Amplify Maternal Heterosis with Sexed Semen and Crossbreeding

ABS Global’s Sexcel female semen opens the door to a number of possibilities for producers interested in making the most profitable and productive replacement females. We often find ourselves in a debate over the importance of any number of “Maternal” traits, EPDs, or physical characteristics of cattle. While those are important pieces of the discussion, the well documented positive impacts of crossbreeding and maternal heterosis on a cowherd’s productivity are often forgotten in the conversation.  

The impacts of crossbreeding can be profound, however implementing a planned crossbreeding system can present challenges. Female sexed semen provides us a tool to overcome the difficulties that have historically prevented producers from taking advantage of maternal heterosis. 

Crossbreeding fundamentally works in two ways: 

  1. Provides an opportunity to combine complimentary traits from multiple breeds. 
  1. Overcomes the negative effects of inbreeding that are the result of the relatively close genetic relationship of individuals within the same breed.  

Undeniable Benefits 

The benefits of hybrid vigor are undeniable. When created thoughtfully, crossbred progeny can exceed the productivity of their parents, often with less input cost. The icing on the cake is that the most marked impacts of crossbreeding tend to be on traits that are hardest to improve in purebred cattle. These traits are invaluable for maternal profitability. Characteristics like fertility, longevity, health, and fitness all benefit from hybrid vigor. Table 1 depicts some well-known benefits of crossbreeding on maternal function. 

Table 1. Documented Impacts of Maternal Heterosis* 

Trait Units % 
Calving Rate, % 3.5 3.7 
Survival to Weaning, % 0.8 1.5 
Weaning Weight, lb. 18.0 3.9 
Longevity, year 1.36 16.2 
*Adapted from Cundiff and Gregory, 1999. 

Crossbreeding Systems 

There are several crossbreeding systems that can be used to take advantage of hybrid vigor. Each system has its pros and cons. The key to a successful crossbreeding system is it should be planned.  

Crossbreeding at its Best 

The effect of crossbreeding is the most profound in a first cross of two purebred parents of different breeds with the resulting progeny known as an F1. This cross of unrelated individuals captures 100% of the available heterosis. The iconic F1 Hereford by Angus cross, “Black-Baldie”, is perhaps the most recognizable example. The Black Baldie female is legendary for her fertility, longevity, and efficiency.  

Researchers at Oklahoma State University recently demonstrated that pregnant Black Baldie females consumed almost two pounds per day less dry matter as compared to straight-bred Angus females on a cow weight adjusted basis. While two pounds may seem insignificant on a given day, multiplying those two pounds across a cowherd and production year will get your attention. Crossbred females also consumed less but maintained a higher body condition score throughout the trial (Lalman, et al, 2019).  

This is a great demonstration of breed complementarity at work in a cowherd. The F1 cross is ideal in terms of maximizing heterosis, but for producers breeding and developing their own replacements, it is nearly impossible to implement. Unfortunately, many producers cannot afford to keep or manage a nucleus of purebred females just for production F1 replacement heifers.  

Rotational Crossbreeding Systems 

For producers unable to maintain a system of producing F1 females, a rotational crossbreeding system can capture a majority of available heterosis year-after-year. A rotational crossbreeding program is manageable to implement, particularly with Sexcel female semen and a cowherd segmentation approach (ie. Sexcel 60/40 Synch).  

In the breeding program, females selected to be bred with sexed semen are mated to a sire from the breed which represents the smallest portion of the female’s own breed composition. In simple terms using an Angus and Simmental system, females with a high percentage of Angus composition are mated to Simmental bulls, and high percentage Simmental females are bred to Angus.  While it does require more management than a straight-bred herd, there are multiple tagging and identification approaches that can be used to simplify breeding decisions chute-side. 

A 2-breed rotation can capture two-thirds of the available heterosis, and you can capture nearly 86% of the potential hybrid vigor by adding a third breed to the rotation. Adding more breeds to the rotation would continue to improve our utilization of hybrid vigor, but the reality is we struggle to find enough breeds with the combination of maternal traits we desire to incorporate.  

While heterosis improves the productivity of resulting progeny, it cannot overcome the disadvantage of adding significantly inferior genetics to the mix. Adding too many breeds to the system can result in substantial phenotypic variation. Two and three breed rotations optimize retained heterosis, while allowing us to focus on progressive breeds with recognized maternal excellence. 

A Simple Way to Utilize Hybrid Vigor 

Perhaps, the simplest way to take advantage of hybrid vigor is to utilize composite-breed genetics. Traditionally, a composite was the result of a breeding program crossing two or more breeds over multiple generations to ensure phenotypic variations had been stabilized (i.e. Santa Gertrudis and Beefmaster). More recently, the terminology has been used more broadly to describe crossbred genetics, regardless of whether the composite has truly been stabilized (i.e. SimAngus).  

Utilizing a composite breed simplifies breeding decisions and necessary records because all females can be mated to the same “composite-breed” of sire. The only limitation is that we don’t fully capitalize on the benefits of hybrid vigor. A 2-breed composite retains only 50% of the possible heterosis. Nonetheless, composite breeds offer a good compromise between retained heterosis and ease of use. 

ABS offers an exceptional lineup of maternally focused bulls in several breeds that fit the goals of nearly any operation. While we think of certain breeds bringing particular traits of interest to the table, there can be as much variation within breeds for given traits as there is between breeds. Individual bulls can help or hurt your breeding objectives, no matter the breed. For instance, Hereford cattle tend to have a reputation for being low maintenance, low intake cattle. Nonetheless, we can still identify Hereford sires with the potential to sire high appetite progeny, and conversely, we can identify sires from other breeds that can move the needle in the opposite direction.  

Take home message is don’t assume sires from a particular breed fit the established stereotype for that breed’s characteristics. 

Do your homework and make sure the EPDs and indices match your expectations. We have identified maternally focused sires in Bull Search that we believe will suit the maternal needs of most production scenarios. There may be other sires in our lineup beyond those listed below that meet the needs of your operation. Please note that the right sire selection decision is unique to every operation’s overall goals and labor and management availability.  

ABS Global’s Sexcel female semen gives producers the opportunity to design a heifer calf crop that will benefit from the long-term advantages of maternal heterosis. Producers can take advantage of breed complementarity and heterosis by generating replacement females from a defined portion of their cowherd with Sexcel without concern about the performance of male progeny from the same mating. In fact, strategically creating replacements gives you the flexibility to utilize another sire breed on the remaining cows to capture heterosis in the portion of your calf crop that will enter the beef supply chain. 

[Maximize Profits with 60/40 Synch] 

Contact your local ABS Representative today to find out how female Sexcel from the right bull can help you build a resilient, profitable, and sustainable cowherd

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