Technological advances have brought conception rates from sexed semen in line with, or even above, conventional semen, which makes it increasingly relevant to block calving systems, says Cogent.
Having dipped his toe in the water last year and used a small amount of sexed semen on the autumn block calving herd at Buscot Wick Farm, Ben Redman is now convinced it is the right ongoing strategy.
It is these results which have shifted his opinion. Having served a proportion of milking heifers to Sexed ULTRA 4M last year, conception rates to sexed were found to be nearly 9% higher than the conception rates to conventional semen.
Mr Redman says: “You cannot not be happy with those results.”
Like many block calving farmers, Mr Redman had largely dismissed the use of sexed semen due to historically low conception rates. However, the development of Sexed ULTRA 4M, which uses double the usual number of sexed semen cells per straw, brings conception rates closer to conventional. As a result, he was willing to experiment with sexed again.
Mr Redman says: “We have not used much [sexed] in cows before this year, as I was worried about conception rates. I need cows back in the block. Fertility is what pays the bills and keeping that block tight is so important.
“We cannot risk losing it.”
Mr Redman is herd manager at Buscot Wick Farm, on the Oxfordshire/Gloucestershire border, where the Kinch family manages 1,000 hectares, a quarter of which is committed to the 380-cow dairy herd, with the rest in arable.
The farm is an autumn block calving Strategic Farm for AHDB Dairy. Most of the herd calves in a 12-week block, with the herd achieving a six-week calving rate of 86%.
Eighty cows calve in a spring block; largely as a result of slipping out of the autumn block and due to concerns over sourcing high health, bought-in replacements.
Producing highly fertile animals has been the number one aim over the last decade or so, following a period where the herd drifted from an autumn block to an all-year-round calving system, largely following an outbreak of digital dermatitis, which affected fertility.
In the last six years, Mr Redman has been moving to a four-way cross-breeding strategy to help drive this fertility.
This has involved crossing the predominantly black and white herd to Norwegian Red, then Fleckvieh and back to a Holstein or Ayrshire.
Mr Redman says: “We wanted to keep fertility pushing on and I wanted a stronger cow and to get a stronger cow quickly. I had used Norwegian Red before and I knew it worked.
“Although this is a crossing programme, we are not losing sight of the importance of functional conformation traits, such as good udders, legs and feet, sound locomotion, as well as low somatic cell counts.”
The Norwegian Red was selected for fertility and feet, the Fleckvieh for yield and robustness and the Holstein for milk and udders. The four-way cross is not set in stone and will be varied depending on what sire is best suited to each cow.
The fact dairy semen is only used for the first six weeks of service in the autumn block, then followed by beef, also ‘self-selects’ for fertility in replacement heifers.
Remaining animals go to Cogent Beef Visions Aberdeen-Angus and Hereford bulls, with all of the spring block going to these sires. This includes Dunlouise Earlston, Weeton Panther and Romany 1 Lawbreaker.
Cross-breeding and moving to an August to October block from a June to December one, also fits better with their Arla Morrisons contract, while maintaining more consistent milk constituents. The herd averages 8,500 litres at 4.2% fat and 3.56% protein.
Most of the herd are Fleckvieh crosses, so last year Mr Redman selected Holstein sire, Mr Mastermind from Cogent, and bought 150 Sexed ULTRA 4M straws and 150 conventional straws.
Mr Redman says: “We used 90 of each and the Mastermind 4M was 8.7% higher conception rates in milking heifers than conventional.”
This meant conception rates to Mastermind were 59.7% to Sexed ULTRA 4M. He also used 21 straws of Sexed ULTRA 4M semen from Ayshire bull, De La Plaine B-King and achieved 66.67% conception rates.
The pattern was also repeated in maiden heifers which were synchronised for the first time due to labour challenges. These achieved 59.8% conception rates to 4M and 52% to conventional.
Mr Redman says a move to using automated heat detection collars, which advise on insemination timings, has helped conception rates, ‘but there is no doubt 4M has played a part’.
He is so convinced, his plan is to use more of the 4M this season.
He says: “I will probably use a bigger proportion of Holstein 4M in the first three weeks of service. That first cycle will probably all be 4M [on Fleckviehs].”
Sexed semen with the right conception rate is invaluable... you can put more to beef and have more valuable beef calves
In the future, he hopes to improve conception rates further by tackling Neospora issues within the herd, which have lead to problems with abortions seven months into pregnancy. With a large number of public footpaths running across land that fronts on to the River Thames, this is an ongoing problem due to dog walkers.
Mr Redman believes good conception rates to dairy sexed semen will help with the farm’s sexed and beef strategy. The unit currently has a good outlet for dairy beef calves, with calves going at 10-14 days old to Straight Line Beef.
“Sexed semen with the right conception rate is invaluable. If you are getting your daughters early you can put more to beef and have more valuable beef calves,” says Mr Redman, who also believes this is invaluable when it comes to animal welfare and consumer perception of beef from the dairy herd.
Moving forward, he is convinced there is more which can be done to make more of what is produced on-farm.
He says: “Beef income is important to us. I may try some of the male sexed semen beef in spring-calvers this year. If conception rates hold up, there is a high chance I will move to that in the autumn block too.”
Mr Redman says costs more than add up, thanks to the added premium he can receive for male beef calves. For example, he quotes £18 for sexed male beef semen, versus a premium of £40-£45/head on Aberdeen-Angus.