Intra-class correlation attributable to claw trimmers scoring common hind-claw disorders in Dutch dairy herds

Data of a cross-sectional study on prevalence of seven common bovine-claw disorders were used to calculate the intra-class correlation coefficients (ICCs) for claw trimmers. Fifteen professional claw trimmers were trained in diagnosing claw disorders uniformly. During regular trimming of all dairy cows in a herd, they recorded the presence (yes/no) of hind-claw disorders for digital dermatitis (DD), chronic laminitis (CL), sole ulcer (SU), white-line disease (WLD) and interdigital hyperplasia (HYP). For the claw disorders interdigital dermatitis/heel-horn erosion (IDHE) and sole haemorrhage (SH), claw trimmers also recorded (using graduated scores 1-3) the extent of the lesion. Complete information of 21,153 animals from 361 herds in The Netherlands was recorded between July 2002 and December 2003. To assure objective recording of claw disorders, ideally there would not be any correlation between observations. However, quantified ICCs from claw-trimmers observations ranged from 4.9% for DD to 38.0% for CL, while ICCs for herd ranged from 7.9% for SU to 26.7% for DD. Changes in the cut-off values for the diagnosis of IDHE and SH did not result in any relevant changes of the ICCs from claw-trimmers observations and these remained larger than the ICC explained by the herd. Based on these results, we conclude that for estimating measures of frequencies for different claw disorders, uniformity in recording certain diagnoses becomes an issue to consider when involving more than one observer.     

Risk factors for interdigital dermatitis and heel erosion in dairy cows kept in cubicle houses in The Netherlands

Risk factors concerning both the pasture and housing seasons for interdigital dermatitis and heel-horn erosion (IDHE) were studied in dairy cows in a cross-sectional study in The Netherlands. The study population included 2,326 cows (41 herds) and 2,751 cows (46 herds) for the pasture and housing seasons, respectively. Of these animals, 545 (23%) showed serious lesions of IDHE (stages 2 and 3) at the end of the pasture season and 1,269 (46%) during housing. Logistic regression of the pasture study indicated that increased parity, solid concrete floor, restricted grazing time, and herd trimming at long intervals were associated with an increased odds of IDHE, while dry cows and lactating cows within 30 days after calving as well as cows on a slatted floor with manure scraper, and grassland with mixed type of soil were associated with lower odds. In the housing study, odds of IDHE increased with parity, administering low- or medium-energy roughage, and introduction of dry cows into the lactating herd at >2 weeks before calving. The presence of long cubicles, knee-bumpers installed in cubicles as well as rearing calves and heifers within the dairy cows' accommodation decreased the odds of IDHE.     

The effect of digital lesions and floor type on locomotion score in Dutch dairy cows

This study describes the effects of floor system, digital dermatitis (DD) and interdigital dermatitis and heel-horn erosion (IDHE) on locomotion performance in 225 dairy cows of 12 commercial dairy herds. Nine herds were kept in cubicle houses with concrete passageways (either solid, slatted, or grooved concrete) and three herds were kept in straw yards. Animals were at most five times examined at monthly intervals for lesion severity of DD and IDHE and for locomotion score. Locomotion score was rated on a scale ranging from 1 to 5 (from normal to severe) and disturbed locomotion (lameness) was defined as a score > or =3. A logistic regression model was used to analyze the 943 observations using lameness (yes/no) as outcome variable. The proportion of observations scored as lame (locomotion score > or =3) increased from 18% 1 month after trimming to 29% at 4 months after trimming. Severe lesions of DD and IDHE were associated with a significantly higher proportion of lame cows. The proportion of animals with disturbed locomotion increased from 16% to 40% as the severity of DD increased and from 17% to 30% with increasing severity of IDHE lesions. Locomotion performance highly differed between the cubicle house and straw yard group. Only 1% of all gaits in straw yard cows were scored as lame, while in cubicle housed cows these percentages varied from 24% to 46% with grooved floors showing the highest average locomotion score. Due to the extreme low incidence of lameness in straw yards, the statistical analysis had to be restricted to observations on concrete floors (n=744). The logistic regression model with lameness (yes/no) as dependent variable and random effects of cow and herd resulted in Odds Ratios for severe DD and IDHE of, respectively, 3.2 and 3.2, both significantly larger than unity. Cows housed at grooved concrete floors showed the highest OR of 6.5 compared to solid concrete floors. Recovery of lameness was poor as disturbance in gait lasted several months.     

