Hoof Health Research Articles

Genetic parameters for hoof health traits estimated with linear and threshold models using alternative cohorts

A national genetic evaluation program for hoof health could be achieved by using hoof lesion data collected directly by hoof trimmers. However, not all cows in the herds during the trimming period are always presented to the hoof trimmer. This preselection process may not be completely random, leading to erroneous estimations of the prevalence of hoof lesions in the herd and inaccuracies in the genetic evaluation. The main objective of this study was to estimate genetic parameters for individual hoof lesions in Canadian Holsteins by using an alternative cohort to consider all cows in the herd during the period of the hoof trimming sessions, including those that were not examined by the trimmer over the entire lactation. A second objective was to compare the estimated heritabilities and breeding values for resistance to hoof lesions obtained with threshold and linear models. Data were recorded by 23 hoof trimmers serving 521 herds located in Alberta, British Columbia, and Ontario. A total of 73,559 hoof-trimming records from 53,654 cows were collected between 2009 and 2012. Hoof lesions included in the analysis were digital dermatitis, interdigital dermatitis, interdigital hyperplasia, sole hemorrhage, sole ulcer, toe ulcer, and white line disease. All variables were analyzed as binary traits, as the presence or the absence of the lesions, using a threshold and a linear animal model. Two different cohorts were created: Cohort 1, which included only cows presented to hoof trimmers, and Cohort 2, which included all cows present in the herd at the time of hoof trimmer visit. Using a threshold model, heritabilities on the observed scale ranged from 0.01 to 0.08 for Cohort 1 and from 0.01 to 0.06 for Cohort 2. Heritabilities estimated with the linear model ranged from 0.01 to 0.07 for Cohort 1 and from 0.01 to 0.05 for Cohort 2. Despite a low heritability, the distribution of the sire breeding values showed large and exploitable variation among sires. Higher breeding values for hoof lesion resistance corresponded to sires with a higher prevalence of healthy daughters. The rank correlations between estimated breeding values ranged from 0.96 to 0.99 when predicted using either one of the 2 cohorts and from 0.94 to 0.99 when predicted using either a threshold or a linear model.

Effect of floor on lameness in crossbred dairy Cow: a Review

Most walkways, milking parlor and feeding space in cattle houses are presently made up of concrete because it is durable, cheap and resistant to wear and hygienic. However, hard floor surface negatively affect hoof health and comfort, predisposes animal to pain and lameness and ultimately affect productivity. Lameness is world-widely reported as economically important disease. With the increased awareness for animal welfare provision of cushioned flooring in the animal house is gaining popularity. Providing soft rubber floor and sand bedding may be favorable for cow comfort, health, hygiene, and milk production. It probably reduces occurrence of lameness and mastitis in organized dairy farm. In this review attempt has been made to discuss dairy housing system in India, floors being used and problems associated with them. Further possibilities of alternative flooring have been explored.

Source of supplemental dietary copper, zinc, and manganese affects fecal microbial relative abundance in lactating dairy cows

