis estudadas.

ABSTRACT: This study aimed to evaluate the logistic and quadratic response plateau models to describe the growth of Mangalarga Marchador horses to identify the model that best describes growth for the variables height at withers and body length. Data were used from 230 horses aged 6 to 176 months, divided by sex and 16 age classes. All computational work was performed using R statistical software. The logistic model was the best suited to express growth in height at withers and body length of male and female Mangalarga Marchadors aged 6 to 176 months. This allowed creating a table of reference values for these measurements over time based on the confidence interval of the model parameters. Estimates of height at withers obtained by the logistic model ranged from 144 to 154 cm in adult males and from 143 to 151 cm in adult females. For body length, values ranged from 146 to 156 cm in adult males and 143 to 156 cm in adult females. Females achieved stability in both height at withers and body length at earlier ages than did males.

ABSTRACT The objective was to evaluate the accuracy of six body weight (BW) estimating methods in Mangalarga Marchador horses (MM) (n = 318): method A - tape placements at three different positions around the thoracic girth; B - Crevat and Quetelec's formula; C - Hall's formula; D - Hintz and Griffiths’ table; E - Santos’ table; and F - Cintra's formula. For additional analyses, gender, age, and gestational stage were considered. Estimated average BW was compared to the actual scale weight by the paired T test, mean predicted error, and determination coefficient. In the general population, methods A (position 3), B, and C estimated BW that were different from that of the scale. Method A, at positions 1 and 2, was more accurate in predicting the scale weight results compared with all other methods. For pregnant mares, the tape in positions 1 and 2 in method A did not differ from those of the scale. Method A in positions 1 and 2 and the table (method E) may be used to estimate the BW of males and females of different ages and/or gestational stages. To use Methods B and C, correction factors are necessary to precisely estimate the body weights in this breed.

RESUMO: O estudo sobre curvas de crescimento animal com base em modelos não lineares tem sido utilizado para análise do crescimento e desenvolvimento de diversas espécies. Neste trabalho objetivou-se avaliar o ajuste dos modelos Brody, Gompertz, Logístico e vonBertalanffy a dados transversais de peso vivo de equinos Mangalarga Marchador, a fim de selecionar o melhor modelo e predizer sobre o crescimento e a maturidade de machos e fêmeas desta raça. Foram pesados 214 equinos, sendo 94 machos e 120 fêmeas não gestantes, com idade variando entre seis e 153 meses. A estimação dos parâmetros dos modelos foi realizada pelo método de mínimos quadrados, utilizando o processo iterativo de Gauss-Newton, seguindo rotinas do Software R. Os modelos foram comparados pelos critérios: coeficiente de determinação (R²); desvio padrão residual (DPR); critério de informação de Akaike corrigido (AICc). O peso adulto, estimado pelos modelos, variou entre 431kg e 439kg para os machos e entre 416kg e 420kg para fêmeas. O método transversal de obtenção de dados pode ser aplicado no estudo de curvas de crescimento. O modelo de vonBertalanffy foi o mais eficiente para expressar o crescimento nos machos, enquanto que para as fêmeas, o modelo Brody se mostrou mais apropriado. As fêmeas Mangalarga Marchador são mais precoces que os machos para atingir o peso vivo adulto.

ABSTRACT: The analysis of the growth and development of various species has been done using the growth curves of the specific animal based on non-linear models. The objective of the current study was to evaluate the fit of the Brody, Gompertz, Logistic and von Bertalanffy models to the cross-sectional data of the live weight of the MangalargaMarchador horses to identify the best model and make accurate predictions regarding the growth and maturity in the males and females of this breed. The study involved recording the weight of 214 horses, of which 94 were males and 120 were non-pregnant females, between 6 and 153 months of age. The parameters of the model were estimated by employing the method of least squares, using the iteratively regularized Gauss-Newton method and the R software package. Comparison of the models was done based on the following criteria: coefficient of determination (R²); Residual Standard Deviation (RSD); corrected Akaike Information Criterion (AICc). The estimated weight of the adult horses by the models ranged between 431kg and 439kg for males and between 416kg and 420kg for females. The growth curves were studied using the cross-sectional data collection method. For males the von Bertalanffymodel was found to be the most effective in expressing growth, while in females the Brody model was more suitable. The MangalargaMarchador females achieve adult body weight earlier than the males.

