Comparison of milk yield in dairy cows with different degrees of lameness

OBJECTIVE: To compare milk yield among cows classified as nonlame, moderately lame, and lame and to examine the relationship between severity of lameness and milk yield in cows classified as lame during the first 100 days after parturition. DESIGN: Longitudinal study. ANIMALS: 465 Holstein cows. PROCEDURE: Cows were examined weekly during the first 100 days after parturition and assigned a lameness score by use of a 6-point locomotion scoring system (ie, 0 to 5). Milk yield was compared among cows classified as nonlame, moderately lame, and lame. Among cows classified as lame (locomotion score > or = 4), milk yield was compared for cows with low, medium, and high cumulative locomotion scores. Cows classified as lame were further examined on a tilt table for diagnosis and treatment of lameness. RESULTS: 84 (18%), 212 (46%), and 169 (36%) cows were classified as nonlame, moderately lame, and lame, respectively. Among cows in their second or later lactations, milk yield in lame cows was significantly lower than that in moderately lame and nonlame cows. In addition, among cows classified as lame, milk yield was significantly lower in cows with high locomotion scores during the first 100 days after parturition, compared with cows with low scores. Most (58%) cows classified as lame had laminitis. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate a linear relationship between increasing degree of lameness and decreasing milk yield among cows in their second or later lactations. The locomotion scoring system used in this study may be a useful management tool that veterinarians and dairy farmers could adopt for early detection of lameness in dairy cows.     

Association between age and time from calving and reported lameness in a dairy herd in the Waikato region of New Zealand

Abstract

CASE HISTORY: During the 2014/2015 season 823 predominantly Holstein-Friesian cows calved on a pasture-based farm in the Waikato region of New Zealand. A high prevalence and recurrence rate of lameness had been noted for several years but cows feet were not routinely picked up and therapeutically trimmed.

CLINICAL FINDINGS: At a farm visit in December 2015, 23 cows feet were examined and 18/23 (78%) cows had white line disease and 17/23 (74%) sole haemorrhages, as well as severely overgrown and misshapen hooves.

EPIDEMIOLOGICAL INVESTIGATION: Lameness, culling and reproductive data were collected for the farm for the period from 01 July 2014 to 30 November 2015. In the 2014/2015 season, 207/823 (25.2%) cows were recorded lame, and in the first half of the 2015/16 season 120/850 (14%) cows were recorded lame. Of the cows recorded lame, 52/207 (25.1%) in the 2014/15 season had >1 case of lameness, and 39/120 (32.5%) cows recorded lame in the 2015/2016 season had been lame in the previous season. There was an apparent increase in prevalence between 29–37 weeks post-calving. Cows >7-years-old had seven times the odds of being recorded as lame compared to 2–3-year-old cows (p<0.001). Lameness was not associated with culling, empty rate or days to conception (p>0.3).

DIAGNOSIS: No direct cause for the lameness could be determined.

CONCLUSIONS AND CLINICAL RELEVANCE: It was hypothesised that, along with the degenerative changes in the pedal bone as dairy cows increased in age, suboptimal treatment and overgrowth of hooves resulted in permanent changes in the cows feet, resulting in a high prevalence of lameness in older cattle and a high recurrence rate of lameness within and between seasons. This case highlights the importance of prompt identification and treatment of lame cattle.     

Role of ketoprofen in the modulation of hyperalgesia associated with lameness in dairy cattle

Forty lame dairy cows were randomly assigned to receive a course of either the non-steroidal anti-inflammatory drug ketoprofen, or sterile saline, together with conventional treatment for lameness. The effect of the ketoprofen was measured by using locomotion scoring and by testing the cows' nociceptive threshold over a period of 28 days. The locomotion score of all the cows improved but ketoprofen had no significant effect on this change. However, in the cows that received ketoprofen the hyperalgesia associated with lameness, recorded using a nociceptive threshold test, was significantly modulated on days 3, 8 and 28 after their initial examination, drug administration and treatment of lesions.     

