Vet Times The website for the veterinary profession https://www.vettimes.co.uk Cattle lameness: a problem of cows that starts in heifers Author : Roger Blowey Categories : Farm animal, Vets Date : September 5, 2016 The view lameness is a problem of cows that starts in heifers was first introduced by Bicalho et al (2009). An understanding of this important concept is vital if we are to fully appreciate the basics of lameness prevention. Table 1. Prevalence of lameness in first lactation heifers compared to that in adult cows. Source: Bicalho et al, 2009. Bicalho was referring to hoof lesions only, but other studies have since shown the principle also applies to digital dermatitis (DD) and other infectious causes. In his paper, Bicalho compared the prevalence of sole ulcers and white disease in heifers with that in cows (Table 1), and showed although the prevalence of sole ulcers and white line lesions was not particularly high in first lactation heifers, it was the changes occurring in these heifers that led to increased lameness later in life. We need to fully understand this concept ourselves and then use the information to explain the 1 / 8
reasons for the various practical control measures to our clients. It is not the purpose of this article to discuss causation in detail, and those requiring further information should refer to other texts for example, Blowey (2015) although, of course, a detailed understanding of lesion development is essential when giving advice on prevention, and to persuade clients to implement early control. Preventive measures will vary with the type of lameness, although some measures for example, reduced exposure to slurry will be common to both. Lesion development Hoof lesions develop as a result of damage to the corium, the damage often being the result of trauma. This then leads to the production of defective horn, which, when it reaches the bearing surface of the foot, may allow infection to track back up through the damaged horn to reach the corium. Once the corium has been damaged it never fully heals, with some keratogenic cells being replaced by fibrous tissue, thus rendering the animal more susceptible to further lesions. Continual trauma can lead to bone overgrowth, as in the case of sole ulcers (Figure 1), thus, prevention is essential. Figure 1. Sole ulcers may lead to bony changes in the foot, as seen on the flexor tuberosity of the pedal bone on the right, thus predisposing to further lameness (Blowey, 2012). Longer-term changes to the corium for example, a sole ulcer or white line lesion that becomes secondarily infected with digital dermatitis may lead to further bony changes of the type seen in Figure 2. The corium will now be disrupted by both the treponeme infection in its substance and pressure from the bony exostoses above. An important link, therefore, exists between infectious and hoof lesions. 2 / 8
Body condition and changes in the digital cushion Previous articles have discussed the importance of a well-developed digital cushion in the prevention of lameness. Increasing evidence shows the hypothesis of nutritional acidosis causing laminitis, and subsequent lameness, is no longer correct or, if there is an association, it is that acidosis causes weight loss. The original theory was overfeeding of concentrates led to rumen acidosis and this, in turn, produced Inflammation and degradation of laminar suspension, sinking of the pedal bone and finally disruption of the corium. However, this has been difficult to induce experimentally and other studies show no adverse effect of severe overfeeding. The effect of changes in body condition score (BCS) on lameness have been well summarised by Huxley (2015): A BCS of less than 2.5 is associated with an increase in sole ulcer and white line disease in the following two to four months. Once cows go lame they are more likely to be lame in the future (Green et al, 2014 600 cows over 44 months, BCS every 60 days). Cows with low BCS at calving are more likely to go lame, and the longer a cow stays lame, the lower are her chances of recovery (Lim et al, 2015 731 cows, 6,889 records of BCS + mob score). A BCS of less than two increases the risk of lameness in cows, but not in heifers, and animals that lose weight after calving have an increased risk of lameness (Randall et al, 2014 80,000 observations from 724 cows aged eight or older). Figure 2. Bony exostoses on the base of the pedal bone compromise horn production by the corium and so prevent healing. Thus, prevention is vital (Blowey, 2011). Gard et al (2015) have shown exercise on a hard surface increases the size of the digital cushion when compared to control animals left on grazing alone. 3 / 8