Prevalence and interrelationships of hoof lesions and lameness in Swedish dairy cows

The prevalence of hoof lesions and lameness in 4899 heifers and cows was determined at claw trimming one time in a cross-sectional study on 101 Swedish dairy farms, 1996-1998. The percentage of affected animals was 41% for heel-horn erosion, 30% for sole haemorrhages, 27% for erosive dermatitis, 21% for abnormal claw shape, 14% for white-line haemorrhages, 8.8% for white-line fissures, 8.6% for sole ulcers, 3.3% for double soles, 2.3% for verrucose dermatitis, and 1.8% for interdigital hyperplasia (IH). Seventy-two percent of all animals had at least one hoof lesion. The prevalence of lameness was 5.1%; most hoof lesions did not cause lameness. Differences between herds were substantial; the herd-specific, animal-level prevalence of lesions ranged from 25 to 98% and of lameness from 0 to 33%. Sole haemorrhages were found in all herds. The proportion of variance at the between-herd level was particularly high for heel-horn erosion (62%) and abnormal claw shape (54%). Strong correlations between lesions were found within hooves (and animals), e.g. for heel-horn erosion and dermatitis (Spearman's rank correlation, r(s)=0.36 and 0.37, respectively) and for sole and white-line haemorrhages (r(s)=0.25 and 0.28). Most hoof lesions affected hind and front hooves bilaterally, whereas the correlation between hind and front hooves generally was lower. Herds that ranked high for prevalence of sole ulcer also ranked high for sole haemorrhages and for abnormal claw shape and herds that ranked high for dermatitis also ranked high for heel-horn erosion, verrucose dermatitis and IH. Abnormal claw shape was strongly associated with sole ulcer (r(s)=0.41 at cow level)-suggesting the importance of maintaining a correct claw shape for the prevention of hoof-horn lesions.     

Risk factors for digital dermatitis in dairy cows kept in cubicle houses in The Netherlands

The presence of digital dermatitis (DD) in dairy cows has increased considerably over the last 10 years in The Netherlands, resulting in a current prevalence of approximately 30% in cows kept in cubicle houses. Our objective was to evaluate a diversified sample of cow- and herd-related risk factors for DD in dairy cows housed in cubicle houses with different flooring systems. Associations were analysed in random-effects logistic-regression models using 2,134 cows (37 herds) and 2,892 cows (47 herds) in the pasture and housing studies, respectively. At cow-level, the odds of having DD were increased in the case of lower parity and lactation. Important risk factors at herd-level were: restricted grazing time, fast rise in concentrate amount after calving, feeding by-products, herd trimming only at long intervals, and introduction of dry cows into the lactating herd before calving. The odds for DD were lower if cows were housed on a slatted floor with manure scraper and provided long and wide cubicles, and if calves were reared in the dairy cows' accommodation.     

Evaluation of claw health in heifers in seven dairy farms using a digital claw trimming protocol and claw data analysis system

