Elsevier

The Veterinary Journal

Volume 193, Issue 3, September 2012, Pages 622-625
The Veterinary Journal

Interval between detection of lameness by locomotion scoring and treatment for lameness: A survival analysis

https://doi.org/10.1016/j.tvjl.2012.06.042Get rights and content

Abstract

Estimates of point prevalence suggest that locomotion scoring identifies three times as many lame cows than when estimated by farmers. The aim of this study was to ascertain the impact of this under-recognition on the interval between identification of lameness (using locomotion score) and treatment. The study was undertaken on a 463-cow, spring-calving, pasture-fed herd in the lower North Island of New Zealand. All cows were locomotion scored (using a 1–5 scale) weekly during one milking season (July 2008 to May 2009). Survival analyses were then used to quantify the number of days between identification of a specific locomotion score and presentation, by farm staff, of a cow for lameness treatment.

All cows which had a locomotion score of >3 were presented for lameness treatment subsequently, although >40% were treated more than 3 weeks after being identified. Only 75% of events where cows had a locomotion score of 3 were followed by treatment with >65% of those treatments occurring >3 weeks after the first score of 3. Improving the recognition of lameness by farm staff is thus likely to appreciably reduce the interval between reduced mobility and lameness treatment.

Introduction

Surveys based on locomotion scoring have shown, that, on average, the prevalence of clinical lameness is around three times higher than farmer estimates in both housed cows (Whay et al., 2003, Espejo et al., 2006) and cows at pasture (R.A. Laven unpublished observations). However, these figures are all comparisons of point prevalence as they are based on measurements obtained at a single visit, so the long-term impact of this under-recognition of lame cows is unclear. In particular, how this under-recognition of lameness is related to the interval between an increase in locomotion score and treatment for lameness is unknown. This is likely to be important for welfare and perhaps also for productivity as lameness will have a greater impact if, for example, cows have to be observably lame for 6 weeks before they are treated than if the average time to treatment is only 1 week.

To identify how the under-recognition of lame cows delays lameness treatment requires serial locomotion scoring, which can be difficult to achieve on a large scale. For example, Archer et al. (2010), recorded locomotion scores monthly on seven farms, which entailed over 11,000 scores, almost 3000 more than the number of scores used by Main et al. (2010) to analyse lameness prevalence on 67 farms. To estimate the interval between an increase in locomotion score and lameness treatment requires at least weekly locomotion scoring but such frequent scoring of a large number of cows has not previously been reported. The present study was designed to fill this gap and to use weekly locomotion scoring to evaluate the time interval between the observation of an increased locomotion score and the presentation for treatment for lameness of dairy cattle in a spring-calving pasture-based dairy farm in New Zealand.

Section snippets

Data collection

This was a cohort study of n = 452 mixed aged dairy cows that calved between July and October 2008 in a dairy herd in the lower North Island of New Zealand. All cows were individually locomotion scored, once weekly, by one trained technician using the 5-point scale described by Sprecher et al. (1997). All cows were locomotion scored as they left the milking parlour after afternoon milking, and were visually identified by ear tag.

Farm staff were not given access to the locomotion scoring records.

Results

LCSs were recorded on 29 occasions between 30 July 2008 and 30 April 2009. The average interval between scoring was 9 days. No scoring was undertaken in the 3 weeks during the study period, i.e. the weeks beginning 13 October 2008, 8 December 2008 and 29 December 2008. Details of the number of lameness events and the incidence of lameness are provided in Table 1.

The mean LCS for the herd was 1.3 (SD = 0.7). On average, 3.1% (525 of 16,831) of the weekly LCS indicated clinical lameness (i.e. ⩾3)

Discussion

Unlike lameness hazard, which peaked at peak lactation (the end of October, Alawneh et al., 2011), LCS estimates tended to increase throughout the lactation, suggesting that overall herd locomotion score does not provide a good reflection of lameness incidence. This is because herd LCS was driven by the ratio between non-lame cows (LCS 1) and cows with only mild changes in gait (LCS 2), not the number of cows that were clinically lame (LCS ⩾3). Combining the mean prevalence of lameness from

Conclusions

Farm surveys have shown that, on average, farmers are aware of <35% of the lame cows on farm (as identified by locomotion scoring). This study showed that the major effect of this under-recognition of lameness is not that lame cows are not treated but that treatment is delayed. Seventy-five per cent of cows with LCS of 3 and all cows with LCS >3 were presented for treatment; >65% of cows with LCS of 3 were treated more than 3 weeks after first identified as LCS 3 and >40% of cows with LCS >3

Conflict of interest statement

None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper.

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Present address: School of Veterinary Science, University of Queensland, Gatton, 4343 Queensland, Australia.

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