The influence of long-term supplementation with biotin on the prevention of lameness in pasture fed dairy cows

Evolving understanding of rumen methanogen ecophysiology

Production of methane by methanogenic archaea, or methanogens, in the rumen of ruminants is a thermodynamic necessity for microbial conversion of feed to volatile fatty acids, which are essential nutrients for the animals. On the other hand, methane is a greenhouse gas and its production causes energy loss for the animal. Accordingly, there are ongoing efforts toward developing effective strategies for mitigating methane emissions from ruminant livestock that require a detailed understanding of the diversity and ecophysiology of rumen methanogens. Rumen methanogens evolved from free-living autotrophic ancestors through genome streamlining involving gene loss and acquisition. The process yielded an oligotrophic lifestyle, and metabolically efficient and ecologically adapted descendants. This specialization poses serious challenges to the efforts of obtaining axenic cultures of rumen methanogens, and consequently, the information on their physiological properties remains in most part inferred from those of their non-rumen representatives. This review presents the current knowledge of rumen methanogens and their metabolic contributions to enteric methane production. It also identifies the respective critical gaps that need to be filled for aiding the efforts to mitigate methane emission from livestock operations and at the same time increasing the productivity in this critical agriculture sector.

Metagenomic insights into the microbe-mediated B and K2 vitamin biosynthesis in the gastrointestinal microbiome of ruminants

BACKGROUND

B and K₂ vitamins, essential nutrients in host metabolism, can be synthesized by the rumen microbiome in ruminants and subsequently absorbed by the host. However, the B and K₂ vitamin biosynthesis by the whole gastrointestinal microbiome and their abundances in different dietary strategies are largely unknown. Here, we reanalyzed our previous large-scale metagenomic data on the gastrointestinal microbiome of seven ruminant species and recruited 17,425 nonredundant microbial genomes from published datasets to gain a comprehensive understanding of the microbe-mediated B and K₂ vitamin biosynthesis in ruminants.

RESULTS

We identified 1,135,807 genes and 167 enzymes involved in B and K₂ vitamin biosynthesis. Our results indicated that the total abundances of B and K₂ vitamin biosynthesis were dominant in the stomach microbiome, while the biosynthesis of thiamine, niacin, and pyridoxine was more abundant in the large intestine. By examining 17,425 nonredundant genomes, we identified 2366 high-quality genomes that were predicted to de novo biosynthesize at least one vitamin. Genomic analysis suggested that only 2.7% of these genomes can synthesize five or more vitamins, and nearly half of genomes can synthesize only one vitamin. Moreover, we found that most genomes possessed cobalamin transporters or cobalamin-dependent enzymes to consume cobalamin directly, and only a few microbial genomes possessed a complete cobalamin biosynthesis pathway. Based on these genomic data, we examined the effect of the high-grain (HG) diet on the vitamin biosynthesis of the rumen microbiome of dairy cattle. We revealed that most vitamin biosynthesis was enhanced in the HG group, while only cobalamin synthesis was inhibited in the HG group, indicating that dietary fiber is vital for cobalamin biosynthesis.

CONCLUSIONS

We primarily provided a gene catalog and 2366 microbial genomes involved in B and K₂ vitamin biosynthesis in ruminants. Our findings demonstrated the regional heterogeneity and dietary effect of vitamin biosynthetic potential in the ruminant gastrointestinal microbiome and interpreted the biosynthesis mechanisms of these microbes and their physiological adaptability. This study expands our understanding of microbe-mediated vitamin biosynthesis in ruminants and may provide novel targets for manipulation to improve the production of these essential vitamins. Video abstract.

Effects of Betaine-Biotin-Chromium Supplementation and Concentrate to Roughage Ratio on Nutrient Utilization Efficiency in Thai Native Cattle

Simple Summary

Feed additives are attracting considerable interest due to the need to effectively improve the level of production, efficiency, and health of animals. A combination of betaine, biotin, and chromium has been developed to enhance nutrient utilization efficiency. Ideally, the addition of a combination of supplements to livestock feed could improve ruminal fermentation, digestibility and nutrient utilization, nitrogen and energy balance, and metabolism.

