Studying the relationship between on-farm environmental conditions and local meteorological station data during the summer

Abstract

High ambient heat and humidity have profound effects on the production, health, profitability, and welfare of dairy cattle. To describe the relationship between summer temperature and relative humidity in the barn and determine the appropriateness of using meteorological station data as a surrogate for on-farm environmental monitoring, a study was conducted on 48 farms in Ontario, Canada, over the summer (May through September) of 2013. Within-barn environmental conditions were recorded using remote data loggers. These values were compared with those of the closest official meteorological station. In addition, farm-level characteristics and heat-abatement strategies were recorded for each farm. Environmental readings within the barn were significantly higher than those of the closest meteorological station; however, this relationship varied greatly by herd. Daily temperature-humidity index (THI) values within the barn tended to be 1 unit higher than those of the closest meteorological station. Numerically, 1.5 times more mean daily THI readings were in excess of 68 (heat stress threshold for lactating dairy cows) in the barn, relative to the closest meteorological station. In addition, tiestalls, herds that were allowed access to pasture, and herds that had no permanent cooling strategy for their cows had the highest mean and maximum daily THI values. Minimum daily THI values were almost 4 units higher for tiestall relative to freestall herds. Overall, due to farm-specific and unpredictable variability in magnitude of environmental differences between on-farm and meteorological station readings, researchers attempting to study the effects of environment on dairy cows should not use readings from meteorological stations because these will often underestimate the level of heat stress to which cows are exposed.

Effect of heat stress on udder health of dairy cows

“…(2016) reported a standard of THI ≥ 68 for a heat stress day by calculating National Oceanic and Atmospheric Administration data for each state of the USA. However, due to the distances between the weather stations and farm, significant differences can occur between daily THI recorded in the cow barn and data from the nearest weather station (Shock et al ., 2016). Therefore, other physiological factors like rectal or vaginal temperatures, respiration rate, panting, sweating, feed intake, standing time and activity are often used to assess heat stress (West, 2003; Schutz et al ., 2008; Hansen, 2013).…”

Effect of the environment on the risk of respiratory disease in preweaning dairy calves during summer months

“…Variable frequency of clinical observation could have affected the results had the disease duration been shorter than the follow-up interval (2 to 3 d), but our frequent observations likely reduced the chance of missing signs of disease. Another limitation of our study was sensor failure for the macroenvironment data; such failures have been reported previously (Shock et al, 2016). Sensor failures could have been avoided by use of multiple sensors at each location, more frequent data downloads, and regular replacing of sensors.…”

“…Furthermore, such environmental data should be used with the awareness that they might be discrepant from what a calf experiences at the hutch level. Indeed, a different study found significant differences between on-farm environmental conditions from data loggers placed in adult cow pens, including freestalls and tiestalls, and local weather stations (Shock et al, 2016). Weather station mean relative humidity daily summary values were not as well correlated with NOAA daily mean humidity, which might imply humidity is more location-specific and can be influenced by other environmental factors, such as flush systems beneath hutches or standing water in the calf hutch area.…”

“…Only healthy calves enrolled for the scoring system validation study were followed up for the purpose of this study until BRD diagnosis or censoring at or soon after weaning. A sample size of 40 to 75 calves was deemed necessary to estimate the prevalence of BRD in study herds with varying calf herd sizes between 200 and 6,000, with a bound on error of estimation of 10% and assumed prevalence of 25% (Scheaffer et al, 2012).…”

Comparison of Conventional and Automatic Milking Systems at Extreme Conditions by Thermographic Method

“…The influence of the environment can not be ignored, as it can cause stress and thus negatively affect the condition of the organism (Fraser and Broom, 1990;Šoch et al 2000, 2005. High ambient heat and humidity have profound effects on the production, health, profitability, and welfare of dairy cattle (Shock et al, 2016). By altering the thermal environment for livestock, climate change could affect the costs and returns of animal production -thereby affecting the animal health, reproduction, and the efficiency with which livestock convert feed into retained products (especially meat and milk).…”