Crossbreeding is an old technology; however, when used in today’s dairy systems, crossbreeding can produce profitable results for dairy producers. Interest in crossbreeding of dairy cattle has become a topic of great interest in the last five years and has developed in response to concerns dairy producers have about fertility, calving difficulty and stillbirths in today’s genetically improved Holstein cows.
There have been many research studies documenting the role of crossbreeding in the dairy industry, but many are quite old and dated. Old research indicated heterosis is greatest for traits related to mortality, fertility, health and survival. The first scientific trials using crossbred dairy cattle date back as early as 1906 in Denmark and used the Jersey and Danish Red breeds. In the 1930s and 1940s, experiments with dairy cattle were conducted to determine heterosis for milk and fat production resulting from crossbreeding.
Crossbreeding has not been studied in research herds in the U.S. for many years. Earlier studies with experimental herds indicated that crossbreds were at least as profitable as pure Holsteins at the University of Illinois and Agriculture Canada. A crossbreeding project involving the Holstein and Guernsey breeds was conducted at the Illinois Agricultural Experiment Station from 1949 to 1969. Heterosis for first-lactation milk and fat production was 4.3 and 4.1 percent, respectively; however, heterosis was considerably higher (12.0 percent for milk, 12.8 percent for fat) in second lactation. Heterosis for days open was 9.4 percent.
When evaluating total performance of purebreds and crossbreds, Touchberry combined measures of survival, growth, production and reproduction into an index to calculate the total income produced per cow per lactation and reported heterosis of 14.9 percent for total income produced per lactation.
A Canadian study was conducted in five research herds during the 1970s and 1980s and heterosis of 16.5 percent was observed for lifetime milk production and 20 and 17.2 percent for lifetime fat and protein production, respectively. In the same crossbreeding study at Agriculture Canada, McAllister et al., reported greater than 20 percent heterosis for lifetime performance in crossbreds of Holstein and Ayrshire.
This [article] will report current results from studies of crossbreeding Holsteins with U.S. Jersey and Brown Swiss sires, as well as sires from European dairy breeds. A recent crossbreeding study from New Zealand will also be discussed.
The California experience
The decline in fertility and survival of pure Holsteins led the managers of seven large dairies in California to mate Holstein heifers and cows with imported semen of the Normande and Montbeliarde breeds from France, as well as the Swedish Red (SRB) and Norwegian Red (NRF) breeds. Some cows continued to be bred to Holstein A.I. bulls for a period of time in these dairies. The Swedish Red and Norwegian Red breeds share similar ancestry and exchange sires of sons; therefore, the breeds were collectively regarded as “Scandinavian Red” for this study.
Crossbreds and pure Holsteins that calved for the first time from June 1, 2002 to January 31, 2005 were studied for production. A total of 1,447 cows calved for the first time during this period, and these cows were followed throughout their lifetimes to gauge production. Actual production (milk, fat, and protein) for 305-day lactations was calculated with the Best Prediction technique used by USDA for national genetic evaluations in the USA.
During first lactation fat plus protein was used to gauge the overall production of the pure Holsteins versus crossbreds. The Scandinavian Red-Holstein crossbreds, Montbeliarde-Holstein crossbreds and the Normande-Holstein crossbreds were all significantly lower (statistically speaking) than the pure Holsteins for fat plus protein (lb).
Production of the pure Holsteins climbed substantially from first to second lactation. The three crossbred groups also greatly increased in production from first to second lactation, but not at quite the rate of the pure Holsteins. Consequently, the pure Holsteins continued to have a statistically significant advantage for fat plus protein production, and the difference from pure Holsteins increased from 9 to 12 percent for the Normande-Holstein crossbreds, from 5 to 7 percent for the Montbeliarde-Holstein crossbreds and from 3 to 6 percent for the Scandinavian Red-Holstein crossbreds.
