The influence of different intervention strategies on the incidence of (Papillomatous) Digital Dermatitis

Claw Health in Dairy Cows in the Netherlands Chapter 7 The influence of different intervention strategies on the incidence of (Papillomatous) Digital Dermatitis M. Holzhauer 1, D. Döpfer 2, J. de Boer 1, G. van Schaik 3 1 Ruminant Health Department, GD Ltd., P.O. Box 9, 7400 AA Deventer, The Netherlands 2 Quantitative Veterinary Epidemiology Group, Division of Infectious Diseases, Animal Sciences Group of Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands 3 Epidemiology Department, GD Ltd., P.O. Box 9, 7400 AA Deventer, The Netherlands Veterinary Record (2006), in press 147

Chapter 71 Abstract The objective of this intervention study was to evaluate the effects of different herd strategies on the incidence of severe digital dermatitis (M2) lesions in dairy cows in The Netherlands. Different intervention strategies were applied in an experimental dairy herd. After a pre-investigation period dairy cows were equally distributed into different groups based on parity, stage of lactation and the presence of M2-lesions. The different groups were systematically monitored from January 1 st till June 30 th 2005. The five different strategies were: 1. weekly, for 1 day, twice a day, a 4% formalin walkthrough footbath; 2. every other week, for 1 day, twice a day, a 4% formalin walkthrough footbath; 3. increased hygiene measurements combined with a 2% multicompound solution walk-in footbath (30 min.) at D0, D7, D30 and D90 and then every 6 months; 4. weekly, for 1 day, twice a day, a 2% multicompound walkthrough footbath; 5. weekly, for 1 day, twice a day, a 3% soda lime walkthrough footbath. The assessment of the success of the strategies was based on a 3 weekly clinical inspection of the hind hoofs of all dairy cows in a chute by one intensively trained claw-trimmer, whereby only M2-stadia of digital dermatitis were locally treated with a chlortetracycline spray. The data were analyzed by logistic regression, whereby the outcome was the number of M2-lesions in the different groups during the whole period of intervention and for each observation period. The outcome was compared with the number of M2-lesions during the preinvestigation period and the recurrence of the DD-lesions, whereby the cows were typed as being a Type I, II or III-cow. A Type I cow remains negative during the whole period of intervention, a Type II cow experiences a normal DD-infection, namely: M2, and a Type III cow is a problem cow, that persists in the infectious stage. The basic assumption in this study was that the more effective the strategy, the less Type II or/and Type III cows would be present. The weekly application of a 4% formalin footbath during 1 day, twice daily resulted in significantly less M2-lesions (p<0.05) compared to the preinvestigation period throughout the whole observation period. The strategy of both bi-weekly formalin application and increased hygiene measurements in 148

Claw Health in Dairy Cows in the Netherlands combination with a walk-in footbath with 2% multicompound were sufficient effective to prevent a DD outbreak within those intervention groups, whereby an outbreak was defined as >3 M2-lesions at leg-level within the same group. Not effective in preventing an outbreak were the weekly application of a 2% multicompound footbath and the weekly application of a 3% soda lime footbath. Application of the latter strategies resulted in a single outbreak in the 2% multicompound group and a continuously high rate of new infections in the soda lime group. The numbers of outbreaks were significantly more frequent than during the pre-investigation period in these groups, when no strategic intervention was applied. The results above were also reflected in the severity of the lesions in the cows. The weekly application of formalin footbaths resulted in Type I infections and the weekly application of soda lime footbaths in the less favorable Type III infections. Keywords: (Papillomatous) digital dermatitis, intervention, footbath, epidemiology. 149

Chapter 17 Introduction Healthy claws are a prerequisite for a good and long-lasting active life of dairy cows (Brand et al., 1996; Webster et al., 1995). Impaired hoof condition is responsible for great economic losses (Enting et al., 1997; Kossaibati and Esslemont, 1997; Green et al., 2002) and is considered to be a main factor in diminished animal welfare (Webster et al., 1995; Logue, 1996). Hoof disorders may be distinguished in infectious disorders ((Papillomatous) digital dermatitis (PDD), interdigital dermatitis/heel horn erosion (ID/HE) and interdigital plegmona) and metabolic/non-infectious disorders (laminitis, interdigital fibroma and trauma). Although PDD has internationally several other names, throughout this paper, the phrase digital dermatitis (DD) will be used. DD is a digital disease of cattle, first described in 1974 in Italy and characterized by inflammation of the skin, mostly localized in the region of the bulb of the heel and coronet of the hoof (Cheli and Mortellaro, 1974; Blowey and Sharp, 1998; van Amstel et al., 1995; Read and Walker, 1998b). Nowadays, the disease has spread all over the world, and has been reported as an endemic disease in Western and Southern Europe and the US (Brizzi, 1993; van Amstel et al., 1995; Rodriguez-Lainz et al., 1999; Wells et al., 1999; Rodriguez-Lainz et al., 1996; Murray et al., 2002; Somers et al., 2003; Clarkson et al., 1996; Read and Walker, 1998a). In other countries such as Japan, Australia and New Zealand DD is observed as an incidental lesion (Kimura et al., 1993; McLennan and McKenzie, 1996; Vermunt and Hill, 2004), while in a country like Norway DD is considered as an increasing problem related to switching of the current housing system from tie stalls to free stalls (Sogstad et al., 2005). A recent investigation by the Dutch Animal Health Service Ltd. (GD) estimated a DD herd prevalence of 91% and a cow prevalence of 21% at the time of regular trimming of all the dairy cows hind hoofs (Holzhauer et al., 2006). In more than 1 of the infected herds the endemic DD infection resulted in serious problems defined as a continuous prevalence of >4 (Holzhauer et al., 2006). Decreasing the DD prevalence will strongly improve dairy cattle hoof health. The results of almost all studies emphasize the multi-factorial background of the DDproblems and support the necessity of an integral approach (Rodrigues-Lainz et al., 1999; Somers et al., 2005; Holzhauer et al., 2006). In many herds, both 150

