Utilising sexed semen for the top 15-20% of a herd accelerates the rate of genetic gain by focusing on generating replacements from your top cows. Farmers can then consider alternative beef AB or short gestation options for their poorer-performing animals, enabling them to either significantly reduce the number of bobby calves leaving the farm or capture additional milking days, both options adding to the value obtained from the bottom end of the herd.
“If farmers used short gestation semen on their bottom end, you get more days in milk, which is money in the bank, particularly given the current milk price,” Ellis says.
“The alternative beef option opens other opportunities; there’s value to be had there as well. It’s important to look to make gains at both ends of the herd.”
Typically in a herd situation, the BW differential between the top 20% and the bottom 20% is in the order of 100-150 BW. Even at 100 BW, if farmers can obtain more of the required heifer calves from their top cows, and by using dairy beef or short gestation options for the bottom end, those heifer calves from higher ranked cows will be 50 BW superior to the expected outcome of breeding from the poorer-ranked portion of the herd.
“When I talk about this example, that’s the ‘aha’ moment for a lot of farmers,” he says.
“When we were in the cow growth years, no one cared much about this sort of selection pressure, but now as a consequence of that, we have a big range of BW within individual herds and in the wider national herd. Sexed semen is an effective tool to drive the rate of genetic gain.”
The technology for sexed semen has been around for a few decades, but since the country hit ‘peak cow’, interest in the technology has been rising. He says the increased demand is driven by a deeper understanding and realisation among farmers that if they aren’t going to be milking more cows in the future, they will need to be milking better cows.
“Since hitting peak cow in 2015, cow numbers have started to decline, and farmers are recognising the need for fewer but better-quality cows and retaining offspring from the best cows. We’re heartened by the fact that the majority of our farmers that are using fresh sexed semen, say their main driver is the positive impact on genetic gain they’re getting,” he says.
Ellis says that herd improvement will do a lot of the heavy lifting to offset cow number and milk decline. Average cow production has increased by around 5.9kgMS each year over the last 10 years. It is estimated that 40% of this is directly attributed to genetics.
“If national gains in the rate of genetic gain increased from 10 to 15-20 BW points per year, the associated productivity gains would go a long way to counteract declining cow numbers and overall milk production,” he says.
Otorohanga farmer Marian Numan used sexed semen for the first time last season, to help reduce the number of bobby calves their herd produced.
“It was always disappointing to see some of our lovely crossbred bulls going on the bobby truck. Using sexed semen across our top-tier cows has allowed us to produce roughly 30 heifer calves that would have otherwise been bobbies. It’s a win-win. We can retain more of our good genetics with less waste overall,” Numan says.
Prior to the current upward trend of sexed semen, there was a degree of negativity around the associated non-return rates. In a 2017 blind trial comparing frozen sexed semen with frozen conventional semen, the differential came in at -13.4%.
When Ellis first came into his role in 2016, he says he knew the potential of sexed semen and hoped gains could be made to improve that non-return rate figure.
“Getting cows in-calf is one of the most important parts of any dairy farmer’s seasonal focus, so it’s critical we deliver a sexed semen option that doesn’t notably compromise that goal,” he says.
The breakthrough was in using fresh sexed semen where the differential can be significantly reduced to -5%, with LIC’s most recent data for 2021 spring mating’s sitting at -4.7%.
For the 2021 mating season, a staggering 201,700 cows were mated using sexed semen, up on the previous years 110,000 and 33,000 the year before that.
“Next season, we are projecting growth to 300,000. We have to be really clear in our projections to ensure we’ve got the daily processing capacity,” Ellis says.
To meet the increasing demand, LIC repurposed an area within their Hamilton headquarters to accommodate a new laboratory facility solely for the production of sexed semen. The state-of-the-art lab sits alongside LIC’s bull farm and semen processing lab and is the world’s biggest fresh sexed semen sorting facility. The lab hosts Sexing Technologies, a US-based company who is contracted to sex-sort semen from LIC’s top dairy and beef artificial breeding bulls.
“It means we no longer need to transport semen offsite to be sex-sorted, so the time between collection and insemination is reduced, enabling longer use in the field, which ultimately allows more farmers to tap into its value,” he says.
“While any big investment like that comes with risks, we knew that we needed to increase capability and capacity because of where the market was heading. It’s been a big couple of years in this space and it’s only set to get bigger as more farmers realise the potential of sexed semen within their herds.”