Abstract

The objective of this study was to evaluate the effects of supplementation with a feed additive containing a combination of betaine, biotin, and chromium (BBC) and concentrate-to-roughage ratio (C:R ratio) on nutrient digestibility, blood metabolites, ruminal fermentation, nitrogen balance, and energy utilization in Thai native beef cattle. Five Thai feedlot native beef bulls at one year old of age and 87.6 ± 15.7 kg of body weight were assigned in a (2 × 2) + 1 augmented factorial experiment according to a 5 × 5 Latin square design with five periods of 21 days. The two levels of BBC were 3 g/kg DM and 6 g/kg DM, and the two ratios of C:R were 60C:40R and 70C:30R. A C:R ratio of 70C:30R without BBC supplementation was used as a negative control. The cattle were offered feed at 3% BW, which provides sufficient energy and protein to support a weight gain of 500 g/day. The results showed that dry matter intake (DMI) and organic matter intake (OMI) were not different (p > 0.05), but the intake of crude protein (CP) and ether extract (EE) was higher (p < 0.05), whereas neutral detergent fiber (NDF) and acid detergent fiber (ADF) were lower (p < 0.05) in the 70C:30R ratio diets compared to the 60:40R ratio diets. Energy balance and nitrogen balance were not influenced (p > 0.05) by the C:R ratio or the addition of BBC. Rumen pH and ammonia-nitrogen (NH₃-N) did not differ (p > 0.05) among treatments groups. Total volatile fatty acid (VFA) production was higher (p < 0.05) in bulls fed with the 70C:30R ratio diet. The addition of BBC resulted in a lower (p < 0.01) glucose-to-insulin ratio compared to cattle fed with the control diet. Energy and protein utilization efficiency did not differ (p > 0.05) among the experimental treatment groups, which were higher (p > 0.05) than the control group. In conclusion, BBC supplementation showed greater growth performance of cattle compared to the control. BBC supplementation appeared to improve glucose uptake and insulin sensitivity and energy and protein utilization efficiency. Whether BBC supplementation increases glucose production in the liver remains to be determined in future studies.

Risk of Lameness in Dairy Cows with Paratuberculosis Infection

Simple Summary

Johne’s disease (JD) is an important disease affecting cows in the UK dairy industry, as is lameness, and both cause milk production losses and cows losing weight. The aim of this work was to see if cows with JD were more likely to be lame and if so, what the order of occurrence of these two events is. We looked at the JD and lameness records of two farms and paired 98 JD cows (half of them with a high response to the test for JD) and compared them with herd mates. We evaluated the timing and the proportion of lameness in JD-positive cows compared to their controls and proportion of lameness before and after the first JD-positive test. JD cows turn lame on average three months earlier and are lame 2.7 times more often than non-JD cows. Further, high positive cows were 2.8 times more likely to develop lameness after JD diagnosis compared to medium positive cows. Results of this study suggest that there is a link between JD and lameness and that JD precedes lameness. The underlying mechanisms for this association remain unknown and were not the scope of this study.

Abstract

Johne’s disease (JD) is an important disease affecting the UK dairy industry, as is cattle lameness. An association between JD and lameness has been suggested; however, little evidence exists to support this. The purpose of this study was to determine if cows affected by JD were more likely to be lame and if so, what the temporal association is. Retrospective dairy cow mobility and JD status (based on milk ELISA) data were obtained from two farms of 98 JD cows (49 high and 49 medium positive) and their matched controls. We evaluated the timing and the proportion of (chronic) lameness in JD-positive cows versus controls and proportion of lameness before and after the first ELISA positive test. Compared to their controls, JD cows are lame more often (Odds Ratio = 2.7 (95% Confidence Interval = 1.2–6.0) p = 0.017) and became lame on average three months earlier (p = 0.010). High positive cows were more likely to develop lameness after seroconversion (OR = 2.8 (95% CI = 1.1–7.5), p = 0.038) versus medium positive cows. Results of this study suggest that there is a link between JD and lameness and that JD precedes lameness. The underlying mechanisms for this association remain unknown and were not the scope of this study.