Claw Health in Dairy Cows in the Netherlands the individual and the herd therapy are considered to be labor-intensive, while little scientific information is available especially about the effectiveness of the herd therapy (Hoblet, 2002). The studies about topical application were mainly focused on the investigations of antibiotics and copper and/or zinc containing skin pharmaceuticals, which are observed to be effective, but labor-intensive and therefore less suitable to apply in larger herds and/or herds with a high DDprevalence (Brizzi, 1993; Shearer et al., 1995; Berry et al., 1996, 1998 and 1999a; Britt and Mc Clure, 1998; Hernandez et al., 1999). For a DD herd-treatment strategy, up to now antibiotics (e.g. oxytetracyclin, lincomycin and erythromycin) containing footbaths are used in several countries. This was also the case in The Netherlands until the end of the nineties, but is currently prohibited by law because of the risk contamination of milk and the environment and development of resistance against antibiotics (Law on the Use of Veterinarian Drugs, The Netherlands, 1998). The use of heavy metals in footbaths is, according to the Dutch Law on Reduction of Chemical Litter in the Environment, only permitted in very low concentrations (0.5 for copper sulphate and 1% for zinc sulphate). Especially in the UK and the US, short-term studies were performed into the effectiveness of initially antibiotics and later formalin, zinc and copper sulphate and disinfectants like glutar aldehyde and hydrogen peroxide or combinations of these in multi-compounds footbaths (e.g. Grongnet et al., 1996; Shearer and Elliot, 1998; Berry et al., 1999a; Shearer and Hernandez, 2000; Berry et al., 2002; Laven and Hunt, 2002; Nowrouzian and Zareii, 2002). In a recent study, Zemljic (2004) found that improper footbath management could even facilitate the spread of DD. In our study was chosen for a formalin 4% solution as the reference treatment, because of good experience with formalin in earlier studies (Blowey, 2000; Laven and Hunt, 2002) and good results reported by Dutch farmers, after which this strategy was advised by GD as a standard herd strategy. Nevertheless formalin solutions remain a potential respiratory and conjunctival irritant and carcinogen (e.g. Collins and Lineker, 2004; Heck and Casanova, 2004). Therefore the GD advice was always combined with the advice of precaution and good ventilation at the moment of preparation and the place where the bath is situated. 151

Chapter 17 The objective of the present study was to investigate the effects of different intervention strategies for several months and to investigate the possibility to reduce the use of treatments with formalin. Materials and methods Study population The intervention study was performed between January 1 st and June 30 th 2005 in the experimental herd Nij Bosma Zathe of the Animal Sciences Group of Wageningen University and Research Centre, in the Northern part of The Netherlands. On January 1 st 2005 the herd comprised 140 lactating dairy cows; the dry cows were excluded from the study. All lactating cows got the same basic ration since December 1 st 2004, composed of grass silage and maize silage, barley/pea, soy and compound feeds. The quantity of compound feeds (0-8 kg) depended on the milk-production level of the individual cow. More than 95% of the present dairy cows were Holstein Friesian. Based on the sample size calculations with a distinguishable power of 8 and a confidence 95%, experimental groups of 15 cows were considered sufficient. The sample sizes were without correction for intra-cluster correlations. Information on the presence (and stage) or absence and the clinical presentation of DD in hind hoofs was collected during clinical examination of all hind legs in a chute every third week, 8 times in total (see figure 1.). 152

Claw Health in Dairy Cows in the Netherlands Figure 1. A time frame of the observations for the pre-investigation and the intervention period. 1/12 3/1 24/1 14/2 7/3 28/3 18/4 16/5 7/6 28/6 period 6 period 7 period 8 period 9 period 10 period 11 period 12 period 13 4 weeks 3 weeks 3 weeks 3 weeks 3 weeks 3 weeks 3 weeks 3 weeks 3 weeks start of pre- start of 1 st observ. 2 nd observ. 3 rd 4 th 5 th 6 th 7 th 8 th investigation intervention 153

Chapter 71 Additionally, all dairy cows were inspected daily for the presence of clinical DDlesions (permanent lifting of a leg, careful walking, resting on the tip of the claw, typical smell). The detected M2-lesions were topically treated immediately with chlortetracycline spray (CTC-spray, Eurovet, The Netherlands) for animal welfare reasons. When other claw horn diseases were diagnosed, they were treated as well. In addition, all M2-lesions that were detected during the 3 weekly examination period were topically treated, whether they caused clinical lameness or not. All diagnoses were made by 1 professional hoof-health manager and recorded by a student on an individual leg level. An outbreak within the group was defined as > 3 hind legs with M2-lesions in a 3-weekly examination. To differentiate original DD-lesions from incomplete cure, the location of the lesion at each moment were very precisely marked in a note book. During observation 1 and 2, the observers were intensively trained to use the score system, whereby the data from observation 1 were excluded from the investigation. Observation data 2-5 were used for pre-investigation, while no systematic intervention was applied. The recordings of DD were performed with a diagnostic system based on visual inspection, as developed by Döpfer et al. (1997). In our study the location, clinical aspect, size and pain reaction was registered: = normal skin, no signs of DD; = small superficial dermatitis spot, Ø: 0.5-2 cm, not painful at palpation; M2= erosive dermatitis, Ø: 2-4 cm, painful at palpation; = recovering stage of M2, with a scab, not painful at palpation; = recovered M2-lesion, not painful at palpation. If different stages of DD were present, the classification category selected was that of the most prominent M-lesion. Because of the clinical aspect, the most prominent stage, the M2-stage, is chosen as the most important outcome variable (Mumba et al., 1999). The different groups and the applied interventions The dairy cows were allotted to five groups (1 reference group and 4 experimental groups) based on the results of the pre-intervention study. Deviation from random selection was based on the presence of M2 lesions, parity and stage of lactation and considering the fact that some cows were not accustomed to robot-milking. 154

