Photo: Supplied
Sexed semen breeding programmes for the beef industry have primarily focused on developing genetically superior replacement heifers.
“Male sexed semen is an opportunity to capture value. The opportunity’s greater when the price spread between oxen and heifers is significant,” says Dr Ken Odde, professor and department head emeritus of the Department of Animal Sciences and Industry at Kansas State University.
Since retiring from academia, Odde has focused on creating more profitability for his family’s commercial cow-calf ranch in South Dakota in the US.
“About six years ago, I was sitting at the sale barn in Mobridge, South Dakota, and the price spread between [oxen] and heifers just struck me that day,” says Odde.
From that ‘aha’ moment, Odde started to pursue what a sexed semen breeding programme could look like for his ranch.
He shares strategies and protocols to consider for success, including fertility differences between cows and heifers, the use of split-time or fixed-time artificial insemination (AI), and the value of using breeding indicator patches to measure oestrus intensity.
Value of breeding for bulls
Before breeding with sexed semen, Odde looked back at industry trends to see the economic impact of breeding for more males.
“We’ve got years of history when most sexed semen was targeted at producing females,” says Odde. “Breeding for males is a shift in thinking, and ultimately it’s driven by how high the price difference is between oxen and heifers.”
Data from Superior Livestock (see Table 1) shows that the price per hundredweight (cwt) difference between oxen and heifers has been on an upward trend for nearly three decades. Odde says the price difference between oxen and heifers has been primarily driven by increasing carcass weights and the rising cost of gain.
Feedlot close-out performance data in Kansas (see Table 2) from August 2017 showed the average cost of gain was US$5,66 (R106,75) per cwt higher for heifers versus oxen. That year, maize was relatively cheap to feed at $3,91/bushel (R2 704/t). In August 2022, the average cost of gain was US$12,77 (R240,40) per cwt higher for heifers than for oxen, when the maize price was US$8,69/bushel (R6 010/t).
“Oxen can be fed to higher weights more efficiently,” Odde adds. “The trend of increasing carcass weights could be a driver of producing more male calves with sexed semen, particularly when feed prices are higher.”
On-ranch experience
The first set of females to be bred with sexed semen on Odde’s ranch used maternal female sexed semen on heifers (see Table 3) and predominantly utilised terminal male sexed semen on cows (see Table 4). Following an oestrus synchronisation protocol, heifers were bred by visual heat detection using Estrotect Breeding Indicator patches to aid in oestrus detection during five days of monitoring.
The heifers’ AI pregnancy rate was 63,4%. In the first year, cows were bred using multiple protocols. With fixed-time AI, cow reproduction rates were 40,9%. Two cow groups were bred using split-time AI at 70 hours post-prostaglandin injection for cows with activated Estrotect patches.
If patches weren’t activated, insemination happened at 90 hours with an injection of GnRH. The split-time groups had pregnancy rates of 45% and 47%.
“We think with split-time AI, we were able to pick up a few more cows running them through a second time. However, it is pretty labour-intensive, so we’ve moved towards more fixed-time AI with the cows.”
In the third year of research, male sexed semen was used across all the heifers and cows.
“We have learnt we get better fertility on our yearling heifers than on mature cows,” says Odde. “We can easily produce more bull calves from our heifers, so that’s something we want to evaluate further.”
Words of advice
If you are considering breeding with sexed semen, Odde suggests using a protocol that helps make chute-side breeding decisions based on oestrus intensity gathered via a breeding indicator patch. If half of the patch or more is rubbed off, females are good candidates to be bred with sexed semen.
Should less than half of the patch surface ink be rubbed off, it’s best to use less expensive conventional semen to help manage costs of your genetics investment.
Keeping an eye on market trends is another management practice to consider. “You need an understanding of the economic dynamics,” he says.
For some herds, it may work better to develop more replacement heifers via sexed semen and marketing those replacements to terminal-focused operations, particularly when replacement females are in demand.
“It could be that male sexed semen works well in some situations, and a few years later, it may not have the same incentive,” Odde adds.
“When there is a good price difference between oxen and heifers, it can really work well.”
Odde presented his on-ranch research findings during the Beef Improvement Federation Annual Symposium in Calgary, Alberta, Canada, on 3 July.
For more information on breeding indicator patches, visit Estrotect.com.
The Estrotect Breeding Indicator is the industry standard for optimising cattle breeding efficiency and economics. With millions and millions of units sold around the world, Estrotect is the only breeding management tool tested in a multitude of university studies by researchers. Email Dr Kenn Odde at [email protected].
