The Resistance Part II: The bacteria battle

Antibiotics have their work cut out for them

by Miranda Reiman

April 22, 2020

Penicillin was introduced in 1928, antibiotic resistance followed in the decades after. Methicillin came next, a year later its first resistant bacteria were detected. So it’s not surprising that common cattle cures are now subject to the same fate.

“For many years, the bacteria that caused [bovine respiratory disease] didn’t seem to be becoming resistant,” says Amelia Woolums, Mississippi State University veterinarian. New data from the last decade show they’ve not only developed it, but “surprisingly, they have developed resistance to multiple different antibiotics, and that can become evident even when we treat cattle with just one.”

Treatment with one drug may lead to less effective options the next time around, no matter the class.

“If a cow has an antibiotic-resistant bacteria that’s causing an infection, the cow many not get better if we treat it with antibiotics,” she warns.

But how does it happen in the first place?

Different classes of antibiotics work to defeat bacteria in different ways, like disrupting the cell wall or membrane, inhibiting protein synthesis or DNA replication, or altering the metabolism.

“Antibiotics basically block or prevent different things the bacteria have to do to live, or destroy structures of the bacteria,” Woolums says. “If the bacteria change those things so the antibiotic no longer works, that’s how they become resistant. The sensitive ones are killed and that just leaves the resistant ones, and they get together and say, ‘Let’s have a family.’”

They use several different tactics for building resistance, such as:

Genetic mutation. That’s the spontaneous change in a portion of the DNA of the bacteria. “If the protein changes, and that’s the target of the antibiotic, it no longer works,” Woolums says. That change is coded into the bacteria’s progeny, too, so it passes on the resistance.
Efflux. “That basically pumps the antibiotic right out,” she says. The drugs aren’t in the cells long enough to work.
Destruction by enzymes. “Many bacteria possess genes that then produce enzymes that chemically degrade or inactivate the antibiotics.”

“Research shows bacteria are very generous with their DNA,” Woolums says, noting they can share them across different kinds of organisms.

A Pastuerella or Mannheimia can pass along resistant chunks of DNA—called integrative and conjugative elements, or ICE—to E.coli or salmonella, for example.

“Bacteria replicate at crazy rates,” she says. So when one of these mutations sticks, very quickly there are millions of cells with the same tactics. “It’s survival of the fittest.”

Producers can help in the battle against resistance.

“Keeping cattle healthy really should be the first focus,” Woolums says. “We were so lucky in the last half of the 20th century to come up with new antibiotics that did some amazing things.”

But the penicillin example is bound to keep repeating itself.

“We really should try to focus on husbandry and things that keep cattle healthy,” she says, “using antibiotics only when we really need them.”

Read part I: Works today, not tomorrow?

The Resistance Part I: Works today, not tomorrow?

Combating antibiotic resistance in cattle

by Miranda Reiman

April 22, 2020

Antimicrobial resistance might sound like a challenge straight out the headlines, but it could become awfully personal when you find routine antibiotics no longer cure a sick calf.

“I think we thought, in the arms race against bacteria, that we could win it,” says Amelia Woolums, Mississippi State University veterinarian. But bacteria replicate quickly, and disclose their tricks to other bacteria by sharing DNA. “It’s really not a race we are winning.”

It’s been a concern in the medical community ever since penicillin debuted early in the last century, but cattle health protocols have been seemingly immune to the challenges….until now.

Studies show antibiotic resistance is on the rise, especially in the last decade.

“There are diseases cattle get where in the past we might have said, ‘Well, let’s just give an antibiotic, just in case,’” Woolums says. “That’s the attitude we’ve got to get away from.”

Bovine respiratory disease (BRD) provides one complex case study, she says. There are four main bacteria that cause BRD, and 11 antimicrobials on the market are labeled to treat the most common one: Mannheimia haemolytica.

That’s where much of the research rests.

Studies from 1994, 2004 and 2011 showed an increase from virtually no resistance. Then work from Kansas State University’s diagnostic lab caught the attention of the animal science community.