Claw Health in Dairy Cows in the Netherlands The 5 groups were separately housed and milked during the intervention study in such a way that there was no physical or manure contact between groups. Removing and returning animals to the experimental group was arranged according to a protocol. Dairy cows that due to illness or a dry-cow period were temporarily separated from one of the groups, were randomly replaced to one of the 5 groups. This replacement was always done after a standard examination (careful inspection of all 4 hoofs of the cow) and a standard treatment (2 times spraying for 3 seconds and 2 minutes rest between each treatment) with CTCspray and regardless of the presence or absence of lesions. This protocol was meant to prevent reintroduction of new infections by cow movements. For the introduction of heifers the same protocol was used. Additionally, the hoofs of dairy cows that were introduced into group 3 were cleaned with a water cleaning apparatus (for reasons presented later). Reference treatment group (group5): This reference treatment group comprised 64 dairy cows, which were milked in an automatic milking system (visit frequency: ± 2.8 times per day). The group was forced through a walkthrough footbath with a 4% formalin-solution out of a 37% formaldehyde solution (the current Dutch standard advice) weekly, for 1 day, twice a day. Directly afterwards, the cows were locked at the feeder gate at a clean floor, for at least 30 minutes. The walkthrough footbath was not cleaned and/or refreshed between the two passages on the same day. Half the reference treatment group (group1): This group comprised 15 dairy cows, which were milked twice a day in a traditional milking parlour with a herringbone design. This group was treated like the reference herd, but the frequency was halved, so the animals were forced through a walkthrough footbath with a 4% formalin-solution out of a 37% formaldehyde solution, every other week, for 1 day, twice a day. Additional hygiene group with a multi-compound standing bath (group2): This group comprised 15 dairy cows, which were also milked twice daily through the herringbone parlour. The slatted floors and the hind hoofs (incl. the interdigital space) of the dairy cows in this group were indirectly (through the 155

Chapter 17 floor) intensively cleaned with a medium pressure water cleaner. This cleaning was performed according to a composed scheme on day 7, 30 and 90. After the cleaning the cows were treated in a walk-in footbath in which cows stood for 20 minutes at a stretch, with a 2% multi-compound (Feetcare, ICI) for 20 minutes to achieve intensive disinfection (according to the recommendations of the manufacturer). Multi-compound group (group 3): The group comprised 15 dairy cows, which were also milked twice daily through the herringbone parlour. The group was forced through a walkthrough footbath with a 2% multi-compound solution (Feetcare, ICI) weekly, for 1 day, twice a day. Soda lime group (group 4): The group comprised 14 dairy cows, which were also milked twice daily through the herringbone parlour. The group was forced through a walkthrough footbath with a 3% soda lime solution weekly, for 1 day, twice a day. Dimensions and capacities of the footbaths The dimensions of the footbath of the groups 1, 3, 4 and 5 were 300 cm long by 80 cm wide and 15 cm high, which result in a capacity of 277 litres. The dimension of the footbath of the groups 2 was based on 400 cm long by 300 cm wide and 15 cm high, which result in a capacity of 1800 litres. Cleaning and disinfection of the chute and hands of the claw trimmer The chute was cleaned with high pressure water and/or a steam cleaner between the inspections of the different groups. In addition, the equipment and the hands and boots of the claw trimmer/investigators were cleaned systematically. After examination and treatment of a dairy cow with a M2-lesion during routine inspection, only the straw and manure were removed before entering a cow of the same group in the chute for routine inspection. 156

Claw Health in Dairy Cows in the Netherlands Typing of DD-infections of cows The types of DD infection of cows ( DD-type ) was based on the repeated presence of M2-lesions in the same cow. Based on the transmission of the different M-stages ( M2,, etc) within a cow in a group (population dynamics), the cows were categorized as a Type I, II or III-cow, according to the following scheme (Döpfer et al., 2004): a Type I cow remains negative during the whole period of intervention, usually 1 of the dairy cows; a Type II cow experiences a normal DD-infection, namely: M2, usually 30 6 of the dairy cows; a Type III cow is a problem cow, that persists in the infectious stage: M2 () /M2, within a time period of 2-3 weeks, usually 30 6 of the dairy cows. DD-type was used as the dependent variable in the regression models. Statistical analyses The data were checked for missing values and typing errors. The descriptive statistics were done at leg level and the multivariate regression models on cow level. The rank-sum test was used to determine whether differences between the intervention groups were significant at p 0.05. The presence of the different DD-types of cows was analyzed with a logistic regression model, with an autoregressive correlation structure to correct for repeated measures on a cow (SAS 9.1; SAS Institute Inc., 2003). The 5 intervention periods, type of intervention, stage of lactation and parity were included as explanatory variables. The observation periods were divided into the following intervals: the pre-intervention period (period 3-5); the early intervention period (period 6-8); the middle intervention period (period 9-11); the late intervention period (period 12-13). The hypothesis was that the more effective the intervention, the smaller the number of type II and/or III cows in the specific intervention group. Results Descriptive results The total number of observations (during both the pre-intervention and the intervention period) was 2,718. During the intervention period in the groups 1-5 157

