Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy Cows
Heat stress affects production and health in cows severely. Since it is difficult to define heat-tolerant animals, studies of response to heat stress are important for understanding dairy cows’ health and production. However, information on the impact of heat stress on various indicators in heat-tol...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-08-01
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| Series: | Animals |
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| Online Access: | https://www.mdpi.com/2076-2615/13/16/2562 |
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| author | Xiaoyang Chen Hang Shu Fuyu Sun Junhu Yao Xianhong Gu |
| author_facet | Xiaoyang Chen Hang Shu Fuyu Sun Junhu Yao Xianhong Gu |
| author_sort | Xiaoyang Chen |
| collection | DOAJ |
| description | Heat stress affects production and health in cows severely. Since it is difficult to define heat-tolerant animals, studies of response to heat stress are important for understanding dairy cows’ health and production. However, information on the impact of heat stress on various indicators in heat-tolerant and heat-sensitive cows is sparse. This study aimed to investigate the effects of heat stress (HS) on blood, production, and physiological indicators in heat-tolerant and heat-sensitive cows. A total of 43 dairy cows were used from 9 May to 7 August 2021, under Temperature–Humidity Index (THI) measurements that ranged from 65.9 to 86.7. We identified cows that were tolerant or sensitive to HS based on the slope of the response of physiological and production traits against THI during the HS period by using a clustering method. After HS, serum glucose (Glu), cortisol (COR), 5-hydroxytryptamine (5-HT), and interleukin-6 (IL-6) levels of cows in the heat-tolerant group were lower than in the heat-sensitive group (<i>p</i> < 0.05). With THI as the predictor, the R<sup>2</sup> for predicting respiration rate (RR) and body surface temperature (BT) in heat-tolerant cows was 0.15 and 0.16, respectively, whereas the R<sup>2</sup> for predicting RR and BT in heat-sensitive cows was 0.19 and 0.18, respectively. There were low to moderate, positive correlations between RR, BT, and MY with THI, with Pearson correlation coefficients ranging from r = 0.11 to 0.4 in the heat-tolerant group, and from r = 0.24 to 0.43 in the heat-sensitive group. There was a low positive correlation between VT and THI, with a Spearman correlation coefficient of r = 0.07 in the heat-sensitive group. The heat-tolerant dairy cows had lower MY losses and had lower MY (<i>p</i> = 0.0007) in mixed models. Heat-tolerant cows with low-stress levels, through upregulating RR rapidly, increased their adaptability to thermal environments. They have better thermoregulation capability; the hypothalamic–pituitary–adrenal (HPA) axis regulated the thermoregulatory in animals by releasing a variety of neurotransmitters and hormones. |
| first_indexed | 2024-03-11T00:11:28Z |
| format | Article |
| id | doaj.art-5c87b95045ce4e4eaac7f8d85b81e377 |
| institution | Directory Open Access Journal |
| issn | 2076-2615 |
| language | English |
| last_indexed | 2024-03-11T00:11:28Z |
| publishDate | 2023-08-01 |
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| spelling | doaj.art-5c87b95045ce4e4eaac7f8d85b81e3772023-11-18T23:57:00ZengMDPI AGAnimals2076-26152023-08-011316256210.3390/ani13162562Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy CowsXiaoyang Chen0Hang Shu1Fuyu Sun2Junhu Yao3Xianhong Gu4State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, ChinaAgricultural Information Institute, Chinese Academy of Agricultural Sciences, Beijing 100086, ChinaState Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, ChinaCollege of Animal Science and Technology, Northwest A&F University, Xianyang 712100, ChinaState Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, ChinaHeat stress affects production and health in cows severely. Since it is difficult to define heat-tolerant animals, studies of response to heat stress are important for understanding dairy cows’ health and production. However, information on the impact of heat stress on various indicators in heat-tolerant and heat-sensitive cows is sparse. This study aimed to investigate the effects of heat stress (HS) on blood, production, and physiological indicators in heat-tolerant and heat-sensitive cows. A total of 43 dairy cows were used from 9 May to 7 August 2021, under Temperature–Humidity Index (THI) measurements that ranged from 65.9 to 86.7. We identified cows that were tolerant or sensitive to HS based on the slope of the response of physiological and production traits against THI during the HS period by using a clustering method. After HS, serum glucose (Glu), cortisol (COR), 5-hydroxytryptamine (5-HT), and interleukin-6 (IL-6) levels of cows in the heat-tolerant group were lower than in the heat-sensitive group (<i>p</i> < 0.05). With THI as the predictor, the R<sup>2</sup> for predicting respiration rate (RR) and body surface temperature (BT) in heat-tolerant cows was 0.15 and 0.16, respectively, whereas the R<sup>2</sup> for predicting RR and BT in heat-sensitive cows was 0.19 and 0.18, respectively. There were low to moderate, positive correlations between RR, BT, and MY with THI, with Pearson correlation coefficients ranging from r = 0.11 to 0.4 in the heat-tolerant group, and from r = 0.24 to 0.43 in the heat-sensitive group. There was a low positive correlation between VT and THI, with a Spearman correlation coefficient of r = 0.07 in the heat-sensitive group. The heat-tolerant dairy cows had lower MY losses and had lower MY (<i>p</i> = 0.0007) in mixed models. Heat-tolerant cows with low-stress levels, through upregulating RR rapidly, increased their adaptability to thermal environments. They have better thermoregulation capability; the hypothalamic–pituitary–adrenal (HPA) axis regulated the thermoregulatory in animals by releasing a variety of neurotransmitters and hormones.https://www.mdpi.com/2076-2615/13/16/2562heat stressdairy cowsbloodphysiological indicatorsproductionheat-tolerant |
| spellingShingle | Xiaoyang Chen Hang Shu Fuyu Sun Junhu Yao Xianhong Gu Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy Cows Animals heat stress dairy cows blood physiological indicators production heat-tolerant |
| title | Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy Cows |
| title_full | Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy Cows |
| title_fullStr | Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy Cows |
| title_full_unstemmed | Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy Cows |
| title_short | Impact of Heat Stress on Blood, Production, and Physiological Indicators in Heat-Tolerant and Heat-Sensitive Dairy Cows |
| title_sort | impact of heat stress on blood production and physiological indicators in heat tolerant and heat sensitive dairy cows |
| topic | heat stress dairy cows blood physiological indicators production heat-tolerant |
| url | https://www.mdpi.com/2076-2615/13/16/2562 |
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