Comparison of the calving-to-conception interval in dairy cows with different degrees of lameness during the prebreeding postpartum period

OBJECTIVE: To compare calving-to-conception intervals among cows classified as nonlame, moderately lame, or lame during the prebreeding postpartum period and to examine the relationship between severity of lameness and time to conception in cows that were classified as lame. DESIGN: Longitudinal study. ANIMALS: 499 Holstein cows. PROCEDURE: Cows in the prebreeding postpartum period were classified as nonlame, moderately lame, or lame by use of a 6-point locomotion scoring system. Time to conception (days) was compared among cows. A low, medium, or high cumulative locomotion score was assigned to lame cows, and time to conception among those cows was compared. Cows classified as lame were examined on a tilt table for diagnosis and treatment of lameness. RESULTS: 154 (31%), 214 (43%), and 131 (26%) cows were classified as nonlame, moderately lame, and lame, respectively. Most cows classified as lame had laminitis (54%) or disorders of the claw (33%). Median time to conception was 36 to 50 days longer in lame cows than in nonlame cows. Among lame cows, the median time to conception was 66 days longer in cows with high cumulative locomotion scores than in cows with low scores. CONCLUSION AND CLINICAL RELEVANCE: Nonlame cows became pregnant more quickly than lame cows. Lame cows with low cumulative locomotion scores during the prebreeding postpartum period became pregnant sooner than lame cows with high scores. Early diagnosis and intervention may mitigate the effects of lameness and improve reproductive performance in lame dairy cows.     

Assessment of the duration of the pain response associated with lameness in dairy cows, and the influence of treatment

AIM: To assess the welfare impact of lameness on dairy cattle in New Zealand by measuring the duration of allodynia (decreased nociceptive threshold) and increased locomotion score, and to evaluate the influence of treatment on that duration. METHODS: After lame cows were treated using corrective paring by a veterinarian, they were allocated to one of six treatment groups. If the veterinarian determined that additional elevation of the lesion was not required the cow was randomly allocated to receive one of four treatments, viz 2 mg/kg tolfenamic acid, a plastic shoe to elevate the lesion, both treatments, or no further treatment. Cows that required additional elevation were treated using a plastic shoe and then randomly allocated to two separate treatment groups, either 2 mg/kg tolfenamic acid or no further treatment. Assessments of locomotion score (based on posture and gait) and mechanical nociceptive threshold (using a pneumatically actuated blunt pin) were made prior to treatment, and 3, 8, 28 and 100 days later. RESULTS: Data were collected from 149 lame cows from nine dairy farms. There were significant improvements in mean locomotion score and nociceptive threshold in all treatment groups. At all time-points after treatment, locomotion score and nociceptive threshold were significantly improved when compared with the previous time-point. Thus, in these cows, the deleterious effects of lameness persisted for longer than 28 days, despite treatment, as the mean locomotion scores and nociceptive threshold on Day 100 were better than those on Day 28. No significant long-term benefit of using tolfenamic acid at the time of treatment was observed on either locomotion score or nociceptive threshold, nor was there any benefit in using a plastic shoe in cases where it had been determined that such treatment was not necessary. CONCLUSIONS: This study demonstrated that the welfare impact of lameness on dairy cattle in New Zealand is of long duration even when treated effectively. In contrast to previous studies, no significant long-term benefit of using non-steroidal anti-inflammatory drugs (NSAID) at the time of treatment was observed, probably because unlike those previous studies the nociceptive threshold improved in the cattle which did not receive an NSAID, perhaps because treated cattle were kept on pasture rather than housed. CLINICAL RELEVANCE: The long duration of increased allodynia after treatment demonstrates that prevention of lameness rather than therapeutic treatment is the key to reducing its impact on the welfare of dairy cows.     

Evaluation of the efficacy of prophylactic hoof health examination and trimming during midlactation in reducing the incidence of lameness during late lactation in dairy cows

OBJECTIVE: To assess the efficacy of prophylactic hoof health examination and trimming during midlactation at reducing the incidence of lameness during late lactation in dairy cows. DESIGN: Randomized field trial. ANIMALS: 333 Holstein cows. PROCEDURES: Cows without apparent lameness were randomly allocated into 1 of 2 groups approximately 204 days after calving. Cows allocated to the treatment group (n = 161) were examined on a tilt table for diagnosis and underwent hoof-trimming procedures, if needed, for treatment of hoof disorders or lesions. Cows in the control group (n = 172) were not examined. Cows were assigned a locomotion score weekly for 28 weeks after allocation to a group. The number of cows classified as lame during late lactation (approx 205 to 400 days after calving) was compared between groups to assess the efficacy of prophylactic examination and trimming. RESULTS: Incidence of lameness during late lactation was 24% in cows in the control group and 18% in cows in the treatment group. CONCLUSIONS AND CLINICAL RELEVANCE: The 25% decrease in number of new cases of lameness in cows undergoing prophylactic hoof health examination and trimming during midlactation may be relevant for the well-being of dairy cows and should not represent a major economic burden to producers.     