proportion of M-stages Chapter 17 these numbers were 242, 232, 246, 236 and 994, respectively. The mean sizes of the groups during the intervention were 15.1, 14.5, 14.8 and 62.1 dairy cows, respectively. The mean numbers of cows, parity and stage of lactation for the different groups are shown in Table 1. Table 1. Composition of the different groups in relation to lactation number and DIM at the start of the study. No of cows at the start of the intervention No of lactations mean SD DIM Mean SD Group 1 14 1.4 0.9 149 123 Group 2 16 1.8 1.5 220 128 Group 3 14 1.7 1.4 166 112 Group 4 15 1.5 1.6 172 126 Group 5 62 2.2 1.2 162 113 The groups slightly differed for parity and stage of lactation, but were not statistically significant (Rank-Sum test). The proportions of the different M- stages in the intervention periods are presented in Figure 2 and the cumulative proportion across the whole study-period in the different groups is shown in Figure 3. proportion of M-stages 8 6 4 2 M2 6 7 8 9 10 11 12 13 Figure 2. Proportion of M-lesions for the whole dairy herd for each of observation (= every 3 weeks; period 6 = 1-21 January 2005 and period 13 = 7-30 June 2005). 158

proportion of M-stages proportion of M-stages Claw Health in Dairy Cows in the Netherlands proportion of M-stages 8 6 4 2 M2 1 2 3 4 5 group Figure 3. Cummulative proportion M-lesions for each group across the whole study period (8 observations). The cumulative proportion across the whole study period in the different groups is shown in Figure 4 a-e. Figure 4a-e. Development of different M-stages in time in the different groups during the intervention period scored 1x per 3 weeks (period 6=1-21 January 2005 and period 13=7-30 June 2005). Figure 4-e. proportion of M-stages proportion of M-stages 8 8 6 6 4 4 2 2 M2 M2 6 7 8 9 10 11 12 13 6 7 8 9 10 11 12 13 Figure 4a. Reference treatment group, intervention formalin 4% walkthrough footbath every week during 1 day. 159

proportion of M-stages proportion of M-stages proportion of M-stages 385 386 387 388 389 390 391 392 393 394 385 395 386 396 387 397 388 398 389 399 390 400 391 401 392 402 393 403 394 404 395 405 396 406 397 407 398 408 399 409 400 410 401 411 402 412 403 413 404 414 405 415 406 416 407 417 408 418 409 410 proportion of M-s Chapter 4 71 2 proportion proportion of M-stages of M-stages 6 M2 4 385 M2 4 2 386 8 2 387 6 M2 388 6 7 8 9 10 11 12 13 4 389 6 7 8 9 10 11 12 13 2 390 8 Figure 4b. 391 Group 1, half the reference 6 7 group. 8 9 10 11 12 13 392 Figure 6 4b. 393 Group 1, half the reference group. M2 4 394 Figure 4b. Group 1, half the reference group. 8 8 395 6 2 8 396 6 M2 8 4 397 M2 6 4 398 6 2 6 7 8 9 10 11 12 13 M2 M2 4 399 4 2 400 2 2 6 7 8 9 10 11 12 13 401 6 7 8 9 10 11 12 13 402 6 7 8 9 10 11 12 13 6 7 8 9 10 11 12 13 403 Figure 4c. 404 Group 2, intervention additional hygiene measures and walking-in Figure bath 2% 4b. 405 multi-compound. Group Figure 1, half 4c. the Group reference 2, intervention group. additional hygiene measures and walking-in 406 bath 2% multi-compound. Figure 4c. 407 Group 2, intervention additional hygiene measures and walking-in bath 2% multi-compound. 408 8 8 8 409 6 6 6 410 M2 M2 M2 4 4 M2 4 411 8 4 2 4122 2 2 6 413 M2 6 7 8 9 10 11 12 13 4144 6 7 8 9 10 11 12 13 4152 6 7 8 9 10 11 12 13 416 Figure 4d. Group 3, intervention multi-compound 2% walkthrough footbath Figure 4d. 417 Group every 3, intervention 6week during 7 1 multi-compound 8day; during 9 period 10 2% 1211 in walkthrough the 12 graphic 13 an footbath outbreak was 418 estimated. every week during 1 day; during period 12 in the graphic an outbreak was Figure 4c. Group 2, intervention additional hygiene measures and walking-in estimated. bath Figure 2% 4d. multi-compound. Group 3, intervention multi-compound 2% walkthrough footbath protportion protportion proportion protportion of M-stages of M-stages of M-stages protportion of M-stages proportion proportion of M-stages of M-stages 8 8 6 7 8 9 10 11 12 13 6 every week during 1 day; during period 12 in the graphic an outbreak was estimated. 160 8 6 M2 of M-stages proportion of M-stages Figure 4b. Group 1, half the reference group. protportion of M-stages protportion of M-stages Figure 4c. Group 2, intervention additional hygiene measures and walking-in bath 2% multi-compound. proportion of M-stages proportion of M-stages Figure 4d. Group 3, intervention multi-compound 2% walkthrough footbath every week during 1 day; during period 12 in the graphic an outbreak was estimated. 6 M2 14