Cow Lying Behaviour and Bedding Quality Changes during Five Weeks on a Stand-Off Pad

Simple Summary

New Zealand dairy farmers place cows in uncovered off-paddock facilities for a part (e.g., 18 h) of the day to reduce their impact on pasture during winter. Lying time is a key indicator of whether these hybrid pasture systems are meeting welfare requirements. While it is easy to measure lying time in a research setting using accelerometers, it is not yet common to measure it on farm, and more convenient indicators are needed. We investigated the lying behaviour of dairy cows as bedding quality deteriorated over a five-week period to determine what measures may be useful as farmer-friendly indicators of cow welfare. The daily lying time of the two groups of cows on bedding according to normal farm practice (NFP) declined over the five weeks and was significantly less than that of cows on fresh bedding during the last 10 days of the trial. The fresh woodchip bedding contained less than 65% moisture throughout the trial. By week 3 and week 4, the moisture content of the lying surface exceeded 75% for NFP Group 2 and Group1, respectively. A bedding moisture threshold of 75% assessed by a ‘gumboot score’ and cows lying rather than grazing when on pasture may be useful farmer-friendly indicators of cow welfare because of their relationship with reduced lying time.

Abstract

Bedding quality and cow lying time were measured during five weeks in a normal farm practice (NFP) off-paddock system with no bedding refreshment. Two groups of 100 non-lactating dairy cows were compared to groups of 8 cows with fresh bedding (FB). The cows were on a woodchip pad for 18 h/d at a space allowance of 5.4 m²/cow, with 6 h/d on pasture for 5 weeks. Lying times were recorded continuously for 60 cows per group using accelerometers. Bedding moisture content was measured weekly. Data for each NFP group were analysed and compared with those of their respective FB group using repeated measures. The lying time declined over five weeks from 11.6 h/day during the first week to 5.6 h/day during the fifth week (SED = 0.3; F_1,25 = 351.56; p < 0.001). The moisture content of the bedding increased over the five weeks and was significantly higher for both NFP groups (NFP Group 1: F_5,59 = 8.33; p < 0.001; NFP Group 2: F_5,61 = 5.54; p < 0.001) than those of the respective FB groups. The percentage of total time lying when in the paddock increased for the NFP groups, reaching 15% in the last week of the trial. During five weeks on a stand-off pad, bedding quality deteriorated, and cows lay down less, to such an extent that welfare was compromised.

Muddy conditions reduce hygiene and lying time in dairy cattle and increase time spent on concrete

Dairy cattle spend less time lying and show signs of increased stress when housed in rainy and windy conditions, but no work has separated the effects of exposure to inclement weather from muddy conditions underfoot. Our objective was to evaluate the effects of muddy conditions alone on lying behavior, hygiene, and physiological responses. We housed pairs of pregnant, nonlactating dairy cattle (n = 12; 6 primigravid heifers, 6 multiparous cows) in enclosed pens with dirt floors and a concrete feed apron. Cattle were exposed to 3 levels of soil moisture: 90 (dry), 74 (muddy), or 67% (very muddy) dry matter for 5 d each in a replicated 3 × 3 Latin square design. Lying time was measured on all days with data loggers, and lying locations and postures were recorded on the final day of each treatment. Before and after each treatment, blood samples were collected, and the percentage of dirty surface area was measured on the udder, hind leg, and side of each animal. Cattle spent less time lying down in muddier conditions, especially in the first 24 h of exposure, when cows and heifers spent only 3.2 and 5.8 h, respectively, lying down in the muddiest treatment compared with 12.5 and 12.7 h on dry soil. When the soil was dry, cattle never chose to lie down on concrete, but in muddier conditions they spent a greater proportion of their lying time on concrete (mean ± SE: 56 ± 14 and 10 ± 8% in the very muddy and muddy treatments, respectively). The shift in lying location was more marked for heifers, and all 6 spent ≥87% of their lying time on concrete in the muddiest treatment. When cattle chose to lie down on wetter soil, they limited the surface area exposed to their surroundings by tucking their legs beneath their bodies (mean ± SE: 30 ± 11, 15 ± 4, and 5 ± 2% of lying observations in the very muddy, muddy, and dry treatments, respectively). Despite cattle spending less time on wetter soil, all 3 measured body parts became dirtier in muddier conditions (1.4-, 1.6-, and 1.8-fold more on the leg, udder, and side, respectively, in the muddiest compared with the driest treatment). In addition, higher soil moisture levels resulted in greater reductions in white blood cell counts relative to baseline levels (-0.95, -0.43, and 0.34 × 10⁹/L relative to baseline levels in the very muddy, muddy, and dry treatments). Muddy conditions, even in the absence of wind or rain, are aversive for cattle and have negative implications for their welfare.

