Association between adenosine triphosphate luminometry of feeding equipment and environmental and health parameters of preweaning calves on dairy farms.

The objective of this study was to examine the influence of different environmental factors on ATP luminometry measurements of feeding equipment and to investigate associations with health of preweaning calves and the levels of ATP identified through luminometry. On 50 commercial dairy farms in Quebec, Canada, ATP luminometry measurements (in relative light units, RLU) were obtained using the direct swabbing technique with Hygiena UltraSnap swabs and a liquid rinsing technique with the same swab for automatic milk feeders (AMF), bottles, buckets, esophageal tube feeders (ET), milk replacer, nipples, and water. During this visit, environmental factors (including temperature, air draft, humidity, ammonia, and bacterial count) were collected, and a clinical examination (including respiratory score and fecal score) was performed for all preweaning calves present at the farm. This process was repeated 4 times in a year, leading to collection of luminometer results, environmental parameters, and overall health of calves for each season per farm. Overall, a difference in luminometer results was seen between the different periods sampled for all feeding equipment (except the ET), milk replacer, and water, showing higher RLU values in spring and summer and lower values in autumn and winter. When comparing RLU measurements with environmental factors, only a low to negligible correlation could be found. When feeding equipment was classified as not contaminated or contaminated based on previously described cutoff values, a good agreement within a farm for the different seasons was noticed only for nipples (Gwet's agreement AC1 = 0.64), with a poor to moderate agreement for other feeding equipment. Regarding the different models of nipples, Peach Teat nipples showed higher RLU values compared with Merrick's nipples. An association was seen between the proportion of preweaning calves suffering from diarrhea on the farm and the contamination of AMF based on ATP luminometry (logistic regression estimate = 0.52). For other feeding equipment, milk replacer, and water, no significant associations were found. This study showed that ATP luminometry measurements of feeding equipment from preweaning calves are susceptible to seasonality and type of nipple. Thus, these factors should be taken into consideration when interpreting results. Additionally, an association could be made between diarrhea in preweaning calves and the contamination of AMF based on ATP luminometry, showing the potential clinical importance of this on-farm hygiene assessment tool.

Progesterone profiles in postpartum dairy cows with inflammatory disorders.

The objective of this prospective cohort study was to determine if progesterone (P4) profiles differed between dairy cows with or without inflammatory disorders early postpartum. A total of 708 cows from 2 commercial herds were enrolled 3 wk before parturition and examined for clinical health disorders (difficult calving, retained placenta, metritis, displaced abomasum, mastitis, or lameness) until 5 wk postpartum. Serum haptoglobin (Hp) was measured in blood at 2 and 6 DIM (range ±2 d); metritis was assessed at 4, 8, 11, and 15 DIM; and purulent vaginal discharge and endometritis (≥6% PMN in endometrial cytology sampled by cytobrush) were assessed at 35 ± 3 DIM. As Hp ≥0.8 g/L or endometritis were associated with ovarian dysfunction in previous studies, cows with serum Hp ≥0.8 g/L at either time point and endometritis, regardless of clinical disease, were classified as the cohort with inflammatory disorders (INFLAM; n = 139). Clinically healthy cows without difficult calving, with singleton birth, with Hp <0.8 g/L at both sampling times, without endometritis or purulent vaginal discharge, and BCS ≥3.00 (1 to 5 scale) were classified as healthy (n = 133). Cows with only one of the 2 conditions (high Hp or endometritis) were excluded. Cohorts had serum P4 measured twice weekly from 35 to 70 DIM (±3 d), and the first detected luteal phase (LP) during the sampling period was defined as the period from onset of luteal activity (P4 increase to ≥1 ng/mL) until decline of P4 to <1 ng/mL. The odds of prolonged LP (≥21 d long), average LP length, peak P4, and time to P4 decline (hazard rate) were analyzed using multivariable mixed logistic, linear, or Cox proportional hazard regression models including INFLAM status, parity, sampling day (when applicable), and herd as a random effect considering the covariates of season, milk yield at first DHIA test, and DIM at onset of cyclicity or LP length (when applicable). Cows with INFLAM had greater odds of prolonged LP (LSM ± SEM; 67% vs. 37% ± 7%), greater average LP length (17 vs. 15 ± 2 d), lesser P4 at d 4 (4.6 vs. 5.5 ± 0.3 ng/mL) and d 7 (6.0 vs. 7.7 ± 0.3 ng/mL) of the LP, and lesser peak P4 (6.9 vs. 8.2 ± 0.3 ng/mL) during the LP than healthy cows. Status of INFLAM was associated with time to P4 decline in multiparous but not primiparous cows; the LP of INFLAM multiparous cows was less likely to have luteolysis (P4 decline) by d 14 (adjusted hazard ratio [AHR] and 95% CI: 0.54; 0.31 to 0.94) or by d 21 (AHR: 0.32; 0.12 to 0.84) than in healthy multiparous cows. In conclusion, postpartum cows with markers of systemic inflammation at wk 1 and uterine inflammation at wk 5 had altered luteal function (prolonged LP and lower P4 concentrations) before first breeding, which is a possible pathway linking postpartum health disorders and reduced fertility.

