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Now is the Time to Embrace Genetics in the Sheep Industry
SUSAN SHULTZ, ASI President
Much discussion and dialog have taken place in recent years regarding how the American sheep industry can become more efficient in order to meet the demands of our consumer. Those demands include making American lamb and wool premium products on a consistent basis and improving productivity and profitability for a sustainable industry.
Tracing conversations back to the Industry Roadmap in 2014, the productivity improvement committee I chaired recognized the need to improve collaboration and explore new technologies to modernize within our industry. Committee members agreed that prioritizing ways to improve productivity and increase the speed of adopting new technologies was especially important in the area of genetic improvement.
Through the ASI Let’s Grow initiative that followed, there were numerous examples of pockets of producer groups that were attempting to do just that – collaborate in order to utilize the latest in genetic technology. But even with all the generous industry support for genetic improvement, there has always been a void in bringing together under one umbrella all of the key stakeholders to collectively move projects forward that could benefit our industry.
It had become increasingly clear that with limited resources and the rapid pace of change in both quantitative and molecular genetics that the time for structured collaboration and the prioritizing of projects that had the potential to make significant changes to our production efficiencies had arrived. I can only imagine the changes that our industry could make if we were able to embrace and adopt the genetic tools that are currently available, such as estimated breeding values, genomic marker panels and now genomically enhanced breeding values, plus the future tools that are currently being studied.
Several events are merging together and that leads me to believe that this could be the decade of genetic change for our sheep industry. First, the coming of age of a very talented young group of genetic scientists who are working together to implement change. Second, is the cooperation and coordination between our Agricultural Research Service stations to create new and focused scientific, genetic advancement. Third is the rapid reduction in the cost of DNA analysis, which makes it more affordable for many sheep producers.
This brings us to the fourth event in these new developments. Soon after a formal meeting of stakeholders with much discussion and dialog about American sheep genetics at the 2019 ASI Annual Convention in Scottsdale, Ariz., a group of five progressive producers were tasked to move the discussion forward to an action plan. The concept was to create a separate organization supported by the American Lamb Board, ASI and the National Sheep Industry Improvement Center, along with industry stakeholders, with a vision of being a proactive, collaborative initiative focused on improving genetic tools to enhance profitability. By including all of the sheep industry stakeholders, this effort would create the critical mass needed to drive genetic research, development and adoption to new levels.
During the pandemic, this group of producer volunteers worked on the vision and mission, wrote bylaws and reached out to numerous stakeholder groups for their input, thus turning a concept into a reality. Rusty Burgett (Iowa), Ben Lehfeldt (Mont.), Bill Shultz (Ohio), Brad Boner (Wyo.) and Tom Boyer (Utah) are leading the way for the recently formed non-profit organization Sheep Genetics USA. Tom will share more of the story in this issue.
Through their designated action committees, Sheep Genetics USA will bring together stakeholders representing consumers, producers, educators, researchers, feeders, packers and breed organizations to focus on supporting constructive projects to improve genetics.
As one of their first initiatives, ASI is pleased to team with Sheep Genetics USA to launch this August issue of the Sheep Industry News dedicated to genetics. Hopefully this will be an annual occurrence and will showcase how producers can increase profitability and efficiencies by using modern genetic technologies.
I hope you enjoy this special issue, and thank you to all the volunteer leaders and organizations that have worked together to bring these ideas to fruition.
JULIE STEPANEK SHIFLETT, PH.D.
Juniper Economic Consulting
This year, the American lamb industry has broken multiple records with record high feeder lamb prices, slaughter lamb prices and wholesale prices. The combined influence of tight supplies and strong demand is exerting pressure on markets.
It is assumed that the ethnic market demanding lighter-weight lambs is driving the current run-up in prices, forcing lamb processors of heavier lambs to pay higher prices to secure supplies. The niche lamb markets at foodservice, retail and ethnic markets overlapping the two will play tug-of-war with lamb supplies. In the year ending March 31, “consumer demand for lamb increased considerably compared to the same time period one year ago” according to IRi/Fresh Look Marketing for the American Lamb Board in June. There was a 27 percent increase in dollar sales at retail from a year ago and a 19 percent increase in pounds sold.
As discovered in Midan Marketing’s Multicultural report to the American Lamb Board, one “factor that could be influencing lamb’s popularity in recent years is growing demand among first-generation Americans from the Middle East and Southern Europe, where lamb is closer to a food staple in their diets.” Further, Midan explains, non-white meat eaters purchase lamb more often than white meat eaters. One in four Asian meat eaters have purchased lamb in the past month, while one in five Hispanic and black meat eaters have also purchased lamb.
This year, feeder lamb prices flirted with $300 per cwt., bouncing between $250 and $292 per cwt. By June, prices settled closer to $250 per cwt. – a level not previously thought possible.
On average, 60- to 90-lb. feeders averaged $261.41 per cwt. in June, up 5 percent monthly and up 57 percent from the COVID-low last summer. Prices in San Angelo, Texas, averaged $258.05 per cwt. in June, up 13 percent monthly and up 54 percent from a year ago. Prices in Sioux Falls, S.D., averaged $264.96 per cwt., up 4 percent monthly and 60 percent higher year-on-year.
Slaughter lamb prices moved sharply higher in June, driven by tight supplies and strong demand. Live, negotiated slaughter lamb prices averaged $257.51 per cwt., 5 percent higher monthly and 41 percent higher year-on-year. The last time slaughter lamb prices topped $200 per cwt. (at $205 per cwt.) was July 2011 when domestic and imported supplies were tight.
In San Angelo, 100 to 150-lb. wooled and shorn slaughter lambs averaged $200.22 per cwt., up 27 percent monthly and up 57 percent year-on-year. Lambs in Sioux Falls saw $263.07 per cwt., up 18 percent monthly and nearly double from a year ago.
Lamb prices at the market in New Holland, Penn., saw some monthly softening, but still sharply higher than last summer. Wooled slaughter lambs at the New Holland auction (Choice and Prime 1-3) averaged $280.28 per cwt. in June, down 3 percent monthly and up 26 percent year-on-year for 90 to 100 lbs. Heavier, 100- to 150-lb. lambs averaged $281.16 per cwt., down 2 percent monthly and up 50 percent from a year ago.
