Effect of environmental factors on estrus synchronization and artificial insemination success in farmers flock in sheep under semi-arid tropical region

Environmental cues in the different seasons might influence the estrus and lambing percentages. The present study was conducted to assess the effect of environmental factors on estrus synchronization (ES) and artificial insemination success in sheep. During the period from 2012 to 2017, a total of 1,197 ewes of Kheri and Malpura breeds of 34 farms originating from 10 villages were synchronized for estrus and then fixed-time artificial insemination (FTAI) was done. Oestrous synchronization was done by intravaginal progesterone sponges and eCG protocol. Fixed-time cervical insemination was performed 48 and 56 hr after sponge removal in ewes exhibiting estrus, using liquid chilled semen containing 100 million sperm per dose of Patanwadi/Malpura rams. Mean sunshine hours, maximum and minimum ambient temperatures, temperature amplitude, mean relative humidity (RH), temperature-humidity index (THI), mean temperature during sponge-in to sponge-out-12-day period, sponge-out and next day, AI day and AI to next 15 days have been calculated. The estrus response and lambing percentage were higher (p < .05) when ES and FTAI were done during hot-humid with rainfall season. Successful (p < .05) ES occur when the minimum temperature was higher in cold-humid season, and the sunshine hour was higher in hot-humid with scanty rainfall season during sponge-in to sponge-out period. The success of the lambing percentage was higher (p < .05) when maximum temperature, minimum temperature, mean temperature and THI was higher on the day of AI and the next 15-day period, irrespective of the season. The success of FTAI indicates the adaptability of the local breed to tolerate the harsh climate of the hot semi-arid region without much hindrance in lambing percentages.