Average production of Swedish Red cows versus Swedish Holsteins in Sweden suggests that the production of Swedish Red-Holstein crossbreds should be very near the production of pure Holsteins if heterosis of 5 percent for production traits is assumed. Perhaps less than 5 percent heterosis for production was realized is this study, because the Swedish Red and Holstein breeds share distant ancestry and because they were developed in the same general region of northern Europe.
On the other hand, the Montbeliarde and Holstein breeds share little ancestry, even distantly; therefore, Montbeliarde-Holstein crossbreds might express a higher average level of heterosis than crosses strictly among dairy breeds of the plains or islands of northern Europe, which include Holstein.
Calving difficulty and stillbirths
Results for calving ease and stillbirths are the same as previously reported. Calving difficulty was measured on a 1 to 5 scale, with 1 representing a quick and easy birth without assistance and 5 representing an extremely difficult birth that required a mechanical puller. Scores of 1 to 3 were combined and regarded as no calving difficulty, and scores of 4 and 5 were combined and represented calving difficulty. Stillbirths were recorded as alive or dead within 24 hours of birth. Calving difficulty and stillbirth are traits of both the sire and the dam.
Inadequate numbers prevented the evaluation of Normande sires; however, some Brown Swiss semen was used by these dairies. Scandinavian Red sires had both significantly less calving difficulty and significantly less stillbirth than Holstein sires when dams of calves were first-calf pure Holsteins.
To estimate differences in breed group of dam for calving difficulty and stillbirths, breeds of sire were limited to Brown Swiss, Montbeliarde and Scandinavian Red, because numbers of births by sires of other breeds were small and were not well distributed across breed group of dam. All crossbred cow groups had significantly less calving difficulty than pure Holsteins at first calving. Stillbirth rates tended to follow the averages for calving difficulty respective to breed group of dam, and Montbeliarde-Holstein dams and Scandinavian Red-Holstein dams had significantly lower stillbirth rates than pure Holstein dams.
First-lactation cows that calved from June 2002 to May 2005 in six of the seven California dairies were compared for survival to 30 days, 150 days and 305 days post-calving. Because one of the dairies participated in the whole-herd buy-out program (heifers were retained to continue dairying), cows from that dairy were removed from the analysis of survival. Pure Holsteins left these dairies sooner than all crossbred groups, with 86 percent of pure Holsteins surviving 305 days post-calving compared to 93 to 96 percent of crossbreds. To put this in context, pure Holsteins were 3.5 times more likely to leave these dairies before 305 days after first calving than the Montbeliarde-Holstein crossbreds.
Cows that had an opportunity to calve a second time were compared for three thresholds for calving interval by breed group – within 14 months of first calving, within 17 months of first calving and within 20 months of first calving. All crossbred groups had significantly higher percentages of cows calving a second time within the fixed windows of opportunity than the pure Holsteins. From 16 to 20 percent more crossbred cows calved a second time within 14 months of first calving compared to pure Holsteins. When cows were provided more time to calve a second time (20 months – which is an ideal 12-month calving interval plus an additional 8 months), the difference of the crossbred groups from the pure Holsteins narrowed; yet the differences remained substantial and highly significant statistically.
Fertility of the pure Holsteins and crossbreds was measured as actual days open for cows that had a subsequent calving or had pregnancy status confirmed by a veterinarian. To be included in the analysis, cows were required to have at least 250 days in milk, which meant the pure Holsteins had an advantage because they were a more highly-selected group compared to the crossbreds – a smaller percentage of pure Holsteins than crossbreds survived to 250 days postpartum. Cows with more than 250 days open had days open set to 250.
The 677 pure Holsteins in these dairies had average days open of 156 days during first lactation, and all of the crossbred groups had significantly fewer days open than the pure Holsteins. The difference from the pure Holsteins ranged from 14 days for the 529 Scandinavian Red-Holstein crossbreds to 23 days for the 421 Normande-Holstein crossbreds. These results agree with most other recent research on fertility of pure Holsteins versus F1 crossbreds involving Holstein, which have typically reported two to three weeks fewer days open of crossbreds versus pure Holsteins.
