**5. Conclusion**

Currently fresh, chilled and frozen-thawed semen are used extensively for AI in animal breeding and production throughout the world. Dairy herd size has increased with increas‐ ing pressure to maximize milk yield, whilst at the same time reducing production costs is necessary. Accurate oestrus detection crucial for timed and successful AI and early detection of the success or otherwise of insemination can meaningfully reduce the time delay before repeated insemination if this is necessary. For these reasons it is very important to have a reliable method to accurately detect the occurrence of oestrus. Errors in efficiency and accu‐ racy of heat detection result in high semen cost and an increase in the interval from calving to conception, reducing cow production and net returns. The use of ultrasonography prior to AI for determining the ovarian status can significantly improve the success of AI.

Conversely, reproductive management is currently a major factor affecting profitability in the dairy industry. Early identification of non-pregnant dairy cows and heifers post AI can im‐ prove reproductive efficiency and pregnancy rate by decreasing the interval between AI serv‐ ices and increasing AI service rate. Thus, imaging technologies such as ultrasound to identify non-pregnant dairy cows and heifers early after AI may play a key role in management strat‐ egies to improve reproductive efficiency and increase profitability on commercial and small holder dairy farms. Early detection of non-pregnancy will lead to earlier intervention and de‐ cision that will shorten the calving interval, which has economic effect on the diary farm. Transrectal ultrasonography has also been used to determine foetus viability and hence can improve the outcome of AI by allowing knowledge based decision on problem cows.