proportion of M-stages Claw Health in Dairy Cows in the Netherlands proportion of M-stages 8 8 6 6 4 4 2 2 M2 M2 6 7 8 9 10 11 12 13 Figure 4e. Group 4, intervention soda lime 3% walkthrough footbath every week during 1 day; during period 9-13 in the graphic an outbreak was estimated. The proportion of M2-lesions for each observation was about 1. Figure 2 shows a temporarily decrease of the proportion M2-lesions in the beginning of the intervention (period 6 9), followed by an increase at the end of the intervention period (> period 10). During the pre-intervention, the reference treatment group (group 5) already had a lower number of M2-lesions compared to the groups 1-4 and this number of M2-lesions initially substantially decreased during the first period of intervention (up to <1% at period 9), followed by a slight increase. The proportion of M2-lesions seemed to increase in all other groups, especially in the groups 3 and 4. This resulted in an outbreak in group 3 and 4 during end May (period 12) and from mid April until June (period 9-13), respectively. Logistic regression on DD-type The Tables 2a-c contain the results of the logistic regression of the DD-type of the cows for the different groups relative to the reference treatment group (group 5) and corrected for parity, stage of lactation and observation period. 161

Chapter 17 Table 2a. The results of the logistic regression for DD Type I-cows. Variables Categories S.E. Sig. OR Intercept 2.68 1.01 0.01 14.60 Group 5 Ref. - - - 1-1.72 0.98 0.08 0.18 2-0.16 0.77 0.84 0.85 3-3.50 1.66 0.04 0.03 4-1.08 0.94 0.25 0.34 Interval of Pre-intervention Ref. - - - observation 6-8 0.32 0.26 0.21 1.37 9-11 0.35 0.26 0.19 1.42 12-13 0.36 0.27 0.18 1.44 Parity 3 Ref. - - - 1-2.10 0.89 0.02 0.12 2-1.93 0.91 0.03 0.15 Stage of lactation >180 dgn. Ref. - - - 0 60-0.39 0.25 0.12 0.68 61-120 -0.07 0.19 0.72 0.94 120-180 0.05 0.12 0.67 1.05 162

Claw Health in Dairy Cows in the Netherlands Table 2b. The results of the logistic regression for DD Type II-cows. Variables Categories S.E. Sig. OR Intercept -2.07 0.75 0.01 0.13 Group: 5 Ref. - - - 1 1.30 1.05 0.22 3.66 2 0.46 0.80 0.57 1.58 3 2.33 0.97 0.02 10.31 4 1.38 0.89 0.12 3.96 Interval of Pre-intervention Ref. - - - Observation 6-8 -0.70 0.30 0.02 0.50 9-11 -0.78 0.32 0.01 0.46 12-13 -0.87 0.34 0.01 0.42 Parity 3 Ref. - - - 1-0.10 0.76 0.90 0.91 2 0.63 0.85 0.46 1.88 Stage of lactation >180 days Ref. - - - 0 60-0.12 0.37 0.74 0.88 61-120 -0.27 0.33 0.41 0.76 120-180 -0.03 0.18 0.88 0.97 163

Chapter 71 Table 2c. The results of the logistic regression for DD Type III-cows. Variables Categories S.E. S.E. Sig. Sig. OR OR Intercept -3.48-3.48 0.74 0.74 <.01 <.01 0.03 0.03 Group Group 5 5 Ref. Ref. - - - - - - 1 1 1.16 1.16 0.55 0.550.030.03 3.18 3.18 2 2 0.88 0.88 0.87 0.87 0.31 0.31 2.41 2.41 3 3 1.80 0.55 <.01 6.06 1.80 0.55 <.01 6.06 4 4 1.51 1.07 0.16 4.51 1.51 1.07 0.16 4.51 Interval of Interval of observation observation Pre-intervention Pre-intervention Ref. Ref. - - - - - - 6-8 6-8 0.15 0.31 0.62 1.17 0.15 0.31 0.62 1.17 9-11 0.20 0.31 0.53 1.22 9-11 0.20 0.31 0.53 1.22 12-13 0.22 0.31 0.48 1.25 12-13 0.22 0.31 0.48 1.25 Parity 3 Ref. - - - Parity 3 Ref. - - - 1 1.32 0.70 0.06 3.74 1 2 1.32 0.70 0.06 3.74 0.99 0.54 0.07 2.70 Stage of lactation 2 >180 days 0.99 Ref. 0.54-0.07-2.70 - Stage of lactation >180 days 0-60 Ref. 0.29 0.29-0.31-1.34-0-60 61-120 0.29 0.29 0.31 1.34 0.02 0.27 0.95 1.02 120-180 61-120 -0.23 0.02 0.20 0.27 0.24 0.95 0.80 1.02 120-180 -0.23 0.20 0.24 0.80 According to Table 2a, there were significantly less Type-I cows present in group 3 relative to the reference treatment (group 5; P=0.04) and there was a trend of less Type-I cows in group 1 relative to the reference treatment group (P=0.08). Across groups, there were also less Type-I cows in first and second parity compared with parity three and up. Table 2b shows that in group 3 there were significantly more Type-II cows than in the reference treatment group (P=0.02). There were less Type-II cows in the intervention periods than in the pre-intervention period. Table 2c shows that there were significantly more Type- III cows present in the groups 1 and 3 relative to the reference treatment group (p< 0.05). There was a strong correlation between repeated observations on a cow. 164

