January 6, 2020
After 10 years of trial and another two years of analysis, the results are finally in and they are unequivocal:
Using a three-breed rotational crossbreeding system will produce more daily profit per cow than breeding purebred Holsteins over three generations.
At least 150 of these foundation animals in each herd were then mated to Holstein bulls to maintain a purebred Holstein line. At least 100 foundation animals were then mated to either Viking Red or Montbeliarde sires to initiate the 3-breed rotational program, known as ProCROSS. The 2-breed crossbred offspring were mated to the 3rd breed to create 3-breed crossbreds. And finally, the 3-breed crossbreds were mated to Holstein bulls to keep the rotation moving forward.
The reason for the study was to determine if a continual crossbreeding program can be more profitable, and as important, offset the increasing level of inbreeding within the Holstein breed. “Inbreeding depression silently steals profit from dairy producers because it is expressed mostly for traits that are not readily noticeable such as embryo loss, less disease resistance and shortened survival,” says Les Hansen, a U of M dairy geneticist and the lead researcher on the project.
“The adoption and use of genomic selection in the United States over the past 10 years has greatly accelerated the annual increase of average inbreeding of Holstein females, mostly because the generation interval has been halved,” he says. He notes that the average inbreeding has increased roughly 0.35% in each of the past 4 years, with the average inbreeding coefficient rising to 8% for Holstein females born during the very beginning of 2019.
“For reference, the inbreeding resulting from bull mated to his own daughter is 25%, and the mating of 1st cousins results in inbreeding of 6.25%,” he says.
Crossbreeding eliminates inbreeding depression. “When parents of different breeds are mated to create a crossbred animal, the 2 genes at the same location on the chromosomes cannot be identical from a common ancestor,” Hansen explains. “Therefore, recessive genes of both major and minor consequence are not likely to be expressed with crossbreeding.”
At the same time, it’s important to note that hybrid vigor does not replace genetic progress within breeds, which typically increases the frequency of desirable genes. Consequently, it’s important to use the very best bulls of each breed--and to continue to do so—in a crossbreeding program.
In the trial, herd managers were asked to select Holstein bulls that ranked in the top 10% for Net Merit. The semen for Viking Red and Montbeliarde bulls was imported from Europe and ranked highly on either the Nordic Total Merit index for Viking Red bulls or the French ISU index for Montbeliarde sires. The Viking Red and Montbeliarde sires were imported by Creative Genetics of California. The Holstein sires all came from Select Sires.
• The combined 2-breed and 3-breed crossbreds had 153 more days in the herd than their Holstein herdmates.
• Daily profit was 13% higher for 2-breed crossbreds and 9% higher for the 3-breed crossbreds than their Holstein herdmates. Note: Daily profit included not only milk production but health and fertility costs.
• Daily fat plus protein production was 1% higher in 2-breed crossbreds and 1% lower for 3-breed crossbreds than Holstein herdmates—a wash.
• Health treatment costs were 23% lower for the 2-breed crossbreds and 17% lower for the 3 breed crossbreds.
• All generations of crossbreds had lower stillbirth rates.
• Fertility was higher in crossbreds, with 2-breed crossbreds having 12 fewer days open and 3-breed crossbreds having 17 fewer days open than Holstein herdmates.
• Lifetime death loss was 4% lower for the crossbreds.
Bottom Line: More Profit
The bottom line is that crossbreeding is more profitable. “The main factor was 153-day longer herd life of the crossbreds with their Holstein herdmates,” says Amy Hazel Loeschke, one of the primary research scientists involved with the study. (Note: Other studies have shown that herd replacement and turnover costs are the biggest driver of profitability in dairy herds.)
“The crossbred cows, on average, had delayed replacement, and therefore, their cost for replacement was substantially reduced,” says Loeschke. The superior fertility (fewer days open and higher conception rate) of the crossbreds also influenced persistency of production, frequency of calving and herd life, she says.
The next most important factor affecting profitability was reduced health treatment costs in the crossbreds, which were concentrated on less ketosis, milk fever and displaced abomasa and less mastitis, she says.
The crossbreds also had increased calf value, because they had lower stillbirth rates which resulted in more calves born during their lifetimes. The crossbred bull calves also had higher value.
Some herds who have used Montbeliarde AI bulls have reported more calving difficulty and have gone to sexed semen. But in the U of M trial, this was not an issue. “Because of these observations…, we don’t have a special recommendation for the use of Montbeliarde sexed semen for calving ease,” Loeschke says. “For all breeds, it is wise to avoid AI bulls with calving difficulty or poor disposition.”
Some farmers have also expressed concern about crossbreeding simply because they view it as complex, knowing which bulls to breed to which cows when. But using a color-coded ear tag system or codes within the farm’s management software can greatly simplify the process.
And maintaining an updated semen inventory of the three breeds is critical. But Loeschke notes that all three breeds have total merit indexes than can be used to select top ranking bulls. “Managing ProCROSS for a herd is much less complex than mating A.I. bulls appropriately to cows of the same breed in order to provide inbreeding protection,” says Loeschke.
“If daughter-proven bulls are chosen, then perhaps as few as three sires per breed can used at a time,” she says. “When semen from genomic-only AI bulls are used, a larger number of bulls should be used and they should be turned over more frequently.”
She also notes AI bull selection should be done three times per year after each sire evaluation is released to ensure top sires are always used.
In the end, the U of M trial confirmed that crossbreeding is a viable, reasonable option. “For all seven herds in the study, the ProCross cows had more profit per day than their Holstein herdmates,” she says. “Five of the seven dairy herd owners in the study intend to maintain or increase the proportion of crossbreds in their herds with time.”