Hair lambs, 70 to 80 lbs., brought $265 per cwt. in June at New Holland, down 4 percent monthly (Choice and Prime 1-3). Eighty- to 90-lb. lambs averaged $253.02 per cwt., down 7 percent monthly. There were no comparable price reports published for last summer.
It is common for feeder lambs to top $200 per cwt., not slaughter lamb prices. As slaughter lamb prices approach levels previously reserved for feeder lambs, the distinction between the two is blurred.
The heavier-weight, traditional lamb market will face continued pressure by the lighter-weight, ethnic market to secure supplies. In general, desired weights in the ethnic market range from about 80 to 120 lbs., not as heavy as 140-lb. plus lambs that the traditional market historically harvests. While hair breeds have been popular in the ethnic market, by some accounts, the ethnic market prefers wooled breeds because the meat is more pink than red. Reportedly, the wooled breeds also dress better, have a higher-percentage yield for comparable weight lambs.
Eid ul-Adha (Muslim Festival of Sacrifice) on July 20 and Muharramm/Hajra (Islamic New Year) on Aug. 10, will signal high-demand periods for lighter-weight lambs, meaning continued short-term price support at already high levels. Depending upon import levels in the next few months – and an actual count of feeders coming to the market this fall – tight supplies might persist for some time, keeping prices high through the December holidays.
Lamb at Wholesale Sets New Record
In the first week of July, the lamb cutout hit a new record high, $540.05 per cwt. In June, the average cutout value was $513.84 per cwt., up 9 percent monthly and up 45 percent year-on-year.
The rack, 8-rib, medium, brought $1,210.38 per cwt. in June, up 9 percent monthly. The further fabricated rack, roast-ready, frenched topped $22 per lb. The loin, trimmed 4×4, averaged $848.31 per cwt., up 7 percent monthly. The shoulder, square-cut, saw $438.33 per cwt., up 12 percent monthly. The leg, trotter-off, averaged $779.53 per cwt., up 7 percent monthly.
The lamb primals averaged 45 to 57 percent higher year-on-year. Ground lamb brought $751.12 per cwt. in June, up 6 percent and up 46 percent year-on-year.
Pelts See Some Support
The American pelt market saw some recent uplift, with skin credits to producers back to 2018 levels, or a three-year high. Export shipping is an issue with orders in a delivery window of six weeks to four months, challenging payment and marketing plans. Overall, international shipping is more expensive. However, this also means imported international pelts to the United States are less competitive, which might give American pelts some domestic support.
The growing popularity of hair sheep – such as Dorper and Katahdin – begs the question of the value of hair skins. Hair skins have value, but face competition from the sizable cattle hide market. What gives lambskins value from wooled breeds is the shearling. Shearling is the pelt of a sheep or lamb with the wool left on.
Tight Supplies Pressure Prices
Tight lamb supplies dictate that prices are being bid up and that lambs are going to harvest at lighter weights. Lamb and yearling federally inspected harvest was 912,900 head in January through June, 1 percent higher year-on-year from 2020 (which in turn, was down 7 percent from 2019). However, the first-half of 2021 remains 6 percent lower than the same period in 2019 and 3 percent lower than the first six months of 2018.
Estimated lamb production January to June was 43.3 million lbs., down 1.5 percent year-on-year and down 10 percent from the first-half of 2019. Estimated production is lower due to lower harvest numbers, but also lower harvest weights.
Between the first-half of 2019 and the first-half of 2021, average harvest weights dropped 5 percent from 137 to 130 lbs. The difference is statistically significant at 5 percent. Lighter weights at harvest might be due to tight supplies, but also due to expanded demand by the ethnic market that prefers a lighter-weight carcass.
Freezer inventories continued to contract in June, to low levels not seen since early 2017. Lamb and mutton in cold storage fell for the third consecutive month in June to 21.9 million lbs., down 12 percent monthly and down 54 percent from a year ago.
Lamb imports fell 4 percent in January to May year-on-year to 91.8 million lbs. Australian imports were down 10 percent to 65.3 million lbs. and New Zealand lamb was down 13 percent year-on-year.
According to the Australian Weekly Times on July 5, Australian lamb exports to the United States posted a 19 percent gain on volumes from May to June – the largest monthly volume of Aussie lamb exports to the United States on record. Thomas Elder Markets Analyst Matt Dalgleish commented in the Weekly Times that increased Australian lamb exports to the United States are due to the strong rebound of the high-end foodservice trade from COVID-19.
Dry Conditions Threaten Fall Feed Supplies
This summer, most of the Western United States faces unprecedented drought conditions. By the end of June, 22 percent of the U.S. was categorized as extreme to exceptional drought, with another 35 percent labeled abnormally dry to severe drought, according to the U.S. Drought Monitor. The Livestock Marketing Information Center reported that as of July 1, 65 percent of Western pastures were rated poor and very poor, 26 percent were fair, and only 9 percent were good/excellent.
In mid-June, the California Farm Bureau Federation documented how some sheep producers are facing tough decisions in finding feed. Some producers are culling mature ewes, some lambs are being sold as feeders (for finishing in a feedlot) or being sold to others with irrigated pastures. However, national harvest numbers and strong live prices support the notion that sheep producers are finding ways to manage (for now).
Dan Macon, University of California Cooperative Extension livestock and natural resources advisor, said he’s trying to maintain his breeding flock numbers – at least for this year.
The big unknown, he said, is what feed conditions will be in the fall, noting that lack of available irrigation water will mean more fallowing of alfalfa fields, reducing the amount of post-harvest stubble on which sheep can graze in October and November. Crippling the industry’s ability to slow lamb growth on deserts and California’s Imperial Valley through the fall and winter could hamper 2022 Easter supplies.
Lamb prices are high, which helps ease the pain if a producer is forced to sell due to lack of feed, but in turn, high lamb prices don’t encourage flock rebuilding if there is a lack of feed.
