Historically, it has been presumed that microbes in the gastrointestinal tract normally synthesize enough biotin to meet the requirements of ruminants. However, the latest research indicates that biotin supplementation may be beneficial in cattle with a history of hoof problems, especially in times of stress.
Indications that biotin insufficiency might affect foot and hoof health first appeared in research with biotin-deficient poultry and swine. In those studies, dermatitis, loss of feathers or hair, and softening of normally hard tissues such as claws all pointed to a role in production of proteins such as keratin.
In studies that induced biotin deficiency in calves, the animals did indeed exhibit soft hooves that were prone to crack--along with poor weight gains, rough hair coats and scouring. In other studies (Hurstel, 1983), fattening veal calves fed supplemental biotin at 500 mg/kg of dry milk replacer showed improved growth rate, weight for age, and feed conversion compared to unsupplemented calves.
Lactating dairy cows with a history of lameness have been found to have lower plasma biotin levels (Roberts and Baggott, 1983). Frigg et al. (1993) noted that feeding supplemental biotin at 20 mg/head/day increased serum biotin levels from 300-800 ng/l to 3,000-8,000 ng/l in yearling heifers. In these studies, increases in serum levels suggest that about 50 percent of supplemental biotin escapes rumen degradation and is bioavailable to the animal.
Cooke and Brumby (1983) fed supplemental biotin at 20 mg/head/day for four months to a herd of Friesian cows with severe lameness, and the animals showed 50 percent reduction in lameness from hoof horn weakness. In this study, cows fed supplemental biotin also had significantly increased plasma biotin levels compared to controls.
These studies and field observations led Distl and Schmid (1994) to assess the role of biotin as a nutrient for responsive claw disorders in dairy cows. Results showed a significant impact on claw parameters in direct proportion to increased plasma biotin when the cows received the vitamin as an oral 20 mg/day supplement for 11 months.
Although the evidence is beginning to suggest positive effects on hoof and claw health from biotin supplementation, there is still no standard recommendation for biotin use or levels for cattle.
A Canadian study of beef cows may yield more suggestions for tying together supplemental biotin and other nutrients and better management to help ensure hoof health. At issue are "sand cracks"--vertical fissures in the cattle's hoof horn, which present a serious problem for ranchers in the western U.S. and Canada.
A 1995 Alberta Agriculture study found that sand cracks affect about 25 percent of beef cows in that province, and up to 80 percent in some herds. (It is estimated to affect approximately one percent of dairy cows.) The Alberta report also found that the average age of cows with sand cracks was 5.2 years. Earlier studies suggested that the claw problems increased from 10 percent in yearlings to 60 percent in five-year-olds. Genetic factors are not considered important.
Sand cracks often become infected and are treated as simple foot rot, but such treatment is complicated and expensive. Culling, the only alternative, is an expensive solution, since a four- to six-year-old cow is roughly at the midpoint in her reproductive life.
Scientists are looking to supplemental biotin, along with zinc and other trace minerals, because they have tried everything else, says Dr. Paul Greenough at the University of Saskatchewan, the team leader on the current study.
Although sand cracks are not caused by clinical biotin or zinc deficiency, they may be related to insufficiency of these nutrients. Adequate biotin through dietary supplementation may help maintain harder hoof horn. Also, along with zinc, biotin is depleted under stress. At weaning and placement on feed, demand for micronutrients is greatest. The preliminary results of Greenough's studies show that yearling heifers receiving supplemental biotin at 10 mg per head daily had a lower incidence of sand cracks than unsupplemented animals (10% vs. 27%).
Biotin and mineral imbalances must be corrected through the various seasons and production cycles, Greenough notes. There are stark differences in a range cow's diet from spring to winter, and maintaining proper balance could make considerable difference. Many factors work together in this area. In the face of a zinc deficiency, biotin alone may help, but it may not help enough, says Greenough. Overall, the potential rumen shock from the switch to pasture with low fiber and high protein in the spring--after a winter of just the opposite--may be the most powerful stress factor to be controlled. Adding biotin, zinc and other nutrients to the ration may help minimize the effects of this stress on hoof health.
References:
- Cooke, B.C. and P.E. Brumby. 1983. Biotin -- A Dairy Herd Feeding Trial, Biotin in Ruminant Nutrition. Roche Basel Pub. Index No. 1874.
- Distl, O. and D. Schmid. 1994. The Influence of Biotin Supplementation on the Conformation, Hardness and Health of Claws of Dairy Cows. Tierarztliche Umschau. 49:581.
- Frigg, M. et al. 1993. The Bioavailability of Supplemented Biotin in Cattle. International Journal of Vit. Nutr. Res. 63, No. 1:122.
- Goonewardene, L.A. and R.K. Hand. 1995. A Study of Hoof Cracks in Grazing Cattle -- Association of Age, Weight and Fatness. Alberta Agriculture, Food & Rural Devel.
- Hurstel, O. 1983. Supplementation of Calf Milk Replacer Diets with Biotin. Biotin in Ruminant Nutrition. Roche Basel Publication Index No. 1874.
- Roberts, C.J. and D.G.Baggott. 1983. Biotin -- Experiments with Dairy Cattle. Ibid.
