Several studies since 2000 have found herd lameness prevalence in the UK to be in the range 20-35% (Barker et al., 2010; Griffiths et al., 2018; Randall et al., 2019), and studies from North America have found similar (Cook, 2003). In the UK, the average cost of a case of lameness, due to reduced milk yield, reduced fertility, increased culling rate and treatment cost was found to be £323 (Willshire and Bell, 2009).
Lameness is a multifactorial condition; there are several different types and causes of lameness, and many different risk factors. One recognised risk factor for lameness is body condition score (BCS); thinner cows are more likely to become lame. Randall et al. (2015) suggested that BCS of 2.5 and above is associated with less lameness. Low BCS at and around calving has been associated with increased lameness risk (Hoedmaker et al., 2009).
The digital cushion is an area of fat and fibrous connective tissue, which lies between the pedal bone in the hoof and the hard ground surface; it acts to dampen the compression of the sole as the cow walks.
Thickness of the digital cushion is proportional to BCS and decreases after calving, in parallel with BCS loss (Bicalho et al., 2009); this can explain the increased risk of claw/horn lameness after calving. Fat mobilisation, which occurs in the post-calving period of negative energy balance, depletes the digital cushion of some of its fat content, causing thinning of that protective tissue. However, the reduction in thickness of the digital cushion may not be due solely to BCS loss (Newsome et al., 2017).
The effect of Glycal Forte® on lameness post-calving was demonstrated in a trial carried out on 90 cows in a high-yielding (>10,000 litres) UK dairy herd:
Cows in the Glycal Forte® group had a significantly lower lameness incidence in the 120 days after calving than the control group (P = 0.045). Glycal Forte® improves energy balance and should reduce BCS loss (see ‘Reduce weight-loss post-calving), which lead to this finding.
Glycal Forte® also raises rumen pH in the post-calving period (see ‘Reduce weight-loss post-calving), and many papers associate laminitis and lameness with reduced rumen pH (Nocek, 1997; Plaizier et al., 2008). However, current thinking in the UK (Huxley et al., 2012) considers the association between rumen pH and lameness less certain and that between BCS and lameness more certain and, therefore, the latter more useful for describing the underlying cause of lameness post-calving.