The success of U.S. ranching depends on savvy business people knowing how best to utilize the various breeds available to them. Taking advantage of the differences in these breeds allows managers to take optimum advantage of breed complementarity and heterosis. Therefore, it is important to know the strengths and weaknesses of breeds, and how they have changed over time.
For characterizing the biological properties of various breeds, this country’s greatest resource—if not the world’s—is the U.S. Meat Animal Research Center’s (US MARC’s) germ plasm studies. Over the years, they have looked at 36 breeds whose biological types varied for size, milk production (including some dairy breeds), body composition, and puberty. This has resulted in as definitive a set of comparisons as has ever existed.
SETTING THE STAGE
It is good to step back and look at what a wonderful and irreplaceable resource US MARC represents, and how it came about. Located in Clay Center, NE, it was acquired by USDA in 1966 from the Department of Defense. Previously, it had served as the Navy’s and Marine Corp’s primary munition depot since World War II. Its location in the center of the country during the war was felt to be ideal for a munitions depot for protection against aerial bombing or invasion.
When touring the 34,000-acre experiment station in 1975, this author remembers vividly the whole station being dotted with munition bunkers and their blast walls in front of the bunker entrances. They can still be seen today, although many have been removed.
Once acquired by USDA, the station was capable of carrying 8,000 cows along with a 5,000-head feedlot.
With the importation of many new breeds, primarily from Continental Europe, in 1969, the US MARC scientists started the germ plasm evaluation (GPE) studies. Originally done in a series of multi-year cycles, 36 breeds have been characterized over the years, with “black baldy” Angus/Hereford crosses serving as the basis for comparisons. The goal of characterizing the breeds was to aid producers in designing crossbreeding systems.
In more recent years, instead of being run in cycles, a continuous approach has been taken with 17 breeds. To evaluate the breeds since the beginning, commercially-available semen that represented typical or high-use sires of a particular breed at the time they were being sampled was used.
Overseeing the GPE have been some of the most gifted scientists this country has ever produced. For many years, geneticist Dr. Larry Cundiff was the coordinator and primary spokesman, but fellow geneticists Drs. Keith Gregory, Robert Koch, Gordon Dickerson, and Dale Van Vleck were also important members of the team. In more recent years, the industry has been lucky to have talented geneticists Drs. Larry Kuehn and Mark Thallman leading the program.
Dr. Cundiff also points out the importance of Dr. Dan Laster in supporting the program first as a scientist and later as an administrator. It was with his backing that the GPE Cycles were able to be maintained over time.
There has also been a multi-disciplinary team of scientists who were intricately involved, which included meat scientists, reproductive physiologists, and nutritionists. In totality the number of experts involved is far too long to list, but their role has been critical to the depth, breadth, and impact of the program.
A RECORD OF CHANGE
From 1969 to the 2002 calf crop, GPE was run in cycles. Each cycle described lifetime production records on a certain group of breeds from two or three calf crops. Each was compared to Angus/Hereford crosses. The last cycle was VIII, which featured certain heat-tolerant breeds. Since then, the approach has been continuous evaluation for a comparatively larger number of breeds. It is very informative to explore the phenotypic trends of the GPE project over the half a century it has been conducted.
Although sweeping differences can be concluded, Dr. Cundiff is quick to point out that management changes have played a part in the magnitude of the phenotypes over time. This should be considered when looking at the data. For instance, the station now calves later in the spring compared to the early years, and also now calves in both the spring and fall. Both of these management changes have an impact on phenotypic trends.
Table 1 shows how birth weight has changed over time from 1982c, when the results of the first three cycles were summarized, to Cycle VII, which was reported in 2004d, and concluding with the 2015 calf crop reported in the 2017g across-breed EPD phenotypic tables.
With birth weight creeping up in the early years, the recent data indicates that the industry has done a good job of either considerably slowing or stopping this trend upward in the case of the British breeds. In the Continental breeds, they have actually slightly moderated the weights. This works against the genetic antagonism of the breeds’ increasing growth and mature weight, which later tables will demonstrate.