In late June, LMIC reported that the forecast for 2021 is 2 percent lower production, 10 percent lower imports and a lamb and mutton disappearance contraction of 10 percent.
LMIC estimated that third quarter slaughter lamb prices could see $180 to $185 per cwt., 34 percent higher year-on-year. Feeder lamb prices, 60 to 90-lb., could see $240 to $245 per cwt., up 44 percent from a year ago. Slaughter lamb prices could dip below current $200 per cwt. levels if sizable imports are reported during the summer and the largest processors are able to secure supplies for the fall.
Wool Continues its COVID-19 Rebound
Australian wool prices have rebounded sharply since the COVID-low during the fall of 2020, and by early July remained about 32 percent lower than the 2018 high in Australian dollars and 28 percent lower in U.S. dollars. The Australian Eastern Market Indicator averaged Australian $6.44 per lb. clean, or U.S. $4.81 per lb. clean on July 9. While finer wools have enjoyed a distinct upward trend in 2021, coarser wools have seen some ups and down, but remained generally flat.
Recall that wool is a niche product, catering to a hyper-targeted consumer. Australian Wool Innovation reported at the end of May that in the United States, “there are signs that quality Italian wool apparel, such as women’s coats and next to skin items like base layer and fine Merino knitwear, has remained resilient throughout the pandemic. There is renewed optimism from the Italian mills for wool orders being secured for the impending 2021 Autumn-Winter season.”
Similar to the pelt market, international shipping remains a concern in wool export trade. Shipping costs are higher, access to ships more challenging, and delivery and off-loading dates are delayed. Lack of timely payment to wool buyers means less money to spend on the next wool purchase. At some point – if not already – increased shipping costs will be deducted from raw wool price offers. Some substitution to coarser wools might prevail, giving lower-end fibers a lift.
Sheep Genetics USA
I have long been fascinated by the power of genetics. Early on, I was fascinated by the foundational genetic grid involving red, white and roan Shorthorn cattle, which later would be built upon by paradigm shifts in plant breeding and quantum productivity leaps in poultry, swine and cattle.
Sheep Genetics USA is all about real science, real data, leading-edge technology and genetic insights that can help make it easier for you to take actions that will lead to easier and more efficient management, increased production, reduced costs and overall greater productivity for your flock, thereby advancing the American sheep industry.
There is great power in “what if” and “why not” questions. There are answers that currently exist to a number of genetically related production dilemmas that will be organized and made available, however, there are a plethora of questions that do not have answers – or only have partial answers – that demand research. Our goal is to reach a little higher, dig a little deeper and find the answers that will make our industry better and more competitive on the world stage.
Agriculture – in particular the animal protein industry – faces many questions when it comes to societal concerns.
How are we creating the right environment for the animals in our care? What are we doing to minimize the amount of waste in the system? These are all valid concerns and areas where we need to be as transparent as possible in our efforts to create a sustainable food system.
How can high-quality genetics make a difference now and in the future? What can we do so lambs are produced in the right environments that maximize animal welfare and are raised in the most effective and efficient way possible? By fully understanding consumer concerns, we can contribute to a more transparent, responsible food system with high quality animal genetics. The sheep industry is currently blessed with a host of young geneticists, scientists, extension specialists and educators which – when coupled with the large number of entrepreneurial-minded producers – holds tremendous promise for the future of the industry.
Socially and economically sustainable pathways for the sheep industry are not as far away as they might seem. A broad array of concerns will be addressed as part of our focus on sustainable sheep breeding. All sheep behavior serves an evolutionary purpose. Through millions of years, they developed certain protective behaviors in order to survive. As new, innovative production systems become the norm, it is important that we lead forward by examining how animals behave in and adapt to a variety of systems, including the extensive systems of the West where ewes are both shed and range lambed and spend all – or nearly all – of their lives on open range lands.
On the other hand, a growing sector of the industry includes a wide variety of intensive systems including farm flocks and confinement systems. As we encounter increasing differentiated and segmented lamb markets and production systems, additional questions and research opportunities arise.
Consumers have the power to steer our entire industry toward what they see as responsible food production. For us – as industry players – we can monitor sentiment with social media, be transparent and educate others on best practices and industry standards. Sheep Genetics USA is designed to engage all stakeholders in the conversation to understand and assist in creating genetic research projects that will align American lamb with consumer desires.
To create our future, we must understand and address stakeholder concerns throughout the value chain. We believe that breeding and selecting healthy, easy to manage animals will translate to better welfare, less waste and minimized labor. As we come together to find solutions and create opportunities in our industry, we will ensure continual increasing quality lamb from the genetic level to the consumer’s plate, thereby steering us all toward a brighter life tomorrow.
Humans have long been shepherds of genetic selection through the domestication of livestock. But traditional methods of selection are inexact and time consuming. The development of technology that started with estimated breeding values has moved on to genomic-enhanced breeding values, genomics and now we are on the cusp of other quantum leaps forward with the intrinsic power of other new genetic technologies that can accelerate genetic improvement in livestock 10 or 20 times faster than what is possible today.
Our promise of tomorrow requires that we continue to build on the foundation of estimated breeding values as we select traits for different environments and production systems resulting in the right sheep for the right environment and end with finished products that create unsatiable consumer demand. This will be a real game-changer for the sheep industry. Indeed, the field of research opportunities is ready for harvest and Sheep Genetics USA is poised to provide leading edge industry leadership.
To learn more, visit SheepGeneticsUSA.org.
RON LEWIS, University of Nebraska-Lincoln
& LUIZ BRITO, Purdue University
Genetic selection is one strategy for changing the performance of farm animals. Although it is relatively slow compared to some other methods – such as improved husbandry or feeding – genetic improvement garners huge benefit by being permanent, cumulative, and in most cases, highly cost effective.
