Sexed semen has been a big hit for us – despite a couple of problems
We got three sexed bull calves in a row and our six-week calving rate was down, but we have seen rapid, focused genetic gain in replacements
For the past two years, since we started using more sexed semen, we had seen a slide in our six-week calving rate (the proportion of the herd calved down within the first 42 days).
This is to be expected as sexed semen has slightly lower conception rates to service than conventional. Nonetheless, it was annoying.
The benefits of using 100pc sexed semen for the herd are immeasurable. Rapid, focused genetic gain in replacements sourced from the elite cows and heifers is a sizeable carrot.
The addition of genotyping this year will further increase those gains.
We always benchmark our herd performance against efficiency targets that reflect solid principles of profitability, and the six-week calving rate is an important one.
When you consider that every percentage drop in six-week calving rate equates to a reduction in profitability per cow of €8.22, it all adds up. Considerably. So how do we overcome it?
Initially we looked at being very tight on sexed semen usage. If there was going to be a reduction in conception rate, then let that reduction only affect the smallest proportion of the herd that is absolutely necessary. In other words, only producing the replacements we needed.
We judged that 50pc conception rate to sexed semen would be a sufficient contingency to cover any problems. If 20 replacements were required, then 40-45 sexed AI straws were used.
Everything else got a beef straw: Angus, Hereford, Charolais, all with a high dairy beef index (DBI).
The plan was to only used sexed semen in the first week of the breeding season so the repeats would occur earlier also. That all worked well the first year, but we still had a decrease in six-week calving rate.
Last year we looked at increasing the proportion of the herd calving in the first three weeks, with longer-gestation beef AI a week before the planned start of mating. Normally we begin breeding on April 26, aiming for February 1 to start calving.
We chose a Limousin bull with a gestation length of 288 days and 3.7pc calving difficulty for cows. Considering our herd is cross-bred, averaging 520kg mature weight, we didn’t want difficult calvings.
Targeting 10pc of the herd, mating began with the long-gestation beef bull on April 19, along with a worrying feeling that our Christmas holidays would be cut short with the arrival of a chunky Limousin calf.
So what were the results? Calving began in the last few days of January, with the first Limousin appearing on the 31st.
Replacement heifer calves hit the ground like clockwork. 50pc of the total sexed pregnancies were born by February 1.
Then a sexed Jersey bull calf arrived. Given that the straws are 90pc sexed, this is to be expected and is built into the breeding plan. A few hours later another sexed bull calf arrived, a Friesian this time. Certainly bad luck to have two in a row.
The next morning we were greeted with a third sexed bull calf in a row — a 1,000-1 chance.
The remaining sexed calvings have gone to plan. The final cow calved down to a sexed pregnancy and we have our full requirement of replacement heifer calves, all born within 10 days.
All the long-gestation beef calves have arrived, making the first week quite busy but certainly improving our six-week calving rate overall.
This approach will definitely be used again this breeding season.
Space for a glut of calves is essential and we are well set up with good accommodation.
The early beef calves are easy to sell on, and genotyping should give greater confidence to buyers on the true parentage and breeding.
A recent Teagasc study demonstrated that every extra kilo of calf weight between 40kg and 100kg equates to €5 in calf price when breed and age are equal.
It found that Belgian Blue and Charolais bull calves commanded over €200/hd at three weeks of age, with Angus, Limousin and Hereford bull calves close to €140 for the same age and weight.
Over the years we have built up good relationships with calf buyers who are looking for healthy calves that don’t give any trouble. That X-factor is invaluable to many who might be farming part-time.
Ten days into calving, the mood is positive. We have come up with a workable plan for sexed semen usage that doesn’t negatively affect sixweek calving rate, and genotyping is a win with both replacements and beef calves.
‘The early beef calves are easy to sell on, and genotyping should give greater confidence to buyers on the parentage and breeding’