[inline_image file=”10853862dda3450595d1721f799a4993.jpg” caption=”BBG19 Bob Table 2 Weaning weight”]
Table 2 shows that there was a great increase in weaning weight from the first three cycles to Cycle VII. Comparatively, the phenotypes continued to increase in the recent data, but at a much slower pace. This would coincide with weaning weights seen in the large commercial datasets being compiled in programs like North Dakota State University Dickinson Research Extension Center’s Cow Herd Appraisal Performance Software (CHAPS) and Texas A&M University Extension’s Standardized Performance Analysis (SPA).
This field data reveals that weaning weights have leveled off in recent years despite the continued increased genetic trend seen in the seedstock industry. Depending on an individual ranch’s environment and management, it can be hypothesized that many of the better-run commercial operations have maxed out their environments’ ability to express weaning weights regardless of genetic potential.
Characterizing yearling weights from the GPE studies is more difficult. Due to lack of standardization, many of the early years weighed cattle at 400 days instead of 365. Even then, it sometimes only had weights on heifers, and male progeny were represented as slaughter weights of the steers between approximately 445-455 days.
[inline_image file=”014c16b09d0bb1704a65c4c656b3832d.jpg” caption=”BBG19 Bob Table 3 Yearling weight”]
However, the phenotypes in the 2009f across-breed EPD tables can be compared to the 2017 report, which is shown in Table 3. In this comparatively short period of time, the weights have noticeably increased. It is especially impressive how much Angus have increased as they have turned into what is now the apparent top growth breed.
[inline_image file=”0888732b64647695350d991f91812275.jpg” caption=”BBG19 Bob Table 4 Mature weight”]
Recent mature weights are not available, although they are expected to be released in the scientific literature soon. Table 4 demonstrates that there has been a notable increase in mature weights from Cycle Ib to Cycle VII. It is also important to note the reranking of the Continental breeds and British breeds, with the British breeds now heavier than their Continental counterparts.
It should be noted that the mature weights shown in 2007e were adjusted to a constant body condition score of 5.5. When not adjusted for body condition, the difference in mature weight between the British and Continental breeds becomes more pronounced as the British breeds maintained higher body condition than the Continental breeds.
[inline_image file=”c7fa1a35f25c56a241332969288bc154.jpg” caption=”BBG19 Bob Table 5 Heifer Pregnancy”]
Table 5 shows the relative differences in pregnancy rate for heifers bred to calve at 2 years of age. The results are variable. While most breeds noticeably increased the pregnancy rate between the first three cycles and Cycle VII, Angus did not and is still at the same approximate level with their earlier Angus/Hereford counterparts. A puzzling observation is Gelbvieh, which declined from being the top breed to the bottom. This is despite them being the most consistent in terms of early puberty.
On the cow side, an important missing observation is in the longevity or Stayability differences of the breeds. Modeling has consistently shown that Stayability is the most important factor in maternal indexes. Therefore, once the breeds are characterized for this all-important trait, it will provide critical information to the industry in helping producers design profitable crossbreeding systems.
[inline_image file=”17fe2b7423af0cd9c94b5f371c3ed1a6.jpg” caption=”BBG19 Bob Table 6 Carcass weight”]
Moving to carcass traits, Table 6 demonstrates the consistent increase in carcass weights over time. This would be expected to coincide with the increased yearling weights and mature weights. From the first three cycles, the British breeds—represented by the Angus/Hereford crosses—were considerably lower than the Continental breeds. However, Cycle VII saw some reranking when compared to the earlier cycles.
The continued increase in carcass weight was seen in the data reported in 2017, with Angus, Charolais, and Simmental having the relatively higher carcass weights compared to the other breeds, which was similar to what was observed in Cycle VII.
[inline_image file=”a397746f57507d05fa52f8a50690fc90.jpg” caption=”BBG19 Bob Table 7 Ribeye Area”]
Ribeye area was not consistently reported in the early US MARC progress reports as scientists logically assumed the industry would move to more refined measures of cutability such as percent retail product. It was available for Cycle I, being reported in 1974a for the Angus/Hereford crosses and certain Continental breeds, as well as in Cycle VII. They can then be compared to the 2017 across-breed EPD phenotypic tables.