The effect of Lameness before and during the breeding season on fertility in 10 pasture-based Irish dairy herds

Background

The effects of lameness on fertility have been documented frequently but few data are available from seasonally breeding, pasture-based herds (such as those used in Ireland) where cows are housed during the winter months but managed at pasture for the remainder of the year. This study determined the prevalence of lameness in a group of 786 cows in 10 pasture-based Irish dairy herds before, during and after the breeding season and assessed the relationship between lameness and the reproductive performance in these herds through serial locomotion scoring during the grazing period.

Results

Lameness prevalences of 11.6 % before, 14.6 % during and 11.6 % after the breeding season were found and these compared favourably to results from housed cattle and are similar to other studies carried out in grazing herds. A Cox proportional hazards model with locomotion score as time varying covariate was used. After controlling for the effect of farm, month of calving, body condition score at calving, body condition score loss after calving and economic breeding index, cows identified as lame during the study were less likely to become pregnant. Cows lame before the earliest serve date but no longer lame during the breeding season, cows becoming lame after the earliest serve date and cows identified lame both before and after this date were respectively 12 %, 35 % and 38 % less likely to become pregnant compared to cows never observed lame during the study. However, these findings were only significant for cows becoming lame after the earliest serve date and cows lame both before and after the start of breeding.

Conclusions

This study found that the reproductive efficiency was significantly (p < 0.05) lower in cows becoming lame during the breeding season and cows lame before and during the breeding season compared to non-lame cows. Cows no longer lame during the breeding season had a lower Submission Rate to first serve within 3 weeks of earliest serve date. However, the Pregnancy Rate was not significantly (p > 0.05) lower in these animals compared to cows never diagnosed as lame. In addition to lameness status, nutritional status and genetics were found to influence the reproductive performance in pasture-based Irish dairy herds.     

Generalised additive models and hierarchical logistic regression of lameness in dairy cows

We examined the relationship between lameness (defined by locomotion score) and four time-related variables using data collected from a study of cattle lameness conducted in the UK from 1998 to 1992. The data were 19,667 locomotion scores for 1790 cows from 27 dairy herds; the four variables were time-from-calving, time of year, parity and time spent in the study. The shape of the relationships between calving and temporal variables and lameness were assessed using loess smoothed terms in a multivariable logistic generalised additive model (GAM). Polynomial relationships derived from the GAM then were included in a Bayesian hierarchical logistic-regression model incorporating between-herd, between-cow and within-cow random effects. The final hierarchical multivariable model showed that the most important variable influencing the probability of lameness was the time of scoring in the study; but, parity, time of year and time-from-calving also were significant. Between-herd and between-cow effects were of roughly equal importance.     

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.     

A case study of lameness in three dairy herds

All cases of lameness that occurred in cows from three dairy herds between August 198'3 and July 1990 were examined every 2 weeks from the onset of lameness until the lesions resolved. The incidences of herd lameness were 38%, 22% and 2%. Some 186 clinical lesions were identified in 134 cases of lameness in 120 cows. Sole bruising (42%) and white line separation (39%) were the most frequently diagnosed conditions. Lateral digits of the hind limbs were the most affected. The mean time from the onset of lameness to clinical recovery was 27 days and to lesion recovery was 35 days. The peak incidence of lameness occurred during winter for autumn-calving cows and during the late spring for spring-calving cows. The onset of lameness was associated with the stage of lactation and wet weather conditions. Survival analysis revealed that the probability of an individual cow lasting in the milking herd for any specified period of time without becoming lame was highly associated with both her herd environment and her age. Total lactation yields of milk, milk fat and milk protein were lower for cows suffering from lameness than for herd-mates matched on age and proximity on calving date (P<0.05). Reproductive performance was also poorer in lame cows than in their herd-mates.     

