Colostrum's impacts on milk production

Speakers on the day were Dairy Australia's James Mann and Glenys Zucco, DairyBio's Jennie Price and DataGene's Peter Thurn.

Additionally, Agriculture Victoria Dairy Production Sciences research manager Bill Wales, Adelaide University pasture agronomy professor Kevin Smith and Mount Gambier vet and Adelaide University student Rebel Skirving spoke during concurrent sessions.

Dr Skirving presented her research project, Get It Right From the Start, on the day which aims to understand more about colostrum and its potential to program cows for the future.

"I started my PhD in 2020 at the start of the COVID lockdown which gave me a lot of time to read journal articles," she said.

"That came with the realisation there's a lot of information already out there about dairy cattle and how they work.

"But the more we find out about cows, the more we realise we actually don't know much about them at all.

"Every research project gets one answer, but then it creates six other questions."

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One question Dr Skirving wanted answered was what impact colostrum had on the rest of a calf's life.

She said research showed piglets that received steady hormones through colostrum from a sow were more likely to become more fertile than those who were not receiving enough.

This led her to research the lactocrine hypothesis, which questions whether an animal's future can be changed by the milk they are fed or if their production is predetermined by their genetics.

"In 2018 a vet did a study looking at the early life events that can affect heifers in their first lactation, and one of the things she looked at was colostrum," Dr Skirving said.

"In her study, she found calves with good colostrum transfer did actually produce more milk at the first lactation.

"However, a year later, another vet did a similar study and her results showed that there was no effect of colostrum and the first lactation results."

Armed with a herd of 2668 calves spread across various dairies in the South East, Dr Skirving said she aimed to support one of the two previous studies, but was unsure what her results would show.

Each cow was blood tested and weighed on day one, then the same again on their first birthday.

Once the herd turns two, they will be blood tested, weighed and then pregnancy tested - this will continue each year as they get older.

Dr Skirving's study will be completed in 2027, and she said either outcome was favourable to the industry.

"If I can show that colostrum does change how a cow turns out then we put all the more effort into colostrum for calves," she said.

"If it turns out that it makes no difference to the milk production and fertility, then it takes the pressure off, because as long as that calf survives the first three months, the colostrum doesn't matter and we can use other genetic factors to make sure she still reaches her potential."