Appropriate trace mineral supplementation can improve immune response and hoof health in cattle and at much higher rates of supplementation to swine and poultry can alter microbial colonization of the gut, resulting in improved gut health. Diet can influence fecal microbial excretion in cattle, and the fecal microbiome may serve as a means for assessing gastrointestinal microbial changes. We hypothesized that feeding diets that differed in source of supplemental Cu, Zn, or Mn would alter the relative abundance of fecal microbes in lactating dairy cattle and that organic Zn would have the greatest effect. Twenty-four cows were fed diets devoid of supplemental Cu, Zn, and Mn for a 16-d preliminary phase (basal diet provided 9, 29, and 32 mg/kg of Cu, Zn, and Mn, respectively), and then were randomly assigned to 1 of 3 treatment diets (n = 8 cows/treatment): one group of cows was fed supplemental Cu, Zn, and Mn from sulfate minerals; the second group was fed glycinate minerals; and the third group was fed Cu and Mn sulfate with glycinate Zn. Assayed total dietary concentrations were approximately 21, 73, and 72 mg/kg for Cu, Zn, and Mn, respectively. Milk production (averaged 38.8 kg/d), DMI (averaged 25.8 kg/d), and milk components were not affected by treatment. Fecal DNA was extracted, amplified using a universal primer targeting the V4-V5 hypervariable region of the 16S rRNA gene, and sequenced to compare microbial community composition between treatments. Relative abundances of Treponema species-level operational taxonomic units (OTU) were less for animals fed Cu and Mn sulfate with glycinate Zn compared with sulfates alone, but were similar to animals fed glycinate mineral sources. Relative abundances for exclusive glycinate mineral and sulfate mineral treatments were similar. Treponema OTU and cultured representatives are often associated with bovine digital dermatitis. These data may provide an additional link between organic Zn supplementation and improved hoof health. To our knowledge this is the first report of a dietary treatment decreasing the relative abundance of Treponema OTU in cattle feces; however, the potential benefits of this response on overall animal health and the mechanism for the observed responses are unknown and warrant further investigation.

Corium molecular biomarkers reveal a beneficial effect on hoof transcriptomics in peripartal dairy cows supplemented with zinc, manganese, and copper from amino acid complexes and cobalt from cobalt glucoheptonate.

Supplying trace minerals in more bioavailable forms such as amino acid complexes (AAC) could help ameliorate the incidence of hoof disorders in peripartal dairy cows. The aim of this study was to evaluate the effects of supplementing metal AAC during the peripartal period on expression of 28 genes in corium tissue related to claw composition, oxidative stress, inflammation, chemotaxis, and transcriptional regulation. Forty-four multiparous Holstein cows received a common diet from -30 to 30 d relative to parturition and were assigned to receive an oral bolus containing either inorganic trace minerals (INO) or AAC (i.e., organic) Zn, Mn, Cu, and Co to achieve supplemental levels of 75, 65, 11, and 1 ppm, respectively, in the total diet dry matter. Inorganic trace minerals were provided in sulfate form, and AAC were supplied via Availa Zn, Availa Mn, Availa Cu, and COPRO (Zinpro Corp., Eden Prairie, MN). Locomotion score was recorded before enrollment and weekly throughout the experiment. Incidence of hoof health problems at 30 d in milk was evaluated before a hoof biopsy in a subset of cows (INO=10; AAC=9). Locomotion score did not differ between treatments in the prepartum or postpartum period. The incidence of heel horn erosion was lower in AAC cows, but the incidence of sole ulcers did not differ. Downregulation of KRT5, CTH, CALML5, and CYBB, and upregulation of BTD in AAC cows indicated a decrease in the need for activation of cellular pathways to regenerate corium tissue and increase biotin availability in the sole claw. These molecular changes in the sole could have been triggered by the lower incidence of heel erosion in response to AAC. Among the genes associated with oxidative stress, the AAC cows had greater expression of NFE2L2, a transcription factor that regulates the antioxidant response, and the antioxidant enzyme SOD1. Among genes associated with inflammation, AAC cows had greater expression of TLR4, and lower expression of TLR2, IL1B, and TNF compared with INO cows. Supplementation with metal AAC during the peripartal period affected the expression of genes involved in composition, oxidative stress, and inflammation status in the corium. The hoof biopsy procedure used in the present study should be further perfected and implemented in future lameness research to expand our understanding of hoof biology in dairy cows.