Nearly 400 samples across a three-year period, from 266 unique locations, gave insight into possible trends.

In 2009, only 5% of the bacteria were resistant to five or more antimicrobials; by 2011 that jumped to 35%.

Treatment history of the animals was unknown, “but these data still worried a lot of people,” Woolums says.

That inspired studies in live cattle.

At the University of Georgia, 169 high-risk stocker cattle were measured at arrival, given metaphylaxis—or preventative antibiotic treatment—and swabbed again two weeks later.

Three-quarters of the cattle came in with bacteria that would respond to any antibiotic they were given. Two weeks later, that 75% number was down to 1%.

“Ninety-seven percent were resistant to the antibiotics we use all the time,” Woolums says. At that point, “they’d only been given one antibiotic.”

Concerning but, she says, “It’s important to note that this was not related to an unusually high rate of morbidity and mortality.”

More research is needed to determine the level that would cause a treatment failure.

Woolums and her colleagues completed an additional study that took those same swabs at four points from day one to day 21. It showed the number of cattle shedding the bacteria went from 10% on the first day to 88%.

“That’s textbook,” Woolums says. “But what we didn’t really expect was that the pattern of multi-drug resistance would completely follow it.”

By day seven, 80% of the bacteria were resistant to multiple drugs, and they were genetically diverse, meaning they didn’t just proliferate from one carrier calf.

This isn’t meant to be a dire warning, Woolums says, but more of a caution sign. More research is needed and best practices need to follow suit.

“The No. 1 goal is efficient use of antibiotics, that we’re really heading off problems before they start,” says Brandi Karisch, Mississippi Extension beef cattle specialist. “Good animal husbandry and hygiene practices, routine health exams and vaccinations.”

To lessen the chances of needing treatment, limit stress, improve nutrition and identify disease earlier, she says. “So, doing a good job of monitoring those cattle.”

Then use antibiotics sparingly—only for the sick or highest-risk cattle—and use them right: follow label instructions, work closely with your veterinarian and observe proper withdrawal times.

“Treat for the recommended time period,” Karisch says. “How many of you know someone who starts feeling better and stops taking the antibiotic?”

The Centers for Disease Control (CDC) has already flagged this as a growing area of concern.

“Antibiotic resistance is one of the biggest public health challenges of our time,” Karisch says, citing the CDC. More than 2.9 million people get an antibiotic-resistant infection each year. “So this is a very serious threat, not just on the livestock side of things, but in human medicine as well.”

There’s a chance every tool your veterinarian has today will work for years, and there’s a chance it won’t work next week.

“We don’t really know yet. The negative impact on morbidity or mortality has not been clearly evident,” Karisch says. “But there’s that ‘yet’ that goes along with that.

“In the meantime, it’s really important that we’re doing a good job taking care of those cows,” she says.

Read part II: The bacteria battle

Fueling your cows

It takes grass to grow grass on the foundation

by Morgan Marley

April 20, 2020

If you’ve built a powerhouse cow herd, its best fueled with robust grass.

“We all understand that a ranch has to be economically viable in the short term to have any opportunity to be economically viable in the long term,” says Hugh Aljoe, director of producer relations for Noble Research Institute.

That’s why management needs to adapt quickly to uncontrollable changes like drought. Record keeping and monitoring are key.

Understanding the basics

In planning for available forage, Aljoe contrasts carrying capacity versus stocking rate: “There’s a difference.”

Capacity is a measure of the forage supply or how much grass is being produced. Stocking rate is a measure of forage demand, or how much grass is being grazed.

“Carrying capacity changes from year to year or season to season based on moisture and our pasture management,” he says. “The better we manage, the more opportunity we have for production.”

Monitoring carrying capacity throughout the year helps determine where adjustments should be made to stocking rate.

It’s a supply-and-demand relationship based on what the pasture produces and what the cattle need.

Rain gauge

Across the country, rainfall varies in amount and timing, which affects growing patterns and pasture management.

The first thing Aljoe looks at is historical annual precipitation. Start by studying rain at the end of the growing season in October “when the water begins to recharge the soils,” Aljoe advises.

