China Animal Husbandry and Veterinary Medicine ›› 2022, Vol. 49 ›› Issue (9): 3362-3371.doi: 10.16431/j.cnki.1671-7236.2022.09.010

• Physiological and Biochemical • Previous Articles     Next Articles

Circadian Rhythm and Influencing Factors of Tympanic Temperature in Lactating Cows in Summer in Beijing

XU Jingyi1, LUO Hanpeng1, FU Qi1, HU Yuyang1, DUAN Yujiao1, HUANG Siqi1, ZHOU Yueling1, YANG Tongtong1, ZHANG Yayi2, GUO Gang2, LIU Qiaoxiang3, WANG Yachun1   

  1. 1. National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China;
    2. Beijing Sunlon Livestock Development Company Limited, Beijing 100029, China;
    3. Beijing Innovation Consortium of Bio-breeding, Beijing 101206, China
  • Received:2022-03-27 Online:2022-09-05 Published:2022-08-24

Abstract: 【Objective】 The objectives of current study were to reveal the population characteristics of tympanic temperature in lactating cows and its change with temperature-humidity index (THI).Further, the influence factors of tympanic temperature and its correlation with rectal temperature under moderate heat stress were investigated.【Method】 The records of tympanic temperature, rectal temperature, as well as environmental temperature and humidity were measured from 638 Holstein dairy cows from Beijing in August, 2021.Descriptive statistics of tympanic temperature, rectal temperature and THI were summarized.Then the correlations between 6 h tympanic temperature and rectal temperature in 161 Holstein dairy cows were analyzed.Finally, a linear mixed model was employed to test the significances of effects, such as collecting time, parity, lactation stage, and reproductive status on tympanic temperature and rectal temperature.【Result】 In Beijing, the average tympanic temperature of Holstein cows in summer was 39.01 ℃±0.40 ℃ under moderate heat stress (THI was 76.11 to 83.18) during the measurement time.Under this circumstance, tympanic temperature was differed between day and night, and when THI changed, it showed a slight delay.To be specific, tympanic temperature was lowest in the forenoon and stay heated in the afternoon and nightfall, with 2 abnormal peak values in the morning and afternoon.The tympanic temperature and rectal temperature were significantly correlated (P<0.05, r=0.35).In addition, tympanic temperature and rectal temperature rose gradually with THI increasing, and the regression coefficients of tympanic temperature and rectal temperature on THI were 0.09 (P<0.05, R2=0.09) and 0.10 (P<0.05, R2=0.08), respectively.Collecting time and parity had significant effects on tympanic temperature, while parity and lactation stage significantly affected rectal temperature (P<0.05).THI had significant regression on both tympanic temperature and rectal temperature of lactating cows (P<0.05).【Conclusion】 The results of current study revealed the rhythmic changes and influencing factors of cow body temperature.The tympanic temperature could effectively reflect the real-time body temperature of lactating cows, which provided a theoretical basis for the fine management of farm.

Key words: lactating cow; tympanic temperature; rectal temperature; circadian rhythms

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