D.N. Logue

Effect of Forage Type on Claw Horn Lesion Development in Dairy Heifers

In a continuous design study the claw health of 54 Holstein-Friesian heifer calves was recorded from three months of age until six months after first calving (30 months of age). Pre-calving heifers were either fed a wet, fermented grass silage-based diet (WF) or a dry, unfermented straw and concentrate based diet (DU), apart from grazing during their first summer. Approximately one month before calving both groups were fed a silage-based diet and afterwards all received a silage and concentrate lactation ration. Claws were examined four times during rearing, once pre-calving, and four times during lactation. Both white line and sole lesions were significantly worse for WF than DU both during rearing and throughout first lactation although the effect was not as consistent over time for white line lesions. It is concluded that for optimal claw health youngstock diets should not be heavily based on wet grass silage (less than 25% DM).

A field evaluation of a footbathing solution for the control of digital dermatitis in cattle

Footbathing is one of the most commonly used methods for controlling digital dermatitis (DD). A farm-based trial was undertaken using six dairy herds involving over 600 cubicle-housed Holstein-Friesian cattle. Split footbaths (length 2.2m) were used to compare the efficacy of two dips, namely, a positive control (5% copper sulphate) and a non-heavy metal-based proprietary dip. The dips were used from early January 2009 for a minimum of 103 days, bathing twice a day for 3 consecutive days every week, using one footbath (three herds) or two in line (three herds). The lesions of DD on the hind feet of cattle were scored by borescope while the animals were being milked, on three occasions (at approximately days 0, 55 and 110) and then compared both directly and by calculating the change in severity from the previous examination (when possible). Data from the 408 cows that had their feet examined for lesions on all three occasions were analysed separately. A reduction in lesion score was seen for both footbath products, but feet bathed in 5% copper sulphate improved more (OR=1.6, CI: 1.14-2.32; P<0.01), and, irrespective of solution, there was a significantly greater improvement in those herds where two footbaths were used (OR=3.39, CI: 2.07-5.19; P<0.001). Lesion improvement over time also increased with lactation number (OR=1.13, CI: 1.02-1.25; P<0.05).

Effectiveness of different footbathing frequencies using copper sulfate in the control of digital dermatitis in dairy cows

Two experiments were conducted to test the effectiveness of different footbathing frequencies using CuSO₄ in the control of digital dermatitis (DD) in groups of dairy cows with low and high DD prevalence in an endemically infected herd. During the study, groups of cows walked through allocated footbath solutions after milking on 4 consecutive milkings each week, 2 wk, or monthly, depending on treatment. The footbath solutions were changed either after 200 cows had passed through the footbath or within 24 h. All cows were scored weekly during milking for DD lesion stage on the hind feet using a 5-point nominal scale. A transition grade was assigned based on whether the DD lesions improved (1) or deteriorated or did not improve (0) from week to week, and was averaged for all cows in the group. Furthermore, from the longitudinal study data, all transitions between different DD lesion stages between the different time points were used in a discrete, first-order Markov chain (state transition matrix) model. In experiment 1, 70 Holstein-Friesian cows with DD lesions present on at least one of their hind feet were allocated to 1 of 2 footbath treatments for 14 wk: (1) 5% CuSO₄ each week or (2) 5% CuSO₄ every 2 wk. At the end of the study, no active DD lesions were observed in cows in either treatment group, but significantly more cows had no DD lesions (0.48 ± 0.097 vs. 0.24 ± 0.094) and fewer cows had lesions in the healing stage (0.52 ± 0.104 vs. 0.77 ± 0.090) for the weekly compared with the 2-wk footbathing regimen. The number of active DD lesions that the transition matrix model predicted over time was 3 and 8% for weekly and every 2 wk footbathing treatments, respectively. In experiment 2, 64 cows with no DD lesions on either of their hind feet were allocated to 1 of 2 footbath treatment regimens for 14 wk: (1) 5% CuSO₄ every 2 wk or (2) 5% CuSO₄ each month. At the end of the trial, significantly more cows had no DD (0.80 ± 0.088 vs. 0.65 ± 0.102) and fewer cows had DD lesions in the healing stage (0.20 ± 0.088 vs. 0.35 ± 0.102) in the every 2 wk regimen than in the monthly footbathing regimen. The number of active DD lesions that the transition matrix model predicted over time was low for both footbathing interventions (1 and 4%, respectively). Increasing the interval between footbaths does not appear the most appropriate mechanism for reducing CuSO₄ usage.