Claw lesions and rumen liquor profile in dairy cattle on high grain diet

The present study is conducted to investigate how long the effect of feeding high grains is sustained in the rumen and how this changed or adapted rumen environment is going to affect the hoof health in approximately 10 weeks. Crossbred cows (18) from university dairy farm were divided into 2 groups keeping equal number of animals with same parity in both. Animals in the feeding group were fed with high grain diets for 75 days. The pH, sodium, potassium and different fractions of total volatile fatty acids (TVFA) of rumen liquor were studied every fortnight. All the animals were evaluated for foot lesions before the start of experiment and then at the end of feeding trial. A significant decrease in rumen liquor pH and sodium concentration was observed in the feeding group animals with the progress of time. TVFA concentration increased in the feeding group with rise in acetate, propionate and butyrate levels at the end of the trial. High prevalence of heel erosions, white line haemorrhages, white line fissures and overgrown soles were observed in the feeding group animals at the end of trial along with an increase in rear leg view index. It was concluded that constant feeding of non-structural carbohydrates may increase total volatile fatty acids and frequency of claw lesions in crossbred dairy cattle.

Fumonisin B₁ (FB₁) Induces Lamellar Separation and Alters Sphingolipid Metabolism of In Vitro Cultured Hoof Explants.

One of the most important hoof diseases is laminitis. Yet, the pathology of laminitis is not fully understood. Different bacterial toxins, e.g. endotoxins or exotoxins, seem to play an important role. Additionally, ingestion of mycotoxins, toxic secondary metabolites of fungi, might contribute to the onset of laminitis. In this respect, fumonsins are of special interest since horses are regarded as species most susceptible to this group of mycotoxins. The aim of our study was to investigate the influence of fumonisin B1 (FB1) on primary isolated epidermal and dermal hoof cells, as well as on the lamellar tissue integrity and sphingolipid metabolism of hoof explants in vitro. There was no effect of FB1 at any concentration on dermal or epidermal cells. However, FB1 significantly reduced the separation force of explants after 24 h of incubation. The Sa/So ratio was significantly increased in supernatants of explants incubated with FB1 (2.5–10 µg/mL) after 24 h. Observed effects on Sa/So ratio were linked to significantly increased sphinganine concentrations. Our study showed that FB1 impairs the sphingolipid metabolism of explants and reduces lamellar integrity at non-cytotoxic concentrations. FB1 might, therefore, affect hoof health. Further in vitro and in vivo studies are necessary to elucidate the effects of FB1 on the equine hoof in more detail.

Effect of diet supplementation with chelated zinc, copper and manganese on hoof lesions of loose housed sows.

BackgroundHoof lesions are very common among sows and have been associated with lameness, early removal and compromised welfare and productivity. Although housing conditions and management can have an external effect on hoof health status, the role of trace mineral intake is vital in developing hoof structure and integrity. Therefore, the objective of this study was to investigate the effect of a diet supplemented with organic complexes of trace minerals (Zn, Cu, Mn), partly substituting their inorganic form, on hoof lesions of sows in three Greek swine herds.ResultsA total of 518 sows were initially examined for hoof lesions and their respective severity was scored. For each hoof, the length of toes and dew claws were evaluated and five anatomical hoof sites, the heel, the sole, the white line, the wall and the coronary band, were examined for lesions. Subsequently, the same sows were re-scored after one or two gestations on diets supplemented with organic trace minerals, partly substituting their inorganic salt form (organic form of Zn 45 ppm, Cu 14 ppm and Mn 25 ppm of the total 125 ppm of Zn, 15 ppm of Cu and 40 ppm of Mn, respectively). The odds of the higher versus the lower lesion scores were significantly lower after than before the inclusion of the organic minerals in sows’ diet, for each of the considered foot sites with the exception of the coronary band, with a distinct effect according to foot location. Specifically, on rear feet the improvement of hoof lesions was either smaller (for heel, sole and wall) than on front feet or not significant (for white line, toe and dew claw length). Additionally, for each foot site and herd examined, after the inclusion of the organic minerals, there were more sows with either the same or lower lesion score, with the exception of the toe and the dew claw length in one of the herds.ConclusionsWithin the specific conditions in the three studied herds, our findings highlight the role of chelated trace minerals in sows’ hoof health, suggesting an applicable and rewarding intervention to prevent hoof lesions.