Claw Health in Dairy Cows in the Netherlands Discussion Because the use of formalin can have negative effects on the health of farmers (e.g. Collins and Lineker, 2004; Heck and Casanova, 2004), copper and zinc sulphate are nowadays frequently applied as a single component or in combinations with formalin. In a study, all dairy farmers stated that the remainders of the footbaths were wasted in the manure pit and thus, eventually would be spread out on pasture (Report WUR-CLM, 2003). The reference-treatment group in this study, which underwent the standard recommended herd treatment in The Netherlands, was included for two reasons. Firstly, because not treating cows with DD may cause discomfort and pain and may significantly increase the spread of DD within the group, which would result in a non-ethical situation. Secondly, the objective was to test the reference procedure of formalin footbaths against alternative strategies that may replace the formalin footbaths applied as a control measure for DD. The study was performed on an experimental farm, of which the staff members were very skilled in the precise execution of different experiments. On this farm, 5 completely separated groups were managed without animal and manure contacts, while the normal activities (dry-period, calving, milking etc.) were continued. To minimise the influence of adding recently calved cows into one of the experimental groups, the cows were (according to the protocol) assigned randomly to the groups and were added after preventive treatment of all legs with chlortetracycline spray. With this protocol we have tried to minimise the potential influence of switching between groups, but the additional treatments may have decreased the total number of M2-lesions during the study. The choice of the applied intervention strategies was based on governmental restrictions (e.g. antibiotics and products with heavy metals were forbidden), positive results in other studies with formalin (Blowey, 2000; Laven and Hunt, 2002), with multi-compounds (e.g. Shearer and Hernandez, 2000), with increased hygienic measurements in another experimental herd (J. Rietjens, personal communication) and with a soda lime walkthrough footbath (different farmers, personal experience). The groups slightly differed for parity and DIM, but the multivariable models corrected for these factors, so they did not influence the results of the analyses. 165

Chapter 17 Unfortunately, the correlation between repeated observations on a cow was high, which resulted in few significant results. The result of less Type-I cows (negative during the whole period of investigation) in first and second parity compared with higher parities is in line with the findings of other studies that also estimated young cows having higher odds for DD (e.g. Frankena et al., 1991; Smits et al., 1992; Read and Walker, 1998b; Rodriguez-Lainz et al., 1999; Somers et al., 2005; Holzhauer et al., 2006). The group with a 2% multicompound walkthrough strategy (group 3) always performed significantly worse than the reference treatment group (group 5). This was reflected in more type II and type III cows, but not in outbreaks. The none significant results may also be caused by the relative small sizes of the different experimental groups and the relative few numbers of M2-lesions (1). The treatment groups 1, 2 and 4 showed a trend of more DD problems than the reference treatment group (group 5). Thus, a weekly footbath with formalin seemed to be the most effective treatment. The strategy of weekly or bi-weekly application of formalin in a walkthrough footbath showed an initial decrease in the incidence of M2 lesions. In the reference treatment group significantly more Type I cows were found, compared to the group 3 and less so, group 1. In both the reference and half the reference treatment group and the group of additional hygienic measurements, the DD-prevalence increased, but without serious outbreaks during the last period of observation (at the end of the stable-period). This increase was similar to the results found in other intervention studies (van Amstel et al., 1995; Read and Walker, 1998a; Shearer and Elliot, 1998; Berry et al., 1999b; Zemljic, 2000) and support the opinion that a multifactorial approach of both systematically intervention combined with increased hygienic measurements may be necessary to obtain a successful reduction of the incidence of M2-lesions. The multi-compound-groups (2 and 3) were tested in a 2% concentration to minimise the farmer s costs and the environmental pollution and were in agreement with the prescription for the use of the product (2-5% concentration). In view of the positive results in other studies with multicompounds (e.g. Shearer and Hernandez, 2000; Blowey, 2004) it may be advisable to repeat the study with a longer period of foot bathing (more 166

Claw Health in Dairy Cows in the Netherlands consecutive days), to increase the frequency of foot bathing and/or to increase the applied concentration of the product. The calculated positive influence of formalin footbath applications may be explained by a combination of a direct positive effect on DD-lesions but presumably also by an indirect positive effect through a reduction of the incidence and seriousness of heel horn erosion (HHE). As estimated in the preinvestigation study and described by Holzhauer et al. (2006) and in other papers, cows with serious HHE were at higher risk for DD (Koniarova et al., 1993; Blowey et al., 1994; Walker et al., 1995; Somers et al., 2005). The observed outbreaks in groups 3 and 4 are in line with the findings of Zemljic (2004), where a sub-optimal hoof disinfection management also contributed to the spread of a DD-infection within the herd. This spread may be stimulated by increased moistness of the housing circumstances. So, intervention strategies should be combined with other measurements like optimal housing circumstances, regular claw trimming of all dairy cows, closed herd strategy in relation to trade and prevention of peri-parturient immune suppression (Berry, 1998; Laven, 1999; Somers et al., 2005; Holzhauer et al., 2006). The results of our study were obtained from one experimental farm and thus need to be confirmed in other dairy herds. A follow-up study should result in an unequivocal, practically applicable, well founded and affordable advice for the treatment and prevention of DD. The optimal advice should aim at a decrease of pain for the dairy cows, diminished economic losses, no health risks for the dairy farmers and less environmental pollution. Acknowledgements This study was financed by the Dairy Commodity Board (Rijswijk, The Netherlands) and was very accurately performed by the staff of the experimental farm Nij Bosma Zathe (Leeuwarden, The Netherlands). The products for the footbaths were kindly made available by Eurovet, Bladel, The Netherlands. We are also grateful to Gerben Huizinga (Van Hall Institute at Leeuwarden) for the accurate collection and registration of the data. 167

