Investigating the impact of 1 hour of daily outdoor access on the gait and hoof health of nonclinically lame cows housed in a movement-restricted environment.

Tiestalls, known for restrictive housing, can reduce cows' locomotor skills over time. While outdoor access benefits clinically lame cows, its effect on nonclinically lame cows is less known. This study evaluated 1 h daily outdoor access on gait and hoof health of nonclinically lame Holstein cows in tiestalls. Thirty cows, blocked by parity and DIM, were assigned to exercise (1 h outdoor access 5 d/wk for 5 wk) or nonexercise groups. Visual scoring assessed 6 gait attributes and overall gait (on scales of 0-5 and 1-5, respectively) at pre-trial, post-trial, and 8-wk follow-up stages. A total of 15 cows (9 exercise, 6 nonexercise) underwent visual gait scoring, with logistical challenges and exclusion criteria leading to this selection. Hoof health for all 30 cows was evaluated during pre-trial and follow-up hoof trims, documenting claw lesions. Hoof thermography captured dorsal coronary band views in wk 1 and 5. No significant gait score changes were observed, but exercise cows showed a 1-point improvement in overall gait score and 3 gait attributes after 5 wk of outdoor access, which persisted at follow-up. Sole hemorrhages were the only claw lesions observed, and their prevalence and severity remained consistent between pre-trial and follow-up for both groups. Thermography showed consistent coronary band temperature metrics across groups and over time. In conclusion, brief outdoor sessions resulted in noticeable, albeit not statistically significant, improvements in the gait of nonclinically lame cows in restrictive housing settings without adverse hoof health effects. Further studies should evaluate different outdoor access benefits and use precise gait and hoof health analysis technologies for a more accurate detection of subtle changes.

The associations of early-life health and performance with subsequent dairy cow longevity, productivity, and profitability.

Selecting and raising dairy animals that are more likely to reach their potential is a strategy to increase milk production efficiency and overall profitability. However, indicators are necessary for the early identification of animals that are less likely to perform well, allowing for their early culling and ensuring that resources are allocated to those with the highest potential. The objective of this study was to analyze the association between early-life animal health and performance with longevity, production, and profitability. After data cleaning, the following early-life measures (i.e., predictors) were available for 363 female calves born between June 2014 and November 2015 in eight dairy herds from New Brunswick, Canada (average: 45 calves/farm; SD: 26.1 calves/farm; median: 42 calves/farm; range: 15-95 calves/farm): birth weight, weaning weight, weaning age, weaning average daily gain (weaning ADG), immunoglobulin G (IgG) serum concentration, the occurrence of navel infection, diarrhea, and pneumonia, and if animals received antibiotic treatment between birth and weaning. Their subsequent length of life (LL), length of productive life (LPL), lifetime cumulative energy-corrected milk (ECM), and lifetime cumulative milk value (i.e., response variables) were provided by the Canadian dairy herd improvement agency. Bayesian Additive Regression Tree models were trained for each response variable using 5-fold cross-validation. Models were evaluated using the RMSE and R2. The three most important predictors were identified using permutation, and the relationship between response variables and important predictors was assessed using accumulated local effect plots. The RMSE for LL, LPL, ECM, and milk value were 1.43 years, 1.37 years, 16 314.94 kg, and $CAD 11 525.68, respectively, whereas the R2 values were 0.30, 0.25, 0.29, and 0.29, respectively, indicating a moderate relationship between predictors and response variables. Non-linear relationships were found between the response variables and important predictors. Animals born with low or high birth weights were associated with decreased LL, LPL, ECM, and milk value. The highest LL, LPL, and milk value was observed for calves weaned between 1.9 and 2.0 months old, followed by a decline for calves weaned at older ages. The lowest LL and ECM were associated with weaning ADG of 0.786 kg/day, while 0.787 kg/day was associated with the lowest LPL. Lastly, both ECM and milk value were highest when serum IgG values were 1 659 mg/dL. These findings provide valuable insights for optimizing early culling decisions and enhancing the productivity and profitability of dairy farms.

Using the Herd Status Index to remotely assess the welfare status of dairy herds based on prerecorded data.

The use of prerecorded data to remotely assess the herd welfare status is a promising approach to reduce the need for costly and time-consuming on-farm welfare assessments. Therefore, the objective of this study was to validate the Herd Status Index, an index developed based on Dairy Herd Improvement data from Canada, to remotely evaluate the welfare status of dairy herds. Herd-level prevalence of five animal-based welfare outcomes, measured once on 2 986 Quebec - Canada dairy herds between 2016 and 2019, were used to generate clusters with different welfare status using the algorithm partitioning around medoids. Dairy Herd Improvement data from 12 months prior to the welfare assessment were extracted and used to calculate the Herd Status Index. A linear model was used to carry out comparisons between clusters. Three stable clusters were found to best describe the data. Cluster two had the best overall welfare status since it had the lowest prevalence of all welfare issues while cluster three had the highest prevalence of most welfare issues, with the exception for the prevalence of neck lesions that was not different than cluster one. Cluster one had an overall intermediate welfare status. The Herd Status Index was higher (i.e., indicating a good welfare status) on cluster two compared to cluster three, but neither cluster three nor two differed to cluster one. In its current format, the Herd Status Index has a weak potential to identify herds with varying prevalence of welfare issues and it requires further improvements before it could be used to accurately assess the welfare status of the herds.

Keeping profitable cows in the herd: A lifetime cost-benefit assessment to support culling decisions.

Increasing the productive lifespan of dairy cows is important to achieve a sustainable dairy industry, but making strategic culling decisions based on cow profitability is challenging for farmers. The objective of this study was to carry out a lifetime cost-benefit analysis based on production and health records and to explore different culling decisions among farmers. The cost-benefit analysis was conducted for 22 747 dairy cows across 114 herds in Quebec, Canada for which feed costs and the occurrence of diseases were reported. Costs and revenues related to productive lifespan were compared among cohorts of cows that left their respective herd at the end of their last completed lactation or stayed for a complete additional lactation. Hierarchical clustering analysis was carried out based on costs and revenues to explore different culling decisions among farmers. Our results showed that the knowledge of lifetime cumulative costs and revenues was of great importance to identify low-profitable cows at an earlier lactation, while only focusing on current lactation costs and revenues can lead to an erroneous assessment of profitability. While culling decisions were mostly based on current lactation costs and revenues and disregarded the occurrence of costly events on previous lactations, there was variation among farmers as we identified three different culling decision clusters. Monitoring cumulative costs and revenues would help farmers to identify low-profitable cows at an earlier lactation and make the decision to increase herd productive lifespan and farm profitability by keeping the most profitable cows.