Patologías podales en ganado lechero y feedlot del partido de Tandil, provincia de Buenos Aires, Argentina

<p>Las patologías podales del bovino son multicausales, incluyendo alta producción, estrés, nutrición, causas ambientales, infecciosas, genéticas, razas, estado fisiológico y comportamiento tanto animal como humano. Están adquiriendo gran importancia debido a la intensificación  de la producción. El objetivo del presente trabajo fue determinar la prevalencia de enfermedades podales en explotaciones lecheras y en comparar ambos tipos de explotación en la región de Tandil, Buenos Aires, Argentina. Se evaluaron 24 tambos en 2005 y un en 2013 en busca de patologías podales. Los animales que presentaron claudicación se separaron del rodeo y se revisaron. Se calculó la prevalencia bruta y por patologías de mayor presentación en ambos tipos de producción y además proporción según miembro afectado. Se estimaron diferencias entre las prevalencias de cada tipo de producción por medio de Chi cuadrado (lt;0,05) y razón de prevalencias. La prevalencia en los 12132 animales lecheros fue del 2,71% y en los 14500 de <em>feedlot</em> del 0,57% (Razón de prevalencia=4,73 (IC95%=3,72–6,02). La prevalencia de traumatismos en <em>feedlot</em> fue del 0,17% y en tambos 0,016% (p&lt;0,05); dermatitis digital (tambo 0,69%, <em>feedlot</em> 0,13%; p&lt;0,05) e interdigital (tambos 0,81%, 0,1%; lt;0,05). En ambas producciones los miembros más afectados fueron los posteriores (90,4% y 88,1% tambos). La baja prevalencia en podría deberse a la baja edad de los animales. En los animales de hay significativamente más prevalencia en traumatismos que en tambos, mientras que en éstos hay más dermatitis digital e interdigital.</p>

The relationship between serum biotin and oxidant/antioxidant activities in bovine lameness

Serum biotin concentrations, erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), reduced glutathione (GSH) and plasma thiobarbituric acid reactive substances (TBARS) were measured in 36 dairy cows, 18 of them were healthy and served as control. In the 18 cows with lameness problems, there were 5 cows with interdigital necrobacillosis, 5 cows with subsolar abscessation, 2 cows with solar ulcers, 2 cows with white line disease, 2 cows with chronic laminitis and 2 cows with septic arthritis. The degree of lameness was estimated to be slight in 3 cows, moderate in 11 cows and severe in 4 cows. Plasma fibrinogen levels and TBARS concentrations were increased significantly (P≤0.05) in lame cows compared to control group. The antioxidant enzymes GSH-Px, and CAT concentrations were increased significantly (P≤0.05) in lame cows. The level of reduced glutathione and the activity of SOD were significantly decreased in affected cows compared to healthy ones. Serum biotin levels in healthy cows ranged from 2.25 to 3.5ng/ml while in lame cows, biotin levels ranged from 1.17 to 2.3ng/ml. Biotin levels correlated positively with blood GSH (r=0.870, P≤0.05), (r=0.735, P≤0.05) and with GSH-Px (r=0.539, P≤0.05), (r=0.637, P≤0.05) and with SOD (r=0.637, P≤0.05), (r=0.449, P≤0.05) and with catalase (r=0.533, P≤0.05), (r=0.585, P≤0.05) in both healthy and lameness affected subjects, respectively.

Effect of biotin supplementation on hoof health and ceramide composition in dairy cattle

The effect of biotin supplementation on various foot lesions and hoof ceramide composition of toe (wall) and sole portions of hooves was studied in crossbred dairy cattle. Biotin supplementation was done for five months in 14 cattle at a farm and the other 14 animals kept as control. A significant decline was observed in heel erosions and sole avulsions along with total disappearance of white line fissures and double soles in the biotin supplemented cattle resulting in decrease in the overall disease score. Thin layer chromatographs of the hoof lipids revealed 11 types of ceramides in sole lipids and 6 types of ceramides in toe (wall) lipids. The ceramides were typed and identified according to their Rf values. A qualitative increase in the density of thin layer chromatographs of sole lipids was observed in biotin supplemented cattle whereas a non-significant difference in density of thin layer chromatographs of toe lipids was observed after supplementation of biotin.

