Health indicators in surplus calves at the time of arrival at auction markets: Associations with distance from farms of origin in Québec, Canada.

This study evaluated the associations between estimated distance from farms' locations to auction markets, and health indicators of surplus dairy calves sold during summer 2019 and winter 2020 in Québec, Canada. A total of 3,610 animals from 1,331 different farms were used in this cross-sectional cohort study. Geographic coordinates (latitude and longitude) were obtained for each farm and the 2 participating livestock auction markets. Calves' abnormal physical signs (APS) were noted upon arrival at the auction market as they were examined by trained research staff. The haversine distance between the farm and the auction market was evaluated using geographic coordinates and categorized. Generalized linear mixed models were used for statistical analyses. The main APS observed were ocular discharge (34.9%), abnormal hide cleanliness (21.2%), swollen navel (17.2%), dehydration score 1 (at least one of the 2 following clinical signs: persistent skin tent or sunken eye, 12.9%), and dehydration score 2 (both clinical signs mentioned above, 6.5%). Calves from farms located at greater distances from the auction markets (≥110 km) had a higher risk ratio [RR = 1.08; 95% confidence internal (CI) = 1.03, 1.13] for dehydration than those from lesser distances (0-25 km). During the summertime, a RR of 1.18 (95% CI = 1.15, 1.22) was observed for dehydration compared with wintertime. A 2-way interaction between estimated distance and season showed a higher prevalence of ocular discharge for calves from farms at distances greater than or equal to 110 km during the summer (RR = 1.11; 95% CI: 1.04, 1.20) than for calves from farms located at lesser distances (0-25 km). These results demonstrate that calves from farms located at greater distances from the auction markets had more APS, mainly during the summer. A better understanding of the transport conditions and interaction with management at the farm of origin is determinant to mitigate the impact of the journey on surplus calf health.

Inter-Rater Reliability of Scoring Systems for Abomasal Lesions in Quebec Veal Calves.

The objective of this study was to determine the inter-rater reliability of current scoring systems used to detect abomasal lesions in veal calves. In addition, macroscopic lesions were compared with corresponding histological lesions. For this, 76 abomasa were retrieved from veal calves in a slaughterhouse in Quebec and scored by four independent raters using current scoring systems. The localisations of the lesions were separated into pyloric, fundic, or torus pyloricus areas. Lesions were classified into three different types, i.e., erosions, ulcers, and scars. To estimate the inter-rater reliability, the coefficient type 1 of Gwet's agreement and Fleiss κ were used for the presence or absence of a lesion, and the intra-class correlation coefficient was used for the number of lesions. All veal calves had at least one abomasal lesion detected. Most lesions were erosions, and most of them were located in the pyloric area. Overall, a poor to very good inter-rater agreement was seen for the pyloric area and the torus pyloricus regarding the presence or absence of a lesion (Fleiss κ: 0.00-0.34; Gwet's AC1: 0.12-0.83), although a higher agreement was observed when combining all lesions in the pyloric area (Fleiss κ: 0.09-0.12; Gwet's AC1: 0.43-0.93). For the fundic area, a poor to very good agreement was also observed (Fleiss κ: 0.17-0.70; Gwet's AC1: 0.90-0.97). Regarding the inter-rater agreement for the number of lesions, a poor to moderate agreement was found (ICC: 0.11-0.73). When using the scoring system developed in the European Welfare Quality Protocol, a poor single random rater agreement (ICC: 0.42; 95% CI: 0.31-0.56) but acceptable average random rater agreement (ICC: 0.75; 95% CI: 0.64-0.83) was determined. Microscopic scar lesions were often mistaken as ulcers macroscopically. These results show that the scoring of abomasal lesions is challenging and highlight the need for a reliable scoring system. A fast, simple, and reliable scoring system would allow for large scale studies which investigate possible risk factors and hopefully help to prevent these lesions, which can compromise veal calves' health and welfare.

Use of ATP luminometry to assess the cleanliness of equipment used to collect and feed colostrum on dairy farms.

