25 November 2020

While scanning the cattle IVF literature, you will likely see the references that a medium, especially culture medium, is “serum-free”. As we have already discussed in previous blogs, addition of serum is a ‘two-edged sword’. On the one-hand it can promote development, particularly if embryo growth is slightly retarded and morula formation is hindered. But on the other-hand, serum addition at levels of 5% or more will increase triglyceride content that negatively impacts cryo-survival, especially with ‘slow-freezing’ protocols. Furthermore, serum addition is a causal factor for ‘Large Offspring Syndrome’.