The Prevalence of Lameness on New Zealand Dairy Farms : A Comparison of Farmer Perception and Mobility Scoring11 June 2013
This study, by Jessica Fabian, Institute of Veterinary, Animal and Biomedical Sciences, Massey University compared prevalence of lameness with farmer perceptions in cows kept in New Zealand pasture conditions.
Several studies have previously looked at the issue of farmer perceived lameness and that of lameness tested through locomotion or mobility scoring. However, these studies looked at housed animals, not cows at pasture.
In total, 60 herds were used in the data, 27 in the South Island and 33 in the North Island. All farms were visited on one occasion at the expected peak time for lameness, i.e. October/November for North Island farms and January / February for South Island farms.
In the North Island, average herd size was 294 and average production was 357 kgMS/cow/year, while in the South Island the figures were 580 and 406 kgMS/cow/year, respectively. Of the 60 farms, lame cows were treated by farm staff only on 38 farms, by a combination of veterinarian and farm staff on 21 farms, and on one farm by veterinarians only.
On average, farmers estimated that 2.2 per cent of their herd was lame (range 0 to 20 per cent ), while mobility scoring identified that, on average, 8.1 per cent of the herd was lame (mobility score =2) (range 1.2 to 36 per cent ). This means that on a herd basis, only 27.3 per cent (range 0 to 95 per cent ) of the cows with reduced mobility had been identified as lame by farm staff.
There was no significant effect on herd size on this percentage (P=0.8), nor was there a significant differences between the two islands (South Island 28 per cent ± SEM 4.2; North Island 23 per cent ± 2.6).
The prevalence of lameness in this study was much lower than that reported in housed cattle, but the percentage of cows with reduced mobility recognised as lame was very similar, even though in pasture-based cattle, farmers spend more time watching cows walk (to and from milking).
In her conclusion Jessia Fabian stated that the study showed significant room for improvement in the detection of lameness on New Zealand farms, and suggests that routine mobility scoring, particularly at critical periods, could be a valuable tool for identifying lame cows.