The claw health of 139 heifers with a mean age of 22.1 months (SD: 2.6) in seven free stall dairy farms in Lower Austria was evaluated. Claw lesions were assessed during functional claw trimming and documented and analysed using the digital program Claw Manager. For documentation of lesions, each claw was divided into ten zones. The prevalence of lameness, claw lesions and their severity were determined, furthermore the Cow-Claw-Scores (CCS), Farm-Claw-Scores (FCS) and Farm-Zone-Scores (FZS) were calculated.The FCS between farms was tested for significant differences. A lameness prevalence of 9.4% and an overall prevalence of claw lesions of 98.5% were recorded in these 139 heifers.The most commonly diagnosed disorders were white line lesions (WLL) with a prevalence of 87.1%, heel horn erosion (84.9%), double soles (DS; 47.5%), sole haemorrhages (SH; 33.1%) and a concave dorsal wall contour in 15.1% of the heifers. High correlation coefficients (r > or = 0.93) were found between SH and DS, WLL and DS. 86.5% of all diagnosed claw lesions were score 1 (mild), 11.1% score 2 (moderate) and 2.4% score 3 (severe) lesions. The CCS in all heifers ranged between 0 and 267, and the FCS in the seven herds was between eleven and 55. Claw zone 3 was affected most frequently and severely. Following the results of this study, systematic functional claw trimming and consequent documentation of detected claw lesions is highly recommended for heifers at the time of their first insemination to prevent claw disorders in lactating cows and to improve their well-being.     

Genetic aspects of claw disorders,claw measurements and ‘type’ scores for feet in Friesian cattle

Data on claw measurements and disorders were collected on Black and White Friesian or Holstein heifers in 82 herds. Disorders were sole lesions and dermatitis interdigitalis and were determined on all heifers that had been milking between 40 and 100 days at the time of the visit. Heritabilities and genetic and phenotypic correlations among claw measurements and claw disorders were computed.Heritabilities for claw measurements were: angle, 0.25; length, 0.26; heel depth, 0.16; and heel depth-difference, 0.08. Angle and length estimated by eye had heritabilities of 0.18 and 0.22, respectively. The total of all lesion scores from different regions of the sole on both hooves had a heritability of 0.39. Heritabilities of dermatitis interdigitalis and sole ulcer (presence or absence) were 0.23 and 0.16, respectively.Claw measurements seemed to be more related to lesion scores than to dermatitis interdigitalis scores. Genetic correlations suggested that cows with higher claw angles had fewer dermatitis interdigitalis, total lesions and sole ulcers. Longer claws were genetically associated with higher total lesion scores and more sole ulcers. Claw measurements estimated by eye showed low genetic relations with claw disorders.Further research is needed to determine whether claw shape is a predisposing factor for or a result of a claw disorder.     

Foot lesions in lame cows on 10 dairy farms in Ireland

Background

Little is known about foot lesions in dairy cattle in Ireland, managed under a pasture based system with housing during the winter and grazing for the rest of the year. Ten Irish dairy herds, with a lameness prevalence ranging from 9 to 17 % were locomotion scored routinely during the 2013 grazing season. Lame cows were foot trimmed and foot lesions recorded.

Findings

11.8 % and 89.6 % of cows had lesions recorded on front and hind feet respectively. No lesions were found in 6.9 % of cows. Sole haemorrhage and white line disease were the most prevalent lesions, and overall 76.8 % of lesions affecting the claw horn were diagnosed on the lateral hind claw.

Conclusions

Treatment success, as measured by improved LS post treatment, was not significantly affected by the LS prior to foot trimming, the presence of lesions or the type of lesion identified. Exposure to both risk factors for lameness at housing and pasture may have resulted in the development of a combination of foot lesions typically associated with zero-grazing or all-year-round grazing management systems.     

Prevalence and severity of foot lesions in Danish Holstein heifers through first lactation

