Mineral composition and microstructure of the abaxial hoof wall in dairy heifers after biotin supplementation.

The aim of this study was to evaluate the effect of daily biotin supplementation on the mineral composition and microstructure of the abaxial hoof wall in dairy heifers. The heifers were housed on a concrete floor and fed for weight gain more than 800 g per day, which is a challenging environment for the hoof. Twelve crossbred dairy heifers (Jersey × Holstein) were divided into two treatment groups. Animals in the control group (n = 6) received a diet without supplemental biotin, while the heifers in the biotin-supplemented feed group (n = 6) each received 20 mg of biotin daily for 120 days. Samples of the abaxial hoof wall were collected from the outer claw of the fore and hind limb, before and after supplementation. The samples were evaluated by X-ray fluorescence spectrometry, computed microtomography, atomic force microscopy and confocal laser scanning microscopy. Biotin supplementation increased the sulphur content and decreased the calcium and potassium content in the abaxial hoof wall. Biotin treatment also increased the percentage of horn tubules with smaller diameter marrow (17-51 µm). However, biotin did not influence the surface relief of the hoof wall, suggesting that its action is limited to the inner layers of the stratum corneum. Daily supplementation with 20 mg of biotin promoted changes in the mineral composition and microstructure of abaxial hoof wall of crossbred dairy heifers. These findings suggest biotin supplementation improves hoof quality and may help to understand the function of biotin in the stratum corneum.

Comparative study of biotin supplementation on weight gain and occurrence of digital diseases in cattle (Bos taurus x Bos indicus) / Estudo comparativo da suplementação com biotina sobre o ganho de peso e ocorrência de enfermidades digitais em bovinos (Bos taurus x Bos indicus)

This study aimed to assess the weight gain and the incidence of foot diseases in male, crossbred (Bos taurus x Bos indicus) bovines that were supplemented with biotin. An amount of 240 animals, supplemented or not with biotin, allocated in 12 groups of 20 animals, was assessed for a period of six months. The study was conducted during three years and the groups were divided according to the forage available, corn, corn residue and sorghum silage, and initial weights between 100 and 200 kg and between 200 and 300 kg. The statistical analyses used were the Tukey's Test, in triple factorial scheme (type of silage x use of biotin x initial body weight) and the Fisher´s Exact Test, both at 5% significance level. The biotin supplementation in bovines did not influence weight gain and the incidence of foot diseases, however, when comparing only the type of forage, corn and sorghum silage provided higher weight gain than silage made of corn residue.

Esse estudo teve como objetivo avaliar o ganho em peso e a ocorrência de enfermidades digitais em bovinos do sexo masculino, mestiços (Bos taurus x Bos indicus) que foram suplementados com biotina. Avaliaram-se, por um período de seis meses, 240 bovinos, suplementados ou não com biotina, alocados em 12 grupos de 20 animais. O estudo foi realizado durante três anos e os grupos foram divididos de acordo com o volumoso disponibilizado, silagem de milho, de resíduo de milho e de sorgo, e pesos iniciais entre 100 e 200 kg e entre 200 e 300 kg. As análises estatísticas empregadas foram o Teste de Tukey, em esquema de fatorial triplo (tipo de silagem x uso da biotina x peso corporal inicial) e o Teste Exato de Fisher, ambas em nível de significância de 5%. A suplementação com biotina nos bovinos não exerceu influência sobre o ganho em peso e a ocorrência de enfermidades digitais, mas, quando se comparou apenas o tipo de volumoso, a silagem de milho e sorgo, pode se observar um maior ganho em peso que a silagem confeccionada de resíduo de milho.