Tag: Cow-calf

Genomic Testing From Parentage to Performance

Posted on by Twin Rivers Media

By Jaclyn Krymowski for American Cattlemen

Genomic testing has made a significant difference in the way cattle are bred and managed.  The technology can help producers isolate noteworthy traits like average daily gain and calving ease to make genetic gains far more quickly than through traditional methods.

Genomic testing can be used by producers with a myriad of objectives, from seedstock to freezer beef to stock show. 

“Genetic verification is particularly useful in situations that involve multi-sire breeding pastures, artificial insemination (AI) or embryo transfer followed by clean-up bulls (natural mating), calves that may have been switched at birth, and ambiguous data records,” write Johnny Rogers and Felipe Silva of North Carolina University Extension in their bulletin Genomic Testing and Its Uses in Beef Cattle.

This information also allows producers to catch errors or mistakes that happened during breeding, like when the wrong straw is pulled at the time of insemination. Incorporating it into the breeding program can ensure accurate data is included in ancestry and herd records.

Background of Genomic Testing

Genomics has been extensively utilized by the dairy sector since its introduction in 2008. Since then, especially with more recent improvements and increased accuracy, beef has followed suit and has quickly picked up its pace in adoption.

“Genetic testing is based on the principles of inheritance. Inheritance is most easily explained using “simply inherited” traits,” explain Jacob Segers and Daniela Lourenco in the University of Georgia Extension bulletin Genomic Testing in Beef Cattle: How Does It Work? “Genomic testing simply inherited traits is controlled by one or a few genes.” 

 Expected Progeny Differences (EPDs) provide a prediction of the genetic transmitting availability and can be used to make selection decisions. For a given trait, EPD values are calculated based on data submitted by producers based on various performance data points. These evaluations, along with related metrics like dollar indexes, are calculated and determined by breed associations and the multi-breed collaborative, International Genetic Solutions. 

It has become standard for many operations to seek bulls with documented genomic testing because of the benefits of parentage verification and the calculation of Genomic Enhanced -EPDs (GE-EPDs). 

However, with more data and more accurate results, more operations are also investing on testing their females as well.

The Benefits

Recently, genomic testing for beef cattle has evolved to include “high-throughput” testing, meaning that thousands of markers (single nucleotide polymorphisms, or SNPs) are read from an animal’s DNA.

Genomics enables more accuracy for younger animals and provides clear information about the genetic traits of interest.

“GE-EPDs are the best estimate of an animal’s genetic value as a parent,” says the Penn State Extension bulletin Understanding EPDs and Genomic Testing in Beef Cattle. “The lack of confidence associated with EPDs on young cattle comes from not having progeny or performance data, both of which increase the accuracy of the EPD.”

An increase in EPD accuracy doesn’t necessarily change the EPD value itself. Instead, higher accuracy gives producers greater confidence in the EPD because it reflects more robust data. For younger animals, genotyping can enhance EPD accuracy by providing valuable genetic insights early on, offering a cost-effective way to maximize the return on investment in breeding decisions.

For producers who sell their entire calf crop at weaning or after a backgrounding phase, these traits can help guide breeding and marketing decisions:

  • Birth Weight (BW)
  • Calving Ease (CE) or Calving Ease Direct (CED)
  • Weaning Weight (WW)
  • Yearling Weight (YW)

These traits are especially important as their selection not only adds dollars but can also help reduce the daily production workload.

The technology that evaluates SNPs has evolved rapidly since genotyping first began. Today higher density chips that evaluate at least 50,000 SNPs are used to genotype elite animals for potential marketing, mating and selection. Heifers being tested for herd management decisions are often genotyped with lower-cost, lower-density chips that evaluate 10,000-20,000 SNPs, according to USA Cattle Genetics.

What Does the Future Hold?

Although we have made solid advances in genomic testing, the sky is the limit.

“The big gamble with using EPDs as a fail-safe selection tool is the accuracy of the prediction in young cattle that have few, if any, progeny,” note Segers and Lourenco. “The lack of confidence associated with EPDs on young cattle comes from not having progeny or performance data, both of which increase the accuracy of the EPD.”

As the database continues to become populated with data, the more reliable and easier selections will be. The unknowns will slightly decline as more progeny have data available.

