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The effects of orally administered biotin supplementation on the growth of claw horn in young, clinically healthy cattle were analyzed. Twelve, 1-year-old Girolando cattle were randomly assigned to receive either 12.5 mg of diluted powdered biotin (GI) or a control treatment (GII) for 40 consecutive days. Cattle in the GI group showed an average hoof growth of 11.3 ± 0.72 mm, while those in GII had an average hoof growth of 7.2 ± 0.78 mm. The results confirmed the positive effect of biotin supplementation on the growth of angle and length of the dorsal hoof wall, hoof sole length, and on resistance to wearing, in young cattle extensively managed.
Effet de l’administration d’un supplément à la biotine sur la croissance de la corne des onglons chez les jeunes bovins en bonne santé clinique. Les effets de l’administration orale d’un supplément à la biotine sur la croissance de la corne des onglons chez les jeunes bovins en bonne santé clinique ont été analysés. Douze bovins Girolando âgés de 1 an ont été assignés au hasard pour recevoir soit 12,5 mg de biotine en poudre diluée (GI) ou un traitement de contrôle (GII) pendant 40 journées consécutives. Les bovins du groupe GI ont montré une croissance moyenne des sabots de 11,3 ± 0,72 mm, tandis que ceux du groupe GII ont eu une croissance moyenne des sabots de 7,2 ± 0,78 mm. Les résultats ont confirmé l’effet positif de l’administration d’un supplément à la biotine sur la croissance de l’angle et de la longueur de la paroi dorsale des sabots, de la longueur de la semelle du sabot et sur la résistance à l’usure chez les jeunes bovins qui font l’objet d’une gestion intensive.
(Traduit par Isabelle Vallières)
Hooves protect thoracic and pelvic distal extremities of ruminants allowing them to bear their own weight, particularly during movement; they also provide a protective barrier for the internal structures of the hoof horn against injury and infection (1). The bovine claw structure consists of the periople, sole, bulb, and wall; each area’s strength depends on the number of epidermal layers (2). This structure results from a dynamic process of keratinization of living epidermal cells, characterized by a high rate of synthesis of keratin and intercellular cement substances (3,4). The intensity with which keratinization occurs depends on the pressure and abrasion to which the epithelium is submitted (5,6).
For physiological keratinization, the epidermal cells require an adequate and balanced supply of vitamin and mineral nutrients, particularly biotin (7–10), a water-soluble B-complex vitamin, important in various physiological processes (11). Also referred to as vitamin H, biotin is essential for the 2 main keratinization processes: keratin synthesis and lipogenesis, acting as a fundamental co-factor for enzymes involved in keratin synthesis (10,12).
Until recently, supplementing ruminants with B-complex vitamins, such as biotin, did not receive much attention, since it was thought that the amounts provided in feed and synthesized by the rumenal biota were enough to meet these animals’ needs in all age groups (13). Currently, the effects of biotin supplementation on the recovery of claw epithelium in cattle with several hoof conditions have gained interest among practitioners and researchers (14,15). In a trial using cows with low-grade sole ulcers it was observed that the new epidermis covering the sole ulcer in cows that had been supplemented with biotin had improved histological quality compared with that of the untreated animals. In addition, given the significant improvement in the histology of the hoof of cows in the treated group, it became apparent that biotin played a positive role in recovery from the condition (16).
Although there is no evidence of biotin deficiency in animals with functioning rumens, there is evidence that supplementation of this vitamin in clinically healthy animals contributes to intensification of the keratinization process and to hoof growth (13). The use of biotin supplementation has already been reported in Canada as well, suggesting beneficial effect on claw health in beef cattle (17).
Literature reports state that breed does not influence growth and wearing of the hoof; however, there is a remarkable influence of anatomic, physiologic, seasonal, nutritional, environmental, and management variables on growth and wear of bovine hooves (18). Thus, both aging and cross-breeding may be directly linked to the response to nutritional supplementation and its relation with hoof development in cattle. The Girolando breed, created in Brazil by cross-breeding Gir and Holstein animals, has a record of productivity in various regions of the country, mainly in the northeast region. Girolando cattle are well adapted morphologically and physiologically for the tropics; they have excellent udder capacity and support and teat size (19). However, hoof problems have been reported in this breed (20).
