Sexed semen - Precious cargo

STOCK SEXED SEMEN

Precious cargo

Fresh liquid sexed semen is now a major part of artificial breeding. Story and photos by Karen Trebilcock.

It’s early afternoon on Tuesday, October 20, and LIC Artificial Breeding (AB) technician assistant Chrissy Taylor-Claude is waiting at Dunedin Airport for flight NZ5749 from Christchurch.

On it are 34 straws of liquid (fresh) sexed semen from bull Bagworth DM League, 34 straws of Lightburn Free Range and 33 straws of Busy Brook Convict.

The semen was collected from the three Friesian bulls in the morning the day before at the LIC Newstead bull farm, delivered to Sexing Technologies next to Hamilton Airport at 1.30pm where it was spun and sorted, finishing in the early hours of the morning.

It was back at Newstead by 4am to be put into the straws and sealed and not much later on Tuesday morning the 101 straws were at the loading bay ready to be picked up by a LIC courier who carried it as hand luggage on to the flight from Hamilton to Christchurch and then onto Dunedin where Chrissy was waiting.

By 4pm that day it was inseminated into 101 of Taurima Farms’ yearlings on the Taieri which had been synchronised.

LIC national AB manager Dave Hale said it was a busy season this year with liquid sexed semen collections now a big part of the LIC AB product mix. Sexed semen collections started on September 20 and will finish on November 30.

Sexed semen for synchronised yearlings and cows went out each morning as carryon luggage with couriers on flights from Hamilton and Auckland airports while sexed semen for naturally cycling cows went as freight with standard conventional liquid semen deliveries in the afternoon and early evening.

“With freight, we have to have it at the airport more than an hour before the flight and that’s at every airport on the route.

“As carry-on luggage with someone, it’s 20 minutes and as we only have the mornings to get it there for animals to be mated that afternoon, it works really well.

“If we need to, if it’s a large synchro, the courier can also assist the technician with the inseminations.”

All sexed semen for synchro inseminations was used in the afternoon of the delivery, he said.

“With naturally cycling matings, which uses semen collected from bulls in the afternoon, it’s used in the morning as part of the daily scheduled AB run with the aim they are all done before lunchtime.”

The tight timelines ensure the sexed semen is as viable as possible.

Liquid sexed semen has a similar conception rate to non-sexed (conventional) liquid or frozen semen if used within 24 hours of processing.

However, frozen sexed semen conception rates were about 13% less hence the importance of the liquid product.

“Farmers have become acutely aware that if they are unable to milk more cows, they need to milk better ones. “

Rates of pregnancy and resulting days in milk are critical elements of farm profitability making the ‘fresh sexed advantage’ a game changer for New Zealand dairy farmers, LIC general manager NZ markets Malcolm Ellis said.

LIC is the only provider of liquid sexed semen in New Zealand and this year sales of the product are triple that of last year.

“With farmers proactively looking at

ways to mitigate consumer, environmental and animal welfare concerns relating to bobby calves, sexed semen is a useful tool to have in their tool box,” he said.

“Clearly the additional opportunity for farmers to accelerate the rate of genetic gain on farm by targeting heifer calves as replacement stock out of the herd’s most superior cows was also driving demand for fresh sexed semen.

“Over recent years the New Zealand dairy sector has very much reset with the capital gain model that thrived running out its course and regulatory and environmental considerations instead front of mind and putting pressure on cow numbers.

“Farmers have become acutely aware that if they are unable to milk more cows, they need to milk better ones.

“This means that increasing genetic gain through breeding the best quality heifer calves has become an even more valued aspect of dairy farmers’ seasonal focus.”

Ellis said the increase in sexed semen demand had seen LIC invest in its widest distribution of the product to date across New Zealand including, for the first season, the inclusion of all three major dairy breeds with Jersey added to last year’s offering.

Taurima Farms owner Robert Scurr said he had had little idea of the logistics involved when he decided on a liquid sexed semen plan.

He’s used it for contract matings of his cows for the export heifer market about

five years ago so knew the product but this season decided to use it for his yearlings.

“We usually do a 10-day PG synchro with our yearlings with nominated semen and we’ve always had good results with that and I was thinking of this year ordering two or three sexed straws to use over our top cows each day with the natural cycling matings.

“But then I thought that was going to be so much hassle for everyone to identify those cows and find them each morning.”

Instead he’s used the same amount of sexed semen but for 50% of his highest BW yearlings using a CIDR programme to line them up on the one day.

The other 50% were inseminated the next day to nominated, non-sexed semen.

“Last year we did the bottom 10% BW

Left: Robert Scurr is keen to see the results at scanning of how his liquid sexed semen CIDR yearling synchro went on the Taieri. Above: IC AB technician assistant Chrissy TaylorClaude carries the liquid sexed semen in a chilli bin from Dunedin Airport.

cows with beef straws and this year, with using the sexed semen, we’re going to do 15% because we should get all of our replacements easily.

“It’s still probably a bit conservative.”

The aim is to bobby less calves from the 820 cows milking, selling the beef animals to rearers, as well as making the most of his top genetics to produce replacements.

“We’ll see at scanning how good conception was with the sexed semen and in nine months how many heifers we get.

“If I had thought about all the things that could have gone wrong, especially with the Covid lockdowns, I probably would have worried a lot more although we did have frozen nominated semen as backup just in case.

“But it went really, really smoothly.”