Changes in Measures of Biotin Status Do Not Reflect Milk Yield Responses When Dairy Cows Are Fed Supplemental Biotin

A sensitive indicator of biotin status for lactating dairy cows is necessary to understand factors that affect milk yield responses to biotin supplementation. 3-Hydroxyisovaleric acid (3HIA) is an alternative metabolite in the pathway of Leu catabolism when the biotin-dependent enzyme methylcrotonyl-coenzyme A carboxylase is limiting. We evaluated urinary excretion of 3HIA as a determinant of biotin status in lactating dairy cows. We hypothesized that high-producing cows would have a greater biotin requirement and excrete more 3HIA than low-producing cows and that biotin supplementation would decrease 3HIA excretion. Twenty high-producing and 20 low-producing Holstein cows (43 +/- 5 and 23 +/- 4 kg/d of milk, respectively) were fed diets that contained either 0 or 0.96 mg/kg of supplemental biotin. On d 16 cows were given an intraruminal infusion of 1.4 mol of isovaleric acid and urine was sampled. Biotin supplementation did not affect basal urinary excretion of 3HIA. The infusion of isovaleric acid increased urinary excretion of 3HIA (maximum at 8 h after infusion), but biotin supplementation did not attenuate this increase. The increase in urinary 3HIA excretion was less for low-producing cows than for high-producing cows. Biotin increased yields of milk and milk components in high-producing cows but had no effect in low-producing cows. However, potential measures of biotin status (concentrations of avidin-binding substances in the plasma, milk, and urine, and urinary 3HIA excretion) responded similarly to biotin supplementation for both high- and low-producing cows. A sensitive indicator of biotin status for lactating dairy cows is still needed.

Characterization of maleuric acid derivatives on transgenic human monoclonal antibody due to post-secretional modifications in goat milk

A fully human antibody to tumor necrosis factor-alpha was expressed in the mammary glands of transgenic goats. The goat expressed antibody (gAb) is heterogeneous and has several isoforms due to typical cellular post-translational modifications. In addition, one post-secretional modification on gAb was discovered by high-resolution cation exchange chromatography (CIEX). The presence of these variants in the final product was shown to be dependent upon the initial milk storage and traditional purification methodologies used. These observations allow for the development of new sample recovery and purification processes to eliminate these variants. Various enzymatic treatments were used to characterize different gAb heavy chain C-terminal lysine and sialic acid variants. In addition, an unknown derivative with the additional mass of 140 Da was found in transgenic gAb using mass spectrometry (MS). The modification sites were identified as the N-termini of gAb light chains and heavy chains using Q-TOF MS. Characterization of transgenic gAb isoforms was facilitated by utilizing different enzymes, CIEX and MS techniques. A maleuric acid modification on the N-terminal portion of gAb was shown to be consistent with the available data characterizing this new derivative of transgenic gAb isoforms in goat milk.

Review of the relationship between nutrition and lameness in pasture-fed dairy cattle

Lameness of dairy cattle fed predominantly on pasture is increasingly recognised as one of the most costly disease conditions affecting dairy herds in New Zealand and Australia. Numerous risk factors are involved in the aetiology of claw lameness, including environment and factors associated with the conformation of individual cows. The role of nutrition requires further definition. Australasian pastures are characterised by low levels of fibre and effective fibre, rapid rates of fibre degradation, high water content, and high concentrations of rumen degradable protein during the autumn, winter and spring months. Relationships between high-quality vegetative pastures and ruminal acidosis may increase the risk of laminitis, particularly where pasture is supplemented with grains or other feeds containing significant amounts of starch. This article reviews the incidence, prevalence and pathophysiology of ruminal acidosis and laminitis and considers mechanisms by which acidosis may occur in pasture-fed cows. Techniques for diagnosing ruminal acidosis are reviewed, and practical strategies to avoid it are proposed. Currently, there is little information on the incidence and prevalence of ruminal acidosis and laminitis in pasture-fed cattle. The evidence gathered in this review suggests that ruminal acidosis and laminitis should be considered in the aetiology of lameness in pasture-fed dairy herds.

