Diurnal Temperature Patterns of Early Lactating Cows with Milking Parlor Cooling,

Abstract

Ten cows in early stages of lactation (less than 100 days postpartum) were used to test the effect of sprinkler/fan cooling on vaginal temperature patterns. Cows were assigned to two groups matched according to milk production. The trial was divided into three periods: period 1, when one group was treated and the other group was not, period 2, when neither group was treated, and period 3, when treatment was switched from period 1 between groups. Treatment consisted of forced air misting in a premilking holding pen, fan cooling during milking, and forced air-sprinkling in a postmilking holding area. Weather conditions were measured by dry bulb, wet bulb, and black globe temperatures. Black globe temperatures in pre- and postmilking holding areas were used to estimate treatment magnitude. All measures were obtained through radiotelemetry at 15-min intervals for 31 days. Animals were milked twice a day. Animals spent an average of 140 min in treatment at each milking. In both morning and afternoon milking, treatment caused a transient increase of body temperature. However, this was followed in the afternoon by low vaginal temperatures for 1 to 2 h beyond treatment with lower temperatures throughout the day.

Cooling cows efficiently with sprinklers: Physiological responses to water spray

“…These patterns are likely due to cows in our study having access to shade after treatment: relative to no cooling resources, shade alone can reduce body temperature but is less effective than sprinklers (e.g., Kendall et al, 2007). Others have similarly found that body temperature remained lower than controls for 1.5 h (Brown-Brandl et al, 2010) or even 2 to 4 h after spraying stopped (Araki et al, 1985;Kendall et al, 2007). Before converging with the control, body temperature in our sprinkler treatments returned to baseline values.…”

“…When we applied ≥1.3 L/min, wind extended the duration, similar to when sprinklers are combined with fans (as reviewed by Collier et al, 2006). Others have similarly found body temperature to reach a nadir between 30 and 60 min after spraying stopped (Araki et al, 1985;Flamenbaum et al, 1986;Kendall et al, 2007).…”

“…Reduced skin temperature on the leg is consistent with vasoconstriction in response to cooling (Finch, 1986;Osborn et al, 1992), but it is also possible that this change reflected the cooler microclimate surrounding the cow, also associated with spray (Araki et al, 1985;Kendall et al, 2007;Chen et al, 2013).…”

“…To determine how much water is needed to cool via evaporation, Arkin et al (1991) estimated the evaporative potential of a wet, excised hide (≤0.23 L/m 2 ), and heat transfer models have been created for different ambient conditions Gebremedhin and Wu, 2002). However, there has been little experimental validation on live cows, and comparing cooling effectiveness across studies is challenging, as some do not report how much water is used (Araki et al, 1985;Igono et al, 1987;Valtorta and Gallardo, 2004), or use variable units of measure: most commonly liters per minute (e.g., Chen et al, 2013) or liters per hour (e.g., Gallardo et al, 2005), but also cubic meters per hour (Flamenbaum et al, 1986), millimeters per centimeter squared per hour (Granzin, 2006), milliliters per meter squared per minute , or millimeters per hour (Kendall et al, 2007). The only study to date that directly compared sprinkler flow rates (mounted over the freestalls and without unsprayed controls) found no differences in heat load when spraying 5.2, 8.2, or 11.7 L/min in 1.5min applications in a hot, humid climate (Means et al, 1992).…”

Sprinkler flow rate affects dairy cattle preferences, heat load, and insect deterrence behavior

“…Physiological responses to spray in milder weather also indicate attempts to conserve heat. When cows are sprayed in the morning (Araki et al, 1985) or on days with air temperature <23 • C (Kendall et al, 2007) body temperature temporarily increases afterward. Also, when the torso is sprayed, skin temperature on the extremities decreases, consistent with vasoconstriction (Chen et al, 2015).…”