Now that calves are appearing on the ground, the real results of sexed semen inseminations carried out last year are coming to light. At this stage, over 80% of the calves have been born and registered and hence we have an indication of the success rate or otherwise. The results to date show conventional semen (normal straws) coming in with a conception rate of 42.8% compared with approximately 38% for the various sexed semen treatments. This means a number of things:
Sexed conception rates are coming in near 90% of normal semen which is an improvement compared with when previous technology was used; Conception rates are lower than scanning results presented earlier in the year, based on 4,000 scans which suggested normal semen had a 49% conception rate compared with 42% for frozen sexed semen. Preliminary analysis shows conception rates much lower in cows at 34% compared with maiden heifers at 43%. However, not all calves have been registered yet and full results will be available at the end of March, once all calves are born and registered.
In the 2013 trial, over 15,000 sexed semen inseminations were completed and, so far this week, over 12,000 of those inseminations have passed 290 days. The 290-day figure is the normal gestation length plus eight days, which is the average time it takes a farmer to register a calf.
Speaking at a stakeholder meeting for partners involved in the large-scale trial this week, Juan Moreno, Sexing Technologies (ST); said that there is now even better technology available for sexing. ST has developed the sorting machine and materials even more since the trial took place last year. Using new developments, he expects conception rates with ‘fresh’ sexed semen to be closer to 97% of conventional semen, almost the same. He expects ‘frozen’ sexed semen to come in between 93% and 95% of normal semen.
Moreno said: “Overall, these are good trial results based on the set-up and rushed logistics associated with getting the trial set up in Ireland last year. There should be no reason why numbers won’t increase by 5% if a proper long-term laboratory, for example, was set up.”
Sexed semen will reduce conception rates by 20% compared with normal conventional semen. This means that if normal conception rates to first service are 50%, if you use a sexed semen straw, conception rates will be 40%. The trial results show that the technology is now closer to 90% of normal AI straws, which increases this figure from 40% to 45%.
Does sexing actually work?
The aim of sexing is to get more females or males, depending on what objective you require. Results from the 2013 trial show between 85% and 86% sexed semen.
This means that a dairy farmer using sexed female semen will get approximately eight out of 10 female calves and the other two male calves.
When asked if this could improve, Moreno said if the machine was run at a slower speed, he could guarantee a higher ratio, closer to 94%, but the time was not available last spring to run the machines slower, process the semen and get it to farmers.
Breed and sire differences
In the trial last year, Jersey crossbred herds had higher conception rates compared with straight Holstein Friesian herds.
The results show conception rates approximately 39% for Holstein Friesian herds (4,059 calves from 10,438 inseminations) compared with 46% for Jersey crossbred herds (532 calves from 1,157 inseminations). The number of inseminations to Jersey cross cows are much smaller.
When the pregnancy results are broken down in terms of EBI, particularly fertility EBI, it is clear that more fertile cows have a higher success rate.
The top 20% of cows (2,200 inseminations) in the trial had a fertility EBI of €124 and 973 calves were born from these inseminations, so it was a 44% pregnancy rate. The bottom 20% of cows (2,200 inseminations) in the trial had a fertility EBI of €33 and 727 calves were born, so there was a 33% pregnancy rate.
There were also some significant male fertility differences. One particular bull (OGH) had low conception rates across all four treatments. Conception rates for this bull were poor, down by approximately 26% for normal semen. When semen from this bull was sexed, it fell to less than 20% across the sexed treatments.
The rest of the bulls had a conception rate of between 43% and 48% with normal semen. When this semen was sexed, frozen conception rates generally fell to between 36% and 45%. It is not yet clear why semen from different bulls react differently to sexing and freezing.
Beef sexing trial underway
At the stakeholder meeting this week, Andrew Cromie from ICBF updated the meeting on progress in the beef sexed semen trial.
In recent weeks, a new proposal was drawn up which allowed a farmer to get two sexed straws for one conventional straw at a reduced price of €15 for the sexed straws and €30 for the normal straw. Free synchronisation drugs were provided to participating suckler farmers.
