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Mathematical models that describe gas production are widely used to estimate the rumen degradation digestibility and kinetics. The present study presents a method to generate models by combining existing models and to propose the von Bertalanffy-Gompertz two-compartment model based on this method. The proposed model was compared with the logistic two-compartment one to indicate which best describes the kinetic curve of gas production through the semi-automated in vitro technique from different pinto peanut cultivars. The data came from an experiment grown and harvested at the Far South Animal Sciences station (Essul) in Itabela, BA, Brazil and gas production was read at 2, 4, 6, 8, 10, 12, 14, 17, 20, 24, 28, 32, 48, 72, and 96 h after the start of the in vitro fermentation process. The parameters were estimated by the least squares method using the iterative Gauss-Newton process in the software R version 3.4.1. The best model to describe gas accumulation was based on the adjusted coefficient of determination, residual mean squares, mean absolute deviation, Akaike information criterion, and Bayesian information criterion. The von Bertalanffy-Gompertz two-compartment model had the best fit to describe the cumulative gas production over time according to the methodology and conditions of the present study.

Hay production is the most common form of forage conservation methods for horse feeding. However, haylage can be an alternative to hay. The present research assessed the nutritional value of Tifton-85 haylage by fermentation pattern, bromatological composition, and apparent digestibility compared to hay in the diet of Quarter Horse mares. Haylage was prepared with 700.0 g of dry matter (DM) kg-1 added with a biological inoculum and was assessed at 1, 3, 7, 14, 28, and 56 days of production. At 14 days, the protein content had decreased from 192.0 to 173.2 g kg-1 DM. The opposite was found for ammoniacal nitrogen, which rose from 0.61 to 1.14 g kg-1 DM of total nitrogen. No differences were found for the variables NDF, ADF, hemicellulose, pH, acetic acid, propionic acid and butyric acid, whose values were 734.3, 316.5 and 416.9 g kg-1 DM, pH 5.47 and 0.06, 0.003, 0.03 g kg-1 DM, respectively. Lactic acid contents were higher after 28 days of haylage production, reaching 2.39 g kg-1 DM at the last assessment. The contents of aflatoxins, fumonisin, and zearalenone in the plant were similar to those in the haylage at 0.95 µg kg-1, 0.60 mg kg-1, and 0.71 µg kg-1, respectively. The digestibility assay showed an increase in protein digestibility in the diet with haylage (675.1 g kg-1 DM) compared to hay (579.1 g kg-1 DM) of the same grass. Haylage can potentially be used to feed horses and its use is recommended starting at 28 days of production.

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ResumoO trabalho avaliou o efeito da suplementação com leveduras sobre a digestibilidade e consumo dos nutrientes de equinos Mangalarga Marchador submetidas a treinamento. Quatorze éguas Mangalarga Marchador foram distribuídos em dois grupos: Probiótico (equinos suplementados com 20 g de Saccharomyces cerevisiae diariamente) e Controle. A dieta foi composta por volumoso e concentrado comercial, na proporção de 50:50. As éguas foram treinadas durante seis semanas, de segunda a sábado, sendo o exercício realizado diariamente alternando o trabalho em esteira ergométrica e caminhador automático. A digestibilidade dos nutrientes foi avaliada utilizando o indicador LIPE ® (6 dias) e a coleta de fezes foi realizada durante cinco dias. Foi analisado MS, FDN, FDA, PB, EB, hemicelulose e consumo de matéria seca. Não houve diferença (P>0,05) em nenhuma das variáveis analisadas. A suplementação com 20 g de Saccharomyces cerevisiae não interfere na digestibilidade e consumo dos nutrientes em éguas Mangalarga Marchador submetidas a seis semanas de treinamento aeróbico. Palavras-chave: Equino, fibra, hemicelulose, levedura, probiótico AbstractThe study evaluated the effect of yeast supplementation on the digestibility and intake of nutrients of Mangalarga Marchador horses in training. Fourteen Mangalarga Marchador mares were divided into two groups: Probiotic (horses supplemented with 20 g of Saccharomyces cerevisiae daily) and Control. The diet consisted of commercial concentrate and roughage in the ratio of 50:50. The mares were trained for six weeks, Monday to Saturday, and the exercise performed daily alternating work on a treadmill and automatic walker. Nutrient digestibility was assessed using the indicator LIPE ® (6 days) end fecal collection was performed for five days. Was analyzed DM, NDF, ADF, CP, GE, hemicelluloses and dry matter intake. There was not difference (P>0,05) in any of the variables analyzed. Supplementation with 20 g of Saccharomyces cerevisiae does not affect the digestibility and nutrient intake in mares Mangalarga Marchador submitted six weeks of aerobic training.