The New Zealand Dairy industry relies on artificial breeding to produce high genetic
merit replacement stock. Proven bull semen is extended and preserved as either
ambient temperature product or as frozen doses. High fertility is essential to maintain
synchronicity of lactation with the spring surge of grass growth.
To improve efficiency in the utilization of the very best bulls producers try to lower
sperm dose rates without compromising fertility. Livestock Improvement
Corporation's (LIC) Long Last Liquid ™ (LLL) is most commonly used during the
peak season and is their most important product. However, shortfalls and specifically
targeted matings are met with frozen semen. Lowering sperm dose rates in both liquid
and frozen semen maximises the usage of elite sires increasing genetic gain, lowering
overheads and garnering premium prices for the semen producer.
A product for improving frozen semen technology was developed whereby a discrete
quantity of pretreated semen was placed alongside a beneficial post-thawing
redilution medium in a standard semen straw. This emulated a larger-scale process
developed to freeze semen in times of low demand and redilution into the LLL form
for use as an ambient temperature product. This rediluted product has been proved to
enhance semen survival and to allow fertility to be maintained at sperm dose rates
lower than the widely accepted standard for frozen semen.
The physical packaging of the semen into the industry standard single dose straw in a configuration that separated incompatible components was novel. This configuration
was essential to prevent damage to the sperm during the freezing process from low
solubility components in the post-thaw redilution medium. Separation between the
semen and diluent within the straw was achieved by the introduction of a gas partition
or air bubble between the two liquids.
A large-scale field trial showed that the new product could produce savings of up to
25% of the sperm needed for a semen dose to achieve equivalent fertility.
Furthermore, the production cost per dose was lowered in comparison to the standard
semen processing system used at LIC.