So far, 86 herds have signed up to take 1,460 inseminations (an average of 17 straws per herd) and ICBF is signing up about 25 herds per week. ICBF expects to finish signing up beef herds in the next month, when it has 120 herds participating in the trial.
Future ongoing research required
There is no doubt but there are still a lot of questions to answer with regard to sexed semen usage in dairy herds. At the stakeholder meeting, Steven Butler suggested a number of field trials that need to verify results.
He said: “We need to test the new generation of sexed semen that promises better results than we achieved this year.
‘‘We need to see what conception rates we can get if heifers and cows are synchronised and we need to identify what herds should look at the option of using sexed semen and what herds need to stay away from sexed semen.”
Challenges
At the stakeholder meeting, Cromie outlined some of the challenges to get sexed semen off the ground in the Ireland.
He said there are concerns among farmers given the farm-to-farm variation in terms of conception rates. There are concerns within the AI organisations that if sexed semen was widely available, the market for semen in Ireland would be reduced.
Over 800,000 doses of dairy semen are used in Ireland and AI industry surveys suggest that if it were used and widely available, farmers would use less semen.
Trial proposal
ICBF has a proposal on the table that there is a need for ongoing research over a five-year period and this would cost in the region of €400,000 per year. It would allow the industry to get answers to some of the remaining questions and verify for Irish farmers the success, or otherwise, of this technology.
ST says it has eight ongoing trials in six countries, with different breeds of cattle. All results suggest that a conception rate of between 95% and 97% can be achieved. Sexed semen usage usually depends on milk price, beef price and seasonal issues, so seasonal variation in usage does occur. Research results from a Harvard study suggest cows that deliver a female calf produce more milk in the next lactation.Dairy farmers will need to use six weeks of AI – expecting stock bulls to clean up the rest of the herd after three weeks of AI is not on. Dairy farmers will have to use more beef AI. Indirect genetic selection, benefits such as keeping females only from the first cows calved, will lead to better fertility females.
Now that calves are appearing on the ground, the real results of sexed semen inseminations carried out last year are coming to light. At this stage, over 80% of the calves have been born and registered and hence we have an indication of the success rate or otherwise. The results to date show conventional semen (normal straws) coming in with a conception rate of 42.8% compared with approximately 38% for the various sexed semen treatments. This means a number of things:
Sexed conception rates are coming in near 90% of normal semen which is an improvement compared with when previous technology was used; Conception rates are lower than scanning results presented earlier in the year, based on 4,000 scans which suggested normal semen had a 49% conception rate compared with 42% for frozen sexed semen. Preliminary analysis shows conception rates much lower in cows at 34% compared with maiden heifers at 43%. However, not all calves have been registered yet and full results will be available at the end of March, once all calves are born and registered.
In the 2013 trial, over 15,000 sexed semen inseminations were completed and, so far this week, over 12,000 of those inseminations have passed 290 days. The 290-day figure is the normal gestation length plus eight days, which is the average time it takes a farmer to register a calf.
Speaking at a stakeholder meeting for partners involved in the large-scale trial this week, Juan Moreno, Sexing Technologies (ST); said that there is now even better technology available for sexing. ST has developed the sorting machine and materials even more since the trial took place last year. Using new developments, he expects conception rates with ‘fresh’ sexed semen to be closer to 97% of conventional semen, almost the same. He expects ‘frozen’ sexed semen to come in between 93% and 95% of normal semen.
Moreno said: “Overall, these are good trial results based on the set-up and rushed logistics associated with getting the trial set up in Ireland last year. There should be no reason why numbers won’t increase by 5% if a proper long-term laboratory, for example, was set up.”
Sexed semen will reduce conception rates by 20% compared with normal conventional semen. This means that if normal conception rates to first service are 50%, if you use a sexed semen straw, conception rates will be 40%. The trial results show that the technology is now closer to 90% of normal AI straws, which increases this figure from 40% to 45%.
Does sexing actually work?
