Lameness and fertility of sows and gilts in randomly selected loose-housed herds in Finland

The prevalence of lameness among 646 sows and gilts in 21 selected herds was determined; 8.8 per cent of the animals were lame and the most common clinical diagnoses were osteochondrosis, infected skin lesions and claw lesions. The lame animals had higher serum concentrations of haptoglobin and C-reactive protein than the sound animals. Animals housed on slatted floors had twice the odds of being lame and 3.7 times the odds of being severely lame than animals housed on solid floors. Yorkshire pigs had 2.7 times the odds of being lame than Landrace or crossbred animals. Higher parity and the use of roughage decreased the odds of the sows not becoming pregnant; however, lameness was not a risk factor for non-pregnancy.     

Prevalence of herd specific factors and limb disorders,and their associations in intensive swine production

A longitudinal observational study in 180 pig breeding herds was performed to calculate prevalences of herd specific factors as well as typical limb disorders and to estimate their associations in a 2-step regression analysis. Regarding herd size, genetics, feeding and weight gain herds were distributed almost equal. The population density and the hygiene status were considered proper in most herds. In the farrowing units partially slatted floors of metal or plastic with slats > 9 mm, in the weaning units fully slatted floors of plastic, and in the rearing units fully slatted floors of concrete were most common. Less than 6% of the farms housed their pigs on solid concrete with straw bedding. Herd prevalences of fault floors varied between 18 and 43%. As a herd health problem (morbidity > 25%) claw hematomas and limb abrasions in just 1-week old piglets, overgrown claws and bursa swellings in weaned pigs, and bursa swellings in rearing pigs were wide spread. Leg deformations by osteopathy or arthritis occurred only sporadically. In the risk analysis claw hematomas of piglets were associated with slatted floors, particulary with slats < 10 mm. Abrasions were associated with concrete and rough floor surfaces at all. Overgrown claws and bursa swellings in weaned and in rearing pigs were associated with damaged, slippery or rough floor surfaces. Other associations were not detected. The quality of floor might be more important than the type of housing.     

Housing of Pregnant Sows in Loose and Confined Systems–a Field Study 1. Vulva and Body Lesions,Culling Reasons and Production Results

A field study was carried out in 18 herds with loose housing of pregnant sows (loose herds) and in 18 herds with tethered or stalled pregnant sows (confined herds). Three of the loose herds were excluded due to different kind of flooring from the rest of the herds. The remaining 15 herds had partly slatted concrete floors and electronic sow feeding. The frequencies of sows with vulva and body lesions, thin sows as well as the culling reasons and production results were used as animal welfare indicators for the herds. Vulva lesions were found only in the loose herds and the mean prevalence proportion of sows with lesions within these herds was 15.2%. All vulva lesions observed in this study seemed to be caused by biting. The relative risk of vulva lesions was 2.6 times higher in the loose herds with no roughage feeding as compared to loose herds with appetite feeding of roughage. The sows in the loose herds, that had a feeding station with a mechanical hind gate had 1.8 greater risk of vulva lesions than sows in the loose herds that used a feeding station with an electronic gate.The mean prevalence proportion of sows with body lesions was 13.1% in the loose herds and 4.0% in the confined herds. Aggression between sows seemed to be the main cause of body lesions in the loose herds, while decubitus ulcers on the shoulders were the main cause of body lesions in the confined herds. Sows in loose herds that were not fed additional roughage feeding had 1.7 times greater risk of body lesions than sows in herds that used additional roughage feeding.The main culling reasons and production results were similar in the loose and confined herds. This study showed that there were welfare problems both in confined and loose herds, however, with improved management, many of the welfare problems associated with loose housing can be reduced.     

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 of lameness and of associated claw disorders in Greek dairy cattle industry

The aim of this study was to assess the prevalence of lameness as well as the prevalence of claw–horn disruptions, abnormal claw shape and dermatitis in lame cows in Greek dairy farms and to evaluate their risk factors. Forty dairy farms were visited twice, during winter and during summer, and the lameness of milking cows was scored using a 5-point scale. In total 760 cows were lame (lameness score ≥ 3) and were further examined to identify macroscopically the claw disorders. The herd size, the trimming and footbathing frequency, the floor surface, the cleanness of the herd, the scraping frequency and the disinfectant used in the footbaths were recorded. The mean lameness prevalence was 18.7% and that of claw disorders observed in the lame cows was 75.4% for abnormal claw shape, 30.2% for dermatitis and 30.6% for claw–horn disruptions. Large herd size and the absence or only once per year trimming were associated with increased risk for the presence of lameness.     