By the end of March, the Southern Great Plains should already have 40% of its annual rainfall, he says. The amount of precipitation accumulated in the soil will determine whether it’s going to be an early or delayed spring.

“Did we receive abundant rainfall and can add more numbers?” he asks. “Or did we receive less rainfall and need to de-stock in order to preserve our pastures?”

Regardless of where a ranch is located, 30% to 35% of annual forage production should occur by the end of May. That increases to 65% by the end of June when the water year rainfall should reach 65% to 75%, Aljoe says, referring to water-table records.

“If we’re not there in the spring, we’re probably never going to catch up,” he says. Livestock can have compensatory gain, but unfortunately pastures are limited.

Another important component is variance, or how much rainfall is normal, positive or negative? Small differences are less critical than those above 10 to 15 percentage points.

Aljoe shares one example when forward-looking management saved the ranch. Charting a major drought as it developed in the spring, management at the typically 1,000-cow ranch sold down to 700 head before major downward price pressure. By September, those pastures stood out for not showing much drought stress.

“The land resource was maintained,” Aljoe says. “That’s what is possible when you use the water table.”

Look down

“Take half, leave half” is a good starting rule, but grass growth rate and forage type help set rotation plans and grazing-pressure thresholds.

“In the South there’s Bermudagrass or fescue in the North,” Aljoe says. “On those introduced pastures, we can take as much as 50% to 65% of the production every time we graze, because they’ll recover rapidly. On the other hand, on native range pastures we only want to take 25% at best.”

How often do you walk across your pasture and look down and score your pastures? Is the ground cover highly unfavorable, unfavorable, favorable or highly favorable?

“You want to rate it on a system where there is no middle ground,” Aljoe says. Even numbers make it easier to see if land needs improvement or maintaining.

Building small exclusion plots with wire panels and T-posts is another way to monitor the amount of forage grazed.

“We never want to take more than half,” he says. “And in the early growing seasons, we don’t want to take but the top third in a good grazing program.”

During the dormant seasons, some cattlemen like to make cattle “hustle,” eating what’s probably better left as residual ground cover, Aljoe says. Forced “cleanup” grazing may damage the forage’s ability to come back and leave soil unprotected. It can take years to recover.

Photo points

Sometimes it’s hard to see the changes, so Aljoe suggests visual evidence from the same “photo points” each year.

Take pictures at the peak and end of growing seasons, marking locations with a simple T-post or through a downloaded global positioning system (GPS) app.

“We had a producer that bought a degraded resource and through management planning he took it from poor condition to what we would consider excellent condition in just five years,” he says, noting the photos played a key role.

Aljoe shares those pictures with others, “to help them see what their future could look like.”

Doing something is better than doing nothing. Be consistent and only make it as complicated as you’re willing to stand, he says.

It can be as simple as these examples, or customized with free consultation from resources like the Oklahoma-based Noble Research Institute or the government’s Natural Resources Conservation Service.

A powerhouse cow can’t grow a calf of the same caliber without the grass to match.

Aljoe shared these tips for cattlemen at the 2020 Cattle Industry Convention in San Antonio.

Beef AI can pay

Capturing the value of artificial breeding from ranch to rail

By Natalie Jones

March 9, 2020

Most dairymen use a breeding technology also proven profitable for beef cattle enterprises, but no more than 10% of commercial cattlemen bother with it.

Why? Lack of facilities, labor, confidence and convenience lead the list of reasons artificial insemination (AI) hasn’t become commonplace on the ranch.

Idaho Extension Beef Cattle Specialist John Hall led producers to reexamine barriers and capitalize on the value of AI at last fall’s Range Beef Cow Symposium in Mitchell, Neb.

Developed more than 80 years ago, with frozen technology since 1945, AI has included sex-sorting options for a dozen years.

Rather than just turning bulls out for natural service and moving on to other ranch projects, Hall urged producers to consider the value they could capture with AI. That’s because consumers are calling for more high-quality beef, and the call must be answered.

