STUDIES ON THE IMPACT OF SEASONAL VARIATION ON VARIOUS REPRODUCTIVE PARAMETERS IN DAIRY COWS OF HIMACHAL PRADESH
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Date
2022-11-04
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Palampur
Abstract
The study was carried out in Livestock Farm Complex, CSKHPKV Palampur to assess
the impact of different seasons on cow’s reproduction. A total of 30 Jersey crossbred cows
(n=10 cows in each season) in their 1
st to 5th lactation, aged around 2-8 years having body
condition score around 2.5-3.5 were selected for the study. The year was divided into three
seasons viz., summer (May to August), winter (November to February), and isothermic season
including both spring (March and April) and autumn (September and October) seasons. Daily
temperature-humidity index (THI) was calculated using a dry and wet-bulb thermometer
placed outside all the animal sheds. All cows were subjected to the sonographic examination
every 48 hours for ovarian structures from the day of estrus till the completion of one estrous
cycle. Seasonal variation in the developmental patterns of follicles and corpus luteum during
three-follicular waves (all cows showed 3 wave pattern) of the estrous cycle were studied.
Blood samples were collected on day 0 (day of estrus), 5, 10, 15 and day 20 to study the
impact of seasonal variation on different hormones (cortisol, estradiol-17β and progesterone),
haemato-biochemicals (alanine transaminase, aspartate transaminase, alkaline phosphatase,
creatinine, total protein and cholesterol and complete blood count), minerals (calcium and
phosphorus), and electrolytes (sodium, potassium and chloride). The THI recorded during
different seasons showed significant variation (p0.05) and did not show any relation with the variations in follicular dynamics parameters
during different seasons. Plasma cortisol levels showed significant variation (p<0.05) in
different seasons with increased levels in the winter season followed by the summer season.
Blood biochemical profile like aspartate transaminase, alanine transaminase, and alkaline
phosphatase showed significant variation (p<0.01-0.05) during different seasons. Potassium
was the only electrolyte to exhibit significant variation (p<0.01-0.05) in different seasons.