We want to justify those claims. We will begin with some of the in’s and out’s of selection programs, including the factors affecting progress and some limits to overcome. Those constraints can be addressed through a systematic genetic evaluation system, which combines information collected across flocks to estimate genetic merit more reliably. That is our second topic. Lastly, we venture into the opportunities that new molecular (genomic) technologies offer sheep breeding. Importantly, they complement rather than replace our traditional tools by allowing us to accelerate genetic gains for a broader more inclusive set of traits. The outcome is even more sustainable and profitable flocks.
The in’s and out’s of selection
Genetic selection programs are built on some guiding principles. Foremost is defining their direction, which is based on pinpointing those attributes or traits that we consider most important economically to improve in our flocks. Next, we measure our animals’ performance for those traits. Lastly, we combine that information to identify and then select those individuals with the highest genetic merit for the traits we want to improve. The outcome is bettering our flock in our desired direction.
The rate of genetic gain we can achieve – our selection response – is affected by four factors. The first is selection accuracy. The more we know about an animal and its relatives, the more accurate is its evaluation. The reliability of our decision making improves, thereby increasing selection response.
The second is selection intensity. By being more choosey when selecting the rams and ewes we breed, their genetic merit becomes higher. This also leads to faster selection response.
Third is the genetic variation intrinsic to each trait we wish to improve. At least within a breed, this tends to be static for extended periods. Its context might be easiest to understand in terms of the heritability. The heritability is the ratio or proportion of genetic to total variation present for a trait. It therefore ranges from zero to one. Values near zero indicate the environment defines nearly all differences in the way animals perform. Values near one indicate that animals’ genetics essentially define their performance. The higher the heritability, the greater the selection response.
The fourth and final factor is generation interval, which is the average age of parents when their progeny are born. When the generation interval is shorter, selection response accelerates. In short, we want to increase selection accuracy and intensity while reducing generation interval.
In practice, this can be challenging since there are antagonisms among these factors. An increase in selection accuracy and intensity typically coincides with an increase in generation interval, and vice versa. This necessitates forethought in our design of breeding programs and is where our new molecular (genomic) technologies can help. We will return to genomics a bit later.
Beyond addressing the antagonism affecting selection response, we must consider two further constraints in the layout of our breeding program. One is biological and the other is structural. Compared to other farm species – with poultry and swine as good examples – sheep are older in age at sexual maturity and produce litters of only a couple offspring.
That slows turning over generations and reduces the number of candidates available for selection. Furthermore, structurally the size of many seedstock operations is small. Introducing breeding stock from outside flocks becomes an attractive option. Yet that too can be challenging. Differences in management and geography (environment) among flocks can mask differences that are genetic. This is where a systematic genetic evaluation program fits in.
Quantifying flock genetics
Since 1987, genetic evaluation services in American sheep breeds have been provided through the National Sheep Improvement Program. Participation in NSIP is dominated by four breed-types: hair, maternal, fine-wool and terminal sire. The primary role of NSIP is to provide Estimated Breeding Values for a range of production traits. An EBV estimates an animals’ genetic merit for a particular trait and can be used to predict how an animal’s progeny will perform.
When EBVs are estimated more accurately – particularly in younger animals – selection decisions are more reliable and can be made earlier. Selection response thereby increases. Many economically important traits are evaluated through NSIP, including: live weights from birth through adult age, reproductive rate (number of lambs born and reared), ultrasonic measures of fat and loin muscle depths, fleece weight and quality measurements, and fecal egg count. Producers receive EBVs on these traits to augment their selection decisions.
NSIP also provides producers with economic selection indices. Rarely does our breeding objective – our direction – involve focus on only one trait. Selection indices provide a single value that breeders can use to select several traits simultaneously that define overall profit. They are constructed by considering the economic contribution of the various traits included in the breeding objective. In being a single value, these indices certainly make the selection process much easier. NSIP provides several indices tailored to individual breed types and production conditions.
Still, what about fairly comparing animals raised in different flocks? That too is rectified through NSIP. By sharing primarily rams across flocks, those flocks become genetically connected (related). Through those connections – combined with the statistical tools we use in genetic evaluation – we can disentangle differences in performance due to genetics from those due to environment. Animals can be reliably compared across flocks, generating a much larger pool of sheep to select among. Selection intensity increases along with selection response.
As an illustration, let us consider genetic gain in a maternal breed with a focus on number of lambs reared and dams’ (maternal) contribution to their offspring’s weaning weight. In Figure 1 (above), selection response is shown by plotting the average EBV against birth year in the past 10 years for these two traits. The gains have been substantial. The number of lambs reared have increased by 1.2 percent annually. The maternal weaning weight has increased by 0.11 pounds annually.
Combined, they equate to more and heavier lambs weaned, with improved profitability.
But can we do even better? The answer is yes, and that is where genomic technologies provide tremendous opportunity.
The wonder of genomics
Genomics is now routinely used in most livestock breeding programs in the United States and worldwide, and has made tremendous contributions toward increasing the rates of genetic progress in many populations. Based on a small tissue sample of an animal, a technology called a Single Nucleotide Polymorphism chip is used to read the DNA sequence of an animal at thousands of different sites distributed across the animal’s chromosomes. The DNA sequences at those sites are referred to as genetic markers and capture genetic differences in animals that impact their performance. Different SNP chips are commercially available, and they mainly differ in the number of genetic markers that are included.
The information generated through the SNP chips enable the estimation of more accurate relationship among animals and, therefore, better estimates of inbreeding and genetic diversity in general. Such information also allows the identification of animals carrying genetic conditions that might be lethal or unfavorable, such as ovine progressive pneumonia and scrapie susceptibilities, or with major impact on performance, such as myostatin and fertility genes.
Furthermore, it can be used for parentage assignment and correction of pedigree errors.
The information from these genetic markers can also be combined with pedigree and phenotypic records to calculate Genomic-enhanced Estimated Breeding Values in a process known as genomic prediction. The outcome is that selection response can be increased at an unprecedented rate in sheep and other livestock species (greater than 60 percent for some traits). However, to obtain GEBV we first need to establish a reference population, which are animals both with performance measurements for the traits of interest and genomic data. We then use the animals in this reference population to determine which SNP are favorably or unfavorably associated with a given trait. That information is combined with pedigree and performance records to predict the genetic merit of genotyped – and related non-genotyped – animals more accurately.