Use of force sensors to detect and analyse lameness in dairy cows

Force sensors were used to detect lameness in dairy cows in two trials. In the first trial, leg weights were recorded during approximately 12,000 milkings with balances built into the floor of the milking robot. Cows that put less weight on one leg or kicked frequently during milking were checked first with a locomotion scoring system and then with a clinical inspection. A locomotion score of more than 2 was considered lame, and these cows' hooves were examined at hoof trimming to determine the cause and to identify any hoof lesions. In the second trial 315 locomotion scores were recorded and compared with force sensor data. The force sensors proved to be a good method for recognising lameness. Computer curves drawn from force sensor data helped to find differences between leg weights, thus indicating lameness and its duration. Sole ulcers and white line disease were identified more quickly by force sensors than by locomotion scoring, but joint problems were more easily detected by locomotion scoring.     

Temporal associations between low body condition,lameness and milk yield in a UK dairy herd

Previous work has hypothesised that cows in low body condition become lame. We tested this in a prospective longitudinal study. Body condition score (BCS), causes of lameness and milk yield were collected from a 600-cow herd over 44-months. Mixed effect binomial models and a continuous outcome model were used to investigate the associations between lameness, BCS and milk yield. In total, 14,320 risk periods were obtained from 1137 cows. There were 1510 lameness treatments: the most common causes of lameness were sole ulcer (SU) (39%), sole haemorrhage (SH) (13%), digital dermatitis (DD) (10%) and white line disease (WLD) (8%). These varied by year and year quarter. Body condition was scored at 60-day intervals. BCS ranged from 1 to 5 with a mean of 2.5, scores were higher in very early lactation but varied widely throughout lactation; approximately 45% of scores were <2.5. The key finding was that BCS < 2.5 was associated with an increased risk of treatment for lameness in the following 0–2 months and >2–4 months for all causes of lameness and also specifically for SU/WLD lameness. BCS < 2.5 was associated with an increased risk of treatment for SH in the following 0–2 months but not >2–4 months. There was no such association with DD. All lameness, SU/WLD, SH and DD were significantly more likely to occur in cows that had been lame previously, but the effect of BCS was present even when all repeat cases of lameness were excluded from the analysis. Milk yield was significantly higher and fell in the month before treatment in cows lame with SU/WLD but it was not significantly higher for cows that were treated for DD compared with non-lame cows. These findings support the hypothesis that low BCS contributes to the development of horn related claw lameness but not infectious claw diseases in dairy cows. One link between low BCS and lameness is a thin digital cushion which has been proposed as a trigger for claw horn disease. Cows with BCS 2 produced more milk than cows with BCS 2.5, however, this was only approximately 100 kg difference in yield over a 305-day lactation. Given the increased risk of lameness in cows with BCS 2, the direct costs of lameness and the small variability in milk yield by BCS, preventing cows from falling to BCS < 2.5 would improve cow welfare and be economically beneficial.     

Prevalence of lameness among dairy cattle in Wisconsin as a function of housing type and stall surface

OBJECTIVE: To determine the prevalence of lameness as a function of season (summer vs winter), housing type (free stalls vs tie stalls), and stall surface (sand vs any other surface) among lactating dairy cows in Wisconsin. DESIGN: Epidemiologic survey. ANIMALS: 3,621 lactating dairy cows in 30 herds. PROCEDURE: Herds were visited once during the summer and once during the winter, and a locomotion score ranging from 1 (no gait abnormality) to 4 (severe lameness) was assigned to all lactating cows. Cows with a score of 3 or 4 were considered to be clinically lame. RESULTS: Mean +/- SD herd lameness prevalence was 21.1 +/- 10.5% during the summer and 23.9 +/- 10.7% during the winter; these values were significantly different. During the winter, mean prevalence of lameness in free-stall herds with non-sand stall surfaces (33.7%) was significantly higher than prevalences in free-stall herds with sand stall surfaces (21.2%), tie-stall herds with non-sand stall surfaces (21.7%), and tie-stall herds with sand stall surfaces (12.1%). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the prevalence of lameness among dairy cattle in Wisconsin is higher than previously thought and that lameness prevalence is associated with season, housing type, and stall surface.     