Using genomics to enhance selection of novel traits in North American dairy cattle ,

The objectives of this paper were to briefly review progress in the genetic evaluation of novel traits in Canada and the United States, assess methods to predict selection accuracy based on cow reference populations, and illustrate how the use of indicator traits could increase genomic selection accuracy. Traits reviewed are grouped into the following categories: udder health, hoof health, other health traits, feed efficiency and methane emissions, and other novel traits. The status of activities expected to lead to national genetic evaluations is indicated for each group of traits. For traits that are more difficult to measure or expensive to collect, such as individual feed intake or immune response, the development of a cow reference population is the most effective approach. Several deterministic methods can be used to predict the reliability of genomic evaluations based on cow reference population size, trait heritability, and other population parameters. To provide an empirical validation of those methods, predicted accuracies were compared with observed accuracies for several cow reference populations and traits. Reference populations of 2,000 to 20,000 cows were created through random sampling of genotyped Holstein cows in Canada and the United States. The effects of single nucleotide polymorphisms (SNP) were estimated from those cow records, after excluding the dams of validation bulls. Bulls that were first progeny tested in 2013 and 2014 were then used to carry out a validation and estimate the observed accuracy of genomic selection based on those SNP effects. Over the various cow population sizes and traits considered in the study, even the best prediction methods were found, on average, to either under-evaluate observed accuracy by 0.20 or over-evaluate it by 0.22, depending on the approach used to estimate the number of independently segregating chromosome segments. In some instances, differences between observed and predicted accuracies were as large as 0.47. Indicator traits can be very useful for the selection of novel traits. To illustrate this, protein yield, body weight, and mid-infrared data were used as indicator traits for feed efficiency. Using those traits in conjunction with 5,000 cow records for dry matter intake increased the reliability of genomic predictions for young animals from 0.20 to 0.50.

Umgestaltungsmaßnahmen im Giraffengehege des Zoos Osnabrück zur Förderung der Klauengesundheit

The Bachelor thesis answered many questions regarding the hoof health of giraffes. It determined that it is dependent on many different factors like the horn wear. From the biomechanical view an adequate, natural horn wear is essential for healthy hooves. The rougher the ground material and the more sharp-edged the grain shape, the stronger is the horn wear. At the Zoo in Osnabrück the sharp-edged, crushed grit on the concrete surface in the giraffe stable is responsible for the horn wear. Thus, an adequate natural horn wear is guaranteed. However, the ground in the area around the feed baskets should be set up with concrete and grit because of the long lasting of the giraffes in this area at day. Additional sharp-edged material should be placed on the itineraries of the giraffes as well. The grain size should be over 8mm and compacted very well to prevent a possible removal of the material.The analysis of the gradient and the ground samples of the “Samburu-Land” showed that the formation of channels and the material removal was caused by the interaction of different factors like the water permeability of the ground, the hoof pressure, the amount of the water runoff and the gradient in the enclosure.The visitor survey revealed that the “Samburu-Land” seems very “grey” and “deserted” in the winter month. A possible solution could be a planting with evergreen wood, the creation of a grassing element or the planting of redtop (Agrostis gigantea.)

Association between chelated trace mineral supplementation and milk yield, reproductive performance, and lameness in dairy cattle