Correlations of measurements of subclinical claw horn lesions in dairy cattle

Measurements were made of the extent of sole and white line lesions on the claws of 115 Holstein-Friesian cows on at least three and at most 16 occasions, and some cows were followed up to their third lactation. All the measurements were made between 12 weeks before calving and 45 weeks after calving. In total, 1016 repeated observations were made. Correlations were calculated between pairs of claws, between types of lesion (sole and white line), and between pairs of the different measurements (number of lesions, proportion of the claw affected, maximum severity score and proportion of the claw affected weighted for severity). The outer hind claws had the greatest extent of lesions of both types. Spearman correlation coefficients and confidence intervals measured the strength of the association. All the associations between claws were positive, suggesting that the lesions did not occur in isolation. Sole and white line lesions were not associated at individual observation points. Lesions on the left and right claws were markedly similar, except for sole lesions on the two inner hind claws, and for white line lesions on the two outer hind claws.

Bovine Staphylococcus aureus mastitis: strain recognition and dynamics of infection.

Restriction enzyme fragmentation pattern (REFP) analysis was used to recognise Staphylococcus aureus strain variation in naturally occurring bovine subclinical mastitis. Multiple colony REFP analysis identified eight distinct strains of S. aureus in addition to the original strains A and B that were infused via the intramammary route, indicating that individual quarters of the udder may be colonised simultaneously by more than one strain of S. aureus. Examination of multiple colonies per milk sample may benefit bacterial strain recognition as an epidemiological tool in mastitis investigations. The dynamics of intramammary infection were determined using a novel double crossover experimental challenge. Quarters remained persistently infected for several weeks following challenge in all four cows, irrespective of the challenge strain. This indicated that no alteration of the original subclinical infection, including the possible induction of clearance of the quarters infected with S. aureus, or replacement of the original strain by the infused strain was induced by challenge. The persistent subclinical infection in all four animals supports previous reports on the chronicity of S. aureus intramammary infection in dairy cows.

Efficacy of two non-antibiotic therapies, oxytocin and topical liniment, against bovine staphylococcal mastitis.

Eight cows were challenged by a single quarter intramammary infusion of a relatively low-virulence strain of Staphylococcus aureus on four occasions five weeks apart and, after each challenge, each cow received one of four treatments, according to a duplicated Latin-square design. The treatments were massage alone (negative control), massage with a proprietary liniment, oxytocin, and a single course of a proprietary intramammary antibiotic. The massage treatments were applied at every milking for three weeks, oxytocin was given for one week, and the antibiotic was given after three successive milkings. Milk samples were collected immediately before and for three weeks after each challenge, and a scoring system was used to quantify the presence of bacteria during the whole of the period. None of the treatments completely eliminated bacteria from all the cows. Relative to the negative control, the liniment had no significant effect, but both oxytocin and the antibiotic reduced the numbers of bacteria significantly and did not differ significantly in efficacy.

Developing a framework for risk-based surveillance of tuberculosis in cattle: a case study of its application in Scotland

SUMMARY Due to its substantially lower prevalence of bovine tuberculosis (bTB) relative to other areas of Great Britain, Scotland was designated as an officially (bovine) TB-free region in 2009. This paper investigates resultant possibilities for reducing surveillance by developing risk-based alternatives to current 4-year testing of eligible herds. A model of freedom of infection was used to develop strategies that specifically tested herds that are at risk of infection but would probably not be identified by slaughterhouse meat inspection. The performance of current testing is mimicked by testing all herds that slaughter fewer than 25% of their total stock per year and regularly import animals from high-incidence areas of England and Wales or from Ireland. This system offers a cost reduction by requiring 25% fewer herd and animal tests and 25% fewer false positives.

Clinical differentiation of malignant catarrhal fever, mucosal disease and bluetongue.