As expected, Table 7 demonstrates the Continental breeds consistently had larger ribeye areas than the British breeds, and the breeds’ ribeye areas have continued to increase over time. This would be expected given the increased carcass sizes.
[inline_image file=”bb6eb7aa25605f1e1efca42f75a5e03b.jpg” caption=”BBG19 Bob Table 8 Backfat”]
Table 8 on backfat is perhaps one of the more interesting tables. From the first three cycles to Cycle VII, backfat consistently decreased. However, this trend reversed in the data reported in 2017. This is in keeping with what has been seen in the commercial industry.
Early on, the industry had a concerted “war on fat” in an effort to make beef more desirable to consumers. However, during this “war,” per capita consumption steadily declined. Since then, the industry moved its focus away from leanness and back to beef quality. This has helped restore consumer demand for beef and would help explain the trend upward on fat reported in 2017.
[inline_image file=”8074684ec61cb71e317d64abc56966df.jpg” caption=”BBG19 Bob Table 9 Marbling”]
This trend of adding quality in the form of marbling back into the cattle—which is being seen in the field—makes Table 9 , perplexing to explain. Although marbling noticeably increased from the early cycles to Cycle VII, this trend did not continue to the latest data reported in 2017.
These recent phenotypes observed at the station are not in keeping with genetic trends and may be an artifact of management or environment. The increased use of Angus genetics in commercial herds would also help explain the differences between what has been observed in the station data and field data. It is also interesting to see in the 2017 US MARC data the relative gains in marbling made by Simmental. It appears the breed has distanced itself from the other Continental breeds for the trait.
AN INVALUABLE RESOURCE
The US MARC germ plasm studies are tremendously informative. In general, seedstock breeders producing the sires used in the studies have done a great job of increasing growth while maintaining reasonable birth weights. With this increased growth, mature weights have also glaringly increased.
There has also been an apparent reranking with the British and Continental breeds in terms of mature weight. In general, as with the other weight traits, the major differences between British and Continental breeds are no longer consistent and in some cases have been reranked. The differences between British and Continental breeds for certain carcass traits like backfat and ribeye area have remained consistent, while this is not the case for carcass weight and marbling.
Overall, there are still significant differences between breeds, and these differences can be used to design crossbreeding systems in order to take full advantage of breed complementarity. There is no one breed that “does it all,” and breed differences and heterosis are still important tools to our industry. Although the data from GPE are extremely informative, data on traits such as longevity still need to be explored to complete the picture of breed complementarity.
The industry is indebted to the US MARC scientists who have done this work and continue to do to this day. The station’s value to the industry cannot be overemphasized. With their current work on genomics, as well as characterizing breeds for traits like disease susceptibility and other novel traits, the research done at US MARC will only increase in importance in the years to continue to do to this day. The station’s value to the industry cannot be overemphasized. With their current work on genomics, as well as characterizing breeds for traits like disease susceptibility and other novel traits, the research done at US MARC will only increase in the years to come.
a1974. Germ Plasm Evaluation Program. Progress Report No. 1. U.S. Meat Animal Research Center. ARS-NC-13. Clay Center, NE.
b1977. Germ Plasm Evaluation Program. Progress Report No. 5. U.S. Meat Animal Research Center. ARS-NC-55. Clay Center, NE.
c1982. Beef Research Program. Progress Report No. 1. Robert L. Hruska U.S. Meat Animal Research Center. ARS-NC-21. Clay Center, NE, pp 1-16.
d2004. Germ Plasm Evaluation Program. Progress Report No. 22. Robert L. Hruska U.S. Meat Animal Research Center. Clay Center, NE.
e2007. L.V. Cundiff, R.M. Thalman, L.D. Van Vleck, G.L. Bennett and C.A. Morris. Cattle breed evaluation at the U.S. Meat Animal Research Centre and implications for commercial beef farmers. Proceedings. New Zealand Society of Animal Production. Vol. 67.
f2009. Across-breed EPD table. U.S. Meat Animal Research Center. Clay Center, NE. Find it HERE
g2017. L. Kuehn and M. Thallman. Across-breed EPD table and improvements. U.S. Meat Animal Research Center. Clay Center, NE. www.eBEEF.org
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