The objective of this experiment was to evaluate the effects of feeding a ration with partial replacement of chelated trace minerals (CTM; Zn, Cu, and Mn supplied as Mintrex®) compared with a ration containing only inorganic trace minerals (ITM; supplied as sulfates, carbonates, and oxides at a commercial level) on locomotion score, milk production, and reproductive performance of dairy cows in different herds. Twenty-seven dairy herds members of a dairy cooperative (La Pirenaica, La Seu d’Urgell, Spain) that fed the same total mixed ration (TMR), were enrolled in a 6-month study. Fifteen herds continued to receive the same TMR (containing ITM), and the remaining 12 herds fed the same TMR with the only difference being a partial replacement of ITM for CTM. The ITM premix provided 57ppm of inorganic Zn, 9ppm of inorganic Cu, and 27ppm of inorganic Mn, whereas the CTM premix contained 32ppm of inorganic Zn and 25ppm of chelated Zn, 3ppm of inorganic Cu and 6ppm of chelated Cu, and 17ppm of inorganic Mn and 10ppm of chelated Mn. The first month of study was used as a basal period, and then herds were exposed to dietary treatments for 5 months. The total number of lactating cows enrolled in the study was 2880. There were no differences in feed offered (24.1±0.20kg/d) or milk production (31.4±0.23kg/d) between treatments. The overall proportion of cows with a lameness score ≥3 (considered lame cows) was not different between ITM and CTM herds, but there was an interaction between treatment and month of experiment due to a numerically greater prevalence of lameness in CTM than in ITM herds during the first 2 months of study, and a lesser prevalence in the last 3 months of study. Cows in ITM herds had a greater risk of being culled due to lameness. A partial replacement of inorganic for chelated forms of Cu, Mn, and Zn (CTM) showed a greater potential for improving hoof health in herds with a relatively low prevalence of lame cows. Lastly, when considering only cows that were exposed to treatments for at least 30 days, cows in CTM herds had greater odds of becoming pregnant at first service and tended to have greater odds of becoming pregnant at second service than cows in ITM herds.

Radiographic measurements of the hooves of normal ponies

Knowledge of the normal radiographic anatomy of the equine foot and the relationship between the distal phalanx and the hoof capsule is imperative for objective assessment of hoof health. Little information is available for the hooves of ponies. The aim of this study was to establish a database of reference values for normal ponies and to investigate the relationship between the height at the withers and radiographic measurements of the hooves. Radiographic examinations were performed on 81 ponies, ranging from 81.5 to 148.0 cm height at the withers, immediately after foot trimming. Eighteen parameters were measured in the lateromedial view (front and hind feet) and 13 parameters were measured in the dorsopalmar view (front feet). Most linear measurements had a strong positive correlation with the height at the withers. The influence of height on angular measurements was weak. A linear regression model was adopted to enable calculation of reference values for a defined height at the withers. Left feet were longer in 72% of front feet and 67% of hind feet. The medial part of the hoof was more upright generally, but the medial hoof wall was shorter only in the right front feet. The front feet tended to be more upright than the hind feet. Compared to height at the withers, the hooves of ponies were relatively larger than the hooves of adult Warmblood horses investigated in a comparable study. The present study provides a database for farriers and veterinarians for hoof conformation, on the basis of which hoof preparation and an accurate diagnosis of lameness can be made.

Tips and tools for dairy practitioners to take an active role in a dairy's foot health program

There are copious opportunities for veterinarians to get involved in providing foot health services. The type of services that could be offered include; lame cow detection and treatment, comprehensive hoof trimming, monitoring or training of farm staff and routine monitoring of hoof health data. These opportunities come with their own unique set of barriers and challenges. However, veterinarians are ideally positioned to overcome these challenges and, at the current time, there is limited competition for these type of services thus veterinarians should consider foot health management as a practice growth opportunity.

Descriptive study on hoof trimming methods in North America

Hoof trimming is a routine procedure done to dairy cows, but no data exists to determine appropriate trimming methods. In the literature, functional hoof trimming is commonly described as the method of choice. However, other methods are commonly reported in the field. This has resulted in a continuous debate within the hoof health industry with respect to what is the appropriate trimming method. To address this question, there is a need for more scientific data on the prevalence of different trimming methods, the effect of these methods on key hoof measurements, and ultimately on the welfare of the cow. The objective of this study was to describe the effect of different trimming methods on key hoof measurements taken on cadaver hind feet of dairy cattle.

