Free pay rise in shorter joining periods
16 September 2016
What do comedy and herd fertility have in common?
According to Holbrook veterinarian and commercial producer Shane Thomson, success with both is all in the timing.
“It is a mind shift from traditional thinking but high pregnancy rates do not necessarily mean high fertility, although, as producers, we’re very much drawn to that simple percentage to quantify and compare our joining periods,” he said.
Shane said the litmus test for fertility is the timing – the ability for large numbers of calves to be born, unassisted, early in the calving period, that is, as many cows as possible pregnant in the first cycle.
Shane, who will talk on this topic at next week’s Rosewood ReproActive event, said a herd’s average calving date was a far more reliable way of assessing herd fertility.
“Producers can work this out by using early age pregnancy diagnosis with ultrasound, or by recording how many calves are born at the end of each cycle of the calving period,” he said.
“To ensure accuracy, early pregnancy diagnosis needs to be undertaken four to six weeks after the bull-out date and no later than 14 weeks after the bulls go in.”
Why shorten calving periods?
Shane said the economics of a six-week versus a 10-week calving period speak loudly.
“A calf born at the start of a 10-week calving period will grow at 1kg/day and will be 70kg heavier than a calf born at the end of that period,” he said.
“Based on 100 calves born, being able to move that average calving date earlier by just one day will earn the producer an extra $350 (based on $3.50/kg liveweight).
“To move from a 10-week calving period to a six-week calving period is worth $4,900 per 100 calves – and it’s free.
“Profitability is driven by when the cows are pregnant, not just if they are pregnant.”
Where to start
Shane said setting up well-grown heifers for early joining is the best way to tighten up calving periods.
“The preparation starts at weaning,” he said.
“Aim to join 90% or more of your heifers, understand your herd’s critical mating weight, determine, record and achieve target weights and join the heifers two weeks prior to the main cow herd.
“This gives their calves extra growing time and the heifers more recovery time before being re-joined.
“Joining a heifer early sets her up as an early calver for the rest of her life.”
Let bulls do the culling
According to Shane, the only consultants qualified to select heifers for joining are the production system and the bulls.
He encouraged producers to resist temptation to select the top, say 60%, of heifers, on weight, conformation and type and, instead, let the bulls be the judge.
“By joining 90% of heifers, it enables producers to capture all those females that will join in their first cycle and provides more market options for those deemed culls later on,” he said.
“A high percentage of heifers also gives producers the freedom to cull more late calvers from the cow herd.”
Select for early calving females
Shane said producers shouldn’t feel pressured to achieve pregnancy rates of 90% and above unless they are herd-building.
“If you are joining 90% of your heifers, for example, you only need 75% of your entire herd pregnant to retain the same breeding numbers,” he said.
"As these fertile herds are capable of achieving pregnancy rates much higher than this, even with short joining periods, producers are empowered to select and retain with priority, the early calving females in their herd.”
Shane reminded producers that fertility is a low heritability trait and the best way to improve fertility is through good management.
ReproActive workshop
The workshop will be held at ‘Calrossi’, 1373 Tumbarumba-Wagga Rd, Rosewood, NSW, from 8.30am to 3pm on Friday 23 September.
For more information and to register online visit http://www.reproactiverosewood.eventbrite.com.au by 22 September.
Contact: Shane Thomson T: 0499 986 838 E: shane@holbrookvetcentre.com.au
Tools and resources
A calving histogram calculator to identify percentage of cows conceiving at each cycle
