Reproductive performance of cows under homoeothermal disturbances

Abstract

Based on the data on the maximum minimum temperature and humidity for a period of two years a year of study was divided into four seasons of JJA SON DJF and MAM The mean maximum environmental temperature of the seasons were 29 56 31 52 32 73 and 34 88°C respectively Two thousand two hundred and ninety eight cows brought to the AI centre from the homesteads of Mannuthy were grouped into 11 treatments of pre and post insemination rests and no rests They were bred by artificial insemination and results of insemination were assessed on the basis of non return Mean conception rate of the seasons were statistically analysed to know the effect of environmental temperature and the effect of pre and post insemination rests to the animals There was no significant difference m conceptions between seasons between the post insemination rests and no rests and between pre insemination rests of 30 and 60 minutes and no rest Conception per cent was significantly higher in the animals those were given pre insemination rest for 90 and 120 minutes Animals with light coat colour had a significantly higher conception rate than those with dark colour irrespective of the seasons Animals inseminated m the afternoon were generally found to have a better conception rate than those inseminated m the forenoon There was no significant difference in the conception rate of heifers and cows both between seasons and between themselves So also there was no significant difference in conception rate of parity groups both between seasons and between themselves Statistical analysis of seasonal mean weight of foetal membranes mean number of cotyledons and mean area of cotyledons and mean birth weight of calves did not show any correlation to suggest influence of seasonal environmental temperature on placental development and birth weight of calves