Chapter 17 References Amstel, S.R. van, Vuuren, S. van and Tutt, C.L.C. 1995. Digital Dermatitis: report of an outbreak. Journal of South African Veterinary Association 66: 177-181. Berry, S.L., Graham, T.W., Mongoni, A. and Arana, M. 1999a. The efficacy of Serpens spp bacterin combined with topical administration of lincomycin hydrochloride for treatment of papillomatous digital dermatitis (footwarts) in a dairy cows in California. The Bovine Practitioner 33: 6-11. Berry, S.L., Read, D.H. and Walker, R.L. 1999b. Recurrence of PDD in dairy cows after treatment with lincomycin HCl or oxytetracycline HCl. Journal of Dairy Science 82, Supplement 1, 34. Berry, S.L., Reed, B.A., Maas, J. and Schechter, A. 1996. The efficacy of 5 topical spray treatments for control of papillomatous digital dermatitis in dairy herds. Proc. 29 th Annual Conference American Association of Bovine Practitioners. San Diego, CA. USA. p.: 188. Blowey, R.W. and Sharp, M.W. 1988. Digital dermatitis in dairy cattle. Veterinary Record 122: 505-508. Blowey, R.W., Done, S.H. and Cooley, W. 1994. Observations on the pathogenesis digital dermatitis in cattle. Veterinary Record 135: 115-117. Blowey, R.W. 2000. Control of digital dermatitis. Veterinary Record 146: 295. Blowey, R.W. and Williams, M. 2004. Use of a novel foot foam in the control of digital dermatitis. Proc. of the 13 Th International Symposium and 5 th Conference on Lameness in Ruminants. Maribor, Slovenia. pp.: 30-32. Brand, A., Noordhuizen, J.P.T.M. and Schukken, Y.H. 1996. Herd health and production management in dairy practice. Wageningen Pers, Chapter 7 part 1. Britt, J.B. and McClure, J. 1988. Field trials with antibiotic and non-antibiotic treatments for PPD. The Bovine Practitioner 32.2: 25-28. Brizzi, A. 1993. Bovine digital dermatitis. The Bovine Practitioner 27: 33-37. Cheli, R. and Mortellaro, C. 1974. La dermatite digitale del bovine. Proc. of the 8th International Conference on Diseases of Cattle. Milan Italy, pp.: 208-213. Clarkson, M.J., Downham, D.Y., Faull, W.B., Hughes, J.W., Manson, F.J., Merritt, J.B., Murray, R.D., Russell, W.B., Sutherst, J.E. and Ward, W.R. 1996. Incidence and prevalence of lameness in dairy cattle. Veterinary Record 138: 563-567. Collins, J.J. and Lineker, G.A. 2004. A review and meta-analysis of formaldehyde exposure and leukemia. Regulatory Toxicology and Pharmacology 40: 81-91. 168

Claw Health in Dairy Cows in the Netherlands Döpfer, D., Koopmans, A., Meijer F.A., Szakall, I., Schukken, Y.H., Klee, W., Bosma, R.B., Cornelisse, J.L., Aasten, A.J.A.M. van and Huurne A.A.H.M. ter. 1997. Histological and bacteriological evaluation of digital dermatitis in cattle, with special referrence to spirochaetes and Campylobacter faecalis. Veterinary Record 140: 620-623. Döpfer, D., Boven, R.M. van and Jong, M.C.M. de. 2004. A mathematical model for the dynamics of digital dermatitis in dairy cattle. 13 th ICPD July 19 th to 22 nd 2004, Lansing/ MI/USA. Proceedings, p.: 36. Enting, H., Kooij, D., Dijkhuizen, A.A., Huirne, R.B.M. and Noordhuizen-Stassen, E.N. 1997. Economic losses due to clinical lameness in dairy cattle. Livestock Production Science 49: 259-267. Green, L.E., Hedges, V.J., Schukken, Y.H., Blowey, R.W. and Packington, A.J. 2002. The impact of clinical lameness on the milk yield of dairy cows. Journal of Dairy Science 85: 2250-2256. Grongnet, J.F., Roignant, M. and Serieys, F. 1981. Le Choix des antiseptiques pour les pédiluves destinés aux bovins. Annales de Recherches Veterinaires 12: 129-132. Heck, H. d A and Casanova, M. 2004. The implausibility of leukaemia induction by formaldehyde: a critical review of the biological evidence on distant-site toxicity. Regulatory Tocicology and Pharmacology 40: 92-106. Hernandez, J., Shearer, J.K. and Elliott, J.B. 1999. Comparison of topical application of oxytetracyclin and four non-antibiotic solutions for treatment of papillomatous digital dermatitis in dairy cows. Journal of American Veterinary Medical Association 214: 688-690. Hoblet, K. 2002. Footbaths: Seperating truth from fiction and clinical impressions. Proc. of the 12 th Int. Symp. Disorders Ruminant lameness. Orlando, USA. 2002, pp.: 35-37. Holzhauer, M., Hardenberg, C., Bartels, C.J.M. and Frankena, K. 2006. Herdand Cow Level Prevalence of Digital Dermatitis in The Netherlands and Associated Risk Factors. Journal of Dairy Science, 89: 580-588. Kimura, Y., Takahasi, M., Matsumoto, N., Tsukida, H., Satoh, M., Ohkawara, K., Kanoe, M., Gotoh, N., Kubo, M., Aoki, O. and Hayata, M. 1993. Verrucose dermatitis and digital papillomatosis in dairy cows. Journal of Veterinary Medicine Japan. Index Vet 1994; 62: 1084. Koniarova, I., Orsag, A. and Ledecky, V. 1993. Role of anaerobes in the occurrence of digital and interdigital dermatitis in cattle. Veterinarni Medicina (Praha) 38: 589-596. Kossaibati, M.A. and Esslemont, R.J. 1997. The costs of production diseases in dairy herds in England. Veterinary Journal, 154: 41-51. 169

