Effects of environmental and animal factors on conception rate at the time of insemination of shahiwal cattle in dry zone of Sri Lanka.

Abstract

Study was conducted to assess the relationship of environmental and animal (cow) factors on conception rate at the time of insemination onSahiwal cattle and their crosses inBatticaloa District (dry zone) of Sri Lanka. Breedable female Sahiwal cattle and their crosses (204) were used in this study. All cows were artificially inseminated (AI) and selected 40 cows were used for the synchronization using PGF2α injection. Data on cow such as age, breed, parity, post-partum period (PPP) and milk yield were collected from the available records.Environmental temperature (ET), relative humidity (RH), rectal temperature (RT), respiratory rate (RR), body condition score (BCS), heat sign score and time interval between first detection of heat and the insemination were recorded at the time of insemination.Conception rate was assessed by per-rectal palpation at 90-120 days post insemination. The mean ± SD of the environmental temperature (ET) and the relative humidity (RH) at the time of insemination were 28.12 ± 2.08 0C and 77.29 ± 5.64%, respectively. Environmental Temperature (ET) at the period of insemination was (p<0.05) negatively correlated with the relative humidity. The overall conception rate (57.25%) was effected by ET>29ºC, RH>85% and RT>38ºC. Cattle those were supposed to be with the BCS of 3 and the intense of heat signs and used for synchronization had higher conception rate (p<0.05). The results recommended that the conception rate of cattle is significantly affected by the hot thermal environment, poor energy nutrition and the management practices. Synchronization increases the possibility of heat detection. Hence, inseminating healthy cows during the high heat sign by the skilful AI technician under the suitable environmental condition can improve the conception rate in breedable cows.