Factors affecting fertilization in inseminated cows
Fertilization rates of dairy cows are almost the same during lactation or without lactation, about 76,2 - 78,1% on the average. The main reasons of low fertilization rates are viral (infectious rhinotracheitis, viral diarrhea) and bacterial infections (brucellosis, chlamydia, proteus), mycotoxins, heavy metals, improper feeding. To increase the reproduction rates of the herd it is necessary to induce ovulation in females within 7 - 18 hours right after artificial insemination. In this case pharmacological methods are used to regulate estrus with prostaglandins and analogues of GnRH.