Standardization and validation of ATP luminometry as a diagnostic tool to assess the cleanliness of feeding equipment in preweaning calves.

The objective of this cross-sectional study was to standardize a reliable and repeatable swabbing technique using ATP luminometry (light emission proportional to the amount of ATP with result provided in relative light units [RLU]) to describe the cleanliness of various feeding equipment used for preweaning calves in dairy farms. A total of 7 Québec commercial dairy herds were selected conveniently. Following visual hygiene scoring, the cleanliness of every available piece of feeding equipment was assessed using direct surface swabbing for buckets and nipples with Hygiena UltraSnap swabs. A liquid rinsing technique was used for esophageal feeders, bottles, and automatic milk feeders (AMF) with UltraSnap, AquaSnap, and MicroSnap swabs. To validate direct swabbing technique of buckets, a stage within and between operators was realized, as well as a conventional bacterial culture. A total of 519 swab samples were obtained from 201 pieces of equipment. The median (interquartile range) contamination in RLU for a bottle, esophageal feeder, AMF, bucket and nipple was 2 (1;6), 2 (0;12), 52 (19;269), 886 (128;7,230) and 899 (142;6,928), respectively. The direct swabbing technique, which consists in swabbing directly the surface of an equipment, showed excellent correlation for intrarater reliability (intraclass correlation (ICC) = 0.93; 95% CI: 0.88-0.96). The interoperator (2 sessions with 3 different operators) reliability also showed high correlation (ICC = 0.88; 95% CI: 0.78-0.94 for the first session, and ICC = 0.89; 95% CI: 0.79-0.95 for the second session). Luminometer values were positively associated with the visual score of esophageal feeders, AMF and buckets. A positive correlation between bacterial culture and direct swabbing of buckets was also found for the UltraSnap (rs = 0.653; 95% CI: 0.283-0.873; P = 0.0003) and MicroSnap (rs = 0.569, 95% CI: 0.309-0.765; P = 0.002). This study describes a standardized and practical on-farm swabbing technique for assessing the hygienic status of feeding equipment by luminometry, which can be integrated in the investigation of preweaning dairy calves problems.

Buyer beware! Disease testing newly arrived cattle to dairy farms in Ontario.

The objective of this cross-sectional study was to evaluate the presence of infectious disease in newly arrived cattle on dairy farms in Ontario. Cattle that were more than 2 years old and arrived at dairy farms within the previous year were tested. A total 321 cattle from 56 dairy farms were sampled and had blood submitted to a diagnostic laboratory. Of all sampled cattle, 0.0%, 39.6%, 2.2%, and 1.3% tested positive for Anaplasma, bovine leukemia virus, Mycobacterium avium subsp. paratuberculosis, and Salmonella Dublin, respectively. Based on these results, it is imperative that dairy producers are vigilant to ensure they do not purchase animals with these important and untreatable infectious diseases.

Acheteur prenez garde! Dépistage des maladies des bovins nouvellement arrivés dans les fermes laitières de l'Ontario. L'objectif de cette étude transversale était d'évaluer la présence de maladies infectieuses chez les bovins nouvellement arrivés dans les fermes laitières de l'Ontario. Les bovins âgés de plus de 2 ans et arrivés dans les fermes laitières au cours de l'année précédente ont été testés. Au total, 321 bovins provenant de 56 fermes laitières ont été échantillonnés et leur sang a été soumis à un laboratoire de diagnostic. De tous les bovins échantillonnés, 0,0 %, 39,6 %, 2,2 % et 1,3 % ont été testés positifs pour Anaplasma, le virus de la leucémie bovine, Mycobacterium avium subsp. paratuberculosis et Salmonella Dublin, respectivement. Sur la base de ces résultats, il est impératif que les producteurs laitiers soient vigilants pour s'assurer qu'ils n'achètent pas d'animaux atteints de ces maladies infectieuses importantes et incurables.(Traduit par Dr Serge Messier).