A case study of lameness in three dairy herds

All cases of lameness that occurred in cows from three dairy herds between August 1989 and July 1990 were examined every 2 weeks from the onset of lameness until the lesions resolved. The incidences of herd lameness were 38%, 22% and 2%. Some 186 clinical lesions were identified in 134 cases of lameness in 120 cows. Sole bruising (42%) and white line separation (39%) were the most frequently diagnosed conditions. Lateral digits of the hind limbs were the most affected. The mean time from the onset of lameness to clinical recovery was 27 days and to lesion recovery was 35 days. The peak incidence of lameness occurred during winter for autumn-calving cows and during the late spring for spring-calving cows. The onset of lameness was associated with the stage of lactation and wet weather conditions. Survival analysis revealed that the probability of an individual cow lasting in the milking herd for any specified period of time without becoming lame was highly associated with both her herd environment and her age. Total lactation yields of milk, milk fat and milk protein were lower for cows suffering from lameness than for herd-mates matched on age and proximity of calving date (p<0.05). Reproductive performance was also poorer in lame cows than in their herd-mates.     

Prevalence of lameness and hoof lesions in all year-round grazing cattle in Brazil

Lameness is a growing concern to the dairy industry worldwide. However, little is known about lameness and its causes in grazing cattle, especially in tropical climates. This study aimed to assess the prevalence of hoof lesions and lameness in dairy herds of all year-round grazing cattle under tropical condition, and to identify the main lesions associated with lameness. We visited 48 farms located in the Minas Gerais state, Brazil, equally divided into four groups based on daily milk production. All lactating cows in the visited farms were locomotion scored, and a representative sample was randomly chosen for hoof inspection. Among the 2267 lactating cows evaluated, 16% were scored as lame and 7% as severely lame. Nearly all cows presented at least one type of hoof lesion, of which heel horn erosion (90%), white line fissure (50%), and digital dermatitis (33%) were the most prevalent. Heel horn erosion was present in all farms and digital dermatitis was present in 96% of the farms. Sole ulcer was observed in a single animal. Additionally, digital dermatitis and white line fissure were correlated to a 2.5 times increase in the odds of a poor mobility score. Collectively, our results demonstrate that digital dermatitis and white line fissure are the main concern and the biggest cause of lameness in grazing cattle under tropical conditions.     

Effect of lameness on the calving-to-conception interval in dairy cows

OBJECTIVE: To examine the relationship between lameness and the duration of the interval from calving to subsequent conception in lactating dairy cows. DESIGN: Cohort study. ANIMALS: 837 dairy cows. PROCEDURE: Cows affected with lameness were classified into 1 of 4 groups on the basis of types of disease or lesions observed, including foot rot, papillomatous digital dermatitis, claw lesions, or multiple lesions. Cows not affected with lameness were classified as healthy. Time from calving to conception was compared between lame cows and healthy cows. RESULTS: 254 (30%) cows were affected with lameness during lactation. Most lame cows (59%) had claw lesions. Lame cows with claw lesions were 0.52 times as likely to conceive as healthy cows. Median time to conception was 40 days longer in lame cows with claw lesions, compared with healthy cows. Number of breedings per conception for lame cows with claw lesions was significantly higher than that for healthy cows. CONCLUSION AND CLINICAL RELEVANCE: Claw lesions were the most important cause of lameness, impairing reproductive performance in dairy cows, as indicated by a higher incidence of affected cows and a greater time from calving to conception and a higher number of breedings required per conception, compared with healthy cows.     

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.     

The effect of hindclaw height differential and subsequent trimming on lameness in large dairy cattle herds in Canterbury,New Zealand

Abstract

AIMS: To determine if inequality in height between claws within each hindlimb of dairy cattle is a risk factor for the development of lameness and to determine the effect of preventive trimming of these claws on the subsequent risk of lameness.

