Many producers are interested in developing a systematic and sustainable crossbreeding plan.

There is general agreement that favorable hybrid vigor (or heterosis) exists for most economically important traits when crossbreeding. Crossbred cows generally have higher yields of milk, fat and protein than would be expected based solely on the average of the original breeds. First-generation crosses of Brown Swiss and Holstein, for example, have fat and protein yields that in some cases exceed those of pure Holstein. The hybrid vigor we gain for fitness-related traits (fertility, disease resistance and survival) is generally thought to be even more than what we observe for yield. I want to be clear that I do not recommend crossbreeding for the sake of increased production. Crossbreeding is for those who wish to improve cow fitness levels more quickly than can be done through selection of sires with high productive life and daughter pregnancy rate.

Let's summarize what the research is telling us about various crossbreeding options that have been tested and then look at the holes left to be filled.

Foreign breeds
The Normande, Montbeliarde and Scandinavian Red breeds have all been researched on U.S. dairy farms. I have lumped Swedish Red and Norwegian Red together into one category of "Scandinavian Red," which is probably not fair to either breed. However, they are related breeds with some common sires, and I've not seen enough research to compare crosses of one against the other. Of these breeds, Scandinavian Red x Holstein crosses have come closest to pure Holstein for production (2 to 5 percent lower), followed by Montbeliarde x Holstein (3 to 6 percent lower), and Normande x Holstein (8 to 13 percent lower).

While days open is not the ideal fertility trait, it is the fertility measure most readily available from DHI records. Advantages in days open appear to be, not surprisingly, highest for the lower-producing Normande crosses, at nearly one month less than pure Holstein. The large gain in fertility may make Normande a good candidate for herds with seasonal calving. Scandinavian Red and Montbeliarde crosses are reported to have a two- to three-week advantage over pure Holstein for days open. All three breeds have been reported to have a larger proportion of cows survive to a subsequent lactation than pure Holstein. Scandinavian Reds have also been selected for calving ability and are reported to have a lower rate of calving difficulties and stillbirth. Scandinavian Reds will be moderate-sized cattle, whereas Montbeliarde will be similar (and in some cases higher) in body weight to pure Holstein. They are not as tall as Holsteins, but carry more body condition.

Domestic breeds
The disadvantage for our domestic breeds is that we know them well, which of course means we are familiar with their faults as well as their strengths. Crosses of Jersey with Holstein are most common due to the use of Jersey sires on Holstein heifers for calving ease purposes. Milk yield is obviously lower for Jersey x Holstein crosses than for pure Holstein, but total fat yield is similar and has exceeded pure Holstein in some studies. Jersey crosses are also quite fertile, with gains in days open that may exceed gains observed for some of the foreign breeds. Jersey x Holstein cows are moderate in size, which may make them more ideal for herds with smaller stalls. A challenge with crossbreds of any type can be variation in body size and production, but this may be more of an issue for Jerseys than other breeds. Some studies have also reported problems with deep udders after first lactation.

As mentioned above, Brown Swiss crosses are most likely to result in production levels and body size that rival those of pure Holstein. Brown Swiss crosses are also more fertile than pure Holstein. Purebred Brown Swiss have behavioral characteristics as calves that can be a challenge to manage. Anecdotal evidence suggests that Brown Swiss crossbred calves do not share the same problematic behavior. This is just one example of the type of information we know about domestic breeds but not about foreign breeds.

Other domestic dairy breeds (Ayrshire, Guernsey, Milking Shorthorn) have their advocates and have been included in crossbreeding plans on some farms, but there really isn't enough research data available to have a strong sense of what we should expect from crosses of these breeds.

The next generation
There is general agreement that first-generation crossbred cows can be productive and economical, but expectations for the future generations are not at all well defined. The first question is, "What do I breed her to"? That Jersey x Holstein cross was born easily, but what happens at calving if I breed her back to Holstein? Most are now recommending that you breed your crossbreds to a third breed and begin a three-breed rotation. Over time, you will capture 86 percent of the potential hybrid vigor with a three-breed rotation (compared to 67 percent for two breeds). Hybrid vigor continues to increase as more breeds are added, but it will also dilute the Holstein influence.

There is also a little-talked-about counterpart to hybrid vigor called recombination that becomes important after the first generation. As genes from various breeds are mixed, potentially favorable gene combinations that have been selected within a breed are disrupted. This disruption appears to result in lower-than-expected yield for future crossbred generations regardless of the number of breeds involved. This disruption might actually boost fertility and survival, so total economic merit does not appear to be adversely affected. However, this issue needs to be more fully researched before the crossbreeding picture can be completed.

Conclusion
The key for any genetic selection or mating program is to develop cows that match your herd management system. Holsteins are the right breed if your system requires high milk yield, you have facilities built for modern-sized Holsteins and current cow fitness levels are not limiting your economic efficiency. You need to rethink your genetic management plan if Holsteins are just too big for your system, you struggle getting cows pregnant, you have a high mortality rate or lose a lot of cows in early lactation. That could simply mean changing sire selection criteria to put more emphasis on selecting for moderate body size, higher productive life and higher daughter pregnancy rate. We should improve more quickly in those areas than in the past due to genomics.

Like careful sire selection, crossbreeding is an effective tool to help match your cow genotypes to your management system. It is likely to help you improve more quickly in the areas of fertility and cow health than sire selection. There are several viable breed options, and selecting the correct breeds is a balancing act between the yield levels you would like to maintain and the cow fitness levels you would like to achieve. PD

Chad Dechow
Dairy Genetics
Penn State University
cdechow@psu.edu