Influence of Neck-Rail Placement on Free-Stall Preference, Use, and Cleanliness

Three experiments examined how the presence of a neck rail at different heights and locations influenced dairy cattle behavior and stall cleanliness. Experiment 1 compared 4 levels of neck-rail height (102, 114, and 127 cm and no neck rail; presented at 160 or 180 cm from the curb) in a preference test. Cows (n = 10) showed no consistent preference based on neck-rail height, regardless of the horizontal position of the neck rail. When cows were restricted to each treatment in turn, however, time spent standing fully (with all 4 hooves) in the stall was least in the stall with the lowest neck rail (mean, 22 min/24 h) and was greatest in the stall with no neck rail (mean, 83 min/24 h). A second experiment examined the effect of a neck rail placed at 3 distances from the curb (140, 175, and 233 cm) when height was held constant (131 cm; n = 12). Time spent standing fully in the stall was least when the neck rail was close to the curb (140 cm; mean, 11 min/24 h) and was greatest when the neck rail was furthest from the curb (233 cm; mean, 86 min/24 h). When the neck rail was far from the curb, the cows were more likely to soil the stall by defecating while standing fully in the stall. Experiment 3 compared soiling of the stall by 14 cows with and without a neck rail at a height of 124.5 cm. When the neck rail was removed, cows were more than twice as likely to soil the stall by defecating while standing fully in the stall compared with when the neck rail was present (1.3 vs. 0.5 defecations/24 h). Thus, restrictive neck-rail placement prevents cows from standing in stall, but helps keep stalls clean. Access to more comfortable flooring surfaces outside the stall may help mitigate the negative effects of restrictive neck rails.

Free-Stall Dimensions: Effects on Preference and Stall Usage

In 2 experiments, free-stall dimensions were examined to determine how they affected stall preference, usage, cleanliness, and milk production in Holstein dairy cattle. In experiment 1, stall width (112 or 132 cm) and stall length (229 and 274 cm from curb to wall) were compared in a 2 x 2 factorial arrangement of stall treatments using 15 individually housed, non-lactating animals. Cows showed no clear preference for stall size as measured by lying time. When animals had no choice between stalls, average lying time was higher in the wide stalls than in the narrow stalls (10.8 vs. 9.6+/-0.3 h/24 h). Both length and width affected time spent standing with only the front hooves in the stall; total stall area is best explained by the variation associated with this behavior. In experiment 2, 27 lactating dairy cattle were alternately housed with access to stalls of 106, 116, or 126 cm in width using a cross-over design with exposure to each treatment lasting 3 wk. Animals spent an additional 42 min/24 h lying in stalls measuring 126 cm in width compared with stalls with only 106 cm between partitions. Free-stall width influenced the time spent standing with the front 2 hooves in the stall; animals averaged 58 min/24 h in the widest stalls and 85 min/24 h in the narrowest stalls. The amount of time spent standing with all 4 hooves in the stall tended to be longer in wider stalls, and these stalls were also most likely to become soiled with feces. Stall width did not affect the number of lying events or milk production. In conclusion, animals spent more time lying down, and less time was spent standing with only the front hooves in larger stalls, but larger stalls were also more likely to become soiled.

Invited Review: Formation of Keratins in the Bovine Claw: Roles of Hormones, Minerals, and Vitamins in Functional Claw Integrity

Keratins are the characteristic structural proteins of the highly cornified epidermis of the skin, feathers, and hoof. Keratin proteins provide the structural basis for the unique properties of the biomaterial horn and its protective function against a wide range of environmental factors. Hoof horn is produced through a complex process of differentiation (keratinization) of epidermal cells. Formation and biochemical binding of keratin proteins and synthesis and exocytosis of intercellular cementing substance (ICS) are the hallmarks of keratinization. It is finalized by the programmed death of the living epidermal cells, i.e., cornification, that turns the living epidermal cells into dead horn cells. The latter become connected by the intercellular cementing substance. The functional integrity of hoof horn essentially depends on a proper differentiation, i.e., keratinization of hoof epidermal cells. Keratinization of hoof epidermis is controlled and modulated by a variety of bioactive molecules and hormones. This process is dependent on an appropriate supply of nutrients, including vitamins, minerals, and trace elements. Regulation and control of differentiation and nutrient flow to the epidermal cells play a central role in determining the quality and, consequently, the functional integrity of hoof horn. Decreasing nutrient supply to keratinizing epidermal cells leads to horn production of inferior quality and increased susceptibility to chemical, physical, or microbial damage from the environment. A growing body of evidence suggests that hormones, vitamins, minerals, and trace elements play critical roles in the normal development of claw horn and correct keratin formation.

