METEOROLOGICAL PROFILE OF THRISSUR AND ASSESSING ITS RELATIONSHIP WITH PHYSIOLOGICAL STRESS PARAMETERS IN CROSSBRED CATTLE
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Date
2020-10-01
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COLLEGE OF VETERINARY AND ANIMAL SCIENCES MANNUTHY, THRISSUR
Abstract
The present study was conducted to (1) prepare meteorological profile of
Thrissur; (2) improvise a respiratory gaseous exchange measurement system for
thermal stress assessment in local crossbred cattle; and (3) assess the impact of
meteorological parameters on stress physiology of the animals.
The ambient temperature, humidity and rainfall, recorded at Kerala
Agricultural University, Vellanikkara, from 1986 to 2016 was used to profile the
local meteorological data. The second phase attempted to fabricate in situ
dwelling thermal probes for continuous recording of rectal temperature (RT),
improvise suitable mask for the animals, and to standardize the Physiological
Monitor with appropriate calibrations. For the third phase, eight crossbred bovine
female animals above the age of six months of uniform body weights were
managed under standard feeding regime with free access to drinking water.
Observations were made in two separate periods of sixty days each, corresponding
to highest annual temperature humidity index (THI, Season I) and lowest annual
THI (Season II). Ambient temperature, relative humidity, solar radiation and wind
velocity were continuously recorded using automatic weather station. Respiratory
rate and exchange of O2, CO2 and water vapour were recorded using the
improvised face mask and the Physiological Monitor, continuously for two
minutes for each animal twice a day, at three days interval. Continuous rectal
temperature from 10.00AM to 03.00PM was recorded using indwelling rectal
probes attached with highly sensitive sensors and data acquisition system at three
days intervals. Pulse rate (manually) and sweating rate (Schleger and Turner,
1965) were recorded at three days interval. Fortnightly venous blood was used for
estimating volume of packed red blood cells (VPRC), haemoglobin concentration
and glutathione peroxidase activity (GPX). The blood serum samples were used
for estimating cortisol, T3 and T4. Body weight was also recorded fortnightly.
The present study was conducted to (1) prepare meteorological profile of
Thrissur; (2) improvise a respiratory gaseous exchange measurement system for
thermal stress assessment in local crossbred cattle; and (3) assess the impact of
meteorological parameters on stress physiology of the animals.
The ambient temperature, humidity and rainfall, recorded at Kerala
Agricultural University, Vellanikkara, from 1986 to 2016 was used to profile the
local meteorological data. The second phase attempted to fabricate in situ
dwelling thermal probes for continuous recording of rectal temperature (RT),
improvise suitable mask for the animals, and to standardize the Physiological
Monitor with appropriate calibrations. For the third phase, eight crossbred bovine
female animals above the age of six months of uniform body weights were
managed under standard feeding regime with free access to drinking water.
Observations were made in two separate periods of sixty days each, corresponding
to highest annual temperature humidity index (THI, Season I) and lowest annual
THI (Season II). Ambient temperature, relative humidity, solar radiation and wind
velocity were continuously recorded using automatic weather station. Respiratory
rate and exchange of O2, CO2 and water vapour were recorded using the
improvised face mask and the Physiological Monitor, continuously for two
minutes for each animal twice a day, at three days interval. Continuous rectal
temperature from 10.00AM to 03.00PM was recorded using indwelling rectal
probes attached with highly sensitive sensors and data acquisition system at three
days intervals. Pulse rate (manually) and sweating rate (Schleger and Turner,
1965) were recorded at three days interval. Fortnightly venous blood was used for
estimating volume of packed red blood cells (VPRC), hemoglobin concentration
and glutathione peroxidase activity (GPX). The blood serum samples were used
for estimating cortisol, T3 and T4. Body weight was also recorded fortnightly. Respiratory rate started increasing at 300
C ambient temperature and THI 82
while rectal temperature started increasing at 340
C and THI 86. GPX was
significantly higher and T4 was significantly lower in Season I compared to
season II. Thus, moderate heat stress was evident at higher THI values prevalent
in the region, usually falling between March and May. Besides, regression
equations for respiratory rate and rectal temperature have been worked out. This
study is expected to predict physiological response in cattle subjected to hot
humid conditions prevalent in the locale.
Description
Submitted in partial fulfilment of the requirement for the degree of
Doctor of Philosophy in CLIMATE CHANGE AND ANIMAL AGRICULTURE