Clinical Study of Estrus Appearance Time, Duration of Estrus and Effect of Temperature and Lighting Hours on Estrus in Iraqi Mares

Abstract

This study was conducted in Southern Iraq. Were subjected to the study  of 15 mares with one adult stallion, between the ages of 5-20 years, during the period from February to September 2021. Cases were diagnosed by rectal palpation ,vaginal examination using a vaginal speculum and  teaser. The result show revealed 13.3% of mares its seasonally polyestrous, 33.3% irregular estrus while its recorded 53.3% polyestrous animals. also The results show decreased in Follicular phase duration in June  4.71±0.19 day  significant (p<0.05), then in May, July and August 5.91±0.08, 5.23±0.23 and 5.84±0.22 day respectively while its increased follicular phase duration during April, February, march and September 6.5±0.15, 7.2±0.20, 7.1±0.17 and 7.25±0.17 day respectively, this results show An inverse relationship between the length of the day and the temperature with duration of the follicular phase. And The results in table 2 show the Number  of mares in estrus 10,10, 12, 12, 14, 13, 13 and 12 with percentage 66.66, 66.66, 80.00, 80.00, 93.33, 86.66, 86.66 and 80.00, from February to September respectively, The highest number of estrus cases was recorded in June month, with 14 at a temperature of 42 degrees and a lighting period of 14.10 hours. While the lowest percentage was recorded in the February  and march months at a temperature of 25 and 27 degrees and a lighting period of 10.52 and 11.49 hours respectively.