Several studies have shown that foot lesions and clinical lameness occur before first calving and develop further during the lactation period. Lameness may cause production losses, but the relationship between foot lesions, particularly in the claw horn, and lameness in heifers is unclear. The objectives of this study were to describe the development of and evaluate the relationship between lameness and foot lesions in Danish Holsteins before and after first calving. In a longitudinal study, 147 heifers were examined for lameness and foot lesions 2–5 times over an 18-month period. Lameness was assessed by means of a visual locomotion score and foot lesion severity was recorded.The prevalence of a locomotion score 3 was 25% before calving, and 90% at approximately 250 days in milk (DIM). Prevalence of moderate to severe sole haemorrhage (SH) was 27% before calving and 56% at 250 DIM, and that of moderate to severe white line lesion (WLL) 44% before calving with a peak of 70% at 200 DIM. There was one case of white line abscess but SH was seen throughout the entire study period. Digital dermatitis (DD) was prevalent prior to first calving (15%) and peaked at 39% at 0–100 DIM. Heel horn erosion (HHE) occurred in almost all cows (93–100%) and was strongly correlated with DD (r = 0.51). The correlation coefficient between SH and WLL was also high (0.42). The relatively high correlations between WLL and both DD and HHE were more surprising (0.38 and 0.35, respectively), those between SH and both DD and HHE were moderate (around 0.18). Interdigital dermatitis was significantly correlated with both HHE and DD, but completely unrelated to SH and WLL.The overall average locomotion score increased by about one-half of a score unit from 1 month prior to calving until 250 DIM, with a large difference between herds, although this was unsurprising as cows may alter their locomotion pattern with management factors (e.g. floor properties). DD and WLL were both associated with a locomotion score 3 but of the cows with severe WLL there was no clear association between a locomotion score 3 and DD. The highest locomotion scores occurred among cows with DD but without WLL.     

Claw trimming routines in relation to claw lesions, claw shape and lameness in Norwegian dairy herds housed in tie stalls and free stalls

We assessed the prevalence of claw lesions, abnormal claw shapes and lameness in relation to most-recent claw-trimming routines in Norwegian dairy herds housed in tie stalls and free stalls. Equal-sized groups were randomly sampled from both tie and free stalls in each of the three most animal-dense regions in Norway. The study population consisted of 2551 cows of the Norwegian Red breed housed in 54 tie stalls and 52 free stalls. Fourteen educated claw trimmers performed claw trimming and recording of claw lesions once during the spring of 2002. A multivariable model including cluster effects and individual-cow factors was fit for each claw lesion and abnormal claw shape.

In tie-stall herds with routine trimming 39.9% of the cows had one or more lesions or abnormal shapes in front or hind claws versus 52.8% in herds with no routine trimming. Hind-claw results in tie stalls with concrete stall base: herds trimmed occasionally had more haemorrhages of the white line (OR = 2.8) and corkscrewed hind claws (OR = 3.6) versus herds trimmed routinely; herds never trimmed had more heel-horn erosions (OR = 2.6) versus herds trimmed routinely and less haemorrhages of the white line (OR = 0.3) and the sole (OR = 0.2) versus herds trimmed occasionally.

In free-stall herds with routine trimming 76.8% of the cows had one or more lesions or abnormal shapes in front or hind claws versus 68.9% in herds with no routine trimming. Hind-claw results in free stalls with concrete stall base: herds never trimmed had less haemorrhages of the white line (OR = 0.3) and the sole (OR = 0.3) versus herds trimmed routinely; and also less haemorrhages of the white line (OR = 0.3) and white-line fissures (OR = 0.3) versus herds trimmed occasionally. Hind-claw results in free stalls with rubber-mat stall base: herds trimmed occasionally had less heel-horn erosions (OR = 0.5) and more dermatitis (OR = 5.4) versus herds trimmed routinely.

The routine claw trimming performed in Norwegian free stalls has not had the desired effects on claw lesions and abnormal claw shapes. Routine trimming in tie stalls, however, seems to have prevented claw disorders.     

Effect of forage type on claw horn lesion development in dairy heifers

In a continuous design study the claw health of 54 Holstein-Friesian heifer calves was recorded from three months of age until six months after first calving (30 months of age). Pre-calving heifers were either fed a wet, fermented grass silage-based diet (WF) or a dry, unfermented straw and concentrate based diet (DU), apart from grazing during their first summer. Approximately one month before calving both groups were fed a silage-based diet and afterwards all received a silage and concentrate lactation ration. Claws were examined four times during rearing, once pre-calving, and four times during lactation. Both white line and sole lesions were significantly worse for WF than DU both during rearing and throughout first lactation although the effect was not as consistent over time for white line lesions. It is concluded that for optimal claw health youngstock diets should not be heavily based on wet grass silage (less than 25% DM).     