All first generation (F1) crossbreds in the seven California dairies are bred to bulls from a third breed; however, these dairies were no longer calving first-lactation pure Holsteins by the time the 3-breed crossbreds began to calve. Therefore, the comparison of 3-breed crossbreds versus contemporary pure Holsteins is not possible in these dairies. On the other hand, comparison of 2-breed and 3-breed crossbreds that calved during the same 4-month herd-year-seasons is possible. Preliminary results comparing 2-breed and 3-breed crossbreds in these seven dairies suggest the production of 3-breed crossbreds is extremely similar to the production of 2-breed crossbreds.
Crossbreeding outside of North America
Crossbreeding of Holstein and Jersey is common in New Zealand, where crossbreds comprise nearly one-quarter of milk-recorded cows. Crossbreeding has grown substantially in popularity, and numerous studies have been performed to assess the benefits of crossbreeding in pastoral production systems. Ahlborn-Breier and Hohenboken analyzed New Zealand field data of Holstein, Jersey and various crosses for additive and nonadditive genetic effects for milk production, fat production and fat percentage. Heterosis of 6.1 percent for milk production and 7.2 percent for fat production of crossbreds of Holstein and Jersey compared to the pure breeds was observed.
Research from New Zealand reports heterosis for milk, fat and protein production. Production records from over 180,000 first-calf heifers were used in this analysis. The objective of this study was to determine if environmental conditions in New Zealand influenced the expression of heterosis. Heterosis was highest for Holstein-New Zealand Jersey crossbreds for milk, fat and protein production and ranged from 5 to 9.5 percent. The study also reports the largest effects of heterosis occur in herds with intermediate production levels. The study concluded that crossbreds of Jersey and Holstein had higher fat and protein production than pure Holsteins due to the expression of heterosis.
Crossbreeding should be regarded as a mating system that complements genetic improvement within breeds. Continuous use of progeny-tested and highly-ranked A.I. bulls is critical to genetic improvement regardless of mating system (purebreeding or crossbreeding). Unfortunately, some dairy producers might interpret the merit of crossbreeding as justification to use natural service bulls rather than A.I. That would be an unfortunate consequence of dairy producers’ interest in crossbreeding.
Heterosis is a bonus that dairy producers can expect in addition to the positive effects of individual genes obtained by using top A.I. bulls within breed. The bonus from heterosis is about 5 percent for production and at least 10 percent for mortality, fertility, health and survival, and heterosis comes on top of the average genetic level of the two parent breeds. Therefore, the impact of heterosis on profit should be substantial for commercial milk production. However, some dairy producers might need to get beyond the notion that level of milk production is the only measure of profitability of dairy cows.
For the study of seven dairies in California, production of the Montbeliarde-Holstein crossbreds and the Scandinavian Red-Holstein crossbreds was slightly reduced (about 5 percent for fat plus protein production across the first two lactations) compared to pure Holsteins. Mating Holsteins to Scandinavian Red, Montbeliarde and Normande A.I. sires resulted in fewer stillborn calves, as well as cows with less calving difficulty, enhanced fertility, and improved survival compared to pure Holsteins.
Crossbreeding systems that use Jersey or Brown Swiss have shown to have similar fat production to pure Holsteins, although milk volume is lower in the crossbreds compared to pure Holsteins. The fertility of Jersey or Brown Swiss-Holstein crossbreds demonstrates an advantage of 2 to 3 weeks fewer days open. Heterosis for production ranges from 2 to 15 percent and heterosis for days open is about 8 percent.
Crossbreeding systems should make use of three breeds. Preliminary results in California and the University of Minnesota show no loss in production by adding a third breed into a crossbreeding system. Individual dairy producers should carefully choose three breeds that are optimum for conditions unique to their dairy operations (facilities, climate, nutritional regime, reproductive status, level of management and personal preferences). PD
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—Excerpts from University of Minnesota 4th Biennial W.E. Peterson Symposium Proceedings