Risk factors of lameness in sows in England

Lameness in pigs is a major welfare concern and one of the most commonly reported reasons for premature culling of breeding sows. In this study, the prevalence of lameness in sows was estimated using data from 76 pig breeding units in England and risk factors associated with the occurrence of lameness were examined. The prevalence of lameness in sows was 4.5% (farm median 5.0%, range 0–40%), with at least one lame sow being observed at 54% of the 76 farms. Relative risk (RR) of lameness was determined by multivariable Poisson regression analysis. Farms with high producing sows had a lower rate of lame sows than farms with a medium level of production (P = 0.01). However, medium levels of production on a farm were associated with higher levels of lameness than farms having the lowest level of production (P = 0.02). Farms where the stockman had responsibility for more sows resulted in an increased risk of lameness (P = 0.0062). When indoor units were considered, the area of the pen and younger sows (two parities or less) had higher risk of lameness (P = 0.001 and P = 0.026 respectively). An increased awareness of the risk factors behind lameness is essential in farm management and can be useful when designing housing areas as well as developing future prevention plans for lameness.     

Evaluation of patterns of removal and associations among culling because of lameness and sow productivity traits in swine breeding herds

OBJECTIVE: To characterize patterns of removal and evaluate the associations among culling because of lameness and sow productivity traits among culled gilts and sows. DESIGN: Cross-sectional study. SAMPLE POPULATION: Data from a convenience sample of 11 farms pertaining to the removal of 51,795 gilts and sows from January 1991 to December 2002. Mean culling and mortality (death and euthanasia) rates for all inventoried gilts and sows ranged from 23% to 50% and 4.7% to 9.5%, respectively. PROCEDURE: An analysis of categories of removal (cull, death, or euthanasia) and reasons for removal of gilts and sows was performed. Multivariate logistic regression was used to determine associations among culling because of lameness and sow productivity traits among culled gilts and sows. RESULTS: Among sows that were removed, the proportion of parity > or = 1 sows that died (both death and euthanasia) was > 3 times the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among lame sows that were removed, the proportion of parity > or = 1 sows that died (death and euthanasia) was higher than the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among sows that were removed, the proportion of sows that died (deaths and euthanasia) was higher during lactation than nonlactation. This was also observed among lame sows that were removed. CONCLUSIONS AND CLINICAL RELEVANCE: The proportion of death among removed sows, especially lame sows, was higher during lactation than nonlactation. Results indicated that risk of death is not the same for sows throughout their lifetime.     

Investigating the value dairy farmers place on a reduction of lameness in their herds using a willingness to pay approach

A survey was conducted to elicit dairy farmers’ willingness to pay (WTP) to reduce the prevalence of lameness in their herds. A choice experiment questionnaire was administered using face-to-face interviews of 163 farmers in England and Wales. Whole herd lameness assessments by trained researchers recorded a mean lameness prevalence of nearly 24% which was substantially higher than that estimated by farmers. Farmers’ responses to a series of attitudinal questions showed that they strongly agreed that cows can suffer a lot of pain from lameness and believed that they could reduce lameness in their herds.Farmers’ mean WTP to avoid lameness amounted to UK£411 per lame cow but with considerable variation across the sample. Median WTP of UK£249 per lame cow was considered a better measure of central tendency for the sample. In addition, the survey found that farmers had a substantial WTP to avoid the inconvenience associated with lameness control (a median value of UK£97 per lame cow) but that they were generally prepared to incur greater inconvenience if it reduced lameness. The study findings suggest that farmers need a better understanding of the scale and costs of lameness in their herds and the benefits of control. To encourage action, farmers need to be convinced that lameness control measures perceived as inconvenient will be cost effective.     

Lameness and claw lesions of the Norwegian red dairy cattle housed in free stalls in relation to environment, parity and stage of lactation

Approximately 88% of Norwegian dairy cattle are housed in tie stalls. Free stall housing for all dairy cattle will be implemented within 20 years. This means that the majority of existing stalls will be rebuilt in the near future. Fifty-seven free stall herds of the Norwegian Red breed were randomly selected and 1547 cows and 403 heifers 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. Environment, management- and feeding routines were also recorded. Fifty-three herds had concrete slatted alleys while 4 had solid concrete. Thirty-five herds had concrete as a stall base, while 17 had rubber mats, 2 had wood and 3 had deep litter straw beds. The prevalence of lameness was 1.6% in hind claws. Models for lameness and claw lesions were designed to estimate the influence of different risk factors and to account for the cluster effects within herd and claw trimmer. Detected risk factors for lameness were: parity three and above and narrow cubicles; for heel horn erosions: lactation stage around 5-7 months after calving and solid concrete alleys; for haemorrhages of the white line: lactation stage around 3-5 months after calving and solid concrete alleys; for haemorrhages of the sole: parity one, lactation stage around 5-7 months after calving and short cubicles, for white line fissures: slatted concrete alleys; for asymmetrical claws: parities two and above and for corkscrewed claws: solid concrete alleys. The prevalence of lameness in heifers was low, however 29% had one or more claw lesions. Heifers that were housed in pens or free stalls had more heel-horn erosions, haemorrhages of the sole and white-line fissures than heifers in tie stalls. As new free stalls are being built, it is important to optimise the conditions for claw health.     

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.     

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.     

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.     

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.     