Prevalence of digital dermatitis in first lactation cows assessed at breeding cattle auctions

The prevalence of digital dermatitis (DD) in first lactation cows (FLCs) presented at 10 breeding cattle auctions was determined in a single auction centre in Austria over a period of 14 months. At each auction, FLCs were selected randomly for claw examination from the monthly auction catalogue. After obtaining owner consent, the hindclaws were examined in a walk-in crush. The type of lesion (M1–M4) and the diameter of DD lesions together with claw horn lesions and the trimming status of the claws were evaluated.From a total of 1110 FLCs registered for the ten auctions, 399 (36%) were randomly chosen for examination and 199 FLCs (17.9%) could be defined. In 63 cows (15.7%), the owners refused consent. A total of 24 FLCs were found to have DD lesions on one or both hindlimbs, resulting in a DD prevalence of 12.1%. The size of lesions ranged from 0.5–3 cm in diameter. No influence of environmental factors (such as season or housing) on the prevalence of DD could be found. In 30/199 (15.1%) of FLCs examined, claw horn lesions such as double sole, white line disease and sole ulcer were observed, but both claw horn and DD lesions were seen in only three cows. Potential buyers at auctions should be aware of both conditions, as the 12.1% prevalence of DD and the 15.1% prevalence of claw horn lesions in FLCs are considerable. Critical evaluation of claw health and DD is essential when purchasing breeding cattle.     

Genetic background of claw disorders in the course of lactation and their relationships with type traits

Random regression threshold animal models were applied to binary longitudinal claw disorder data for studying genetic parameters of all claw disorders (ACD), as well as to claw disorders divided into different categories: non‐purulent claw disorders (NPCD), purulent claw disorders (PCD), dermatitis digitalis (DD), sole ulcer (SU), phlegmona (PH), laminitis (LAM) and interdigital hyperplasia (IH) in the course of lactation. Claw disorder data were obtained from 26 651 Holstein cows kept in 15 large‐scale contract herds in the region of Thuringia over a period of 5 years from 2007 to 2012. If a cow had one or more entries of the same disorder, for example, sole ulcer, within an interval of 30 days, she was scored with a ‘1’, and otherwise, she received a score of ‘0’ for healthy. Heritabilities for the same disorder were relatively stable between DIM 50 and DIM 300, but they tended to increase in early and late lactation. Highest heritabilities in the range from 0.20 to 0.34 were estimated for IH, and lowest heritabilities were realized for LAM (~ 0.05). Genetic correlations for same traits between different DIMs were high for adjacent test days, but close to zero for distant test days. The relationship between the sire EBVs for claw disorders and official sire EBVs for the type traits ‘foot angle’ was slightly antagonistic with correlation coefficients in the range from 0.05 (DD) to 0.33 (PH). Correlations between lactation EBVs for hock quality, rear leg rear view and the feet and leg index with EBVs for claw disorders were slightly favourable and ranged between ?0.01 (rear leg rear view correlated with SU) and ?0.43 (hock quality correlated with PH). Regarding daily EBVs for claw disorders, the strongest correlation coefficient was of value ?0.46 (LAM early in lactation correlated with the feet and leg index). Genetic parameters from the random regression model were verified by applying a single‐trait repeatability model. Correlation coefficients between lactation EBVs from the random regression model and lactation EBVs from the repeatability model for the same claw disorder were close to 1. Correlations were lower between EBVs from single test days and lactation EBVs from the repeatability models, with a minimal value of 0.58 for PCD measured at day 20.     