“AI certainly gives us the opportunity to do that, because we can use those highly proven sires that have carcass information that we know are going to give us the kind of cattle the consumer wants,” Hall said.

But before going all-in with investments in synchronization and semen costs, technician fees and the labor associated with roundup and processing, he suggested making sure basic management is on track.

A successful AI season begins with heifers at a body condition score (BCS) of 6 and cows at BCS 5, after a closed and short calving season so that they can cycle back before insemination.

Costs and benefits

The average cost of a commercial bull is about $5,000, Hall said, and the cost of natural breeding continues to rise. That’s why few commercial producers buy above-average bulls for growth and carcass merit; they simply can’t afford their natural service, which Hall put at $90 to produce a live calf.

On a 300-cow herd and a 50% pregnancy rate, he said each AI calf would cost about $95. With a more typical preg rate at 55%, that AI calf is cheaper than the one from natural service. It also carries superior genetics from bulls in the top breed percentiles that most cannot afford for natural service.

The use of fixed-time AI helps keep labor costs down and can shift calving seasons earlier, with more born in the first 21 to 30 days. Calves in the first 21 days compared to three weeks later result in 35 to 50 pounds, but that’s mainly an advantage for feeder calf value, Hall said.

“What we normally see when using fixed-time AI,” he said, “we’ll pick up a 3 to 5 percentage-point increase in the number of cows pregnant at the end of the year, compared to natural service.”

Another opportunity is replacement heifers.

“You can capture a big advantage in the females created, because of their enormous value to a commercial operation,” Hall said. “You can breed a certain percentage of them to more maternal bulls to fit the environment that you work in.”

Retained ownership

Beyond the cow-calf herd is the potential value capture at the feedyard and packinghouse.

“Taking calves all the way to harvest is arguably the best way to realize return on the AI investment,” Hall said. That’s because carcass traits are the most heritable and high-quality carcasses continue to command premiums that go straight back to producer pockets when they retain ownership.

Data from a 600-head Virginia operation retaining ownership on calves shows having both AI sire and AI-sired dam increased returns to each cow by 22%. It also increased the share of carcasses grading Choice by 38 percentage points compared to calves with no AI genetics.

“What we see is not only an increase in hot carcass weight, but we see an increase in marbling and therefore an increase in quality grade,” Hall said.

Calves sired by high carcass-merit sires have proven greater feed efficiency and growth rate, which adds up to smaller feed bills, he said, “or you’ll receive greater returns for the cost of feed you put in them.”

Greater feed efficiency, higher marbling and higher quality grade score wins for cattlemen and consumers.

What the dairy farm taught me about quality beef

When I attended kindergarten, it was only a half-day requirement. They’ve since changed that at St. Jude Catholic School in Wichita, Kan., but those afternoons free let me do some of my favorite things. I would take a nap, watch a little PBS and, if it was a really good day, I would head to the barn, grab my five-gallon bucket, tip it upside down and help my dad milk cows in our double-six herringbone barn.

I was in charge of the most important step of milking: the pre-dip, which is an iodine solution used to clean away bacteria before milking. A higher amount of bacteria in the milk leads to lower quality milk. Those afternoons helping with our 100 Holstein cows taught me a lot about how to do things right to achieve a good product.

At this point, you may be wondering if you accidentally clicked on the wrong link. This is the Certified Angus Beef^® (CAB^®) blog, right? What is all this talk about kindergarten and dairy cows? Well, as a dairy farmer’s daughter and intern with CAB, I’ve seen a lot of similarities between my upbringing and the work it takes to produce high-quality beef.

As an intern I attended the Youth Leaders Orientation at CAB headquarters in Ohio. I learned about the 10 specifications for the brand, and having been a collegiate meat judger, it all began to make sense.

The reason CAB is so popular with consumers is because they are guaranteed a great eating experience each time — and that’s possible because of the hard work producers put into achieving that high-quality, wholesome product.

