Comparison and interobserver reliability between a visual analog scale and the Wisconsin Calf Health Scoring Chart for detection of respiratory disease in dairy calves.

Respiratory disease is an ongoing challenge for calves in the dairy sector with a relatively high prevalence and impact on welfare and economics. Applying scoring protocols for detecting respiratory disease requires that they are easily implemented, consistent between observers and fast to use in daily management. This study was conducted in one Danish dairy farm from September 2020 through January 2021. The study included 126 heifer calves enrolled in the age of 17 to 24 d. All calves were observed every second day for a period of 46 d. At each visit all calves were scored with a new visual analog scale (VAS) and the Wisconsin Calf Health Scoring Chart (WCHSC). We calculated agreement between the 2 scoring systems based on conditional probability to score higher or lower than a cutoff in the VAS compared with a specified cutoff in WCHSC used as reference test. A generalized mixed effects regression model was developed to estimate the prevalence of respiratory disease and the overall agreement between the 2 scoring systems. The overall agreement between the VAS and WCHSC was 89.6%. The second part of the study assessed interobserver reliability between 2 experienced observers and between an experienced observer and veterinary students. The interobserver reliability was calculated by intraclass correlation coefficient and was 0.58 between experienced observers and was 0.34 between an experienced observer and veterinary students indicating a moderate to poor reliability between the observers. It was possible to use VAS as an alternative clinical scoring method, which primarily focuses on the general condition of the individual calf rather than specific categories of clinical signs. Our study set up lacked a comparison to other diagnostic tools i.e., thoracic ultrasound to confirm the findings which should be considered in future studies when exploring VAS as a screening tool for detection of respiratory disease in dairy calves.

Acute phase protein concentration in pharyngeal swabs from clinically healthy commercial dairy calves.

BACKGROUND: Early diagnosis of disease in calves is crucial for fast recovery and prudent use of antibiotics. The serum concentration of acute phase proteins (APPs) is up- or downregulated in response to tissue injury and has been studied widely in human medicine. There is growing interest in using APPs as biomarkers for different diseases and as a tool to initiate and monitor treatment in veterinary medicine as well. The concentration of APPs in saliva in healthy calves has not been established and the use of pharyngeal swabs offers a non-invasive alternative to blood sampling. Pharyngeal swabs, tracheal aspirate (TA) and blood samples were collected from 84 clinically healthy commercial dairy calves and analyzed for the APPs serum amyloid A (SAA), haptoglobin (Hp) and lipopolysaccharide binding protein (LBP). RESULTS: We found detectable concentrations of SAA, Hp and LBP in pharyngeal swabs from calves, as well as in TA and serum. There were no biologically interesting correlations between the SAA concentrations in serum and TA or pharyngeal swabs. This also applied to Hp and LBP concentrations in serum and TA or pharyngeal swabs. CONCLUSIONS: SAA, Hp and LBP can be measured in saliva and TA from calves, but there was no correlation between the specific APP concentration in serum and pharyngeal swab or TA. There was a considerable technical variation in the sampling method for both pharyngeal swab and TA, and further validation of the methods is needed.

Evaluation of Two Fecal Occult Blood Tests for Detecting Non-Perforating Abomasal Lesions in Cattle.

Non-perforating abomasal lesions occur with a high prevalence in slaughtered dairy cattle. Ante mortem diagnosis is a challenge, but the presence of occult blood in feces is suggested as a diagnostic criterion. The lower detection limit of Hemo-Fec® (Med-Kjemi, Asker, Norway) and Hemoccult II® SENSA® (Beckman Coulter, Brea, California, USA) for fecal occult blood were estimated. The Hemo-Fec® and Hemoccult II® SENSA® could detect 1-2 mL and 2-4.5 mL of blood in 1000 g of feces, respectively. Therefore, the Hemo-Fec® test was selected to access hemoglobin degradation in the rumen to establish if blood from outside the gastrointestinal tract could result in false-positive tests and an observational study to estimate the diagnostic sensitivity and specificity. Rumen microbiota did not degrade hemoglobin in a 1% blood concentration in vitro during 48 h of fermentation. The Hemo-Fec® test was only able to detect cattle with ≥4 acute lesions (diagnostic sensitivity: 0.40 [95% confidence interval (95% CI): 0.32-0.48] and ≥4 chronic lesions (sensitivity: 0.44 [95% CI: 0.35-0.52]). The Hemo-Fec® test had no diagnostic potential to detect superficial erosions or scar tissue in abomasa. Furthermore, the specificity was 0.71 [95% CI: 0.68-0.75%], and a positive test is thus not equivalent with abomasal lesions in cattle.

Higher odds of abortion in dairy cows hoof trimmed late in gestation.