O trabalho foi realizado visando avaliar a influência da suplementação de probióticos ou fitase sobre o consumo diário de matéria seca (CMS), o ganho de peso diário (GPD) e a conversão alimentar (CA) de 24 potros da raça Mangalarga Marchador (16 machos e 8 fêmeas), com 241,6 ± 23,2 dias de idade e 216,7 ± 27,8 kg de peso vivo (PV). O experimento teve duração de 28 dias: os 23 iniciais para adaptação à dieta e ao manejo e os cinco finais para coleta de fezes. A dieta foi composta por pastagem de Cynodon e concentrado comercial (1,2 kg/100 kg PV), além de água e sal mineral à vontade. Os tratamentos foram: dieta basal (controle); dieta basal + 5 g/dia de leveduras vivas (10(9) UFC/g de Saccharomyces cerevisiae); dieta basal + 2 g/dia de bactérias (10(8) UFC/g de B. bifidum, E. faecium, L. acidophilus, L. plantarum) e leveduras vivas (10(5) UFC/g de S. cerevisiae) e dieta basal + fitase (1.250 FTU/dia). Para estimativa do consumo de matéria seca, foram utilizados o indicador externo LIPE® e a técnica de digestibilidade in situ. O delineamento foi inteiramente casualizado, em fatorial 4 × 2, e as médias comparadas pelo teste Student, considerando o efeito da covariável PV inicial para porcentagens de CMS por PV. O consumo de matéria seca total dos grupos variou de 2,4 a 2,8% PV, de modo que os animais sob suplementação com bactérias e leveduras vivas apresentaram menor CMS total e de volumoso. Todos os animais tiveram GPD médio de 0,33 kg/dia e o grupo sob suplementação com bactérias e leveduras vivas teve conversão alimentar do volumoso 32,42 a 43,83% menor que a observada no grupo controle e naquele sob suplementação com fitase. A fitase, na dosagem de 205 FTU/kg de MS da dieta basal, não influenciou os parâmetros avaliados. O probiótico composto por bactérias e leveduras vivas melhorou a eficiência alimentar do volumoso e pode ser utilizado como estratégia nutricional para manutenção da condição corporal de potros durante o período seco.

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 (10(9) CFU/g of S. cerevisiae); basal diet + 2 g/day of live bacteria (10(8) CFU/g of B. bifidum, E. faecium, L. acidophilus, L. plantarum) and yeast culture (10(5) 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.

Objetivou-se caracterizar a freqüência cardíaca de 12 éguas Mangalarga Marchador antes, durante, imediatamente após as provas de marcha e aos 5, 10, 15 e 20 minutos após as provas e identificar os efeitos do cromo sobre o desempenho cardíaco desses animais. As éguas foram distribuídas aleatoriamente em grupos diferenciados pelo fornecimento de 0, 5 e 10 mg de cromo (Cr). O experimento foi dividido em duas etapas, a primeira (24 dias) para adaptação à dieta, ao cromo e ao exercício; e a segunda (seis dias), para as provas de marcha, realizadas em dias alternados, totalizando três provas de 50 minutos. A freqüência cardíaca foi observada utilizando-se um monitor de freqüência cardíaca Polar. O delineamento experimental foi inteiramente ao acaso com arranjo em parcelas subsubdivididas. A comparação das médias foi feita por DMS (diferença mínima significativa) e, para avaliar o efeito de tempos de avaliação, ajustou-se um modelo de regressão. Os resultados comprovaram que o cromo melhorou o desempenho cardíaco, influenciou positivamente na recuperação dos animais e não afetou a freqüência cardíaca durante a prova de marcha. Os valores de freqüência cardíaca encontrados caracterizaram a prova de marcha como exercício de intensidade submáxima.

The objective of this experiment was to characterize the heart rate (HR) of twelve Mangalarga Marchador mares, before, during, and immediately after 5, 10, 15 and 20 minutes of marcha tests, evaluating the effect of chrome on cardiac performance. The mares were assigned into three groups distinguished by supplementation of 0, 5 and 10 mg of Cr, respectively. The experiment was conducted in two phases, 24 and 6 days, respectively. The first phase included diet, Cr and exercise adaptation and the second, three 50-minute marcha tests, every other day. Before the tests, a Heart Rate Monitor was adapted to check the HR. The assay was randomly conducted in split-splot arrangement, with four replications. Mean comparisons were performed through minimal significative difference (MSD) test and the time evaluation was performed through regression adjustment model. The results showed positive effect of Cr on heart rate performance and animal return. Chrome did not influence the heart rate during the marcha tests and the HR values characterized the marcha tests as sub maximal intensity exercise.