Effect of transition diet fortification on lameness and blood metabolites in pre- and post- partum lame Karan Fries cows

Peri-parturient period in high yielding cows always associated with a series of nutritional, biochemical, hormonal changes that leads to lameness in later lactation. Extra supplementation of vitamins and minerals responsible for hoof health is recommended in some dairy herds during this period. The present study was conducted by fortifying 10, 20 and 30 mg/d of biotin and 2 g/d of zinc sulphate during pre- and post-partum period (2 months before and 2 months after calving) of 40 high yielding lame crossbred KF cows, distributed into control and three treatment groups. The study revealed that, fortification of transition diet with biotin and Zn significantly reduced the lameness score and recovery time in supplemental groups compare to control group. In T-1, the lameness score was reduced by 1.3, T-2 reduction was maximum by 2, T-3 by 1.5, and in control 0.02 with their respective recovery period of hoof lesions were 38.9±1.1 (T-1) 19.12±1.8 (T-2), 25.3±1.4 (T-3) and 56.2±2.7 days. The overall glucose concentration was observed significantly higher in T-2 group as compared to control group, while overall NEFA and BHBA concentrations were significantly higher in control group as compared to other supplemental groups after 120 days of supplementation. Thus, it can be concluded from the study that, lameness in high yielding cows can be reduced by fortification of transition diet with biotin and zinc.

Effect of floor type on hoof lesions, dirt scores, immune response and production of beef bulls

The objective of the study was to investigate the effect of old and new concrete slats (CS) with or without rubber mats (RM) on animal performance, hoof health, dirt scores and health status of finishing bulls. Continental crossbred beef bulls (n=72; mean initial live weight=441 (s.d. 45.1) kg) were blocked by breed and live weight and randomly assigned by block to one of four treatments; (1) Old CS (2) New CS, (3) Old CS covered with RM, (4) New CS covered with RM. Each treatment had 3 pens of 6 bulls at a space allowance of 2.9m2 per animal. Bulls were fed a total mixed ration (TMR) of silage and rolled barley on a 54:46 dry matter (DM) basis for 148 days. Feed was weighed into each pen daily and refusals were weighed twice weekly. Bulls were weighed every three weeks to coincide with dirt scoring. Total leucocyte, neutrophil, lymphocyte, eosinophil, monocyte, basophil and red blood cell number and haemoglobin concentrations were measured on day 0 and day 148. Bull's hooves were inspected for the presence of lesions at the start of the study and again at slaughter. After slaughter, carcass weight, carcass gain, conformation and fat score, kidney and channel fat and hide weight were recorded. Bulls on RM had a greater average daily gain (ADG) (0.16kg/day) (P<0.01), kidney and channel fat weight (KCF) (P<0.05), hide weight (P<0.01) and a better feed conversion ratio (FCR) (P<0.05) than those on CS. Floor type had no effect on dry matter intake (DMI), slaughter weight, carcass weight, kill out percentage, conformation score or fat score. Bulls on RM had 44% more hoof lesions (P<0.01) than those on CS. There were slat×time (P<0.05) and mat×time (P<0.01) interactions for dirt scores. Bulls on slats were dirtier than those on mats on days 63, 84 and 126 (P<0.01) while bulls on new slats were dirtier than those on old slats on days 21 (P<0.01) and 42 (P<0.05). Floor type had no effect (P>0.05) on any of the haematological variables measured which suggests that the immunological status of the bulls was not affected by treatment. While there was no evidence of lameness in bulls on RM, the increased number of hoof lesions suggests that hoof health may be compromised in bulls housed on RM.

Observation Regarding Hoof Blocks Use In Dairy Cows

Hoof health, detection and treatment of lameness are major challenges for veterinarians due to the high incidence in the herd and major economical loss. Early detection and treatment minimizes the losses, due to treatment costs and decrease of milk quantity.The research tried to elaborate a therapeutic protocol which minimizes the pain, and diminishes the recovery period by applying hoof blocks in lame cows.The study was performed on 180 dairy Holstein cows (at “Action Felix” Dairy farm) in Oradea, from June 2012 to June 2013, using two types of blocks: foam (Walkease) and wooden (BoviBond). The cows were divided in three lots.If the claw needs longer time for healing, the affected claw can be elevated by applying a foam hoof or wooden block to relieve the weight bearing from the affected claw. Resting the affected hoof is highly efficient to promote healing and pain relief. This encourages the cow to move around, to feed as the pain is relieved.The hoof blocks allows the cow to walk around freely, as the foam or wooden block wears down, the hoof disease is given time to heal. During a period of time, the blocks will worn down completely and the disease will be healed.

