Evaluation of Artificial Insemination Results in Holstein Friesian Heifers after Calving

Abstract

The aim of this study is to investigate the different factors which affect calving parameters in Holstein Friesian (HF) heifers. From all the data collected, the main objective is to give a better understanding of each variable which must be kept in mind when trying to improve the fertility rate and therefore the farm’s production. 1590 HF heifers' conception records were examined and their data was gathered over a twoyear period. These heifers were located on an American dairy farm. Information such as ID number, the birth date of the dam, lactation number of the dam and the number of breedings up to and including conception were recorded. 111 different bulls' sperm was used to inseminate those heifers either by conventional AI (CONV), or sexed semen AI (SS). Likewise, the herd’s embryo transfer (ET) program utilized those bulls are the sires.