Calving is a critical period It is well established the changes that occur around calving predispose to an increase in lameness, and that in the control of lameness, precalving feeding and management are vital. These changes are shown in Table 2 and include: increased hoof wear during a period of reduced horn growth increased laxity of the pedal bone within the hoof producing an increased risk of bruising of the corium increased standing times predispose to sole bruising and increased exposure to slurry weight loss/fall in BCS reduces the effectiveness of the digital cushion periparturient immune suppression increases the risk of DD and foul These changes apply especially to first lactation heifers where the digital cushion is much less well developed. Prompt and effective treatment Recent studies have shown the sooner a lame cow is identified and treated, the higher is the probable recovery rate for that cow. This requires careful observation by farm staff, ideally by regular mobility scoring, accompanied by easily used equipment and well-trained staff. Cows with chronic long-term lameness develop such extensive bony exostoses in the foot (Figure 2) they have no hope of a full recovery. Treatment must also be thorough; this involves modelling the foot to reduce weight-bearing at the sole ulcer site, frequent use of blocks to reduce weightbearing on the affected claw, and NSAIDs to reduce the extent of the bony exostoses on P3. It is well accepted weight-bearing should be on the wall, as the horn of the wall has a higher horn tubule density and is, as a result, stronger. Thus, I prefer the use of blocks (for example, cowslips) that transfer weight on to the wall. Control DD in youngstock and precalving heifers 4 / 8
Table 2. Changes at calving predisposing to lameness. The presence of DD in precalving cows and heifers has been shown to be a significant risk factor for lameness caused by DD post-calving (Laven and Logue, 2007). Similar results were reported by Gomez et al (2015), who found heifers with DD lesions precalving were four to five times more likely to go lame with DD post-calving. Although attempts to find DD treponemes in slurry have not been successful, preliminary studies have shown DD can be identified in fresh footprints from infected cows, with a higher detection rate from rubber than concrete floors. Internal biosecurity measures, such as using different slurry and handling systems for youngstock, may, consequently, be beneficial. Oliveira et al (2015) showed the importance of overall biosecurity in the control of DD. Attention to DD control in both youngstock and in pre-calving cows and heifers is, therefore, essential. Practical prevention advice Unless both vet and farmer understand the reasons for adopting control measures, it is improbable they will be implemented correctly. Large herds in well-designed modern buildings, and managed by trained staff, have lower lameness levels (Chapinal et al, 2014). My utopian regime to minimise lameness is given in the list on page 12. Many of the points refer especially to heifers; they are equally applicable to cows, but it is only by starting the implementation in heifers thereby preventing the development of pedal bone changes and 5 / 8
reducing the risk of chronic DD infections deep within the dermis that the programme will be effective overall. My top 10 tips for practical prevention Rear heifers in cubicles. Lack of cubicle training considerably increases post-calving standing times and this leads to an increased risk of lameness both hoof lesions and DD. Ensure DD is well controlled during rearing and especially pre-calving. This includes a clean underfoot environment, frequent (such as daily) foot bathing, careful hygiene reducing the risk of transfer of DD on foot trimming equipment, keeping pre-calving heifers away from adult cow environment, and avoiding transfer by slurry. Bergsten et al (2016) provide a comprehensive review of DD control measures. Mix heifers with cows pre-calving so they are able to begin their social adaptation to the post-calving grouping. This helps reduce post-calving standing times. Ideally, run the transition group heifers and dry cows through the parlour once daily for at least five days per week. While in the parlour they can be teat sprayed, thereby reducing down calving mastitis in heifers (teat disinfection pre-calving is a common procedure in many countries) and, on exit, they go through the foot bath, thereby minimising DD. After calving the heifers then know how to enter the parlour and they do so during milking rather than towards the end, thereby reducing standing times Ensure precalving cows have access to, and stand on, an area of non-bedded concrete for example, to feed and to drink, and for a loafing area, as this increases the thickness of both the sole and digital cushion. Provide a generous space allowance to promote walking. Figure 3. Deep sand cubicles promote increased lying times, which may, over time, lead to increased yields. After calving, when there is increased laxity of the pedal bone, maximise lying comfort, 6 / 8
