The definitive goal of breeding is to select favorable traits that will prevail in the next generation, and crossbreeding could be one way to do that.

Dr. Frank Buckley of Ireland delved into appreciation for and the power of crossbreeding during the International Cow Fertility Conference in May.

The conference brought together leading scientists, health professionals and farmers to explore the role of nutrition, management, genetics, disease and new technologies to better dairy cow fertility.

“The nuts and bolts of crossbreeding are not entirely understood, with several misnomers,” Buckley said. “It’s not a popular breeding strategy, but the few results it does show bring light to the question, ‘Why is it not more popular?’”

Dairy producers worldwide have been breeding for milk production, as well as other functionality traits that lead toward the ideal image of a cow. Utilizing the crossbreds’ resilience and robust fertility, dairymen can further enhance traits they seek through purebred breeding programs.

More importantly, with crossbreeding comes heterosis, commonly known as hybrid vigor.

“Heterosis allows for big gains within complementary traits of milk production that are traditionally difficult to select for,” Buckley said.

New Zealand has been the leading country in the crossbreeding strategy, in turn reaping the benefits of hybrid vigor.

The country’s dairy producers don’t focus much on the dairy breeds used, but rather the traits each breed can bring to the table. Today, nearly 41 percent of all dairy cattle in New Zealand are Jersey-Holstein Friesian crosses. Within the next two years, the percentage of crossbred dairy cattle is expected to exceed 50 percent.

This particular cross tend to thrive in New Zealand due to its unique production system; however, those genetics tend to be inadequate in the Northern Hemisphere.

According to University of Minnesota professor Dr. Les Hansen, Ph.D., crossbreeding is not a one-size-fits-all solution but rather must be adapted to the current environment and conditions. .

Holstein-Jersey crosses, the primary crossbreed in New Zealand, maintain milk production levels only slightly above-average compared to that of the pure Holstein; however, longevity has improved 227 days, nearly a full lactation longer.

This phenomenon is due in part to hybrid vigor.

“We crossbreed A and B and expect to get about the average, but in turn we get this added bonus,” Buckley said. “It has the opposite effect of inbreeding, where hybrid vigor becomes complementary to the breed.”

Fertility and health traits tend to have a lower heritability and are difficult to select for, but with crossbreeding, these complementary traits are greatly benefited. Buckley demonstrated up to 25 percent positive performance on fertility and health traits due in part to hybrid vigor.

There are three approaches to maintain maternal lines through crossbreeding: two-way rotational cross, three-way rotational cross and crossbred sires.

In Ireland’s dairy industry, a two-breed rotation has been favorable among producers.

For dairy producers in the U.S., however, confinement has been a deciding factor in choosing to use a crossbreeding strategy that produces smaller-framed cattle. The three-way rotational cross is commonly used because it delivers the most benefits and maximizes hybrid vigor.

Popularly known as the ProCross (Holstein-Montebeliarde-Viking Red), this breeding strategy maintains superior genetics over time with the ability to make improvements among all breeds.

Proving Hansen’s notion, the environment and industry conditions must be taken into account in order to maximize the benefits of crossbreeding within a specific region.

Many producers have the perception that hybrid vigor is only valuable in the first generation of crossbreds (F1). In a three-way rotational cross, the first and second generational crosses maintain 100 percent hybrid vigor. At the time of the fourth generational cross, the parent breed is re-introduced, and hybrid vigor is retained at an appropriate level of about 87 percent.

“Because we are retaining hybrid vigor, the third generation that contains one-half of one breed and a quarter of two other breeds has the potential to be as fertile as that first cross,” Buckley said.

One way dairy producers can counteract this loss of hybrid vigor is to identify bulls with high genetic merit for fertility. By capitalizing on this trait, producers will further benefit and reduce the risk of loss of hybrid vigor.

All in all, the idea of a three-rotational cross has to be focused on the profit-generating potential of those animals, not entirely what they look like.

Based on information collected from Ireland herds in 2010 and data verified by the Moorepark dairy research facility, hybrid vigor has improved profitability by the equivalent of $135.74 per cow per lactation. In fact, a significant portion of that amount – $108.68 – is contributed to four days shorter calving interval and a 4 percent increase in survival.

Likewise, a study conducted among California herds in 2011 by Hansen and Dr. Brad Heins demonstrated that crossbred cattle in confined areas hold potential for profitability.

“Montebeliarde-Holstein crosses in the California study were 26 less days open than a purebred Holstein,” Hansen said. “We have seen a substantial increase in fertility, and that is when the full package comes together.”

Similar results have been repeated at the University of Minnesota and Penn State University. In fact, under Hansen’s advising, there is another crossbreeding study under way with Minnesota herds.

“We are just now beginning to collect data,” Hansen said. “In three to four years, large well-managed herds will see profit and have a big advantage in the industry.”

As Buckley has portrayed, crossbreeding is an exclusive program used to select traits within an index that complements a current breeding program of a producer’s choosing in order to improve fertility and ultimately profitability. PD

Jennifer Janak is a 2014 Progressive Dairyman editorial intern.

PHOTO:Hybrid vigor in crossbred dairy cattle has been shown to improve profitability by the equivalent of $135.74 per cow per lactation. Photo courtesy of ThinkStock.