Making genetic progress

By Dairy News

DARREN AND Sharon Parrish have seen genetic trends in their 200-cow Holstein herd head in the right direction, with Genetic Progress Reports giving them clear feedback on their breeding program.

Information on their herd’s performance is a key factor in how the Parrishes run their operation and make better decisions on their farm at Bodalla on the NSW south coast.

Their farm was one of 27 dairy farms across Australia that recently underwent detailed analysis by the ImProving Herds project to investigate the contribution of genetics to dairy businesses.

The study identified the top and bottom 25 per cent of each herd, ranked on Balanced Performance Index (BPI), the genetic index for profit used by the Australian dairy industry, and compared their performance in terms of production, longevity and financial contribution.

Ten years of historical performance data, plus recent farm financial data from the Parrishes’ herd records, were analysed to look at the difference in contribution to the farm business between the top and bottom BPI groups in the herd.

The study found the top 25 per cent of the herd, ranked on BPI, produced 37 more kilograms of fat and 25 more kilograms of protein per cow, per year, than the bottom 25 per cent.

The extra milk production from the top 25 per cent of cows ranked on BPI resulted in an extra $366 income after feed and herd costs per cow per year compared with the bottom 25 per cent. On average, the top 25 per cent of cows also lasted nine months longer in the herd.

“We’ve been keeping detailed cow records for a long time — it’s something I really like doing because the information we collect gives us feedback on our cows,” Mrs Parrish said.

“While it does involve a bit of extra work, the information you get back on your cows shows you what they are doing, the gains we are making and helps us make better decisions.”

The Parrishes’ Genetic Progress Report produced by DataGene showed the Holstein sires they had used over the past 10 years had produced daughters with improved genetics for the traits that contribute to profit, including production, longevity, fertility and mastitis resistance.

In fact, their herd had improved at a rate faster than the national herd average since 2014 for longevity, mastitis resistance, fat and protein.

The Parrishes look at a number of criteria when selecting sires and use the Good Bulls Guide as part of their research.

“I’ll generally select for type traits in bulls — rear udder height and width, or feet and legs,” Mr Parrish said.

“We want sires to be positive for protein, fat and litres for the production traits, then we want daughter fertility traits above 108 and health traits above 100.

“We always look at BPI — if two bulls are comparable, then the bull with the high BPI is the one which is selected.”

Darren’s brother Trevor also plays a role in the herd’s genetics.

“Trevor has one of the leading herds in the country for BPI so I work in with him when I am selecting bulls,” Mr Parrish said.

“He is also my source of genomically tested mop-up bulls that we use over the heifers after the AI program.”

The Parrishes’ Holstein herd is registered under their Darradale prefix so only Holstein sires are used. The herd has split-calving, with equal portions of the herd calving in autumn and spring.

All mature cows in the herd are joined to conventional semen over three rounds of AI — with a spring and autumn program.

Cows that don’t take to AI are generally sold, unless their production is exceptional and then they can be carried over to the next joining period.

Sexed semen was used for the first time on heifers last year and their calves are due this spring.

“We were rearing around 100 heifer replacements a year, but that number is creeping up to more than 110 this year,” Mr Parrish said.

“We don’t cut any corners with our heifer rearing because they are our better genetics and we make sure they grow out well and reach target weights, get in calf and come into the herd.

“We like to keep a lot of heifers coming into the herd because they are genetically better than the older cows they are replacing.

“About 50 per cent of our herd is made up of heifers and the average cow in the herd would be on its third lactation.”

While the size of the farm’s milking area currently limits the expansion of the milking herd, Mr Parrish aims to use the sale of surplus dairy cows in-milk to maximise the contribution of livestock sales to the dairy enterprise.

“Having as many heifers as possible coming into the herd allows me to put selection pressure on the mature cows and I can identify surplus milking cows which are sold to other farmers.”

The Parrishes have not been genomically testing their replacement heifers recently because their priorities have focused on dealing with the dry season, but they intend to genomic-test replacement heifers in the near future.

“We originally genomically tested as two-year- olds for three years when we were a Genetics Focus Farm and did the testing on two-year-old heifers, so it coincided with classification,” Mr Parrish said.

Genomic testing has proven valuable in identifying superior heifers and verifying parentage and he hopes it will help make better use of polled genetics in the future.

“We want to incorporate greater use of polled genetics into the herd as the number of better performing polled sires become available.

“We’ve used a few polled bulls in the past and have daughters in the herds with polled genes.

“It’s a matter of planning for the future and polled genetics will help us optimise animal welfare and save the time and money involved in dealing with horned calves.

“Our herd is very involved with local schools — we have farm visits and supply three schools with bull calves to rear as part of the Cows Create Careers program — so we want to make sure our herd and farm practices are moving in line with community expectations.”

Farm statistics (August 2018)

Herd size




Farm size

218ha total, 65ha milking area

Calving pattern

Split 50:50, autumn:spring


18-a-side swing-over


Three full-time

Feeding system


Herd testing

11 times a year