Effect of including canola meal and supplemental iodine in diets of dairy cows on short-term changes in iodine concentrations in milk

The dietary requirement for iodine is based on thyroxine production, but data are becoming available showing potential improvements in hoof health when substantially greater amounts of I are fed. Feeding high amounts of I, however, can result in the milk having excessive concentrations of I. Canola meal contains goitrogenic compounds that reduce the transfer of I into milk. We hypothesized that including canola meal in diets would allow high supplementation rates of I without producing milk with unacceptable concentrations of I. Thirty midlactation Holstein cows were fed a diet with all supplemental protein from soybean meal (0% of diet dry matter as canola meal) or with all supplemental protein from canola meal (13.9% canola meal). A third treatment has a mix of soybean meal and canola meal (3.9% canola meal). Within canola-meal treatment, cows were fed 0.5 or 2.0mg of supplemental I per kilogram of diet dry matter from ethylenediamine dihydroiodide. Cows were maintained on the canola treatment for the duration of the experiment but were changed from one I treatment to the other after 13d of receiving the treatment. Milk I concentration before the treatments started (cows fed 0.5mg/kg of I) averaged 272μg/L and increased within 22h after cows were first fed diets with 2mg/kg of I. As inclusion rate of canola meal increased, the concentration of I in milk decreased linearly. After 12d of supplementation, milk from cows fed 0.5mg/kg of I had 358, 289, and 169μg of I/L for the 0, 3.9%, and 13.9% canola-meal treatments. For cows fed 2.0mg/kg of I, milk I concentrations were 733, 524, and 408μg/L, respectively. Concentrations of I in serum increased with increased I supplementation, but the effect of canola meal was opposite of what was observed for milk I. Cows fed the highest canola-meal diets had the highest serum I whether cows were fed 0.5 or 2.0mg/kg of I. Feeding dairy cows diets with 13.9% canola meal maintained milk I concentrations below 500μg/L when diets were supplemented with 2mg/kg of I.

First-lactation performance in cows affected by digital dermatitis during the rearing period

The long-term effects of prepartum digital dermatitis (DD) on first-lactation performance were evaluated in a cohort of 719 pregnant heifers. All heifers were followed for a period of 6 mo until calving and classified on the basis of the number of DD events diagnosed during this period as type I, type II, or type III (no DD, one DD event, and multiple DD events, respectively). Health during the initial 60d in milk (DIM), reproductive and hoof health outcomes, and milk production were compared between the 3 heifer type groups. All logistic and linear models were adjusted for age, height, and girth circumference at enrollment, and the type of trace mineral supplementation during the prepartum period. Overall, cows experiencing DD during the rearing period showed worse production and health outcomes compared with healthy heifers during the first lactation. The percentages of assisted calvings, stillbirths, culled before 60 DIM, and diseased cows during the fresh period were numerically higher in type III cows compared with type I cows. However, none of these differences were statistically significant at the 95% confidence level. Significantly lower conception at first service [odds ratio (OR)=0.55, 95% confidence interval (95% CI): 0.33, 0.89] and increased number of days open (mean=24d, 95% CI: 5.2, 43) were observed in type III cows compared with type I cows. In relation to hoof health, a significantly increased risk of DD during the first lactation was found in type II and III cows (OR=5.16, 95% CI: 3.23, 8.29; and OR=12.5, 95% CI: 7.52, 21.1, respectively), as well as earlier occurrence of DD following calving (OR=59d, 95% CI=20, 96, and OR=74d, 95% CI: 37, 109). Compared with type I cows, statistically significant milk production losses during the initial 305 DIM of 199 and 335kg were estimated in type II and III cows, respectively. This difference was due to a greater rate of production decline (less persistence) after peak yield. No differences in monthly fat and protein percentages or somatic cell counts were observed between the heifer types. Given the long-term effects of DD on health, reproduction, and production, one of the priorities during the rearing period of dairy heifers should be efficient DD prevention and control programs. Such intensive intervention programs based on active long-term DD surveillance, mitigation of risk factors, and prompt treatment are expected to increase overall animal well-being and farm profitability by minimizing the effect of DD during the first lactation.