Just like my dad and I are meticulous with the prep work before milking and the environment our cows live in—making sure they stay dry and clean to reduce cases of mastitis—ranchers are also precise about the management of their herds. These past four months, I have heard about the countless hours cattlemen spend selecting the right genetics and then feeding them correctly, making sure they receive all the nutrients and minerals they need. They pay attention to all the management details so that they meet those 10 specs.

If there is one thing I will take away from this internship, it’s that even though high-quality beef is very different from the milk I have helped harvest all of my life, the people involved have much in common. Whether it is beef or dairy, the producers care about attaining a high level of quality and that requires a high level of management. From record keeping, to artificial insemination, breeding programs and nutrition, there are many similarities between those in the beef and dairy industry when it comes to realizing a high-quality end product.

When I go home from college this weekend to help milk I won’t need that five-gallon bucket to reach the cows, but I will have an even greater appreciation of striving for quality.

~Jill

Jill Seiler just completed her 2018 spring producer communications internship. Her dairy farm upbringing, combined with Kansas State University ag communications education, gave her experience to draw on when interviewing ranchers and researchers the past few months.

Early path to quality beef

by Justin Sexten, Ph.D.

You know the role health and nutrition play in feedlot performance, carcass quality grade and profitability. Yet many readers challenge the idea that these benefits can be realized at the ranch, unless they retain ownership beyond the farm or ranch gate.

The increasingly transparent market with buyers tracking results by source underscores that producing high quality beef takes a systematic approach no one segment can afford to ignore. Ever. The time required to influence your herd’s genetic potential is measured in years, so managing for quality is always important.

It takes four years, really: Select a superior sire, gestate for nine months and nurse the cow for another seven months. Develop heifers prior to breeding or seven months, breed those superior replacements, repeat the nine months of gestation and add another 16-18 months to convert that planned mating into beef.

I’ve just summarized four years of hard work selecting sires and replacements, providing care, nutrition and health like it was easy, but you know it requires tremendous coordination and attention to detail. Genetic improvement is not a task to be taken on by those who need instant gratification.

If your target is high-quality beef, whether through retained ownership or marketing the best possible product to the next owners in the supply chain, spring is the time to implement several key “best management practices” to sharpen your aim.

bodey langford's, ambassador award, never gone dry

Those who will soon breed spring-calving females are laying the groundwork for their reality four years down the road. As quality grade continues to improve, make sire choices to position your herd well above today’s qualitygrade average of 75% Choice and better. Consider aiming high enough to earn premiums for hitting the Certified Angus Beef® brand and Prime targets that already make up one-third of the fed cattle supply while earning steady to higher premiums on each animal.

For those looking at the result of decisions made last spring, now is a great time to enhance those quality genetics. If males are not steered at birth, branding or when cows are processed for spring turnout, quality opportunities keep slipping away. Steers begin depositing marbling at earlier ages than bulls and are less likely to suffer a marbling setback due to stress or illness from castration near weaning.

While working cows at turnout, be sure to vaccinate calves as well because maternal antibodies make way for a vaccine response by the time calves reach two months of age. It’s not uncommon to hear of vaccination for clostridia diseases such as blackleg in late spring, but the idea of protecting against pneumonia is less common. Respiratory vaccines at turnout prime the immune system to better respond at weaning, but perhaps more importantly, begin to offer protection before weaning. This is where best management practices for endpoint quality can pay off at the ranch.

Data from the dairy industry suggests heifers that contract respiratory disease early in life tend to be older at first calving and have decreased herd longevity. The more times a heifer calf encounters respiratory disease, the more those differences increase. Early vaccination is a support tool for genetic investment, ensuring heifers calve earlier and remain productive longer.

In later spring, just as cows hits peak lactation two months after calving, their calves’ ability to grow begins to outstrip milk supply. I’ve noted before how the environment can restrict nutrition to the cow and keep a lid on calf growth, but when that limitation comes from internal parasites, you have management options. Treatment of internal and external parasites tend to benefit from delayed application, but you need to balance application timing
with cattle handling opportunities and optimized pasture quality. Talk it over with your veterinarian.

Best practices for quality production are geared toward calves never having a bad day. Given the length of that process, each day for four years, there are many opportunities for all segments to capture value from these practices.