THE 2006/07 outbreak of bluetongue virus infection in northern Europe has been characterised by a higher proportion of cattle showing clinical signs (Thiry and others 2006, Guyot and others 2007). This is not often associated with outbreaks of the disease as it is more usual for cattle to be asymptomatic. Adult cattle have mainly been affected, showing ulcerative and necrotic lesions on the muzzle and in the oral cavity, conjunctivitis, lacrimation and periocular dermatitis, photosensitivity-type skin lesions around the midline (later in the course of disease), a drop in milk yield, mild pyrexia and transient loss of body condition, ulcerative and necrotic skin lesions on the udder, teats and vulva, and oedema of the distal limbs (Guyot and others 2007). Bluetongue was first reported in the UK in September 2007, and there is a real threat of the disease affecting more animals in the country, both from infected midges in the UK and those arriving from continental Europe in wind currents (Gloster and others 2007). This, alongside foot-and-mouth disease (FMD), has led to severe economic consequences in terms of both animal movement restrictions and the export market, and animal welfare. Among the differential diagnoses for bluetongue are malignant catarrhal fever (MCF) and mucosal disease, which are endemic to the UK. The clinical differentiation of these three conditions is therefore highly relevant. The aim of this study was to characterise the clinical findings typical of cases of MCF and mucosal disease, and to compare these with clinical findings characteristic of the recent bluetongue outbreak in northern Europe, to assess their value in differentiating these three conditions. Thirty-eight cases of bluetongue were selected from the database of records of the ambulatory clinic of the Faculty of Veterinary Medicine, University of Liège, from August 2006 to February 2007. The criteria for inclusion were a clinical diagnosis of bluetongue and a positive test result either for detection of antibody by a competitive ELISA or detection of viral nucleic acid by real-time reverse transcriptase-PCR, as described by Toussaint and others (2007). Sixty-six cases of mucosal disease and 11 cases of MCF were selected from the database of records of cattle admitted to the University of Glasgow Veterinary School (UGVS) from January 1989 to June 2007. Cases of mucosal disease were included on the basis of typical pathological changes at postmortem examination and on being antigen-positive (HerdChek BVDV Antigen; Idexx) and antibody negative (Svanovir BVDV-Ab; Svanova) for bovine viral diarrhoea virus (BVDV) by ELISA. Cases of MCF were included on the basis of postmortem examination findings and on being positive for antibody to ovine herpesvirus type 2 (OvHV-2) by an immunofluorescent antibody test (Reid 2004) or for OvHV-2 nucleic acid by PCR (Hussy and others 2001). All cases diagnosed as MCF were antigen-negative for BVDV. All the animals had been subjected to a thorough clinical examination according to standard protocols, albeit with slight differences between the two institutions. Cases of bluetongue were examined on-farm in Belgium, whereas cases of MCF and cases of mucosal disease were examined after being referred to the UGVS clinic. Case data were summarised to determine the most common presenting signs for each disease. A Freeman-Halton extension of Fisher’s exact probability test was performed (VassarStats 2007) to test for significant differences in the frequency of clinical signs between the three conditions (Freeman and Halton Veterinary Record (2007) 161, 858-859

Understanding bovine digital dermatitis

David Logue assesses the significance of a paper summarised in this weeks Veterinary Record describing an association between bovine digital dermatitis treponemes and three ‘non-healing’ bovine hoof horn lesions BOVINE digital dermatitis was first described in Italy by [Cheli and Mortellaro (

Possible natural MCF-like disease in a domestic lamb in Scotland

Malignant catarrhal fever (MCF) is a severe and usually fatal disease of ungulates, including domestic cattle, deer, bison and, occasionally, pigs (Reid and Buxton 1984, Loken and others 1998, Schultheiss and others 2000). The majority of documented cases of clinical MCF in domestic cattle are caused by specific and distinct gamma-herpesviruses, including wildebeest-associated MCF (WA-MCF) due to alcelaphine herpesvirus 1 (AlHV-1), and sheep-associated MCF (SA-MCF) due to ovine herpesvirus 2 (OvHV-2) (Plowright and others 1960, Baxter and others 1993). A long-held belief about these viruses is that they do not produce clinical disease in their natural host. However, this report describes a case of severe clinical disease in a domestic lamb that, on histological postmortem examination and sample testing, strongly resembles MCF. A six-month-old Lleyn cross commercial lamb was referred to the Scottish Centre for Production Animal Health and Food Safety in Glasgow in early October 2011 for progressive respiratory distress that had previously received treatment with long-acting penicillin with no response. On presentation, the animal was in very poor body condition and was tachypnoeic (respiratory rate of 80 breaths per minute) and dyspnoeic. The heart rate was also markedly increased (170 beats per minute) and harsh lung sounds were heard bilaterally on auscultation of the thorax. The animals body temperature was 40.2°C. No change in lymph node size was detected on palpation. Haematological parameters were all within …