The composition of the reference population impacts the accuracy of the GEBV. The following factors are key. First, the reference population needs to represent the genetic diversity observed in the breed under selection. In other words, it is important to choose key ancestors and animals from multiple farms and genetic backgrounds to fully capture this genetic diversity that is present.
Second, when establishing the reference population, all of the genotyped animals should also have performance records – or progeny with performance records – for the most important traits. The animals to be genotyped do not need to be measured for all traits of interest, but at least for some of them. Third, key ancestors – rams and ewes with multiple parities – should be prioritized since they contribute more to the genetic pool. Lastly, those animals genotyped should not be chosen solely based on their performance. In other words, the reference population needs to contain animals across the range of performance levels.
Genomic prediction enables breeders to obtain more accurate breeding values in young animals that have not yet been measured for the traits of interest (e.g., number lambs born and reared), which then can be used in selection decisions. As an example, in Table 1 (above) we show the increase in accuracy achieved when adding genomic information for a lowly (h2 = 0.10) and moderately (h2 = 0.30) heritable trait, such as number reared and adult body weight, respectively. Particularly for traits that are lowly heritable, and where little performance information is yet available, genomics is most advantageous.
Such is also the case for traits that are difficult or expensive to measure (e.g., disease resistance, feed efficiency, meat quality), sex limited (e.g., litter size), or measured late in life (e.g., longevity). As breeding programs in sheep incorporate this wider set of traits, genomic tools will become ever increasingly important.
Systems for genetic evaluation and selection are indispensable to our sheep industry. Combining new genomic technologies with our well-established and tested approaches provides tremendous opportunity to improve traditional and more novel traits in our flocks. Importantly, genomics builds on what we already do, and does not replace it.
In fact, for those already engaged with NSIP, EBVs will appear the same as now but will be predicted more accurately. Genomic evaluation does entail costs – both in terms of time invested and the expense of performance recording and genomic testing. Yet, the payoff is clear. Beyond more accurate EBVs, ancestry tracking is improved and genetic conditions are identified. By defining clear objectives for our breeding programs, and by utilizing the tools available to genetically improve our flocks, the growth and sustainability of our industry looks bright.
TOM MURPHY, BRAD FREKING, JOAN BURKE & J. BRET TAYLOR
USDA Agricultural Research Service
Breed evaluations and the development and dissemination of composite breeds have perhaps been the most recognized sheep breeding and genetics experiments led by the U.S. Department of Agriculture’s Agricultural Research Service scientists.
A key component of both efforts focuses on evaluating average trait performance. Averages are certainly important for many aspects of sheep husbandry, but an often overlooked descriptor of performance is variation or how “spread out” individual animals are around the average.
Figure 1 (at right) displays “bell curves” for number of lambs born per ewe lambing, ewe breeding weight, and lamb 90-day adjusted weight for purebred Polypay and Suffolk reared at the U.S. Sheep Experiment Station in Dubois, Idaho, and purebred Katahdin and Romanov reared at the U.S. Meat Animal Research Center in Clay Center, Neb.
The middle of each breed’s curve represents the average and the width represents the phenotypic variation of each trait. To be clear, this is not a formal breed comparison, but it illustrates an important point: while there are clear differences in average performance between breeds, there is substantial phenotypic variation in performance within all breeds. Are there USSES Suffolk ewes that consistently lamb triplets and USMARC Romanov ewes that consistently lamb singles? It’s rare, but yes.
Likewise, only a couple of USMARC Romanov lambs have weighed 70 pounds at 90 days, while this is about par for the course for USSES Suffolk. This might be considered heresy to some, but no breed can excel in everything and each has their strengths and weaknesses.
Although combining relative strengths of breeds through crossbreeding is extremely valuable for commercial sheep production and will continue to be an important component of USDA ARS genetics research, this article will focus on improving purebred sheep populations. Part of the within-breed phenotypic variation seen in these graphs is due to genetic differences between animals. This is what ultimately matters when making selection and mating decisions in our flocks. The problem is all the non-genetic effects that impact trait performance cloud the ability to see an animal’s genetic merit. Estimated breeding values – which are provided to American sheep producers through the National Sheep Improvement Program – remove most of this non-genetic haze and enable us to select individuals for their genetic merits.
Standard NSIP traits for which EBVs are available are associated with body weight and composition, wool, reproduction and parasite resistance. While these are economically important, they are limited to those that can be easily measured on the farm or ranch (e.g., number of lambs weaned, post-weaning weight, etc.) or inexpensively by experienced technicians (e.g., ultrasound loin muscle depth, fecal egg count, etc.). Furthermore, as one ardent NSIP breeder put it, “we have EBVs for traits that make us money, but we don’t have EBVs on enough traits that lose us money.”
What about traits like survival, feed efficiency and longevity? Are these not economically important? They are, but they’re just too labor intensive, difficult or expensive to measure at the producer level. Enter the genetic reference flock.
Simply put, a genetic reference flock is one that is enrolled in NSIP, acquires representative rams from other NSIP breeders, and quantifies standard and novel traits in their GRF progeny. With strong genetic connectedness between GRF and industry NSIP flocks, new trait EBVs are available for use in selection by all NSIP breeders and commercial producers that purchase NSIP breeding animals. Through this effort, GRF will first be established at the USSES, USMARC and Dale Bumpers Small Farms Research Center in Booneville, Ark., and then, collaborating universities with NSIP enrolled sheep flocks. Katahdin, Polypay and Suffolk have been selected as the first GRF breeds as they are common among ARS locations – Katahdins are reared at all three, and Polypay and Suffolk are reared at the USSES and USMARC.
