<abstract xmlns="http://www.w3.org/1999/xhtml"><p> The main aim of the presented investigation was to determine the effect of the air thermal conditions variability on cow’s milking performance in summer in a moderate climate. The analyses covered the summer months of 2012-2013 (June-September) and shorter, several-day periods characterized by the times of elevated or high air temperatures and by the declines and increases in milking performance. The research was conducted in a free stall barn for Holstein-Friesian cows. The study showed that the thermoneutral temperature for high yielding cows decreases gradually with the registered increasingly warmer summer periods. The decreases in milk yield already commence at an air temperature equal to 20°C and also depend on the dairy cattle sensitivity. July and August, with a high number of hot days, caused that in September the cows responded faster to a worsening of thermal conditions and the decline in milking performance happened almost simultaneously with the air temperature change, at milking yield recovery after the period of 3-4 d (r=-0.84, P&lt;0.04). The percent duration in the individual temperature ranges which caused a decrease of milk yield was also determined. In June, and at the beginning of July, this was 90% of the time with temperatures above 20°C, and simultaneously 45% above 25°C occurred to milking performance decrease (r=-0.89, P&lt;0.02). In September, this was only 30% of the time with temperatures above 20°C (r=-0.91, P&lt;0.01).</p></abstract>

The main aim of the presented investigation was to determine the effect of the air thermal conditions variability on cow’s milking performance in summer in a moderate climate. The analyses covered the summer months of 2012-2013 (June-September) and shorter, several-day periods characterized by the times of elevated or high air temperatures and by the declines and increases in milking performance. The research was conducted in a free stall barn for Holstein-Friesian cows. The study showed that the thermoneutral temperature for high yielding cows decreases gradually with the registered increasingly warmer summer periods. The decreases in milk yield already commence at an air temperature equal to 20°C and also depend on the dairy cattle sensitivity. July and August, with a high number of hot days, caused that in September the cows responded faster to a worsening of thermal conditions and the decline in milking performance happened almost simultaneously with the air temperature change, at milking yield recovery after the period of 3-4 d (r=-0.84, P<0.04). The percent duration in the individual temperature ranges which caused a decrease of milk yield was also determined. In June, and at the beginning of July, this was 90% of the time with temperatures above 20°C, and simultaneously 45% above 25°C occurred to milking performance decrease (r=-0.89, P<0.02). In September, this was only 30% of the time with temperatures above 20°C (r=-0.91, P<0.01).

Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions

Annals of Animal Science

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

The main aim of the presented investigation was to determine the effect of the air thermal conditions variability on cow’s milking performance in summer in a...

Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions

Published Online: Jan 30, 2018

Page range: 195 - 207

Received: Apr 19, 2017

Accepted: Jul 11, 2017

DOI: https://doi.org/10.1515/aoas-2017-0017

Keywords
dairy cows, heat stress, air temperature, milking yield

© by Piotr Herbut

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions

Published Online: Jan 30, 2018

Page range: 195 - 207

Received: Apr 19, 2017

Accepted: Jul 11, 2017

DOI: https://doi.org/10.1515/aoas-2017-0017

Keywordsdairy cows, heat stress, air temperature, milking yield

© by Piotr Herbut

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Keywords
dairy cows, heat stress, air temperature, milking yield