Erratum: Dallago et al. Keeping Dairy Cows for Longer: A Critical Literature Review on Dairy Cow Longevity in High Milk-Producing Countries. Animals 2021, 11, 808.

In the original article [...].

Toward Precision Feeding Regarding Minerals: What Is the Current Practice in Commercial Dairy Herds in Québec, Canada?

This analysis is performed to obtain information on the current situation regarding phosphorus (P), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) concentrations in cow diets of commercial dairy herds in Québec, Canada, and to compare them with National Research Council recommendations. Data are collected on 100 Holstein dairy herds in Québec, Canada, and 4430 cows were involved. Rations are analyzed for selected minerals and cow requirements relative to the recommendations were calculated. Median percentages of mineral recommendations fulfilled by forage were 55%, 196%, 54%, 776%, 181%, and 44% for P, Co, Cu, Fe, Mn, and Zn, respectively. Daily dietary concentrations of P, Cu, Mn, and Zn decreased as lactation progressed, whereas Co and Fe were stable throughout lactation. Phosphorus was the mineral fed the closest to the requirements, cows below 21 days in milk were even underfed by 11%. All studied trace minerals were fed in excess for the majority of cows. Cobalt was fed on average 480% above requirements regardless of the stage of lactation. For Cu, Fe, Mn, and Zn, rations for cows below 21 days in milk were fed 23% (95% confidence interval: 15-32), 930% (849-1019), 281% (251-314), and 35% (22-47) above the recommendations, respectively, and were closer to the requirements than after 21 days in milk. These results show that most nutritionists are aware that precision feeding regarding P is important to minimize detrimental environmental impacts of dairy production. However, some efforts should be made to limit trace mineral overfeeding to ensure environmental resiliency.

Keeping Dairy Cows for Longer: A Critical Literature Review on Dairy Cow Longevity in High Milk-Producing Countries.

The ability of dairy farmers to keep their cows for longer could positively enhance the economic performance of the farms, reduce the environmental footprint of the milk industry, and overall help in justifying a sustainable use of animals for food production. However, there is little published on the current status of cow longevity and we hypothesized that a reason may be a lack of standardization and an over narrow focus of the longevity measure itself. The objectives of this critical literature review were: (1) to review metrics used to measure dairy cow longevity; (2) to describe the status of longevity in high milk-producing countries. Current metrics are limited to either the length of time the animal remains in the herd or if it is alive at a given time. To overcome such a limitation, dairy cow longevity should be defined as an animal having an early age at first calving and a long productive life spent in profitable milk production. Combining age at first calving, length of productive life, and margin over all costs would provide a more comprehensive evaluation of longevity by covering both early life conditions and the length of time the animal remains in the herd once it starts to contribute to the farm revenues, as well as the overall animal health and quality of life. This review confirms that dairy cow longevity has decreased in most high milk-producing countries over time and its relationship with milk yield is not straight forward. Increasing cow longevity by reducing involuntary culling would cut health costs, increase cow lifetime profitability, improve animal welfare, and could contribute towards a more sustainable dairy industry while optimizing dairy farmers' efficiency in the overall use of resources available.

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.

Effects of changing freestall area on lameness, lying time, and leg injuries on dairy farms in Alberta, Canada.

Cow comfort is of increasing importance in the dairy industry, due to an increased focus on animal welfare. However, whether producer changes to the cows' environment affect cow comfort has not been well characterized. Our objectives were to: (1) quantify the effect of freestall area changes on the prevalence of lameness, leg injuries, and average lying time; and (2) compare cow comfort outcomes on farms that had never had an assessment of cow comfort to farms that had had a previous assessment of cow comfort. A sample of 60 Holstein-Friesian cows were selected on each of 15 farms that made changes to the freestall area after an assessment of cow comfort (change, CHG); 15 farms that did not make changes to the freestall area after an assessment of cow comfort (no change, NC); and 14 farms that had yet to be evaluated (new farms, NF). Cows in NC and NF were lame 1.50 and 1.71 times more often, respectively, than cows on CHG farms. Additionally, daily lying time was 0.33 and 0.62 h/d lower in NC and NF, respectively, than on CHG farms. The prevalence of hock and knee injuries was not different among the 3 groups of farms. No differences were detected in the parameters of interest when comparing NF with NC farms; therefore, we concluded that the NC group was not biased by a previous assessment of cow comfort. Farms in the CHG group had a lower prevalence of lame cows and greater lying time than the NC and NF groups.

Technical note: a comparison of 2 methods of assessing lameness prevalence in tiestall herds.

We compared 2 methods for identifying lame cows and estimating the prevalence of lameness in tiestalls. Cows (n=320) in 9 tiestall herds were scored as lame both by the presence of limping while walking and by stall lameness scores (SLS). The SLS was based on the number of the following behaviors that the cow showed while standing in the tiestall: weight shifting, standing on the edge of the stall, uneven weight bearing while standing, and uneven weight bearing while moving from side to side. Two observers watched video-recordings of the cows. Intraobserver agreements for the 4 SLS behaviors ranged from 92 to 100%, and interobserver agreement ranged from 81 to 100%. The overall prevalence of lameness based on an SLS of ≥2 was similar to that of limping (39 vs. 40%). The sensitivity of the classification based on the SLS was 0.63 and the specificity was 0.77 in identifying cows with a limp; accuracy varied across farms from 62.2 to 80.4%, with a mean of 71.7%. A cow with an SLS of ≥2 had 4.88 times the odds of limping than a cow with an SLS of <2. The prevalence of lameness on farms based on SLS was highly correlated with the prevalence of limping (Pearson correlation=0.88; n=9), and prevalence estimates from the 2 methods diverged most when the mean herd prevalence was lower. The SLS method provides an estimate of the prevalence of lameness in tiestall herds comparable with traditional gait scoring, but does not require that the cows be untied. The SLS method could be used to improve lameness detection on tiestall farms and obtain estimates of lameness prevalence without the need to walk the cows.

Soil nitrous oxide emissions after deposition of dairy cow excreta in eastern Canada.

Urine and dung deposited by grazing dairy cows are a major source of nitrous oxide (NO), a potent greenhouse gas that contributes to stratospheric ozone depletion. In this study, we quantified the emissions of NO after deposition of dairy cow excreta onto two grassland sites with contrasting soil types in eastern Canada. Our objectives were to determine the impact of excreta type, urine-N rate, time of the year, and soil type on annual NO emissions. Emissions were monitored on sandy loam and clay soils after spring, summer, and fall urine (5 and 10 g N patch) and dung (1.75 kg fresh weight dung) applications to perennial grasses in two successive years. The mean NO emission factor (EF) for urine was 1.09% of applied N in the clay soil and 0.31% in the sandy loam soil, estimates much smaller than the default Intergovernmental Panel on Climate Change (IPCC) default value for total excreta N (2%). Despite variations in urine composition and in climatic conditions, these soil-specific EFs were similar for the two urine-N application rates. The time of the year when urine was applied had no impact on emissions from the sandy loam soil, but greater EFs were observed after summer (1.59%) than spring (1.14%) and fall (0.55%) applications in the clay soil. Dung deposition impact on NO emission was smaller than that of urine, with a mean EF of 0.15% in the sandy loam soil and 0.08% in the clay soil. Our results suggest (i) that the IPCC default EF overestimates NO emissions from grazing cattle excreta in eastern Canada by a factor of 4.3 and (ii) that a region-specific inventory methodology should account for soil type and should use specific EFs for urine and dung.