Breeding

Semen collection

Anal probe and semen being collected from bull.

Only specific bulls are used for breeding to produce calves of the ‘highest quality’. Semen is collected from bulls through the use of ‘electro-ejaculation’. This involves forcing a large rectal probe inside the anus of the bull that acts to stimulate them until they involuntarily ejaculate.

When bulls are no longer economically viable for farmers they are generally sent to slaughter. Dairy Australia’s Program Manager of Animal Health and Fertility, Dr Kathryn Davis, was quoted in 2015 saying that “85% of Australian dairies use artificial insemination to some extent.” The numbers today are likely much higher. 

Cows being artificially inseminated. Source: No Bull

Artificial insemination (AI):

The AI process involves the farmer forcing their arm into the cow’s anus and holding her cervix as a guide, while inserting a straw (‘gun’) containing the bull semen into the cow’s vagina, through her cervix, and depositing the semen into the body of her uterus.

Diagram of Artificial Insemination technique. Source: In Calf Booklet: Dairy Australia (p. 110)

Dairy cows are impregnated annually to ensure milk production remains consistent. With a gestation period of 9 months, this means that each year they’ll spend 9 months pregnant with 3 months off/’rest’.

Artificial insemination of cows is used widely within the Australian dairy industry, for several reasons:

• AI gives farmers significant control over when their herd will be calving. Many farms split the herd’s calving so that some of the herd will calve over autumn and others will calve in spring. This is done to spread the farmers’ workload over the year and to keep milk supplies consistent. For smaller farms the cost of using AI for their herd is often cheaper than feeding a bull for 12 months of the year.
• Bulls can also be difficult for farmers to handle, so AI proves an easier alternative.
• For larger herds, farmers have the ability to choose ‘better’ genetics and match cattle with bulls that will fix genetic ‘flaws.'