By Dr Jason Archer
As a dairy farmer, why would you take the time to select beef genetics to produce calves with growth and carcase traits that someone else will benefit from?
It’s a good question, but enhancing the quality of this country’s dairy beef has the potential to create greater value right along the value chain and importantly, using superior beef genetics will also reduce the number of bobby calves being processed in line with public sentiment.
I agree that our systems do not always reward the breeder (dairy farmer) for breeding genetically superior dairy beef calves, but we need to make a start. Producing calves that generate greater value for the finisher will have finishers seeking out calves that they are prepared to pay a premium for.
A closer connection between dairy farmers and finishers would certainly help create this value.
The advent of sexed semen has created an opportunity for using quality beef sires, a trend we are seeing around the world, for example in Ireland, Europe and the United States. In the latter, I’ve been involved in creating breeding indexes to identify Angus bulls for use in their dairy systems.
Many myths about using beef bulls over dairy cows have been dispelled and dairy farmers can now use the appropriate beef genetics with confidence that they will not create calving problems or longer gestation periods.
What traits and EBVs should dairy farmers be looking for?
The calf to be born without assistance or damaging the heifer or cow
Select the EBV for calving ease – direct. This incorporates birthweight and gestation length into its prediction. You don’t need to look for calving ease maternal EBV unless the female calves are being retained as beef breeding cows.
The calf to be born early to increase the days in milk and when born at the end of the season, to shorten the calving span
Select on gestation length, a negative EBV is better (shorter gestation).
A calf that is resilient, gets up and going quickly and achieves weaning weight as quickly as possible
Don’t go too low in birth weight EBV, while still maintaining calving ease. While there are no real tools to select for resilience to disease or vigour, a moderate birth weight gives the calf a head-start to achieving a weaning weight in a shorter time frame.
A calf that grows well in the growing and finishing phase
Look for good 400 and 600-day weight EBVs.
A calf that expresses muscle well and has a good dressing-out percentage. Ultimately, a calf that yields the maximum amount of saleable meat. Look for eye muscle area EBV. This is expressed at a standard carcase weight so gives an indication of overall muscling.
A calf that has adequate finish (fat cover) and finishes quickly
Look at EBVs for fat (rib and rump). It’s difficult to set a target unless you know how the calves are performing in a finishing system relative to the breed and genetics being used.
Finishing animals require a minimum 3mm of subcutaneous fat cover and preferably 6mm at slaughter for optimal meat quality. Bear in mind, dairy genetics tend to deposit more fat internally rather than externally, but beef cross animals need to have a decent fat cover. Start by selecting bulls having fat depth EBVs which are slightly above average for the breed being considered and adjust from there based on experience.
Carcase quality (the ability to target premiums is often based on marbling)
Consider a high value IMF% (intramuscular fat) EBV when targeting a high-value markets paying a premium for eating quality. The pH of the carcase is also important and this can be influenced by temperament in beef cattle (with EBVs for docility). This is not usually a problem in dairy cross beef animals due to the influence of their rearing systems.
Comparing apples with apples
It is important to remember that unlike dairy EBVs which are compared across breeds, beef EBVs are within their breed only. This means Angus bulls can only be compared with other Angus bulls and not Hereford or Charolais, for example. This means the emphasis on the traits listed above might change depending on the beef breed being considered. This is why it is not possible to give ranges of numbers to look for, as they differ between different breeds.
Consider the cow
Does the bull selection matter depending on the breed of cow? In the US, the American Angus Association created different indexes to use over a Holstein versus a Jersey cow. For Holstein, the emphasis was on marbling and less on growth and avoided the very tall bulls as processing plants were reporting issues with the very large frame US Holsteins.
We don’t have a height EBV available in NZ for beef bulls, but because cows are a more moderate size with smaller carcase weights there is not the same need. For Jersey, the emphasis was more on muscling (eye muscle area) and growth, as these were the two attributes that needed enhancing when producing beef cross calves. Similar principles would apply in NZ depending on cow type and breed mix. But both major dairy breeds have a natural tendency to produce good levels of marbling, so the potential to produce high eating quality in the beef dairy cross carcase is already there.
- Dr Jason Archer is Genetics Specialist with Beef + Lamb New Zealand Genetics.