ARS scientists have started the GRF by first establishing within breed genetic linkages across our locations. The USSES acquired its Katahdin flock from USMARC in 2020 and both have imported Katahdin rams from DBSFRC. The USMARC Polypay flock was augmented in 2019 and 2020 with USSES Polypay ewes and rams. Finally, USSES Suffolk rams were bred to USMARC Suffolk ewes in 2020. In addition to linkages across ARS locations, it will be important to strengthen connectedness to industry NSIP flocks. Rams from pertinent breeds have been and will continue to be purchased from NSIP flocks at each location and Polypay and Suffolk ewe lambs were purchased from NSIP sources in 2019 and 2020 to establish these breeds at USMARC. These efforts will continue with thoughtful rotation of industry purchased and ARS bred rams across GRF to replicate genetics across diverse production environments.
The novel trait complexes the GRF will focus on are associated with ewe health and longevity, ewe and ram reproductive efficiency in optimal and suboptimal mating seasons, and lamb survival, feed efficiency and carcass characteristics. Many of these novel traits require specialized technologies to suitably quantify.
While the GRF might be able to afford these technologies with grants and internal funding, most industry NSIP flocks cannot. Additionally, it is beneficial if indicator traits – which are genetically related to our novel traits of interest but do not require specialized technologies to record – can be identified and incorporated into NSIP.
Subclinical mastitis is a good example of a novel trait ARS scientists are quantifying in maternal breeds. We have found it is associated with large reductions in total weight of lamb weaned but quantifying it requires milking many ewes and conducting tests to determine bacterial presence and/or degree of udder inflammation. This is obviously not practical to do on farm/ranch because it is labor intensive and can be expensive. For the last two years, USMARC Katahdin ewes have been milked to quantify intramammary health and have also been scored for several udder conformation traits. Udder conformation can be rapidly and inexpensively measured by NSIP breeders and could be an indicator trait for intramammary health. Similarly, feed efficiency is economically important but requires specialized equipment, which is not feasible for most sheep operations. USMARC is expanding its capabilities to measure individual feed intake on GRF animals and will investigate relationships between it and traits already measured on the farm or ranch (e.g., weaning and post-weaning weight and ultrasound conformation).
In addition to quantifying novel traits, the structure of the GRF will provide a means to direct precision animal management through estimating genetic-environment-management system interactions. Moreover, standard and novel traits will be linked to existing and expanding ARS sheep tissue repositories to strengthen molecular genetics studies and accelerate the development of genomic-enhanced EBVs.
Finally, as land grant university flocks join this effort, other common NSIP breeds can be included. Genetic reference populations are not a new concept, they’ve been successfully implemented in other species and sheep producing countries across the world. This is a major undertaking, and its success will be dependent on collaboration among NSIP breeders, industry groups and university and ARS scientists.
ARS looks forward to sharing the progress of this project in future articles and at industry events. If you have NSIP rams that you feel should be represented in the GRF, please contact Tom Murphy at firstname.lastname@example.org.
Sheep genetics USA traveled virtually to Katahdin breeder Lynn Fahrmeier of Wellington, Mo., and to Jack McRae’s Targhee ranch near Jordan, Mont., to discuss why those two breeds were early adopters of new genetic technology.
SGUSA: Katahdins and Targhees are both fairly recently developed composite breeds, especially when we compare them to our traditional British and European breeds. How was your breed developed?
Lynn: The development of the breed began in the late 1950s with the importation of a small number of haired sheep from the Caribbean by Michael Piel of Maine. The Piel Farm had several thousand sheep at the time and Piel felt that “progress in selection for traits important to the production of meat would be greatly enhanced by the elimination of wool as a major factor for selection.”
His goal was to combine the hair coat, prolificacy and hardiness of the Virgin Island sheep with the meat conformation and rate of growth of wool breeds. He began to experiment with crosses between the hair sheep and various British breeds, especially Suffolk. After almost 20 years of crossing the resulting hybrids “in every conceivable combination” and selecting the individuals with the desired combination of traits, Piel eventually collected a flock of ewes he called Katahdins, named after Mt. Katahdin in Maine. During the mid-1970s, the Wiltshire Horn – a shedding breed from England – was incorporated into the flock to add size and improve carcass quality.
From this original flock, new breeders have been able to expand the number of Katahdin sheep in North America and many other countries, and select carefully for hair coat, carcass quality and reproductive efficiency. In 1986, a breeder’s organization – Katahdin Hair Sheep International – was formed.
Jack: The Targhee breed was developed by the U.S. Sheep Experiment Station at Dubois, Idaho. Starting in 1926, the station crossed their crossbred Rambouillet, Corriedale and Lincoln ewes to Rambouillet rams. The offspring were then crossed on each other to develop a breed with high-quality apparel wool and good carcass, which would thrive in rugged conditions. The final result is approximately three-quarters fine wool and one-quarter long wool blood.
SGUSA: Lynn, Katahdins currently register more sheep than any other breed in the United States. What is the reason for their current popularity?
Lynn: The Katahdin breed is riding the wave of three major trends shaping the American sheep industry.
1. Hair. Unless a flock is clipping high-quality wool in large quantities, it is hard to pay for the clipping and shipping of raw wool. This is even more of a problem in smaller Eastern flocks. With a shedding hair coat, the producers save time and shearing expenses.
2. Nontraditional markets. While there are Katahdins that can compete successfully in the traditional lamb markets, it is very easy to produce a plump, healthy looking lamb that weighs 60 to 75 pounds that is weaned right off the ewe. These lambs bring a premium in the nontraditional lamb market.
3. Easy doing. With many new, first-generation farmers looking to raise smaller animals, Katahdins fit right into the mix. Noted as maternal and easy lambing, good Katahdin ewes can lamb twins and triplets on pasture unassisted. Couple that with proven parasite resistance and no shearing, Katahdins are a perfect breed for couples that work in town.
SGUSA: Jack, Targhees have led the way with their early involvement with Estimated Breeding Values and the National Sheep Improvement Program. How did that come about?
Jack: The right people at the right time. The early sheep faculty from Montana State University – J.L. Van Horn and Jim Drummond – had laid the foundation with their talks on the importance of performance testing based on individual ratios. Later, MSU Sheep Extension Specialist Rodney Kott guided us into the world of Expected Progeny Differences. It speaks well of their relationship with the industry that commercial buyers expected such information from the seedstock producers.