The aim of sexing is to get more females or males, depending on what objective you require. Results from the 2013 trial show between 85% and 86% sexed semen.
This means that a dairy farmer using sexed female semen will get approximately eight out of 10 female calves and the other two male calves.
When asked if this could improve, Moreno said if the machine was run at a slower speed, he could guarantee a higher ratio, closer to 94%, but the time was not available last spring to run the machines slower, process the semen and get it to farmers.
Breed and sire differences
In the trial last year, Jersey crossbred herds had higher conception rates compared with straight Holstein Friesian herds.
The results show conception rates approximately 39% for Holstein Friesian herds (4,059 calves from 10,438 inseminations) compared with 46% for Jersey crossbred herds (532 calves from 1,157 inseminations). The number of inseminations to Jersey cross cows are much smaller.
When the pregnancy results are broken down in terms of EBI, particularly fertility EBI, it is clear that more fertile cows have a higher success rate.
The top 20% of cows (2,200 inseminations) in the trial had a fertility EBI of €124 and 973 calves were born from these inseminations, so it was a 44% pregnancy rate. The bottom 20% of cows (2,200 inseminations) in the trial had a fertility EBI of €33 and 727 calves were born, so there was a 33% pregnancy rate.
There were also some significant male fertility differences. One particular bull (OGH) had low conception rates across all four treatments. Conception rates for this bull were poor, down by approximately 26% for normal semen. When semen from this bull was sexed, it fell to less than 20% across the sexed treatments.
The rest of the bulls had a conception rate of between 43% and 48% with normal semen. When this semen was sexed, frozen conception rates generally fell to between 36% and 45%. It is not yet clear why semen from different bulls react differently to sexing and freezing.
Beef sexing trial underway
At the stakeholder meeting this week, Andrew Cromie from ICBF updated the meeting on progress in the beef sexed semen trial.
In recent weeks, a new proposal was drawn up which allowed a farmer to get two sexed straws for one conventional straw at a reduced price of €15 for the sexed straws and €30 for the normal straw. Free synchronisation drugs were provided to participating suckler farmers.
So far, 86 herds have signed up to take 1,460 inseminations (an average of 17 straws per herd) and ICBF is signing up about 25 herds per week. ICBF expects to finish signing up beef herds in the next month, when it has 120 herds participating in the trial.
Future ongoing research required
There is no doubt but there are still a lot of questions to answer with regard to sexed semen usage in dairy herds. At the stakeholder meeting, Steven Butler suggested a number of field trials that need to verify results.
He said: “We need to test the new generation of sexed semen that promises better results than we achieved this year.
‘‘We need to see what conception rates we can get if heifers and cows are synchronised and we need to identify what herds should look at the option of using sexed semen and what herds need to stay away from sexed semen.”
Challenges
At the stakeholder meeting, Cromie outlined some of the challenges to get sexed semen off the ground in the Ireland.
He said there are concerns among farmers given the farm-to-farm variation in terms of conception rates. There are concerns within the AI organisations that if sexed semen was widely available, the market for semen in Ireland would be reduced.
Over 800,000 doses of dairy semen are used in Ireland and AI industry surveys suggest that if it were used and widely available, farmers would use less semen.
Trial proposal
ICBF has a proposal on the table that there is a need for ongoing research over a five-year period and this would cost in the region of €400,000 per year. It would allow the industry to get answers to some of the remaining questions and verify for Irish farmers the success, or otherwise, of this technology.
ST says it has eight ongoing trials in six countries, with different breeds of cattle. All results suggest that a conception rate of between 95% and 97% can be achieved. Sexed semen usage usually depends on milk price, beef price and seasonal issues, so seasonal variation in usage does occur. Research results from a Harvard study suggest cows that deliver a female calf produce more milk in the next lactation.Dairy farmers will need to use six weeks of AI – expecting stock bulls to clean up the rest of the herd after three weeks of AI is not on. Dairy farmers will have to use more beef AI. Indirect genetic selection, benefits such as keeping females only from the first cows calved, will lead to better fertility females. 
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