Continuing to Help You SynchSmartTM
By: Gamal Abdel-Azim, PhD, Research Geneticist, Genex 
Accompanying the January 2010 sire summary, Genex released an updated ranking system for sire fertility. First released in 2007, SynchSmart rankings indicate sire fertility as part of a synchronization program. Since the initial release, Genex has utilized its strong employee technician force to collect additional data on synchronized breedings.
A Missing Answer
When the topic of synchronization fertility was first addressed, Genex staff turned to the scientific community for previous research. What was found was a complete absence of any research on this topic. After two years of data collection, Genex has prepared data and shared these findings with the scientific community through a scientific article published in the Journal of Dairy Sciencei.
Collecting Research Data
Genex artificial insemination (A.I.) technicians recorded 543,941 breedings from 438 herds. Data included synchronization status and protocol, sire, farm name, technician, date and whether the inseminated female was a cow or heifer. This data was recorded due to the effect on fertility. Other factors included were service number and age of the bull. Two protocols were used in the analysis, Cosynch (25 percent) and Ovsynch (75 percent). The two protocols were treated equally in the analysis and were both categorized under one category of synchronized services. Synchronized services accounted for 27 percent of the data. To remove bias, at least 200 synchronized breedings and 200 conventional breedings were recorded for each bull. Each A.I. technician was recorded for at least 1,000 breedings.
Finding the Facts
This analysis showed bulls differed significantly in their reaction to synchronization. To test this, bulls were given two rankings based on conception rates, one ranking for synchronized breedings and the other for non-synchronized breedings. If bulls were indifferent to synchronization, it was expected that no difference would exist between the two rankings. However, this was not the case. There were major rank differences among bulls. For example, 19 percent of bulls differed in rank by at least 10 places. For a breakdown of all rank changes, see Table 1.
Table 1. Differences in bull rankings across two sets of bull conception rates when used with synchronized and non-synchronized services.
| Aboluste change in rank | >30 | >20 | >10 | >5 |
| Number of bulls | 1 | 4 | 22 | 51 |
Producer Advantage
What impact does this research have on your herd? This research has shown changes for bulls could potentially be ±3 points from an average bull when used on estrous-synchronized cattle. This finding can be utilized to ignificantly boost conception rate of bulls by optimizing their usage. For example, if a bull is known to perform poorly when used on synchronized cattle - restrict that sire's usage to only non-synchronized females. Herds that regularly synchronize cows can increase their average conception by carefully selecting bulls that perform better with synchronization.
When it comes to improving conception rate, every little bit helps. Choose high Lifetime Net Merit, SynchSmart sires to complement your synchronization program. Genex cares about your bottom line and is committed to helping achieve the most pregnancies possible. Look to the Genex lineup for the SynchSmart ranking - no other stud can offer this important conception advantage.
iGamal Abdel-Azim. 2009. Effect of synchronization and semen sorting on artificial insemination bull fertility. Journal of Dairy Science 93:420.
posted January 2010