Until now, it is unknown whether hoof trimming late in gestation is associated with increased risk of abortion in dairy cows. Using data from 1,476,013 pregnancies in Danish dairy cows, the objective of the present study was to evaluate risk factors for abortion in cows hoof trimmed during pregnancy. Odds of abortion was lower in first parity cows, lower in Jersey cows compared to other breeds, and higher in cows pregnant with twins. Odds of abortion was 2.4 times higher in cows hoof trimmed within the last four weeks before end of pregnancy. Hoof trimming of cows in late gestation should be done with caution.

Lower odds of sole ulcers in the following lactation in dairy cows that received hoof trimming around drying off.

Sole ulcers negatively affect production and animal welfare in dairy cows. Hoof trimming around drying off is frequently recommended, but has not previously been evaluated scientifically. The association between hoof trimming around drying off and the odds of sole ulcers in the following lactation was evaluated based on recordings from 621,228 hoof trimmings in Danish dairy herds. Overall, 6.2% of cows had sole ulcers at the first hoof trimming 0-180 days in milk. The odds of sole ulcers increased with increasing days in milk, and were approximately 20% lower in cows hoof trimmed around drying off. Odds were higher in older cows, and in cows with sole ulcers in the previously lactation. Hoof trimming around drying off may help reduce the occurrence of sole ulcers in the following lactation.

Effect of non-perforating abomasal lesions on reproductive performance, milk yield and carcass weight at slaughter in Danish Holstein cows.

Non-perforating abomasal lesions are common in Danish Holstein cows, but the impact on production has not been studied. Our objective was to compare milk yield, carcass weight, days to first service and initiation of breeding among cows with different non- perforating abomasal lesion types and locations to cows with no such lesions. The occurrence, type and localisation of non- perforating abomasal lesions were characterised at slaughter in Danish Holstein cows, and first insemination dates (n = 592), milk yield (n = 999) and carcass information (n = 1,317) was also available. Production and reproduction data were retrieved from all other cows from the herds of origin. This information was used to evaluate the expected production performance in the herds. Of the 1,317 cows investigated at slaughter, 572, 428, 677, and 91 cows had at least one lesion Subtype 1a (mucosal erosion), 1b (acute deeper lesion), 1c (chronic deeper lesion) or 1d (scarring following a lesion), respectively. Cows with lesion Subtype 1c and lesions in the pyloric part of the abomasum were generally found to be culled later in lactation than their herd mates. Milk yield and days to first service were not associated with any lesion types. The occurrence of lesion Subtype 1c and lesions in the pylorus were associated with a higher weight at slaughter compared to cows without lesions of this subtype or in this location. Most Subtype 1c lesions was found in the pylorus. Initiation of breeding before 150 days in milk was positively associated with the number of lesions in the corpus of the abomasum. We discovered two sources of selection bias. First, cows with lesions had a higher carcass weight but also remained in the herds for longer after calving than cows without lesions. This would give them more time to overcome the period of negative energy balance in early lactation. Second, although the causes of culling were not known, cows with no lesions generally had a relatively low milk yield and could have been culled for this reason.". While non- perforating abomasal ulcers may have an effect on the production and reproduction data, the observational data presented show no evidence of such a relationship. It may be necessary to employ other study designs to identify any effects that might exist, but if the relationship cannot be demonstrated in a dataset of this magnitude, it is not deemed to be of practical relevance.

Bovine digital dermatitis: possible pathogenic consortium consisting of Dichelobacter nodosus and multiple Treponema species.

Bovine digital dermatitis (DD) is a multifactorial disease involving at least one or more treponemal species. Virulent phylotypes of Treponema and other infectious agents contributing to disease etiology still remain to be identified. This study addressed these questions by analyzing the prevalence and distribution of seventeen phylotypes of Treponema in DD lesions by fluorescent in situ hybridization (FISH) applying species/phylotype-specific oligonucleotide probes. In situ hybridization for Dichelobacter nodosus, the cause of ovine footrot, was additionally performed. We sampled 90 biopsies of DD lesions originating from one Norwegian and six Danish dairy herds, and 24 tissue samples of healthy skin. All lesions revealed intermingled infections with multiple Treponema phylotypes (mean>7). In six herds, the mean number of phylotypes identified varied between 12 and 15. D. nodosus was present in forty-nine (51%) of the lesions and in three of the apparently healthy skin samples. Two "healthy" samples also contained Treponema spp. and D. nodosus, and were histopathologically categorized as subclinical DD. Another eighteen of the "healthy" skin samples showed serious epidermal hyperplasia but were not colonized by bacteria while only four samples were found normal. We hypothesise that external noxious stimuli allow D. nodosus to break down the epidermal barrier creating a suitable environment for the secondary invaders, Treponema species, which gradually take over the infection site. The variety and different distribution of treponemes in the DD lesions observed in this study, suggests that most of the Treponema phylotypes have the potential to be pathogenic.

Prevalence and severity of foot lesions in Danish Holstein heifers through first lactation.

