The single biggest thing dairy farmers can do to improve the beef merit of their calves is to use sexed semen.
This sounds counter-productive as most people associate sexed semen with increased dairy heifers.
However, the real benefit of sexed semen in block-calving dairy systems is that it can mean fewer dairy inseminations and more beef inseminations.
Conception rates with sexed semen can be comparable to conventional semen when the most suitable cows are selected and the correct protocol is followed. Sexed semen ensures that about 90% of the calvings are to female calves.
What has this got to do with breeding beef calves? Well, the fact that sufficient dairy heifer calves can be produced with fewer dairy inseminations means that more cows can be put in calf to beef bulls with a higher beef value. If using sexed semen, you can almost eliminate male dairy calves.
Of course, there are a few provisos to this.
Firstly, if the herd is expanding then extra dairy matings will be required to generate sufficient replacements. Secondly, a good level of female fertility should be present in the herd before sexed semen is used, otherwise calving patterns could be more drawn out.
Even without using sexed semen, dairy farmers should only be breeding as many replacements as they need for their own use. In most cases, this is around a 20% replacement rate. Those supplying milk to Glanbia are not going to be able to expand freely over the next few years so they will not need extra replacement heifers.
The best policy is to only breed dairy to the best cows and use beef on the rest. When a sufficient number of cows are bred to dairy and expected to be in calf, then beef AI can be used. Beef AI is superior to stock bulls as there is more scope to use higher-Dairy-Beef-Index (DBI) bulls.
All AI bulls and beef stock bulls have a DBI value expressed in euro. The main components of DBI are calving difficulty (53%), carcase weight (17%), gestation length (10%), followed by carcase conformation (6%) and then feed intake, carcase bonus, polledness, carcase fat, docility and calf mortality. These are broken down into two categories – beef value and calving value.
When looking at the DBI, you should look at both the calving value and the beef value. Because the overall DBI is a combination of the two, the breakdown of each is important.
Ideally, you should be picking bulls towards the top of the list that are balanced for beef and calving value and have a high reliability for each.
The biggest issue for most dairy farmers is calving difficulty. For obvious reasons, they are very reluctant to use bulls that have a higher risk of calving difficulty.
However, the issue is that most bulls that have a very low calving difficulty score are also relatively poor for beef value. It is hoped that in time and as beef genetics improve we will be able to breed beef bulls that are easy calving but also have good beef characteristics.
How much calving difficulty is acceptable when picking a beef bull? A lot of this comes down to individual farmer preferences. Interestingly, on larger farms where there is more labour around there might be a greater willingness to use higher-calving-difficulty bulls.
On the flip side, dairy farmers who are working on their own need to be really careful about what AI and stock bulls they pick. The last thing they need is to be up half the night jacking calves.
I think that bulls with a calving difficulty score of between 3% and 5% is probably acceptable for most farmers. Seven of the top 10 bulls on the current DBI list have a calving difficulty score of less than 5%.
For heifers, you are going to have to accept a higher risk of calving difficulty when picking beef bulls but there are plenty of bulls on the DBI with a calving difficulty of less than 7% for heifers.
One thing to look for is the reliability of the data, particularly when it comes to heifers. By right, you should only use bulls with a high reliability that is greater than 70% for use on heifers. There is scope to use less reliable bulls on cows.
The main issue with stock bulls is that their reliability is so low compared to proven AI bulls. Using any beef stock bull on heifers is a big risk to take, unless he has been successfully used in the past.
Removing the beef stock bull from the dairy herd is probably the ultimate step to improving the beef value of non-replacement progeny. It will ensure more accuracy of sire recording and allow the use of higher-DBI bulls with greater reliability of beef and calving values.
It’s not just calving difficulty that dairy farmers should be looking at when picking bulls. Gestation length is also critical. The chosen bull can either add or subtract days to the gestation length. Shorter gestation lengths are a blessing to the dairy farmer as they allow cows to come back into milk faster.
At the end of the day, dairy farmers will need to be adequately rewarded for using high-DBI AI bulls. A system needs to be put in place to allow this to happen.