Effects of Biotin Supplementation on Performance and Claw Lesions on a Commercial Dairy Farm

A controlled 14-mo field trial was conducted to evaluate the effect of biotin supplementation on hoof lesions, milk production, and reproductive performance in a commercial dairy herd. One hundred seventy cows were studied and supplemented with either 0 or 20 mg/d of biotin by computer feeder. All were housed in the same free-stall facility with the same environment, base diet, and management. The feet of 99 cows were trimmed three times at 6-mo intervals, and hoof health was evaluated. Milk production and fertility data were captured monthly by the Dairy Herd Improvement Association. At the final hoof trimming, sole hemorrhages were significantly higher in control (50%) vs. biotin-supplemented animals (24%). The incidents of cows affected with double soles, hoof wall grooves, and heel horn erosion did not differ between control and biotin-supplemented animals. Biotin supplementation of trimmed cows resulted in 878 kg more milk than control cows when compared with previous lactation yield (n = 46 biotin supplemented, n = 48 control cows). At the end of the study, for both trimmed and untrimmed animals, biotin supplemented cows (n = 81) produced 481 kg more milk and 25 kg more fat than the controls (n = 81). There was no interaction between biotin supplementation and hoof trimming on milk production. There were variations in the response of fertility to biotin between age groups. First lactation heifers fed supplemental biotin had significantly fewer days from calving to conception and required fewer inseminations per pregnancy than controls of the same parity.

The impact of parity and duration of biotin supplementation on white line disease lameness in dairy cattle

A field study was conducted to examine effects of oral biotin supplementation for up to 18 mo on risks of lameness in dairy cows. The study included a total of 900 cattle from five dairy farms in Gloucestershire, southwest U.K., in a within-herd randomized control trial. The data from this trial were used in this paper to investigate the impact of parity and duration of supplementation with oral biotin at 20 mg/d on white line disease (WLD) lameness. Analysis of the data indicated that WLD increased with increasing parity independent of biotin supplementation from approximately two cases per 100 cow years in primiparous cows to 15.5 cases per 100 cow years in all multiparous cows, but up to 47.7 cases per 100 cow years for cows in parities > or = 5. Supplementation with biotin reduced WLD lameness by 45% in multiparous cows down to 8.5 cases per 100 cow years, whereas the effect of biotin supplementation in primiparous cows was not significant. Although numerical reductions in WLD lameness were observed for shorter periods of supplementation, a supplementation length of at least 6 mo was required to significantly reduce the risk of WLD lameness in multiparous cows. The effect of biotin supplementation in reducing lameness has potential impact for both animal welfare and farm economics.

Research note: effect of increasing dietary concentrate levels on microbial biotin metabolism in the artificial rumen simulation system (RUSITEC)

The effect of varying hay/barley-proportions in the feed ration on biotin metabolism of rumen microbes was studied by means of the rumen simulation technique RUSITEC. The stepwise replacement of hay by barley decreased dietary biotin and the net output of biotin by the microbial metabolism. It is concluded that rumen microbes utilise more and/or synthesize less biotin with increasing proportions of dietary barley. These results indicate that a critical reconsideration of current views with regard to the supply and requirement of the high yielding dairy cow for biotin is necessary.

A longitudinal field trial of the effect of biotin on lameness in dairy cows

A longitudinal prospective intervention study investigated the effect of biotin supplementation on the incidence (new cases per day) of visible lameness in milking cows and heifers on five commercial farms in Gloucestershire, United Kingdom. The trial lasted from June 1997 to April 1999. Each farm participated in the trial for 18 mo. Within each herd the cows were randomly allocated to either receive a supplement of 20 mg of biotin per day or not. All cows were run as one herd on each farm. When a lame cow was identified, the farmer called one of six veterinarians to examine and treat the affected animal; findings were recorded on a standard form. A veterinarian also carried out a bimonthly locomotion assessment to ensure that all lame cows were diagnosed. There were a total of 900 cows, 1120 cow years, in the trial. The overall incidence rate of lameness (per 100 cows per year) was 68.9, with a range of 31.6 to 111.5 per farm. The incidence rates of the four most frequently reported causes of lameness were sole ulcer, 13.8; white line separation, 12.7; digital dermatitis, 12.0; and interdigital necrobacillosis, 7.1 per 100 cows per year. There was a significant difference in the incidence rate of these four lesions between supplemented and unsupplemented cows on two of the five farms, with a significant decrease in lameness in the cows supplemented with biotin. When all the farms were pooled, the risk of lameness caused by white line separation in cattle supplemented with biotin was approximately halved (Cox proportional hazard survival analysis hazard ratio = 0.57).