Therefore, it seemed worthwhile to determine whether supplementation of Girolando cattle with biotin would lead to improvement in the quality of the hoof horn, as has already been reported in other breeds of cattle (15,17). The objective of this study was, therefore, to analyze the effects of orally administered biotin supplementation on the growth and claw horn structure of young, clinically healthy Girolando cattle subsisting on low-quality, dry-season pastures.
The study was conducted at the Veterinary Hospital of the Federal University of Goiás Veterinary School, during July and August, 2004, as approved by the Human and Animal Research Ethics Committee, at the Academic Hospital of Federal University of Goiás, Brazil (protocol 135/06). Twelve, 1-year-old clinically healthy (21) Girolando male calves of similar weight (average of 230.5 ± 14.2 kg) were used. The cattle were judged to be healthy based on clinical and laboratory tests [complete blood (cell) count and aspartate aminotransferase, alkaline phosphatase, creatinine and creatine kinase biochemical profile]. The calves were randomly allocated to 2 groups of 6 animals, namely the treatment group (GI), and the control group (GII).
All animals were from the Veterinary College farm, where they received the same management and feeding. All animals went through 2 adaptation periods. Initially, there was a 10-day adaptation period during which the limbs of the animals from both groups were inspected (22). At the end of this period, the claws were trimmed to assure comfortable, anatomic gait and standing position, thereby avoiding exaggerated compensatory wearing of certain claw structures that could compromise the results. Another period of 10 d was stipulated for adjustment to the claw measurement and the handling system, which consisted of walking the animals daily around corrals equipped with the appropriate containment chutes to facilitate administration of medicine and to diminish stress in handling. Beginning with the first adaptation period, the animals were kept in paddocks and received no mineral mixtures or any other medication. During the adaptation and experimental periods all animals were maintained under the same management and nutrition conditions, and there were no significant alterations in body score.
At the end of the 2nd adjustment period, before feeding the biotin, a demarcation point ~15 mm × 2 mm was carved on each of the 8 digits, between the coronary chorion and the hoof horn (Figure 1). Ringel hoof knives were used to mark all the animals. This mark was used as a reference for measurement of the growth of the hoof horn. On the same time (day 0), the first measurement of the hoof horn (M1) was taken on both groups; measurements were also taken on days 20 (M2) and 40 (M3).
Group GI animals received daily individual doses of 12.5 mg of biotin (Bio Hoof; Vetnil Ind. Com. Produtos Veterinários, Louveira, São Paulo, Brazil) diluted in 10 mL of water and fed during 40 consecutive days, while animals in group GII received only 0.9% saline solution, with the same handling and management as the animals in GI.
The parameters that were evaluated were: growth of angle and length of the dorsal hoof wall, hoof sole length, and heel height (Figure 1). Data on hoof conformation were determined according to a technique described previously (23), using a modified and adapted carpenter’s protractor, called a “hoofmeter” (24). To determine the growth of the hoof horn, the length between the coronary chorion and the carved mark made on day zero of treatment was measured (Figure 1a). Hoof wear was calculated as the difference between the measurements taken from the dorsal hoof wall at M3 and M0.
The SAEG/UFV software (Sistema para Análises Estatísticas, Versão 9.1; Fundação Arthur Bernardes — UFV — Viçosa, 2007) was used for statistical analysis. The Wilcoxon test was used to compare the average whole hoof growth of treated (GI) and non-treated (GII) animals. The same test was used to compare differences in the remaining parameters, 20 and 40 d after the initial measurement in both groups. A 5% significance level was adopted.
The average growth of the hoof horn of the cattle taking biotin supplementation (GI) was greater than that of the control group (GII). At M3, the hooves of animals had grown an average of 11.3 ± 0.72 mm in group GI, and 7.2 ± 0.78 mm in group GII. The difference between the 2 groups was significant (P < 0.001). Analysis of measurements taken at M2 and M3, on days 20 and 40, respectively, revealed that growth of the dorsal hoof wall was significantly greater (P < 0.001) in the GI animals compared with those from GII. At M2, there was a 2.6 ± 0.18 mm growth in cattle in GI and 0.8 ± 0.09 mm in cattle in GII (P < 0.01), compared with day 0; while at M3 the growth was 7.6 ± 1.07 mm for animals in GI and 5.3 ± 0.58 mm for animals in GII (P < 0.001).
