Fresh vs frozen

Over the next few months, Totally Vets will be running a trial to test out the effect of a different type of AI straw on conception rates in autumn calving dairy cows. 

Over recent years Tararua Breeding Centre has been producing high-density beef semen straws and has observed dramatic increases in conception rate (between 10% and 15%) when these straws were used as part of fixed time insemination programs.  There are a few key differences between the high-density straws and standard semen straws. Firstly, as the name suggests, they contain a lot more sperm!  In fact, they contain more than seven times the number of sperm compared to standard fresh straws and about double the number of sperm compared to standard frozen straws.  To preserve the health of the sperm these high-density straws are refrigerated, and the straws are made with a specifically designed egg yolk-based diluent.

Totally Vets is keen to investigate any development that can improve the performance of our dairy farms so during the upcoming autumn mating we will be testing these high-density straws on dairy cows using Friesian, Kiwi Cross and Jersey bulls.  We will be bringing you further information on the trial results in early 2020, so make sure you watch this space for updates.

We are currently in the process of recruiting farms for this trial, so if you are interested in helping us to improve dairy herd reproduction and have an autumn calving herd please contact Laura Beasley at the Feilding clinic.  You can get in touch by either calling the clinic on 06 323 6161 or emailing Laura at

Laura is one of our production animal veterinarians at Feilding and is part way through studying for her Master of Veterinary Medicine degree through Massey University, and this research project will form her final thesis.


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