AIMING to drive production and breed the best cows they can, South Australian dairy farmers Graeme and Michele Hamilton and their son Craig, are focused on keeping good records to help them make informed decisions.
At OB Flat, SA, they run up to 500 dairy cows, mainly red breeds with some Holsteins, calving in September and February.
“Our cow pedigrees go back many generations and we have records for just about everything, including calf size and vigour, pregnancy, health treatments and calving ease, as well as all the usual production and herd tests records,” Graeme said.
“We use Mistro through the phone app and the PC version in the office, but we also enter everything on paper, which might sound unnecessary but if we find an error we can then trace things back with a paper trail.”
Graeme’s parents Don and Pat began herd testing six times a year in 1970, a practice he and Michele have carried on since taking on the operation in 1990.
Don and Pat also initiated the Hamiltons’ involvement with red cattle breeds, establishing an Illawarra stud under the Cluain prefix in 1964.
“Our breeding aim is to have a consistent herd – we want to breed consistency in every drop of heifers – there’s no room for duds,” Graeme said.
“Red breeds are a later-maturing type of cow, so we want longevity combined with fertility and a production target of 9000 litres a cow each year.”
The Hamiltons have 68 hectares under pivot irrigation near the milking area, with another 47ha of irrigation at a block further away, mainly used for growing out young stock and fodder production.
The cows are fed grain at the dairy at an annual rate of 2.2 tonnes per cow, which supplements the pasture base on the milking area – worth 3t/cow. The herd is also fed up to 1.5t silage.
The cows are joined using AI, with home-bred, genomically tested mop-up bulls for the heifers.
“We might keep up to five bull calves from the best performing cows a year, but we put them under intense selection pressure to identify which are the best two to keep as mop-up bulls over the heifers,” Graeme said.
Only the top 80 per cent of the herd is joined to red breed sires. The bottom 20pc – based on Balanced Performance Index, cow family, udders, feet and temperament – is joined to Angus sires through AI.
“Joining to Angus makes (culling) pretty simple – if the calf is black then it goes,” Graeme said.
About 180 heifer calves are reared each year and are grown out to a target weight of 330 kilograms to 350kg for joining at 15 months of age.
Of the 180 calves reared, about 150 will join the herd, while any heifer that fails to meet the target joining weight, has conformation issues or fails to get in calf is sold.
“We are very harsh on our heifers because it’s pretty hard to cull them once they get in calf and go into the herd,” Graeme said.
“The longevity of red breed dairy cattle means our average age in the herd is about 50 months, although we do have some 10-year-old cows.”
In the past, they have relied on genetic information from overseas bulls in Denmark and Germany but have been working with DataGene to build the information available within Australia.
“We’ve also been supplying tail hairs for genomic testing from all our heifer calves for the past five years to help build the database for red breed genomics,” Graeme said.
High performing genetics have also been proven to make a difference for the Hamiltons.
Their herd was one of 27 across Australia that underwent detailed analysis by the ImProving Herds project to investigate the contribution of genetics to production.
It identified the top and bottom 25 per cent of each herd, ranked using the Balanced Performance Index, then used 10 years of records to compare these.
The study found the top 25pc of the Hamilton Run herd produced 60 kilograms of fat and 61kg of protein more per cow each year than the bottom 25pc and were worth an extra $531 annually.
On average, the top 25pc of cows also stayed in the herd 11 months longer than the bottom 25pc.