Sole length increased in both groups at M2; however, animals in GI had an average growth significantly greater than that in GII, 4.3 ± 1.9 mm and −3.6 ± 1.8 mm, respectively. At M3 the average growth of the sole in GI animals continued to increase (5.1 ± 1.7 mm), while in GII, there was still greater wear than growth of this structure (−1.7 ± 0.14 mm), reaching values below those on day 0. As far as heel height growth is concerned, measurements taken on day 20 (M2) indicated that wearing of the structure was greater than mean growth over the same period (GI: −1.2 ± 0.09 mm; GII: −4.1 ± 1.07 mm). At M3, however, both groups showed greater heel height growth, 2.2 ± 0.31 mm in GI and 2.7 ± 0.16 mm in GII. Cattle in the untreated group had a slightly greater growth than those in the treated group, but the diference was not significant (P > 0.05).
Comparing the alterations in the hoof angle at M2 and M3, there was a significantly greater increase in cattle in group GI than for those in GII (P < 0.01). At M2, there was an increase of 0.62 ± 0.12° in GI and 0.06 ± 0.01° in GII. At M3, the increases were 0.77 ± 0.14° for animals in GI and 0.06 ± 0.05° for those in GII. Concerning changes in heel height in cattle from both groups at M2, there was wear rather than growth (1.2 mm wear in GI and 4.1 mm wear in GII compared with M0). According to these results, it may be concluded that biotin supplementation in GI contributed positively to heel resistance in the face of hoof horn wearing observed in GII (P < 0.01). At M3 hoof growth exceeded wear to a greaterextent than that observed at M1 in both groups (2.3 mm and 2.2 mm in GI and GII, respectively), but the differences were not significant.
A balanced supply of nutrients for epidermal cells in the keratinization process is essential for the normal structure and good quality of the claw. Thus, biotin may be used in prevention, reducing the occurrence of hoof wall problems and economic losses. A study of the influence of biotin supplementation on the prevalence of vertical fissures in heifers concluded that while roughly 33% of untreated animals suffered from fissures, only 15% of animals receiving supplementation had this problem (7,15). So far, however, there are no studies comparing biotin effects on young and older animals.
Cattle hoof normally grows an average of 5 mm/month and up to 13 mm/month (1,25). However, in cases of excessive growth, the hoof may grow from 20 to 60 mm over the same period. The results of the present study indicate that the animals in both groups experienced normal claw growth. Nonetheless, on average, hoof growth in the animals treated with biotin was 4.1 mm greater than in the control group. In a study of the growth and wear in the claw in Gir animals, there was a tendency for average hoof growth to exceed average hoof wear (26). The results in this study are consistent with those findings, as far as growth is concerned, and are extended to the animals in the control group. The results observed for dorsal wall growth, the reduction in its natural wear, are consistent with the literature in that biotin may influence both the growth and the resistance of the hoof wall (2).
Keratinization of the epidermal cells that compose the heel region occurs as in other hoof horn structures, through the accumulation of keratin proteins which are concentrated in the epidermis prior to the cornification process (27). However, the pronounced wear observed in this trial probably occurred because the heels are more sensitive than other structures, given that their different arrangement of keratin filaments allows a certain degree of tissue expansion.
Biotin supplementation had a positive effect on average sole growth, even though this is a region where keratinized tissue is less prominent. In addition, the degree of wear in the sole region in animals treated with biotin was significantly lower than that of untreated animals, indicating a greater resistance of this structure, possibly due to an improvement in the quality of the epidermis. Studies on the effect of biotin on hoof histology in cows with low-grade sole ulcers concluded that the vitamin significantly improved the sole’s epithelium. The hoof wall, like the sole, consists of a tubular network of keratinized material; however, some authors state that the sole is organized in a looser network, and thus offers less hardness than the wall. These tubes, composed of cells involved in an intense keratinization process, need an adequate supply of nutrients, including biotin (4,5,14,25).
The whole hoof horn growth for both groups at all times when measurements were taken was within the normal range, and the increase in hoof angle in animals from the treated group was related to whole hoof horn growth (1,25). The results of this study confirm the beneficial effects of oral biotin supplementation on the growth of the claw as a whole, as well as on resistance to wearing in extensively handled young Girolando cattle. CVJ
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