John C. Paugh, Jr. – a Targhee breeder – was involved in the early formation of a genetic-based program for sheep improvement that became NSIP. It seemed that no matter if it was the National Wool Growers, Targhee meetings, Montana Wool Growers or your local sheep meeting, John was there to explain the concept of BLUP and to promote the need for this program. John was the first chairman of NSIP. Chase T. Hibbard was the Targhee association president at this time and also promoted the need for the program. The third major promoter of the program was Judy Scanlan, a Targhee breeder from New Hampshire and later from Oregon. Judy did not have a pedestal to speak from in those early days, but was the most dedicated person we had for promoting the need for and advantages of Expected Progeny Differences.
Targhees – while small in numbers as a registered breed – are large in numbers as a commercial sheep breed in the West. Most of the large sheep operations are also cattle producers, and they were already familiar with EPDs and EBVs as a major part of the cattle industry. They just wondered why it took us so long to catch up to cattle.
SGUSA: Lynn, Katahdin producers are about to achieve what no other United States breed to date has accomplished and that is to have within the next few months Genomic Enhanced EBVs. How was the breed able to accomplish that milestone?
Lynn: Since the first Katahdins left the Piel farm in Maine, the breed has attracted progressive, production-oriented shepherds and animal scientists. Many of the early owners of Katahdins worked with researchers to collect data. That ethic has continued until today. Thanks to forward-thinking researchers, they can leverage the willingness of Katahdin breeders to collect data.
While the U.S. Department of Agriculture’s National Institute of Food and Agriculture provided a lot of funding for the current grant, more than 20 producers invested thousands of hours collecting blood, feces, weights and FAMACHA scores on more than 6,000 lambs in three years for the researchers to evaluate.
Having progressive producers willing to partner with the research community has proven critical for the development of GEBVs.
SGUSA: Jack, the Montana Ram Sale has really embraced and promoted the use of data and EBVs. How has that influenced the Targhee breed?
Jack: Many of the larger purebred Targhee operations are in Montana, and most of them are consignors to the Montana Ram Sale. Before EBVs, much of what was known about the rams was subjective and in the eye of the beholder. Most rams had some wool pulled from them by every person who walked by. If you liked the ram, you convinced yourself that the wool grade was what you were looking for.
The same thing happened with feeling the loin area for size. NSIP would not allow information that was not measured, and the early years were a rude awakening as far as micron and ribeye area were concerned. We went from measuring some animals to measuring all of our rams to measuring our ewes, as well. This has made the Targhee breed much more predictable in what their offspring will be.
It also puts all consignors on equal footing in that a newer producer with a certain EBV is equal to the old established producer with the same EBV.
SGUSA: Lynn and Jack, what do you see as the next genetic step for your breeds moving forward?
Lynn: As a maternal breed, we need to evaluate traits like out-of-season lambing and ewe longevity. There is also a lot of interest in feed conversion and working on an index that focuses on productivity for forage-based flocks. To some extent, we also need to focus on education. We have GEBVs, but now we need to help Katahdin breeders understand the power they have and help them use them to meet their flock goals.
Jack: Collecting data in conjunction with genomic testing to determine longevity factors. Also, using data collection and genomics to find our most efficient animals in their home environments. Targhees are most often found in large range operations with low input, where these traits are seldom measured or analyzed, but have a significant impact on profit.
Reid Redden & Jake Thorne
Texas A&M AgriLife
Historically, Texas producers have pioneered several significant advancements in the American sheep industry, but have not remained present-day leaders when it comes to utilizing some key genetic technologies.
Long-standing production constraints have limited innovation in the seedstock industry in Texas, making the state ripe for a technological revolution that could help producers overcome several of their most significant challenges. Technology that explores and quantifies genetic capability might be the golden ticket for the Texas sheep industry to reach its full potential.
Texas is No. 1 in the United States in sheep numbers and, in many ways, has been forward-thinking in the area of small ruminant production. While mohair and wool were prominent commodities produced by Texas for decades, a paradigm shift has occurred in the 21st century with importation of breeds not requiring shearing and adaptable to the dry, semi-arid landscape of the Edwards Plateau region – the epicenter of small ruminant ranching in the state. Rambouillet sheep still number in the hundreds of thousands, but it is estimated that more than half of the sheep in Texas are now hair sheep, predominantly Dorper.
Prior to the removal of the wool and mohair incentive, wool was the most valued trait and improvement of such has long captivated progressive ranchers and the research arm of Texas A&M. Texas formed one of the first centralized ram tests in the late 1940s at the Sonora, Texas, experiment station with Rambouillet sheep. This test ran for nearly 70 years and certainly accomplished the original goals of improving fleece quality and growth rate, in conjunction with promoting a dual-purpose phenotype.
The National Sheep Improvement Program was formed in the late 1980s to allow on-farm data to translate into Expected Progency Differences – now called Estimated Breeding Values. This system is an improvement over centralized testing as it allows for evaluation of other critically important traits overlooked by the ram test, such as reproduction, range fitness and parasite resistance. However, recording animal lineage is a critical component of utilizing NSIP.
The majority of seedstock in Texas are raised under extensive conditions. They are range lambed, and if they are individually identified, it isn’t until after weaning. This certainly promotes traits such as hardiness, but limits the ability to capture pedigree and makes collection of production data almost impossible.
To work around this, Texas Rambouillet Superior Genetics was formed in the 2000s. This group of West Texas Rambouillet breeders pooled their best sheep into one flock and enrolled into NSIP. The initial results were encouraging, but keeping up with the off-ranch data collection became problematic for the group and unfortunately this project dissolved. This approach was ahead of its time and could have had long-term impact on the regional industry as similar strategies have been used in other countries to develop genomically enhanced breeding values.
The emergence of Dorper sheep in Texas – in lock step with the rapidly growing nontraditional market that prefer these smaller framed lambs – has completely changed the industry landscape. This breed is quite adaptable to Texas range conditions and requires less management than fine wool sheep. Yet neither Dorper, White Dorper or other hair/shedding breeders in Texas adopted advanced genetic improvement technologies, such as NSIP. In contrast, exhibition at stock shows and visual classification standards have dictated perceived genetic potential and the value of breeding animals.