Behind the static, 560-lb. weaning weights

by Justin Sexten, Ph.D.

It looks like weaning weights have gone pretty much nowhere for 15 years. That’s according to a summary of North Dakota State University’s Cow Herd Appraisal of Performance Software (CHAPS) that presents genetic progress as functionally static since 2003. I couldn’t miss that summary, well-publicized and pointed out by just about every contact and source I know.

Static being a relative term—there were fluctuations in the data—weaning weight hovered around 560 pounds (lb.), weaning age was 193 days and average daily gain was 2.5 lb. Seeing the flat trends, author Kris Ringwall suggests genetic progress in the commercial cow-calf sector is “mature.”

The topic came up during a “Bull-Pen Session” at the Range Beef Cow Symposium in Cheyenne, Wyo., in December, where the discussion suggested the beef industry has gone astray, utilizing growth genetics while failing to increase weaning weight but driving cow size up.

Well, some of that rings true. A rise in cow mature weight is evidenced by the increasing yearling weight EPD (expected progeny difference) in all major breeds. But combine that with a steady increase in fed-cattle carcass weights for more than 15 years and the idea that weaning weight remains static seems to defy logic.

CHAPS is not alone in documenting the static trend. David Lalman at Oklahoma State University summarized several data sets across the country with similar results at Cattlemen’s College last year.

How do weights at one sector level off while growing steadily at another? Genotype and environment combine to produce a phenotype. Across the beef industry, genotypic growth potential has certainly grown, as all segments demanded. Virtually no one aims to go backward, in genetics or any other production technologies.

But how many cow-calf producers aspire to participate in any other segment? To the extent that number remains static, weaning weights appear static.Genetic progress aside, two aspects of this “static” equation remain constant in most operations that govern this progress.

The environment for those genetics limit their expression at the commercial cow-calf level, lush environments less so than herds restricted by that governor. Keep in mind environment is no physical location; differences in your pasture or range management offer differing nutrients; abundant and restricted supplies can exist across a fence.

Lalman has shown data where each extra pound of weaning weight requires 27 lb. more dry matter for the cow to make sufficient milk to increase weight gain. That causes some to suggest we should reduce growth potential in all cattle to accommodate the ranch environment, the least-common nutrient denominator. However, challenges arise when we realize the required efficiencies for greater gain in the nutrient-rich environments further down the supply chain.

That’s where the second aspect of the equation is often ignored. The CHAPS summary notes that these static and historical weights are matched with a historically static marketing program. It’s a program where least and greatest growth potential are typically sold to the next user rather than retained to capitalize on genetic investment.

Imagine the growth you could capture at the ranch level if the same 27 lb. of dry matter the cow needs to increase weaning weight were fed to calves after weaning. Even at a poor 9-to-1 feed conversion, you could triple the calf gain compared to feeding it through the cow. Backgrounding calves at the ranch rather than selling your genetic potential at weaning offers not only improvements in nutrient-use efficiency but marketing options of retained ownership or selling weaned, preconditioned calves.

Backgrounding enterprises may not fit every ranching operation, but cattle selected for limited growth don’t fit in any post-weaning feeding operation. And when you don’t retain ownership, you MUST sell to one of those.

As heifers are kept back and sires are purchased this year, look for those that continue to match the ranch environment while offering the next owner upside potential. The tools available to make such decisions have never been more available.

And if you want to understand how important upside potential beyond the ranch can be, try setting up an new enterprise where you are the next owner. ###

Breed all the cows at one time

By Katie Alexander

If your opinion of artificial insemination (AI) for the beef cattle herd is “been there, done that,” you may want to give it another look.

New protocols and synchronization methods have eased the pressure.

“There’s no question that fixed-time AI has gotten easier,” says Cliff Lamb, University of Florida animal scientist. That’s important for those who tried other AI programs in the past but did not find success, and also noteworthy for those who have never tried AI.

Fixed-time protocols allow the average producer who doesn’t know how to AI to synchronize them and schedule a technician to come out and breed the cows.