For young sires, most of their genetic value is based on their pedigree. As animals age and produce offspring, their genetic merit and transmitting ability become clearer. This is reflected in the accuracy value of their EPD, measured on a 0–1 scale. A higher accuracy indicates the EPD is more likely to represent the animal’s true genetic value, regardless of whether the EPD itself increases or decreases. For example, a young bull with an accuracy of 0.2 has a more uncertain EPD compared to a proven sire with an accuracy of 0.8, which gives producers greater confidence in the predictions.

Genotyping a young animal boosts accuracy, as DNA tests (SNP genotypes) provide information equivalent to adding data from 5–50 offspring, depending on the trait. DNA samples can be collected early in life, and unlike metabolism or hormones, an animal’s genetic code remains constant. Genomic testing gives producers a snapshot of key genes influencing economically important traits, increasing confidence in GE-EPDs.

Selecting females for replacement is a challenge for commercial cow-calf production and the expense of heifer development. With a solid breeding strategy and specific selection principles, producers can make more accurate and confident selections in determining replacement vs cull heifers.

Breeding Soundness Examination

Posted on by Amy Wold

Breeding Soundness Examination (BSE) For Bulls

Many factors play a role in fertility and breeding ability, so it is important to make sure every bull passes a breeding soundness examination (BSE). The standard evaluation looks at 5 things: physical soundness (feet/legs, eyes, etc.), reproductive tract soundness, scrotal circumference, percentage of sperm cells that are normal, with acceptable motility. Even if a bull was fertile last year and sired a lot of calves, he may have a problem this year and should be checked before breeding season. Some problems and injuries are not obvious until the bull is evaluated by a veterinarian.

Ryan Grant, DVM has a veterinary practice that covers northeastern Oklahoma and southwestern and southcentral Missouri and does more than 1300 breeding soundness exams each year. He says there are two reasons some producers don’t utilize this service. One is the cost, especially if they have several bulls. “Most veterinarians charge $40 to $50 per bull for the exam itself. Many will also test for trichomoniasis which will be an additional cost,” he says. The cost is minor, however, compared with having an infertile or diseased bull (and open or late-calving cows the next year).

If a bull is an unsatisfactory breeder, or will be passing trichomoniasis to your cows, it’s best to know this before the breeding season so you’ll have time to replace him. Grant recommends testing at least 30 days prior to turnout; this gives the producer time to find another bull if necessary.

The second reason some producers don’t have their bulls tested is due to lack of facilities. “When I first started practicing, if someone wanted bulls tested at their place, and their facilities were poor, I would do it. But now I don’t take those risks. It’s important to have a good chute to handle bulls. Most practitioners use an electro-ejaculator to obtain a semen sample. This sends electrical impulses through the accessory sex gland, which causes a significant reaction,” he says. There is some discomfort, and a bull can tear a chute apart if it’s not adequate for restraining him.

“These bulls can destroy a poor chute and hurt the people around them. Now I am picky about where I test bulls and do most of them in a hydraulic chute–either in my clinic or the sale barn’s hydraulic chute, or on-farm if the producer has a hydraulic chute. I rarely test bulls in a manual chute anymore because it’s more difficult to get adequate squeeze on them for proper restraint. Without proper restraint, the bull can lunge around too much, and injure his back. A person has to be careful to not create injury just trying to get the bull collected,” says Grant.

Basics of the Breeding Soundness Examination (BSE)

Soundness and physical condition are evaluated. “I like to watch each bull’s movement as he approaches the chute. Once he is in the chute, if we have an assistant to mug him I look at his teeth, and also assess his eyes and overall body condition,” says Grant.

“When I start looking at the reproductive organs I feel his sheath and make sure there are no strictures or adhesions, hematomas or swellings. I work back to the scrotum and palpate both testicles to make sure they have normal consistency and that I can feel a good epididymis. I also check scrotal circumference, especially on bulls that will be siring replacement heifers.” Larger testicles usually indicate greater fertility (more storage space for sperm) and fertility in the bull/scrotal circumference seems to have a correlation with fertility in that bull’s daughters.

