Weight distribution and gait in dairy cattle are affected by milking and late pregnancy

There is increased interest in automated methods for lameness detection, such as measures of weight distribution. Still, practical use of such methods depends on knowing the conditions that affect how cows distribute their weight. In 3 experiments, 10, 18, and 12 Holstein cows were trained to stand on a platform that measured the weight placed on each of their legs. The objectives were to evaluate how cows change their weight distribution after milking, after calving, and when standing with the front legs elevated and to evaluate the effect of the udder fill and fetus weight on the gait score. Comparisons before and after milking and before and after calving showed that the weight of milk was carried mainly on the back legs, whereas the weight of the fetus was distributed between front (52%) and back legs (48%). The percentage of weight distributed between front and back legs was not affected by elevation of the front legs. Weight shifting between contralateral legs was greater before calving than after; the weight variability over time decreased by 30% after calving. A full udder increased gait score by 0.3 +/- 0.1 and particularly abduction/adduction of the back legs (increased by 83%). Gait score did not change after calving, although the back arch increased by 25%. Therefore, time since milking and state of late pregnancy need consideration when using gait score and measures of weight distribution to detect lameness.