Several studies have shown that foot lesions and clinical lameness occur before first calving and develop further during the lactation period. Lameness may cause production losses, but the relationship between foot lesions, particularly in the claw horn, and lameness in heifers is unclear. The objectives of this study were to describe the development of and evaluate the relationship between lameness and foot lesions in Danish Holsteins before and after first calving. In a longitudinal study, 147 heifers were examined for lameness and foot lesions 2-5 times over an 18-month period. Lameness was assessed by means of a visual locomotion score and foot lesion severity was recorded. The prevalence of a locomotion score 3 was 25% before calving, and 90% at approximately 250 days in milk (DIM). Prevalence of moderate to severe sole haemorrhage (SH) was 27% before calving and 56% at 250 DIM, and that of moderate to severe white line lesion (WLL) 44% before calving with a peak of 70% at 200 DIM. There was one case of white line abscess but SH was seen throughout the entire study period. Digital dermatitis (DD) was prevalent prior to first calving (15%) and peaked at 39% at 0-100 DIM. Heel horn erosion (HHE) occurred in almost all cows (93-100%) and was strongly correlated with DD (r=0.51). The correlation coefficient between SH and WLL was also high (0.42). The relatively high correlations between WLL and both DD and HHE were more surprising (0.38 and 0.35, respectively), those between SH and both DD and HHE were moderate (around 0.18). Interdigital dermatitis was significantly correlated with both HHE and DD, but completely unrelated to SH and WLL. The overall average locomotion score increased by about one-half of a score unit from 1 month prior to calving until 250 DIM, with a large difference between herds, although this was unsurprising as cows may alter their locomotion pattern with management factors (e.g. floor properties). DD and WLL were both associated with a locomotion score > or = 3 but of the cows with severe WLL there was no clear association between a locomotion score > or = 3 and DD. The highest locomotion scores occurred among cows with DD but without WLL.

Evidence of multiple Treponema phylotypes involved in bovine digital dermatitis as shown by 16S rRNA gene analysis and fluorescence in situ hybridization.

The etiopathogenesis of the skin disease digital dermatitis (DD), an important cause of lameness in cattle, remains uncertain. Microscopically, the disease appears to be polymicrobial, with spirochetes as the predominant bacteria. The objective of this study was to identify the main part of the bacteria involved in DD lesions of cattle by using culture-independent molecular methods. Ten different phylotypes of Treponema were identified either by 16S rRNA gene sequencing of bacteria from DD lesions or by fluorescence in situ hybridization (FISH) analysis using phylotype-specific 16S rRNA-directed oligonucleotide probes. Two phylotypes, phylotype 1 (PT1) and PT2, were not closely related to any characterized treponemal species. PT7 was 99.3% identical to Treponema denticola, while PT9 resembled T. vincentii by 96%. The remaining phylotypes, PT3, PT4, PT5, PT6, and PT8, and Treponema brennaborense had previously been isolated from DD lesions. Forty DD biopsy specimens were examined for Treponema by FISH. With one exception, all of the biopsy specimens revealed epidermotropic, intermingled infection with three or more different phylotypes (mean, 4.7). The most prevalent species were PT1 (95%), PT6 (93%), and PT3 (85%). While colonization by PT3 was confined to the surface of the epidermis, both PT1 and PT6 invaded deep into the stratum spinosum and were seen in ulcerated dermal papillae. In two cases, all 10 phylotypes were demonstrated. Furthermore, FISH with a Treponema group-specific probe showed that Treponema accounted for more than 90% of the total bacterial population in the biopsy specimens. These data strongly suggest that a group of apparently symbiotic Treponema species are involved as primary bacterial pathogens in DD.

The association of hoof lesions at claw trimming with test-day milk yield in Danish Holsteins.

In a cross-sectional study, performed between October 2002 and April 2003 on 55 Danish dairy herds with 6161 predominantly Holstein Friesian cows the prevalence of 9 hoof lesions was determined. All test-day yields (TDY) of kg energy corrected milk (ECM) in the lactation of diagnosis were recorded. For the purpose of including hoof lesions in a decision support model an attempt was made to aggregate the lesions into digital dermatitis (DD), other interdigital diseases (OID, infectious diseases other than DD) and hoof horn diseases (HHD, related to metabolic disorders and trauma). A division was made based on the stage of lactation in which the lesions were diagnosed; during the first 100 days in milk, between days 101 and 200 and between days 201 and 305. Associations between the presence of hoof lesions at trimming and milk production were analyzed by linear mixed modeling at the cow level, clustered within herd. The data of primiparous cows was analyzed separately from the multiparous cows. Based on the associations between TDY and the individual lesions aggregated into HHD, this aggregation as initially planned could not be justified and was therefore not maintained. For OID the value of early diagnosis was apparent; an early diagnosis and early treatment (<101 DIM) was associated with either a positive value or a value less negative compared to a diagnosis and treatment in late lactation (201-305 DIM). This pattern was not as clearly present for the other lesions.