Premiums on standard schedules or possibly at store cattle sales for particular types can easily sway breeding decisions but pursuing a purebred policy for a premium market can mean physical performance is compromised. Andrew Swallow reports.
How much is hybrid vigour worth in a beef cow herd? It’s a hard question to answer precisely but research on the phenomenon shows it’s substantial.
However, it’s a benefit that is rarely split out financially when commercial beef producers are making their breeding decisions, a stud breeder and vet who has tried harder than most to answer the question says.
Dave Warburton runs Angus and Hereford stud herds on agisted grazing, as well as practicing as a vet with Veterinary Services Hawkes Bay’s Hastings clinic. He tackled the cross-breeding topic at a Hereford Association field day last year and revisited it for this Beef Special.
In cows, hybrid vigour has most effect on low heritability traits such as milk, fertility and longevity, with little influence on carcase traits such as eye-muscle area, rib and rump fat, or intra-muscular fat.
‘Many breeders put their B-grade cows to terminals, but it does create an extra mob at mating, and mean that three breeds of bull are needed, so it’s only really possible in larger operations.’
The crossbred cow’s gains in fertility and milk boost calf production (maternal effect), but if the calf is also the result of crossbreeding then there’s a direct effect in its performance too. Combined, maternal and direct effects have been shown to add up to 23% faster growth on average.
There’s limited research data in New Zealand quantifying such effects, particularly in beef x beef crosses, but findings from overseas do translate to our systems, Warburton says.
“These effects stack up in every environment.”
For example, in Australia’s Black Baldy project, comparing the progeny of Hereford or Angus sires put across Angus cows (see p109), calf survival of the hybrids was 5.8% higher, and the calves grew 8% faster than their purebred counterparts, he says.
For heifer calves, 15% more hybrids were cycling at 15 months compared to straight Angus calves, with 6% more getting in calf by natural mating.
Such performance can reduce the number of heifers needed as replacements, especially as the resulting crossbred cows tend to have greater longevity and, on average, produce an extra calf in their lifetime, Warburton says.
A simple way to maintain the hybrid vigour effect in a crossbred herd is to backcross or rotationally cross by marking heifers according to the breed of their sire, then mating them to the other breed making up the hybrid for the rest of their life. So if a heifer calf born to a Hereford/Angus cow was sired by a Hereford, she’s put to Angus bulls, and vice versa.
The resulting progeny from rotational or backcrosses will qualify for most premium schemes based on the sire’s breed, and it keeps the number of mating mobs required down to a minimum of two: one with Hereford bulls and one with Angus bulls, if the aim is to maintain an Angus/Hereford hybrid herd.
Such systems have the benefit of simplicity, but they will miss out on the extra growth a three-way cross can bring, Warburton says. Typically, to grab that a terminal sire such as a Charolais, Limousin or Simmental is used across the maternal hybrid, most likely an Angus/Hereford.
“The main benefits you’ll see are heavier progeny, faster growth and improved yield.”
However, unless hybrid heifers are bought in every year, then there’s a limit to how many of the herd can be put to such terminal sires.
“Many breeders put their B-grade cows to terminals, but it does create an extra mob at mating, and mean that three breeds of bull are needed, so it’s only really possible in larger operations.”
Such three-way cross progeny probably won’t be eligible for breed-based price premiums so working out what will make most money is tricky (see table).
“You need to do your own calculations,” stresses Warburton.
How much finishers pay for store cattle of the different types further complicates the calculations. A price premium for a purebred of 40c/kg carcaseweight is, in theory, worth $40/head on a 200kg weaner assuming an eventual 50% dress out, but by the time it’s 600kg that’s $120/head.
At a base price of $6/kg CW, the three-way cross needs only to be 40kg LW ahead at slaughter – that’s just 6.7% on a 600kg animal – for the finisher to make a better return from it.
A further complication is the interaction of breed, finishing weight, and time of finishing. The three-way cross with its faster growth should hit target finishing weights sooner, even if, because of their genetics, they need taking to slightly higher weights to achieve the same finish.
“The average kill age of beef cattle in NZ, at something like 27-months, is still way too old to be efficient.”
A simpler alternative to three-way crosses is a composite.
“The advantage is you can run one herd and maintain 80% of the hybrid vigour.”
For breeders, to date, extra growth potential of hybrids has tended not to be adequately rewarded at autumn calf sales and/or weaner fairs, he says.
“The terminal-sired calves are always the biggest and heaviest but the disadvantage for the seller is that there tend not to be so many buyers for these top end animals. A lot of buyers come to these sales with a dollar per head figure in mind and if the animals are heavier than they expect, then the price per kg tends to be discounted.”
Warburton says as for which are the most efficient at converting feed into beef, the answer to that isn’t really known for grazed pastoral systems.
“It’s really hard to measure. The only trials that have been done are in feedlots… But if hybrids are not fed to their potential, you won’t see the full hybrid vigour effect.”
One thing that has to be watched with a hybrid herd is mature cow weight, as extra growth in replacement heifers can lead to heavier cows but using bulls with low EBVs for mature cow weight should keep a lid on it, he says.
Another thing to be prepared for, particularly with three-way crosses, is greater variability in progeny. While there will be some great calves among them, inevitably there will be a few that pick up the worst traits of all three breeds.