Pregnancy rates vary by herd and environment, not perfect by any means, but getting better.

“We’ve found that fixed-time insemination has worked so well in heifers and cows with the new protocols that we’ve gotten to where we can get more cattle pregnant on the first day of your breeding season,” says Willie Altenburg, Select Sires beef development advisor.

That’s because it allows for a better conception rate – up to 60% – on the first day of breeding season, he adds.

AI reduces the uncertainty of unproven bulls and serves as a risk management tool., too.

“The advantage of using proven genetics in the heifers, the ability to synchronize and get proven calving-ease genetics – that is where we see the most use of AI today,” Altenburg says. “Then you can use that over into the cowherd, of course.”

Improvements in growth traits, carcass merit and replacement heifers are only the start, he says.

“It’s a stepping stone of just how much the genetics are being utilized more and more to incorporate things like carcass traits to harvest cattle with outstanding carcass merit to enhance the eating quality so that our producers and consumers enjoy that benefit,” Altenburg says.

The large variety of genetics available with AI shouldn’t intimidate producers, he says. One strategy is to narrow choices by selecting for specific EPDs (expected progeny differences).

“The use of EPDs and the database from breed organizations has extended the use of highly proven sires,” Altenburg says. “DNA-marker-assisted selection is the next step.”

AI-sired calves often carry many advantages, too, such as the genetics of bulls with the total package.

“It allows you to improve the reproductive efficiency of your cowherd,” says Lorna Marshall, Select Sires vice president of beef genetic programs. “We shorten your calving interval, we get more of those cows to calve in the first 21 days.

“The other advantage is that it lets you select genetics that are going to fit your marketing environment as well as your feed environment.” she says.

All agree that companies promoting fixed-time AI have trained enough people available to send them out to farms for custom breeding assignments on any given day.

Hot topic, cool solutions

Holistic approach to heat tolerance

by Miranda Reiman

Many challenges in the beef community are tackled with a two-pronged approach: genetics and management.

Heat stress should be no different, says Megan Rolf, Oklahoma State University Extension beef geneticist.

“Certainly from the feedlot side there has been a lot of work done on mitigation strategies, and I think we have a real opportunity in the cowherd to use genetics to work on adapting cows to the different environments,” she says.

The animal scientist outlines some of those possibilities in her research review, “Genetic Selection for Heat Tolerance in Cattle.”

For helping animals through heat events, many of the tips such as shading and altering feeding schedules, apply to cattle on feed. Cowherds already have the distinct advantage of natural shade, like trees, and green grass that absorbs less sun than feedyard pens.

But interventions are also harder to manage at that level.

“Because they’re out on pastures and living on grass, they’re really not in a controlled environment where you can set up sprinklers, for example,” Rolf notes.

That’s why she and other researchers gathered with cattlemen and beef community partners more than a year ago to discuss the role of genetics in heat tolerance.

It all starts at a cellular level and cattle genetics plays a role in heat stress.

“Heat stress responses are controlled by lots of small mutations, spread all throughout the genome,” Rolf says, noting it could be a different fold in the protein due to a slight tweak in an amino acid string. “Just like weights and other production traits, it can be these little things that change a small molecular mechanism, but cumulatively they can have a big impact.”

Much of the current research comes from the dairy production side, because data is easier to gather in those intensively managed herds.

“Heat tolerance is a heritable trait, so genetic selection can be utilized to increase heat tolerance,” the paper notes.

The key to a selection program is defining the right phenotype. Two in the scientific literature are respiration rate (breaths per minute) and body temperature regulation. Both are heritable traits, but there are several practical disadvantages to selection. Respiration rate is very labor-intensive and body temperature regulation requires specialized equipment, Rolf says.

Location also matters. The best bulls for heat tolerance in the Midwest might be different than the best set for the Southeast, for example.

“When you have environmental differences that impact genetics, you have an interaction,” she says. In a favorable environment, there will be one outcome. “When you move those bulls and generate progeny in a really challenging environment, progeny performance might be different.”