Foothold of sows on farrowing crate floors

Three methods of evaluating the goodness of foothold of sows were compared: load hauling, standing and lying frequency while in farrowing crates, and foot movements while rising. Load hauling by harnessed sows was not a useful technique because experienced animals did not pull vigorously. Sows changed posture on the day after parturition half as often as they did before parturition or 7 days postpartum, but crate type or floor type had no effect on the standing or lying frequency. Foot movement of sows while rising was unaffected by farrowing crate type or crate width. Floors of plastic-coated expanded metal or concrete with concrete slats at the rear caused sows to move their hind feet a shorter distance and to take fewer foot movements while rising than did floors of fiberglass slats or perforated metal slats. The best method of evaluating the sureness of foothold of sows on farrowing crate floors was to determine the distance moved and the number of movements by the rear feet while in the act of rising. Because of the high correlation of these two variables, total movements was an adequate index.     

Risk factors for high sow mortality in French swine herds

Episodes of high sow mortality rates affect profitability of swine farms. However, relevant control actions are difficult to implement. The objective of this study was to identify the risk factors for high levels of sow mortality rate (HM) in French swine herds. A case-control study was carried out in 102 swine herds located in Brittany (western France). Level of sow mortality of a herd was quantified by the annual mortality rate using sow-days as denominator. Fifty-five (53.9%) herds which experienced a sow mortality rate over 5% were classified as HM herds. Logistic regression was used to assess associations of managerial practices and disease prevalence with the odds of HM. High prevalence of urinary tract infections, metritis or lameness were significantly associated with a HM herd status (P < 0.10, OR ranging from 3.4 to 5.2). Multiplying herds were herds at higher risk for sow mortality than commercial farrow-to-finish herds. Providing three meals per day instead of two to dry sows decreased the odds of HM. Feeding plans where the maximum daily amount of feed provided to lactating sows was lower than 8 kg and was reached before 15 d in lactation were related to lower odds of HM (P < 0.10). Average age at weaning of 28 d or more and/or small average litter size at birth (12 piglets or less) were associated with higher odds of experiencing HM.     

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.     

Biomechanical aspects of the claw-floor interaction in dairy cattle: implications for locomotion and claw disorders

The prevalence of claw disorders is still high among cows housed on concrete floors. Concrete floors affect the locomotion of cattle, their natural behavior. Although many factors affect the development of claw disorders and locomotor problems, biomechanical aspects have hardly been analysed. In this thesis, mechanical (over)loading of the claw and its significance for claw disorders and lameness are discussed. The mechanical characteristics a floor needs to provide in order to enable unrestrained locomotory behavior. This biomechanical approach, which is a relatively new approach in cattle locomotion, has provided new insights. Despite preventive trimming, the weakest parts of the claw capsule are loaded relatively the most. Concrete floors provide too little friction to enable unrestricted cattle locomotion.     

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.     

Observations of lameness, hoof conformation and development of lesions in dairy cattle over four lactations

Lameness and lesions in the claws of 31 autumn-calving Holstein Friesian dairy cows were recorded from before their first-calving until their fifth lactation. The animals were managed by the same herdsman and housed adjacently in the same building in one of two herds grazed either on clover-rich pastures (herd 1) or on conventional ryegrass (herd 2). All four hooves were examined routinely four times during each lactation, and claw lesions were scored for severity and drawn on hoof maps. Heel erosion and infectious skin conditions of the hoof were also recorded, and hoof conformation, hardness, and growth and wear were measured. The animals' locomotion was scored weekly throughout the winter housing period and any observed to be lame were examined to determine the cause. The development of lesions was modelled by using hierarchic smoothing splines. There was no significant effect of herd except on the prevalence of lameness in lactation 2 when the incidence of (inter)digital dermatitis was higher in herd 2. Lesion and locomotion scores were significantly higher by lactation 4 (P<0.05). There were significant effects (P<0.05) of weeks postcalving on lesion formation, claw conformation, and heel erosion.     

Four-year study of lameness in piglets at a research station

Lameness in piglets up to nine weeks old was studied in a research station herd for four years; 9411 piglets were born alive, of which 9.8 per cent were treated for lameness. In litters born to gilts, 9.9 per cent of the piglets were treated for lameness, in litters born to sows of parity 3, 11.4 per cent of the piglets were treated, but in litters born to sows of parity 4 to 7 the proportion of piglets treated for lameness decreased to about 8 per cent. Around 75 per cent of all cases were observed in piglets less than three weeks old; the incidence risk of lameness decreased from 2.7 per cent during the first week of life to 0.3 per cent after weaning. The average weight of affected piglets was reduced by approximately 8 per cent at nine weeks of age. There was no overall association between lameness and sex or birth weight within sex. The mortality among lame gilts was higher at all ages than among healthy gilts, but among barrows a higher mortality was observed only during the late suckling period. Litters with 12 or more piglets had a higher incidence of lameness. Clinical signs of disease in the sow and whether the piglets were given an intramuscular injection of 200 mg of iron on their second, third or fourth day of life had no effect on the incidence of lameness.