But as the Black Baldy trial results and others show, on average hybrid vigour means crossbreds outperform purebreds.
There’s a win-win
Beef + Lamb’s national beef genetics manager Max Tweedie echoes Warburton’s comments on how hybrid vigour is often overlooked in commercial breeding decisions.
“We’re just not taking advantage of it nearly as much as we could especially the three-way cross… If we can keep the cow-size moderate and gain all the benefit [of hybrid vigour] then that’s a win-win.”
With the national calf weaning rate for beef herds languishing at about 82% of cows mated, the extra fertility a hybrid cow brings could be particularly beneficial, he adds.
“More calves on the ground is a significant driver of profit for a breeder and hybrids bring about a 12% improvement in that trait.”
Finishers targeting breed-based branded premiums has tended to mean purebred calves command higher prices at weaning, at least in cents per kg terms, which is probably the main reason crossbreds aren’t more popular with breeders, he believes.
But the faster growth of hybrid calves (see main article) means finishers should make more money with them, even if they do not qualify for a premium brand, especially if the finisher can buy the hybrid at a discount per unit liveweight to purebreds.
Modern meat grading technology, such as marbling measurement, also means premiums for high quality beef are becoming available regardless of the colour of coat it is delivered in, he adds.
Dairy-beef cross concerns
Dairy-beef hybrids do display the same vigour effects but with only half of the parentage focussed on beef traits history has shown these crosses frequently run into problems, Warburton says.
Excess milk causes udder problems and mastitis, and fertility can be a problem when the going gets tough due to drought or other factors. Also, most dairy farms use beef bulls to cover cows that don’t hold to AI or have other undesirable traits – usually poor feet and/or udders – so the dairy element of the dairy-beef cross tends to come from the worst dairy cows. Another factor against the cross is that the beef bulls used in the dairy industry are not, in general, the best for beef, he adds.
“When you think about it, the dairy-beef ‘breed’ is not going to be ideal for maintaining a hill country breeding cow herd… They produce a good calf, there’s no question about that, but the problem is how long can the cow stay in the system?”
Various reports from Beef + Lamb NZ and Massey University’s 2010-2018 trial comparing performance of Angus cows and progeny with three different Angus x dairy cross cows and their progeny support Warburton’s comments on mastitis, calf growth and, to a lesser extent, udder issues.
Condition scores showed the pure beef cows better able to buffer feed pinches but their pregnancy rates were slightly lower than two of the crosses, and only on par with the third, suggesting hybrid vigour effects on fertility outweighed condition effects in that trial environment. Failure to get in calf was the main reason for culling cows throughout the trial.
Big beef hybrid trial concluding across ditch
A major trial in Tasmania started in 2014 measuring hybrid vigour in grass-finished Angus x Hereford progeny will conclude later this year.
The Black Baldy trial on Musselroe Beef’s breeding unit at Cape Portland on Tasmania’s northeast coast, and its finishing unit inland at Nabowla, is a partnership between the farm, Herefords Australia, Adelaide University and Meat and Livestock Australia.
Data on reproductive capacity, including age of puberty, liveweight, carcase and eating quality is being collected and analysed from progeny of about 600 commercial Angus cows artificially inseminated to 11 industry leading Hereford sires, and Angus sires for comparison.
All sires and progeny are genotyped with Geneseek HD SNP (150k) and Geneseek LD SNP (40k) respectively, providing certainty of parentage.
Back-up bulls of both breeds were sourced from leading Australian studs and used over the three cohorts of heifers and cows drafted for the trial.
Forty per cent of calves in the trial were born to two-year-old maiden heifers and the balance to three- and four-year-old cows. The last cohort of steers from the trial are currently finishing on grass and will be processed in July, with a final report due in December.
Preliminary calving and weaning results show Hereford sired steers were heavier at weaning than Angus-sired, by 9% if born to mature cows, and by 3% from maiden cows.
Adelaide University’s Professor Wayne Pitchford says sire breed differences were not significant for calving ease or calf survival across all age groups but splitting out two-year-old maiden heifer data there was a 5% increase in assistance required for Hereford sired bull calves, reflecting an overall 6% higher birthweight for Hereford sired calves.
Consequently, he suggests using Angus bulls over heifers to reduce risk of calving difficulties, and Herefords over mature cows to add growth.
“As an example, if a commercial Angus herd of 100 cows had 20 heifers and 80 mature cows calving, use of Hereford bulls would mean assisting only an additional three calves but getting the production of an extra 1600kg of weaning weight.’’
Herefords Australia general manager Andrew Donoghue, says the trial’s findings hold true to similar work in the USA where Herefords have experienced “a significant resurgence” thanks to crossbreeding programmes.
Herefords Australia is planning further research to measure maternal values of Hereford F1-hybrid cows.
Angus Australia’s Andrew Byrne says he doesn’t know enough about the Black Baldy results to comment on the trial, but says the challenges with cross-breeding in many cases outweigh the benefits.
“Some markets will only accept cattle of a certain breed. Utilising hybrid vigour remains an opportunity, however considered review of both the advantages and disadvantages is important.”
- Hybrid vigour
- Substantial maternal benefits.
- Compounded with 3-way cross calves.
- Overseas research still relevant here.
- Complexity of breeding management and mature cow size possible downsides.
- Free lunch for beef producers?