References preferably by using deep-bedded sand cubicles. Increasing evidence shows changing from mats and mattresses to sand cubicles will result in significant yield increases over the following 12 months. Putting heifers into a separate heifer group may further decrease standing times. Maximise lying times by providing well-ventilated spacious buildings (heat-stressed cows spend longer standing). Take cows up to be milked in smaller groups (to minimise standing times) and do not forcibly keep them standing for 30 minutes after milking has been completed simply to allow teat canal closure. Ensure adequate feed space (0.6m per cow) with easy access, because cows spend longer standing to feed than any other single activity. Modern well-ventilated and spacious buildings with high roofs and wide passages reduce exposure to slurry and promote improved lying times by allowing better cow flow. In herds with DD, frequent foot bathing of the milking herd is essential. If we teat dip twice daily every day to prevent new mastitis infections from becoming established, then why not foot bathe twice daily every day? This is the simplest and most effective control measure available. I am not in favour of narrow foot baths, because I believe they impede cow flow and may lead to increased faecal contamination. Wide foot baths, preferably with a firm, concrete non-slip floor, are ideal. Ensure access to trace supplements such as biotin and zinc. Trials have shown benefits of 20mg/cow/day of biotin in reducing white line lameness and sand cracks. Supplementing pre-calving heifers with zinc can reduce digital dermatitis. Bicalho RC, Machado VS and Caixeta LS (2009). Lameness in dairy cattle: A debilitating disease or a disease of debilitated cattle? A cross-sectional study of lameness prevalence and thickness of the digital cushion, J Dairy Sci 92(7): 3,175-3,184. Blowey RW (2011). Non-healing hoof lesions in dairy cows, Vet Rec 169(20): 534. Blowey RW (2012). Bovine Bunions : an additional hypothesis for the pathogenesis of sole ulcers, Vet Rec 171(5): 130-131. Blowey RW (2015). Cattle Lameness and Hoofcare (3rd edn), 5M Publishing. Bergsten C et al (2016). Five Point Plan for Control of Digital Dermatitis, Proceedings of the British Cattle Lameness Conference, Worcester, www.delavalcorporate.com/five-point-plandigital-dermatitis Chapinal N, Liang Y, Weary DM, Wang Y and von Keyserlingk MA (2014). Risk factors for lameness and hock injuries in Holstein herds in China, J Dairy Sci 97(7): 4,309-4,316. Gard et al (2015). Effect of exercise and environmental terrain on development of the digital cushion and bony structures of the bovine foot, Am J Vet Res 76(3): 246-252. Gomez A, Cook NB, Socha MT and Do?pfer D (2015). Effects of pre-partum digital dermatitis on first lactation performance, Proceedings of the 18th International Symposium and 10th Conference on Lameness in Ruminants, Valdivia, Chile: 161. Green LE et al (2014). Temporal associations between low body condition, lameness and 7 / 8
Powered by TCPDF (www.tcpdf.org) milk yield in a UK dairy herd, Prev Vet Med 113(1): 63-71. Huxley J (2015). Advances in our understanding of the aetiopathogenesis of claw horn lesions, Proceedings of the 18th International Symposium and 10th Conference on Lameness in Ruminants, Valdivia, Chile: 43. Laven RA and Logue DN (2007). The effect of pre-calving environment on the development of digital dermatitis in first lactation heifers, Vet J 174(2): 310-315. Lim PY et al (2015). Unravelling the temporal association between lameness and body condition score in dairy cattle using a multistate modelling approach, Prev Vet Med 118(4): 370-377. Oliveira VHS, Sørensen JT and Thomsen PT (2015). Can digital dermatitis be controlled through biosecurity measures in dairy cattle herds? preliminary results, Proceedings of the 18th International Symposium and 10th Conference on Lameness in Ruminants, Valdivia, Chile: 114. Randall LV et al (2015). Low body condition predisposes cattle to lameness: an 8-year study of one dairy herd, J Dairy Sci 98(6): 3,766-3,777. 8 / 8