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A. Response of Hoof Disorders to Supplemental Biotin
Sole Ulcer and Heel Horn Erosion.
A controlled field study of 180 dairy cows (Hagemeister and Steinberg, 1996) reported that cows fed 10 mg per day supplemental biotin exhibited a significant reduction in the incidence of sole ulcer and heel horn erosion over a two-year period. Days open were reduced in the biotin group during the second year. Response time of similar hoof disorders was more rapid (six to 10 months) when 20 mg per day of biotin was fed continuously. Hochstetter (1998) reported that feeding 20 mg per day of supplemental biotin significantly reduced the overall incidence and severity of sole ulcer, sole hemorrhage and heel horn erosion in lactating dairy cows in a 12-month clinical experiment.
White Line Separation.
A controlled clinical study was conducted using 100 first- lactation heifers on a large, commercial dairy herd in Ohio (Midla et al., 1998). Heifers were fed either 0 or 20 mg per day of supplemental biotin from calving through the first lactation. Biotin supplementation resulted in a significant reduction in white line separation by 100 days in lactation ( Figure 1) and a significant increase in 305-day milk production (693 lb, or 314 kg) ( Figure 2).
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A controlled, clinical trial with 56 dairy cows over 11 months found that 20 mg per day supplemental biotin resulted in a significant reduction in the incidence of digital dermatitis and sole bruising (Distl and Schmid, 1994) ( Figure 3, 4). Similar results were found in a randomized clinical field trial with 40 dairy cows where 20 mg per day of biotin resulted in a reduction in the incidence of digital and interdigital dermatitis over an eight- to 12-month period (Hochstetter, 1998) ( Figure 5).
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A clinical field study of 236 claw lesions with exposed corium in 160 cows in 82 dairy herds found that cows fed 20 mg per day of biotin experienced significantly better healing of the lesions (Lischer et al., 1996) ( Figure 6). A regression analysis of the data found a highly significant linear relationship between serum biotin concentration and the rate of new horn formation over the lesions. Biotin supplementation also increased the quality of new horn. Hochstetter (1998) reported that supplemental biotin resulted in increased keratinization and cementing of hoof horn and an increase in biotin concentration in the live epidermis (horn-forming) tissue layer of the hoof.
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A controlled 12- month field study of 265 purebred Hereford cows with a 37% incidence of vertical fissures (sand cracks) of the hoof wall was conducted in Western Canada (Campbell et al., 2000) ( Figure 7). Supplementing a balanced mineral program with 10 mg per day of biotin resulted in a 50% reduction in the incidence of new vertical fissures, a similar reduction in coronary band lesions and a significant increase in hoof wall hardness (Campbell et al., 2000). A controlled field trial of 100 dairy cows in Washington State reported that 20 mg per day of supplemental biotin reduced the incidence of horizontal ridging and sole hemorrhage over a 12-month period (Bergsten et al., 1999). Cows in the study were housed in a common environment and dietary treatments were administered by computer controlled feeders.
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One of the larger and more recent trials (Fitzgerald et al., 2000) took place with pastured dairy cows in the Atherton region of northern Australia. Lameness is a problem in this region due to seasonal calving during the wet season, a diet of high quality pasture with supplemental grain, and the long walking distances to and from milking by way of partially paved, partly mud cow lanes. A total of 20 farms (10 control and 10 biotin-supplemented) with a total of 2,700 cows participated in the study. Both the farmers and the evaluators were blind to the treatments to prevent bias. After four months of supplementation, the cows fed 20 mg per day of biotin had a significant reduction in overall lameness, antibiotic treatments, and application of hoof shoes ( Figure 8, 9). The participating farmers kept track of lameness during the trial. The economics of biotin were favorable with a milk price of approximately $9.30/cwt. Besides demonstrating a beneficial effect of biotin on hoof health, the results showed that hoof disorders of dairy cattle are not limited to confinement housing systems. Hoof disorders are more related to the overall level of "hoof stress" in a herd. Increased hoof stress increases the need to rebuild hoof horn and therefore the need for essential nutrients.
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Schmid (1995) conducted a longitudinal study of five dairy cows both before and during biotin supplementation (20 mg per day). After four months of biotin supplementation, heel horn tensile strength increased significantly (12% to 30%), and clinical appearance of hoof improved compared to scores prior to supplementation. Coronary (wall) horn tensile strength increased after 15 months of supplementation, which is consistent with its rate of growth. Hoof hardness was not affected by biotin supplementation. Coronary (hoof wall) horn was much harder than sole horn (76 versus 48 Shore D degrees).
B. Milk Production Responses to Supplemental Biotin in Dairy Cows
In the study by Midla et al. (1998) using only first-lactation heifers, 305-day milk production was increased significantly (+314 kg, or 693 lb) in response to feeding 20 mg per day of supplemental biotin daily. This response was measured over the entire lactation and accompanied a significant reduction in the incidence of white line fissures.
Bonomi et al. (1996) reported a consistent 1-kg increase in daily milk production in Italian Holstein cows fed 10 mg per day of supplemental biotin ( Figure 10). These authors also reported that supplemental biotin increased blood glucose concentration and milk component yields. The milk increase was observed during the first month of supplementation, which began at calving.
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Bergsten et al. (1999) analyzed 305-day milk yield in 98 dairy cows fed either 0 or 20 mg per day of supplemental biotin via computer feeder. Data were adjusted for parity, days in milk and previous lactation milk yield. Cows fed supplemental biotin produced 1,932 lbs (878 kg) more milk over 305 days ( Figure 11). There was a significant reduction in sole hemorrhage and hoof wall ridging in the biotin-supplemented cows, although hoof health was generally good at the outset of the study.
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Most recently, a controlled experiment was conducted supplementing either 0, 10 or 20 mg per day of biotin to high-producing dairy cows beginning 14 days prepartum and continuing for the first 100 days of lactation (Zimmerly and Weiss, 2000). Biotin supplementation resulted in a significant and linear increase in milk production throughout the 100-day experiment ( Figure 12). These results indicate that biotin status of cows was marginal with respect to metabolic processes (i.e. enzyme activities) involved in milk production. The direct involvement of biotin in the enzymatic pathways of rumen propionic acid synthesis and hepatic gluconeogenesis from propionic acid, as well as in fat and protein metabolism, provides a logical basis for such an interpretation.
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Biotin supplementation of calf milk replacer is warranted based on the biotin content of milk, studies of biotin deficiency in calves and unknown aspects of the development of rumen synthesis of biotin.
For dairy cattle, the National Research Council (NRC, 1989) recommends that milk replacer for calves should contain 0.1 mg per kg (0.05 mg per lb) biotin. In acute cases of biotin deficiency in calves, single biotin injections of 100 µg subcutaneously or 1 mg intravenously reversed the deficiency (Wiese et al., 1946).
Biotin is one of the more chemically stable vitamins, but losses during storage can occur. Biotin is readily destroyed by fat rancidity (Pavcek and Shull, 1942). Preparing fresh feeds, limiting storage time and storing feed in a dry, well-ventilated area will minimizes rancidity and other stability problems. Diets high in pro-oxidants such as poor quality, unsaturated fats or oils should be avoided. Biotin is relatively stable in multivitamin premixes and is fairly stable during processing. However, significant losses can occur in premixes that contain choline and trace minerals. In a high quality premix containing only vitamins, biotin will retain 90% to 100% of initial activity over three months of storage. However in the presence of choline and trace minerals retention is reduced to 70% to 90% of original activity (Gadient, 1986). Spray-dried biotin is stable for 18 months or more in the original, unopened container.
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