Effect of heat stress on general physiological and reproductive responses in tropical holstein friesian dairy cows raised in Ratchaburi province, Thailand

Name: Passawat Thammahakin

LCSH: Kasetsart University -- Theses. M.S. (Veterinary Clinical Studies) 2020

Classification :.LCCS: SF208

LCSH: Kasetsart University. -- Faculty of Veterinary Medicine -- Theses

LCSH: Dairy cattle -- Reproduction

LCSH: Dairy cattle -- Effect of heat stress on

LCSH: Holstein-Friesian cattle

Abstract: The study aimed to determine the effect of heat stress (HS) on serum estradiol and progesterone concentrations, reproductive parameters (calving to first service and first service conception rate) and general physiological responses [rectal temperature (RT), reparatory rate (RR), milk yield and body condition score (BCS)] in tropical Holstein Friesian dairy cows raised in Ratchaburi province, Thailand. The study classified cows into two groups using calving date and THI; April 2018 to August 2018 as moderate HS group (n=22) and November 2018 to January 2019 as mild HS group (n=22). Then, cycling cows were detected and injected with PGF2α (the date after injection was designated as day 1). Blood samples were collected to determine the concentration of estradiol and progesterone during day 1-8 and day 22-29. The rectal temperature, respiratory rate, milk yield, body condition score and reproductive parameters were recorded. The average THI of moderate HS group was 80.67±0.79 and mild HS group was 77.81±1.09. The cows showed a significantly lower RT and RR in mild HS (101.24±0.37 °F and 41.04±4.55 bpm, respectively) than in moderate HS (101.97±0.27 °F and 51.17±10.52 bpm, respectively). The cumulative milk yield during 2 months in mild HS (1,149.08±68.63 kg) was higher than moderate HS (1,096.68±91.77 kg). The average BCS in mild was lower than in moderate HS. Cows in mild HS tended to have higher first service conception rate and lower calving to first service (38.99% and 70.27±18.35 days) than cows in moderate HS (15% and 84.60±27.68 days). However, hormones concentrations did not differ between both groups. In addition, the estradiol concentration in mild HS was shown dynamic after PGF2α injection and at following estrus cycle. The progesterone concentration in moderate HS tended to be higher than in mild HS throughout both estrus cycles. These results indicated that heat stress suppressed estradiol and progesterone concentrations throughout a year. Whereas, the general responses were suppressed in moderate HS than mild HS.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Theera Rukkwamsuk

Role: Thesis Advisor

Name: Adisorn Yawongsa

Role: Thesis CO-Advisor

Created: 2020

Modified: 2025-07-07

Issued: 2025-07-07

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2563/passawat-tha-all.pdf

CallNumber: SF208 .P37

eng

DegreeName: Master of Science

Level: Master's Degree

Descipline: Veterinary Clinical Studies

Grantor: Kasetsart University

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