The objective of this observational cross-sectional study was to describe the cleanliness of various equipment used for colostrum harvest and calf feeding procedures on dairy farms in Québec, Canada. The study was performed on 42 commercial dairy herds also enrolled in another study aiming to determine the transfer of passive immunity over a 14-mo period. Information on colostrum quality (using Brix value) and cleanliness (total aerobic and total coliform count) were recorded as well as various practices focused on colostrum-feeding equipment and preweaning period using a standard questionnaire. During the study period, colostrum and milk-feeding equipment cleanliness was assessed using direct surface swabbing with Hygiena Ultrasnap swabs. A total of 155 swab samples were obtained from 6 pieces of equipment. Adenosine triphosphate collected from the swabbed surface reacts with the luciferase solution present in the swab by bioluminescence, which is proportional to the quantity of ATP present and quantified as relative light units (RLU). The description of feed equipment cleanliness (defined as the maximal RLU found for a specific herd, dichotomized as <1,000 RLU vs. ≥1,000 RLU) was compared with the herds' descriptive characteristics, focusing on the first 2 components of a multiple correspondence analysis. The median (range) RLU for buckets used for colostrum harvest, bucket or bottle used for feeding, tube feeders, milking colostrum line, and internal surface of the nipples were 41 RLU (3-1,625 RLU), 78 RLU (<1-3,765 RLU), 29 RLU (<1-2,177 RLU), 83 RLU (<1-9,968 RLU), and 1,101 RLU (2-9,546 RLU), respectively. The first 2 components of multiple correspondence analysis explained 24.7% of data variances and were related to the farms' hygiene and health (13.0%) and feeding practices (11.7% of data variance). The maximal dichotomized luminometry value (<1,000 RLU or ≥1,000 RLU) was associated with hygiene and health dimension. This study gave promising results concerning the potential application of ATP luminometry for calf rearing practices assessment.

Development of a Benchmarking Tool for Dairy Herd Management Using Routinely Collected Herd Records.

Continuous assessment of the herd status is important in order to monitor and adjust to changes in the welfare and health status but can be time consuming and expensive. In this study, herd status indicators from routinely collected dairy herd improvement (DHI) records were used to develop a remote herd assessment tool with the aim to help producers and advisors benchmark the herd status and identify herd management issues affecting welfare and health. Thirteen DHI indicators were selected from an initial set of 72 potential indicators collected on 4324 dairy herds in Eastern Canada. Data were normalized to percentile ranks and aggregated to a composite herd status index (HSI) with equal weights among indicators. Robustness analyses indicated little fluctuation for herds with a small HSI (low status) or large HSI (high status), suggesting that herds in need of support could be prioritized and effectively monitored over time, limiting the need for time-consuming farm visits. This tool allows evaluating herds relative to their peers through the composite index and highlighting specific areas with opportunities for improvements through the individual indicators. This procedure could be applied to similar multidimensional livestock farming issues, such as environmental and socio-economic studies.

Short communication: Use of the Clegg hammer measure as an indicator of stall-surface compressibility in tie-stall housing and its relationship with stall comfort.

Stall base and stall surface (i.e., with or without bedding) are key risk factors in cow comfort in dairy herds. In Canada, rubber mats, concrete floors, and mattresses are the most common stall bases used in tie-stall systems. Straw, wood shavings, and sand, at variable depths, are the most commonly used type of bedding. The Clegg hammer (Clegg Impact Soil Tester Hammer; Lafayette Instrument Company, Lafayette, IN) is a tool used by engineers to test the compressibility of pavement or golf course surfaces. Recently, this tool has also been used to measure the compressibility of the stall surface on freestall dairy farms. A total of 32 tie-stall dairy herds were selected in Québec to test the usefulness of the Clegg hammer as a tool to assess stall surface compressibility in tie-stall housing. This study had 2 main objectives: (1) identify the location and the number of measurements needed to obtain a stable indicator of compressibility, and (2) identify differences in the compressibility of the stall surface depending on the stall base and bedding depth. On each farm, we tested the compressibility of 10 stalls. No significant differences were found between the front and the back of the stall for the location of the Clegg hammer measures. The differences in readings of the Clegg hammer were nonsignificant after the third measure taken at the same location, meaning that 3 measures are sufficient at one location to obtain a compressibility measure. Significant differences were found among the different stall base and surface combinations tested. Rubber mats were less compressible than mattresses. When a large quantity of bedding (>7.5 cm) was added on top of rubber mats, the compressibility results were equal to those of mattresses ≥10 yr old without bedding. To appropriately test the compressibility of stall surface in tie-stall farms, we recommend measuring the compressibility of the stall base on its own and with the usual amount of bedding used on the farm. Our study establishes that both stall base and surface affect compressibility, and that a large quantity of bedding helps increase the compressibility of the bed, especially on a harder stall base.