The Effect of Claw Lesions and Claw Infections on Lameness in Loose Housing of Pregnant Sows

During a 12-month period lameness, claw lesions and claw infections were studied in 15 herds with loose housing of pregnant sows on partly slatted concrete floors. Of these herds, 12 herds had concrete slats and 3 herds had plastic slats. The mean prevalence proportion of lame sows in the herds was 13.1%. The risk of lameness increased with increasing claw lesion score and with the presence of claw infections. In the herds with concrete slats, the relative risk of lame sows was 2.4 times higher than in the herds with plastic slats. In the herds with poor floor hygiene, the relative risk of lameness was 2.8 times higher than in the herds with dry and clean floors. The mean prevalence proportion of sows with claw infections at the 3 separate examinations in the 15 herds was 3.8%. Claw infections were more prevalent in herds with dirty floors and in herds with little space per animal (<2m²). In the herds with concrete slats, the relative risk of claw infections was 2 times higher than in the herds with plastic slats.     

Corynebacterium pseudotuberculosis infection in goats. IV. Course of the infection in two recently infected goat herds

Adult animals from 2 herds were examined clinically and serologically, 5 (Herd A) and 4 (Herd B) times during the same period of 3% years.Serum samples were examined for antibodies against Gorynebac-terium pseudotuberculosis using the bacterial agglutination test (BAT) and the hemolysis inhibition test (HIT).The results of the first examination showed that no animal in Herd A was seropositive, while in Herd B 1 animal showed a high positive titre in BAT. The prevalence of animals with superficial swellings was then 2 % in Herd A and 4 % in Herd B. In both herds, the prevalence of animals with superficial swellings and seropositive reactions increased during the following 1–2 yeairs. About 30 % of animals had superficial lesions and close to 100 % were seropositive. The proportion, of animals with superficial swellings and seropositive reactions was almost constant on subsequent examinations.In some of the animals, superficial swellings were found during 2 or more of the examinations, a few animals having such lesions at the same site on both or all occasions.Animals in Herd A became infected through grazing together with goats from infected herds. Caseous lymphadenitis was introduced into Herd B by animals obtained from infected herds.     

Prevalence of claw lesions in Norwegian dairy cattle housed in tie stalls and free stalls

Approximately 88% of Norwegian dairy cattle are housed in tie stalls. Free-stall housing will be implemented for all cattle within 20 years. This means that most existing barns have to be rebuilt in the near future. We designed our study to estimate the prevalence of claw lesions in Norway and to reveal possible differences between tie stalls and free stalls. Fifty-five tie-stall herds and 57 free-stall herds were sampled by computerized systematic selection and 2665 cows were trimmed by 13 claw trimmers, during the late winter and spring of 2002. The claw trimmers had been taught diagnosing and recording of claw lesions. Environmental factors, management and feeding routines also were recorded. Forty-eight percent of cows housed in tie stalls had one or more claw lesions versus 71.8% in free stalls. Prevalences recorded in the hind claws were: 4.2% of the animals had dermatitis in tie stalls versus 5.7% in free stalls; 7.9% versus 38.0% had heel–horn erosions; 7.3% versus 13.6% had haemorrhages of the white line; 11.7% versus 20.4% had haemorrhages of the sole; 2.8% versus 3.2% had sole ulcers and 5.5% versus 9.7% had white-line fissures. Most lesions were mild. A model was designed to estimate cluster effects within herd and within claw trimmer. The cluster effect within herd was significant for all lesions. The cluster effect within claw trimmer was only significant for heel–horn erosions in front and hind claws and for white-line fissures in front claws. Agreements between some of the claw lesions were revealed. The study confirms that in Norwegian dairy cattle, most claw lesions are more prevalent in free stalls than in tie stalls.     

The effect of herd characteristics on claw disorders and claw measurements in Friesians

Effects of management and herd characteristics on claw disorders and claw measurements were studied. Data were collected on Friesian heifers in 81 herds with freestalls. Disorders were sole lesions (pododermatitis) and infections (dermatitis interdigitalis).The least squares means for herd effects from genetic analyses were analysed for effects of management factors: level of concentrates, days required to reach maximum level of concentrates after calving, ration components, herd production average and formalin footbath. Herd characteristics involved with claws were also studied: housing before and after calving and pasturing.Correlations among disorders and measurements at the herd level were low. Disorders were only affected by the barn floor type after calving. An increase in concentrates and the use of a formalin footbath were associated with longer claws. Cows housed on a combination of a slatted and a flat floor after calving (nearly all outside feeding systems) had shorter claws. Deeper heels were found in herds feeding a high amount of concentrates and in herds with high production averages.Managemental and environmental factors have to be studied in detail under field conditions before their effects can be clarified.     