Adaptability can be increased by crossbreeding with a tropically adapted breed, or by improving the traits related to tolerance in Bos taurus breeds that have distinct performance and carcass quality strengths.

Results from one paper using simulated data suggested it might require fewer generations to take a high-performance breed and make it more heat tolerant, than to take an already-heat-tolerant breed and make it more favorable for some performance traits.

To make that significant improvement, there are a lot of questions: What are the best and most realistic measures to collect? Would it be easier to use the measures breed associations are already tracking that are collected in different environments? Should a selection index be created to balance selection for heat tolerance and performance traits?

“It’s a high-hanging fruit, but there are some options and possibilities,” Rolf says. “We have to consider thermo-tolerance really comprehensively with other treats. I think we can make progress with improving heat tolerance without making sacrifices in production traits, but we have to consider them holistically.”

Today, particularly in the Southeast, some cattlemen watch hair shedding, which could impact calves later on. One area study showed a 25-pound increase in calf weaning weight from cows that shed their hair quickly.

“There’s no national genetic evaluation but hair shedding is heritable, so a producer could go out and take a look and try to keep replacement females that tend to shed hair earlier in the season,” she says. “That’s a win-win, because you’re getting an advantage in terms of increasing heat tolerance and you get that advantage in weaning weight.”

The Angus Foundation is also funding broader research at the University of Missouri on adapting cattle and genetic selections to better fit nine regions across the U.S., furthering both animal wellbeing and producer profit in concert.

Starting at the beginning would be a boon to the entire system, Rolf says, because improving heat tolerance in herds should create progeny with increased ability to adapt in the stocker and feeding phase.

“Anytime we’re trying to produce a great product for a consumer, it’s a combination of a lot of different factors,” she says. “Everything from the genetics and mating decisions all the way to the management choices you make. Anytime we can do things that reduce the stress on those animals, that’s going to help translate into a good quality product for the consumer.”

The complete research paper is available at www.cabcattle.com/research.

Fewer fires to fight

A deliciously UNburnt roast that still sent a poorly placed smoke alarm into fits.

In my book of comfort food, it’s really hard to beat a good pot roast, so when cooler temps dipping into the 50s hit eastern Kansas this week, I jumped at the opportunity to pull out my Dutch oven. As I slid my Certified Angus Beef® roast into the pot for a good braising last night, I almost instantly found myself standing on a chair in the middle of my kitchen feverishly trying to disengage the smoke alarm. That’s the fourth time this week I’ve had the same episode. Shaking my head I wondered, who in their right mind puts a smoke detector that close to a stove top where any kind of searing, sautéing or general cast iron magic is sure to send the kitchen into audible chaos?!

Earlier this summer we had the opportunity to move into a new place to call home. We chose our very modest farmstead because we knew it had a lot of potential, but the truth is, from smoke detector placement to landscape to fencing – we’ve more than once thought, “I sure wouldn’t have done it that way.”

As I was cleaning up the kitchen last night and simultaneously discussing veterinarian preg-checking appointments and planning upcoming weaning logistics with my husband, I couldn’t help but think about feedlots and wonder how often they’ve felt the way I did standing on that chair in my kitchen thinking, “I sure wouldn’t have done it that way.”

It’s no secret that high-risk cattle aren’t attractive for any feedyard buyer, mainly because no one needs an extra fire to put out. Generally, cattle that have been on some kind of a program, especially one with good documentation are worth more. Most cow-calf herds have a health and nutrition plan in place when it comes to weaning. When was the last time you reevaluated yours? Going through the same motions each fall is fine, if it works, but it’s always a great idea to evaluate your strategy annually and see where you can make improvements.

While it’s always best to consult your veterinarian on health management, I’d also recommend reviewing our Best Practices Manual for ways to fine-tune your weaning strategies. When your weaning and backgrounding management are on the same wavelength as your feedlot, you have more room for market negotiation and your feeder is less likely to have a need for putting out fires. The foundation for good cattle marketing is set in good management. Make sure the one you’re laying is one that the feeder can build on for a profitable, high-quality end product.

~Kara

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