Effect of feed allowance at pasture on lying behaviour and locomotory ability of dairy cows

In temperate climates where cows are primarily managed at pasture shortages of grass could result in nutritional deficits for the cow and thus pose a challenge to her welfare. This study investigated the effect of daily herbage allowance (DHA) on dairy cow lying behaviour, locomotory ability, and some aspects of hoof health. Ninety-six cows were randomly assigned to one of eight treatments in a 2×4 factorial design; experimental duration (2 week (2W) or 6 week (6W)), and nutritional levels (DHA) (60%, 80%, 100% or 120% of intake capacity). Cows were assigned to treatment on 25 March (36±16 days in milk). Lying behaviour was recorded using modified voltage dataloggers over 7×24h periods at approximately 4d intervals for cows on the 6W treatments. Locomotory ability (including overall locomotion, ab/adduction, tracking, speed, head carriage and spine curvature scores) was assessed four times at approximately 16d intervals. Hoof health (heel erosion and dermatitis scores) were recorded in the milking parlour on four occasions at approximately 19d intervals. Although there was no effect on daily lying time, DHA tended to affect the duration of lying bouts (P=0.1). Cows allocated the highest DHA (120%) had shorter bouts than all other treatments (P=0.05), whereas cows allocated the lowest DHA (60%) had fewer lying bouts than all other treatments (P<0.05). In general, cows allocated a lower DHA took longer to lie down after milking than cows fed at or above intake capacity. The effect was greatest in the afternoon when there was an effect of DHA (P<0.05); cows on the 60% DHA stood for longer after afternoon milking than all other treatments (P<0.01). There was no effect of DHA on locomotory ability for either 2W or 6W cows. However, in the 2W treatment, cows on the 120% DHA had the best spine arch scores (P=0.01), and cows in the 60% treatment had the worst tracking (P<0.05). Likewise in the 6W treatment cows on the 60% DHA had the worst spine arch scores (P<0.05), yet cows allocated a higher DHA tended to have worse ab/adduction scores (P=0.10). There was no effect of DHA on hoof health. The differences in lying behaviour and locomotion do not imply impaired welfare per se. However, altered lying behaviour could indicate hunger, and impaired locomotion could be a result of a thin digital cushion, which is associated with lameness. This study provides valuable information about how DHA can affect the dairy cow, and can be used to formulate further hypotheses to investigate effects on hunger-satiety status and hoof health.

Effects of chelated Zn/Cu/Mn on redox status, immune responses and hoof health in lactating Holstein cows.

To evaluate the effects of chelated Zn/Cu/Mn on redox status, immune responses and hoof health in lactating Holstein cows, 48 head in early lactation were divided into healthy or lame groups according to their gait score. Cows were fed the same amount of Zn/Cu/Mn as sulfate salts or in chelated forms for 180 days, and foot-and-mouth disease (FMD) vaccine was injected at day 90. The results showed that lame cows had lower antioxidant function, serum Zn/Mn levels, hair Cu levels, and hoof hardness. Moreover, increased antioxidant status, FMD antibody titers, serum and hair levels of Zn/Cu/Mn, and hoof hardness and decreased milk fat percent and arthritis biomarkers were observed in cows fed chelated Zn/Cu/Mn. In summary, supplementation with chelated Zn/Cu/Mn improved antioxidant status and immune responses, reduced arthritis biomarkers, and increased accumulation of Zn/Cu/Mn in the body and hoof hardness in dairy cows.