Chapter 71 Laven, R.A. 1999. The environment and digital dermatitis. Cattle practice. 7: 349-356. Laven, R.A. and Hunt, H. 2002. Evaluation of copper sulphate, formalin and paracetic acid in footbaths for the treatment of digital dermatitis in cattle. Veterinary Record 151: 144-146. Logue, D.N. 1996. Productivity, Management and disease in dairy cattle. Proc. XIX World Buiatric Congress, Edinburgh, pp.: 83-88. McLennan, M.W. and McKenzie, R.A. 1996. Digital dermatitis in a Friesian cow. Australian Veterinary Journal 74: 314-315. Mumba, T., Döpfer, D., Kruitwagen, C., Dreher, M., Gaastra, W. and Zeist, B.A. van der. 1999. Detection of spirochetes by polymerase chain reaction and its relation to the course of digital dermatitis after local antibiotic treatment in dairy cattle. Zentralbl. Vet. Med. B. 46: 117-126. Murray, R.D., Downham, D.Y., Demirkan, I. and Carter, S.D. 2002. Some relationships between spirochaete infections and digital dermatitis in four UK dairy herds. Research in Veterinary Science 73: 223-229. Nowrouzian, I. and Zareii, S. 1998. Comparison of two applications forms of Lincomycin-Hcl for group treatment of digital dermatitis in dairy cows. Proc. 10 th International Symposium on Lameness in Ruminants, Luzern, Schwitzerland, pp.: 287-289. Read, D.H. and Walker, R.L. 1998a. Comparison of papillomatous digital dermatitis and digital dermatitis of cattle by histopathology and immunohistochemistry. Proc. 10 th International Symposium on Lameness in Ruminants, Lucerne, Schwitzerland, pp.: 268-269. Read, D.H. and Walker, R.L. 1998b. Etiology of papillomatous Digital Dermatitis (Footwarts) in Dairy Cattle. http://www.moomilk.com/archive/u-health-18.htm. Accessed April. 6, 2005. Rodriguez-Lainz, A., Hird, D.W., Walker, R.L. and Read, D.H. 1996. Papillomatous Digital Dermatitis in 458 Dairies. Journal of American Veterinary Medical Association 209: 1464-1467. Rodriguez-Lainz, A., Melendez-Retamal, P., Hird, D.W., Read, D.H. and Walker, R.L. 1999. Farm- and host-level risk factors for digital dermatitis in Chilean dairy cattle. Preventive Veterinary Medicine 42: 87-97. SAS User s Guide: Statistics, Version 9.1, 2003. SAS Inst., INC., Cary, NC. Shearer, J.K., Elliot, R. and Giesy R.G. 1995. Effect of oxytetracycline topical spray treatment on prevalence on digital dermatitis (abstract). Journal of Dairy Science 78, Supplement 1, 257. 170

Claw Health in Dairy Cows in the Netherlands Shearer, J.K. and Elliot, J.B. 1998. Papillomatous Digital Dermatitis: Treatment and Control Strategies-Part I. Compendium on Continuing Education for Practicing Veterinarian 20, August, S158-S173. Shearer, J.K. and Hernandez, J. 2000. Efficacy of Two Modified Nonantibiotic Formulations (Victory) for Treatment of Papillomatous Digital Dermatitis in Dairy Cows. Journal of Dairy Science 83: 741-745. Smits, M.C.J., Frankena, K., Metz, J.H.M. and Noordhuizen, J.P.T.M. 1992. Prevalence of digital disorders in zero-grazing dairy cows. Livestock Production Science 32: 231-244. Sogstad, A.M., Fjeldaas, T., Østerås, O. and Forshell, K.P. 2005. Prevalence of claw lesions in Norwegian cattle housed in tie stalls and free stalls. Preventive Veterinary Medicine 70: 191-209. Somers, J.G.J.C., Frankena, K., Noordhuizen-Stassen, E.N. and Metz, J.H.M. 2003. Prevalence of claw disorders in Dutch dairy cows exposed to several floor systems. Journal of Dairy Science 86: 2082-2093. Somers, J.G.J.C., Frankena, K., Noordhuizen-Stassen, E.N. and Metz J.H.M. 2005. Risk factors for digital dermatitis in dairy cows kept in cubicle houses in The Netherlands. Preventive Veterinary Medicine 71: 11-21. Vermunt, J.J. and Hill, F.I. 2004. Papillomatous digital dermatitis in a Holstein- Friesian bull. New Zealand Veterinary Journal 52: 99-101. Webster, J.F. 1995. Animal Welfare: a Cool Eye towards Eden: a Constructive Approach to the Man s Domination over Animals. Blackwell Science, Oxford, U.K. Wells, S.J., Garber, L.P. and Wagner, B.A. 1999. Papillomatous digital dermatitis and associated risk factors in US dairy herds. Preventive Veterinary Medicine 38: 11-24. Zemljic, B. 2000. Pathohystological features and possible infective reasons for papillomatous digital dermatitis on dairy farms in Slovenia. Proc. 11 Th International Symposium on Disorders of the Ruminant Digit. Parma, Italy. pp.: 186-189. Zemljic, B. 2004. Influence of footbathing on prevalence of digital dermatitis after introduction of diseased animal into healthy dairy herd. Proc. of the 13 Th International Symposium and the 5 th Conference on Lameness in Ruminants. Maribor, Slovenia. pp.: 145-147. 171