T

he most common rationale for the use of assisted

reproductive technologies (ART) in humans is

to increase the chance of conception. Terms such

as in vitrofertilisation (IVF) or artificial insemi-

nation (AI) have entered the lexicon of the

layperson as society has become more familiar with the use of

technology to assist reproduction.

What is less familiar to the general public is that assisted repro-

duction is common in agriculture, not only to correct fertility

problems but more commonly to drive genetic improvement and

enhance the production efficiencies of the next generation of farm

animals. Assisted reproductive technologies are used in almost all

animal industries but have been particularly heavily adopted by

dairy farmers.

Take the case of the bull known as Badger-Bluff Fanny Freddie

(or simply Freddie). In 2012 Freddie was the top-ranked proven

producer of cows in America. This ranking was derived from the

production and health traits of Freddie’s daughters to determine

an overall profitability score. In 2012, Freddie’s daughters were

considered $792 more valuable over their lifetime than the average

dairy cow, which made Freddie the most desirable bull in the

country.

If left to his own devices, Freddie could pass on his valuable

genetics to approximately 50 cows per year through natural mating.

This would be beneficial to the one farmer who owned those 50

females, but would have minimal impact on the industry at large.

Genetic improvement relies on high selection intensity, good

accuracy of selection and a short generation interval. What this

means is that genes that are deemed to be superior need to be

disseminated widely and passed on as quickly as possible. To do

this the dairy industry employs AI.

Artificial Insemination

Artificial insemination is an assisted reproductive technique in

which sperm are collected from the male and artificially intro-

duced into the female reproductive tract for the purpose of concep-

tion. AI methods were developed at the turn of the 19th century

and today 84% of dairies in Australia use this technology.

Such manipulation of the natural mating process has seen milk

production in Victorian dairy cows more than double in the past

30 years despite cow numbers remaining steady and the number

of hectares they occupy halving. Less inputs for greater outputs is

not only better for the producer but is a more environmentally

friendly and sustainable agricultural approach.

The ability to extend the fertile life of sperm was critical to

achieving these advances. This was achieved by lowering the meta-

bolic rate of sperm by storing them at cooler temperatures

(5–15°C) in the presence of protective agents such as milk and egg

yolk. Under these conditions, sperm could remain viable for trans-

port for a few days so that semen can be delivered to many prop-

32 | JAN/FEB 2016

The ART

of milk

production

TAMARA LEAHY & SIMON DE GRAAF

Assisted reproductive technologies play an

increasingly important role in the genetic

improvement of the high-yielding dairy cow.