Impact of a sustained-release ivermectin bolus on weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Québec.

This field trial was designed to test the effect of treatment with a sustained-release ivermectin bolus on average daily and total weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Quebec. One hundred and twelve heifers from 12 herds were randomly assigned at turnout either to treatment with a commercially-available ivermectin bolus or to remain as untreated controls. Ninety-six heifers, 49 treated animals and 47 controls, completed the trial. Animals were weighed at turnout, midseason, and at the end of the grazing season. Fecal samples were collected at each of these times and nematode eggs counted. Nematode egg excretion was relatively low throughout the pasture season, which was abnormally warm and dry until midsummer. Over the entire pasture season, average daily weight gain was higher in treated than in control animals (difference = 0.08 kg/day, P = 0.010). Total weight gain was also higher in treated animals than in control animals (difference = 12.82 kg, P = 0.013). The results of this study suggest that preventive treatment of breeding age, grazing dairy heifers with a sustained-release ivermectin bolus provides a significant weight gain advantage, in situations with moderate utilization of moderately contaminated pastures.     

The effect of grazing on cow mortality in Danish dairy herds

The effect of summer grazing in large Danish dairy herds and certain management characteristics of grazing were studied for their impact on dairy cow mortality. Mortality data (from the Danish Cattle Database) from 391 Danish dairy herds (>100 cows) were combined with information from a questionnaire survey of grazing procedures on these herds in 2008. In all, 131 of the herds were identified as summer grazing and 260 as zero-grazing herds. The mortality was affected by an interaction of summer grazing and milking system. The risk of a cow dying was reduced to 46% in a grazing compared to a zero-grazing herd having automatic milking system. In traditional milking system, mortality was reduced to 75% in grazing compared to zero-grazing herds. Within the grazing herds, the risk of mortality decreased with increasing number of hours on pasture during the season. Free access between barn and pasture was associated with increased cow mortality.     

Influence of floor surface and access to pasture on claw health in dairy cows kept in cubicle housing systems

In this study, the effects on the claw health of dairy cows of three different floor types and access to pasture were investigated on 35 farms. The farms were fitted with a given floor type in the indoor walking area of a cubicle housing system: a solid rubber, mastic asphalt or slatted concrete floor. Because we chose farms on which the given floor type was in good condition, the data presented show what can be achieved on these types of floors under ideal circumstances. Cows on half of the farms per floor type had access to pasture during the grazing period. Each farm was visited three times at approx. 6-month intervals at the end of the winter indoor-housing period and at the end of the summer period, i.e. after the period with access to pasture on half of the farms. During each visit, the claw health of the same 10 cows per farm was assessed on the occasion of routine claw trimming. The proportion of cows with haemorrhages increased from mastic asphalt to rubber and slatted concrete floors. A lower proportion of cows kept on mastic asphalt was affected by white-line fissures and needed intermittent claw-trimming, an indicator for lameness. Cows housed in cubicle systems with slatted concrete floors were at the lowest risk of having heel-horn erosions. Access to pasture was associated with a lower incidence of slight white-line fissures and dermatitis digitalis. A higher proportion of cows with sole haemorrhages and sole ulcers were found on all floor types at the end of the summer period than at the end of the winter indoor-housing period. Floor type did not influence the presence of sole ulcers and deep white-line fissures. In conclusion, the effect of floor type on claw health was slight, and none of the investigated floor types was clearly superior to the others. Access to pasture was not effective in reducing the presence of most types of claw lesions associated with the floor type used in the indoor walking area.