METHODS: Cows (n=2,695) on three dairy farms in Canterbury, New Zealand, were examined and the height differential between their hind claws on each limb was measured. Cows were blocked by age, then breed and grouped by height differential, before being randomly assigned to either treatment or control groups. Cows in the control group were not trimmed, whilst cows in the treatment group were all trimmed according to the ‘Dutch Trimming’ method by an experienced foot trimmer. All subsequent clinical incidences of lameness were identified, recorded and classified according to five categories. The overall incidence of lameness, the effect of claw height differential on the incidence of lameness and the effect of trimming on the incidence of lameness were assessed using both GEE modelling and survival analysis.

RESULTS: The incidence of lameness identified in any untrimmed hindlimb irrespective of diagnosis, measured at a limb level and assessing the first incidence of lameness only, was 10.0% for a 6-month period from November to drying off. The predominant lesion identified was white line disease (WLD; 7.9% incidence and 78.6% of all lameness). The overall incidence of hindlimb lameness measured at cow level for the same period was 14.5%. The risk of lameness was influenced by breed (p=0.016), age (p=0.002) and claw height differential (p=0.026). There were no significant interactions. The risk of lameness was lowest where the claw height differential was 0–2 mm. The incidence of lameness in the first 70 days following trimming was higher in older cows than in younger cows (p<0.001). Trimming did not affect lameness incidence (p=0.185). The Cox proportional hazard model demonstrated that farm (p<0.001), trimming group (p=0.021); and age (p=0.021) significantly affected the median days to lameness in the first 70 days following trimming.

CONCLUSIONS AND CLINICAL RELEVANCE: Hind feet with lower height differentials between claws had a lower incidence of lameness. Trimming of these feet to remove the height differential did not reduce their overall incidence of lameness, but did increase days to first lameness.     

Effect of lameness on milk yield in dairy cows

OBJECTIVE: To examine the relationship between lameness and milk yield in dairy cows. DESIGN: Cohort study. ANIMALS: 531 dairy cows. PROCEDURE: Cows affected with lameness were classified into 1 of 3 groups on the basis of type of diseases or lesions observed, including interdigital phlegmon (foot rot), papillomatous digital dermatitis (foot warts), or claw lesions. Cows not affected with lameness were classified as healthy. From Dairy Herd Improvement Association records, 305-day mature equivalent milk yield data were collected at the end of lactation or when the cow left the herd. Milk yield was compared between cows affected with lameness and healthy cows. RESULTS: 167 (31%) cows were affected with lameness during lactation. Lame cows had claw lesions (60%), papillomatous digital dermatitis (31%), or interdigital phlegmon (9%). Milk yield in lame cows with interdigital phlegmon (mean, 17,122 lb) was significantly less, compared with healthy cows (19,007 lb). CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, interdigital phlegmon was associated with a 10% decrease in milk production. Lame cows with claw lesions or papillomatous digital dermatitis produced less milk than healthy cows, but the difference was not significant.     

Prevalence and consequences of subacute ruminal acidosis in German dairy herds

Background

The prevalence and the clinical consequences of subacute ruminal acidosis (SARA) in dairy cows are still poorly understood. In order to evaluate the prevalence of SARA, 26 German dairy farms were included in a field study. In each herd, between 11 and 14 lactating dairy cows were examined for their ruminal pH using rumenocentesis. Milk production data and farm management characteristics were recorded. Each farm was scored for lameness prevalence among lactating animals, and body condition score was recorded three times four to five weeks apart in all animals examined. Farms were grouped on basis of ruminal pH and compared for lameness, body condition, milk production parameters and style of management. Animals were grouped on basis of their measured ruminal pH and compared accordingly for milk production parameters and body condition score.

Results

Of 315 cows examined, 63 individuals (20%) exhibited a ruminal pH of ≤ 5.5 at time of rumenocentesis. Of 26 farms examined, eleven farms had three or more of their cows experiencing a ruminal pH of ≤ 5.5 and were classified as likely experiencing subacute ruminal acidosis. These farms tended to be bigger than the others and offered less lying space to the lactating cows. There was no clear tendency regarding lameness. Among individual cows, animals with a low ruminal pH of ≤ 5.5 were found to be in significantly poorer body condition than animals with higher pH values (p < 0,05).

Conclusions

The study shows 11 out of 26 of herds likely experiencing SARA. Bigger herds tend to be at a higher risk for SARA, while individuals with low ruminal pH tend to be lower in body condition. The study points to the importance of management in preventing SARA.