In other sheep breeds, this approach has failed to measurably improve the genetic potential of range sheep and, in some cases, has promoted genetic change that is counterproductive to commercial production.
Since 2015, Texas A&M AgriLife has enrolled a group of Rambouillet and Dorper sheep into NSIP to demonstrate how technology can be used to capture pedigree and production data from extensively managed flocks. These flocks are also creating genetic linkages with other NSIP breeders to improve the accuracy of across flock comparisons. In addition, we have opened a laboratory to provide fecal egg counting services and hosted several schools to train technicians to collect carcass and pregnancy ultrasound data.
In 2019, Texas A&M AgriLife Extension received grants from the USDA Sustainable Agriculture Research and Education Foundation and the National Sheep Industry Improvement Center. In short, we hoped to confront these issues by using modern tools on private sheep operations. Realizing that convincing all of Texas to adopt such practices was not going to happen overnight, our plan from the outset was to work with some of the leading Rambouillet and Dorper seedstock producers in Texas in hopes of creating a trickle down effect. In the ranching community, watching your neighbor succeed with something new is often more powerful than the spoken word. We initiated these projects with a dozen key producers who collectively run several thousand sheep. The plan has been to utilize the Flock54 genomic panel for parentage determination and disease marker status, and additionally collect data on number of lambs born and weaned, weaning and post-weaning weights, and fecal egg counts for parasite resistance.
While our projects are still ongoing, they have undeniably succeeded in one area: word of mouth about the use of technology to more easily capture production data is definitely spreading. Ultrasound, fecal egg counting and RFID tags are now topics we discuss almost daily with producers. In full transparency, some of the producers on these projects have gone on to enroll in NSIP and some have not. Perhaps the greatest challenge to widespread utilization of the genetic technology is the lack of immediate improvement in their flocks, and for some the price to pay (both literally and metaphorically) is too great.
Many of these producers also “dove in” head first with data collection for a multitude of traits on their entire flock and might have burned themselves out, for lack of a better term. The producers on this project who have stuck with it understand that genetic improvement requires a long-term investment. Those that are starting to see realized benefit also made the increased work manageable on themselves by prioritizing the collection of data for only key traits important to their operation and customer base, and only doing so on their best subset of breeding animals.
Ultimately, there are tremendous opportunities for the sheep industry in Texas and the entirety of the United States. Society has rediscovered wool and lamb.
Now, the challenge is on our industry to deliver the quality of product they are learning to love.
Improving the genetic potential of the Texas and American sheep flocks will help the industry reach this goal. Sticking to visual appraisal and traditional methods of sheep improvement alone will let the opportunity for industry growth slip away as we’ll once again be held down by the same old limitations.
Albert Einstein once said, “Nothing happens until something moves” and the genetics movement in Texas has been steadily picking up steam.
With more than four years of experience working for AgResearch – a division of New Zealand’s Crown Research Institutes – Andrew Hess, Ph.D., knows a thing or two about turning scientific efforts into practical tools that can be implemented at the ranch level.
In his new position as an assistant professor in the University of Nevada-Reno’s Department of Agriculture, Veterinary and Rangeland Sciences, he will be tasked with exactly that. While he will work with both sheep and beef cattle in his new role, he was hired as part of the university’s investment in the Great Basin Research and Extension Center. Announced in fall of 2020, the center is now home to the Rafter 7 sheep flock that was developed by the university some 30 years ago.
“It’s great that the university has the Rafter 7 flock back,” said Hess, who got his undergraduate degree from UNR in 2011. “They sold the flock around the time I graduated from UNR. I’m really excited to have that flock available as a resource to conduct some of these studies.”
UNR hired Hess in the summer of 2020, but his arrival was delayed by the global COVID-19 pandemic. He returned to the United States in late June of this year and had been on campus in Reno for just a week when he was interviewed for this story.
Despite that, Hess has some clear ideas about where his research is headed in the months to come, and it will involve genetic research that lends itself to practical application for the ranchers of Northern Nevada.
“I’ve got a few projects that I’m trying to get underway. One of them is focused on improved health in sheep,” Hess said. “Mostly what I’m focusing on right now are polymicrobial diseases that cause pneumonia in sheep. I’m looking at the microbial profile to see if we can better use that to characterize the disease and select on those to improve the health of our sheep flocks.”
“With pneumonia, it’s usually caused by multiple microbes. Usually, one comes in and makes the animal more susceptible to another one. It’s the combination of those different pathogens that actually causes the disease. So, one of the things that I am interested in – rather than focusing on just one of those microbes – is focusing on the whole profile to see if I can better characterize that animal’s disease status and use that information to select for healthier animals.
“Another area that I am interested in pursuing is trying to get a feed efficiency measurement – or a proxy for a feed efficiency measurement – for animals that are out in the field in our rangeland environments. The goal is to be using digital agriculture tools to assist in that and get more so a proxy than a direct measurement of feed efficiency.”
Hess is on board with the ongoing push for the use of genetic and genomic advancements to improve the American sheep industry.
“The first step is helping producers understand the benefits of genetic testing and getting genomic information, and the gains that they can make when using genomics compared to your standard pedigree-based analysis,” Hess said. “So, part of what I’m focused on doing here first is just reaching out to the local ranchers and talking to them about some of the potential benefits of genomics. From there, it’s just extending it further into a broader toolkit.”
At AgResearch, Hess worked with implementing genomics in multiple species – from sheep and beef cattle to mussels and deer/elk.
“I got a really rich experience across a range of different species that are at various stages of implementing genetics or genomics,” he said. “It was a really neat experience for me. Sheep were probably the furthest along in that area, while mussels were in the very early stages. My experience with mussels was actually demonstrating the benefit of genomic selection when they were considering implementing that into their breeding practices.
“I’m just excited about this opportunity to come home – most of my family lives in the Reno area – and I look forward to working with the ranchers of Nevada and the American sheep industry.”