Metabolic hoof horn disease. Claw horn disruption

Low-quality hoof horn is a frequent underlying cause of lameness in cattle. Because the lesions that are observed are the result of insults that affect horn production at the cellular level, the term claw horn disruption has been proposed to describe the disease process. Although claw horn disruption may result from multiple etiologies, the response of the keratinocytes is relatively nonspecific in that lesions often appear the same regardless of cause. To solve herd problems, the investigation of possible etiologies must be integrated with a basic understanding of the anatomic and physiologic features of hoof horn production.

Rumen undegradable protein, rumen-protected choline and mRNA expression for enzymes in gluconeogenesis and ureagenesis in periparturient dairy cows

The objective of this study was to profile mRNA expression of argininosuccinate synthetase (AS) and ornithine transcarbamylase (OTC), two enzymes that participate in the formation of urea in liver and compare these with changes in mRNA for pyruvate carboxylase (PC) and phosphoenolpyruvate carboxykinase (PEPCK) during the periparturient period in dairy cows. Forty-eight multiparous Holstein cows were fed isoenergetic prepartum diets that contained 10% RDP and either 4.0% RUP or 6.2% RUP and either 0, 6, or 12 g/d of rumen-protected choline (RPC) as CapShure (Balchem Corp., Slate Hill, NY). After calving cows received a common diet and continued RPC as per their prepartum assignments. Liver biopsies were obtained on d -28, -14, 1, 28, and 56 relative to calving, and the abundances of AS, OTC, PC, PEPCK, and 18S mRNA were determined by Northern blot analysis of total RNA. The abundance of OTC mRNA was lowest at calving and was decreased by RPC and 6.2% RUP feeding. Feeding 6.2% RUP did not alter AS, PC, or PEPCK mRNA. The expression of AS mRNA increased and PEPCK mRNA tended to increase from calving to 56 DIM. Pyruvate carboxylase mRNA increased more than twofold at calving. The data indicated adaptation to lactation for gluconeogenic enzymes that is not matched in direction and magnitude by changes in mRNA for urea cycle enzymes. Feeding additional protein, as RUP, failed to induce mRNA for key enzymes in gluconeogenesis or ureagenesis.

Effects of supplemental dietary biotin on performance of Holstein cows during early lactation

This study determined the effects of supplemental dietary biotin (0, 10, or 20 mg/d) on performance of Holstein cows (n = 45; 18 primiparous and 27 multiparous). Treatments started at 14 d prepartum and continued until 100 d in milk (DIM). Blood samples were taken at 14 d prepartum, and blood and milk samples were taken at calving, and 30, 60, and 100 DIM. Dry matter intake during lactation was not different across treatments (19.7 kg/d). Milk production linearly increased with biotin supplementation (36.9, 37.8, and 39.7 kg/d for 0, 10, and 20 mg/d of supplemental biotin, respectively). Biotin supplementation did not affect milk fat and true protein percentages or fat yield but linearly increased true protein yield. Supplemental biotin increased concentrations of biotin in plasma and milk at all time points. Concentrations of biotin in plasma and milk (colostrum) at calving were higher than at other time points for cows fed supplemental biotin. In an ancillary experiment, plasma biotin concentrations were not as high when cows were fed 20 mg/d of supplemental biotin for 14 d during the middle of their dry period as when cows were fed 20 mg/d of biotin for the last 14 d of gestation. This suggests that events associated with parturition altered plasma biotin concentrations. Plasma concentrations of glucose, insulin, nonesterified fatty acids, and molar proportions of ruminal volatile fatty acids were not affected by biotin supplementation. Biotin supplementation had no effect on change in body weight or condition score. Supplemental biotin linearly increased milk and protein yields, however, the mode of action that caused these increases was not determined.