A circumference of 30 to 31 centimeters would be bare minimum for a 15-month-old bull, and older bulls should have larger testicles. “Keeping records on scrotal circumference also allows me to go back to last year’s records and I can know if the bull is a lot bigger (or smaller) than he was the year before,” says Grant. A young bull with small testicles will often have more adequate circumference the next year. Sometimes an older bull will start to lose circumference as he becomes older and less fertile.

“Then I check the bull rectally because this allows me to feel the accessory sex glands, the ampulla and the prostate—to make sure that both lobes of the prostate are symmetrical. I also check the seminal vesicles as much as possible to make sure there’s no seminal vesiculitis,” he says.

After that examination he inserts the probe rectally and begins collecting a semen sample. The goal is to have the bull extend enough to also examine the penis, but not all bulls will extend. There are some problems that may not be detected (such as hair rings or penile warts) unless the penis can be visualized. Most bulls will extend, but Grant says about 15 to 20% (especially older bulls) try to resist and fight the probe. If they’ve been through this before, they may not cooperate.

“Once we get the bull to ejaculate we have a semen sample to look at under the microscope to assess sperm motility (percentage of cells that are moving),” he says. A stain is used on the slide to check morphology and determine the percentage of sperm that are normal or abnormal—assessing form and structure, shape of the sperm heads, size and appearance. The bull is then graded on motility and morphology.

If the bull has acceptable motility and morphology, Grant takes a sample of material from deep inside the sheath, to send to a lab to check for trichomoniasis. “We record all identification numbers for the bull and put an official ID number in his ear, and that number goes on the pouch we send to the lab, and give him an ear tag for ID.”

Once the breeding soundness examination (BSE) is complete, each bull is given a score of satisfactory, unsatisfactory or deferred. A young bull may be deferred—to be checked again later. “If a young bull is too immature to pass his test, we may give him more time. He may have been pushed hard to get him bigger, but he may still be very young and not mature enough to successfully breed cows. We retest a lot of young bulls,” says Grant.

“I may also retest a bull if I see a lot of white blood cells in the sample. A young bull with white blood cells in the ejaculate will often clear up the infection, even without medication, and be fine. An older bull, however, that has white blood cells or signs of vesiculitis, often still has the infection when we retest him later. Treatment generally doesn’t make much difference. A young bull may just need time, but an old bull may not clear up, and he’s generally finished as a breeding bull.”

 Monitor Bulls During Breeding Season

“A breeding soundness examination (BSE) is a great tool, but just one piece of the picture. Some problems (like trich) won’t show up on a typical exam, so producers need to pay attention to what’s happening in the herd. If some cows continue to cycle or some abort, there may be a bull problem. Just because a bull passes his exam, this is no guarantee that everything is ok,” says Grant. That bull may be fertile, and breed all his cows, but if he carries something like trich and passes it to the cows, there will be problems. Or, he may not be breeding the cows.

“I’ve seen bulls that had good structure, good sperm motility—and everything seemed fine—but very little desire to do the job. He may have poor libido, or might be more interested in fighting other bulls than breeding cows. Just because a bull passes a BSE doesn’t necessarily mean he will do the job. Producers need to pay attention and know what’s going on,” says Grant. If a bull has some pain issues, or is intimidated by more dominant bulls in the herd, he may be reluctant to try to breed cows.

Bulls also get injured when fighting or breeding cows. “The producer should be observant and watch for penile hematomas or any swelling or abnormality in the sheath or testicles. Some problems are not apparent until you watch the bull actually breed a cow or try to breed. Some bulls just don’t penetrate, for instance,” he explains.

Testing For Trichomoniasis

This serious reproductive disease causes early pregnancy loss in cows, and is spread from cow to cow by the bull. Once infected, the bull generally remains infected; the protozoal organisms hide in the deep folds of the sheath. To get a sample for testing, the veterinarian takes a scraping from inside the prepuce. “The organism lives toward the back of the prepuce where there are more folds. We take a swab from that area, put it in a growth media, and send it to a lab for DNA testing,” says Grant.

“This is a difficult organism to detect with just one test. If we have a problem herd (with many cows returning to heat and several open cows at the end of the breeding season) this is one of the first diseases we suspect, and we test all the bulls. Even if I get a negative result on a bull from that herd, I will retest him,” says Grant.

It may take 2 or even 3 tests to determine whether a bull is actually negative for trich. “We use a PCR test that looks for the DNA of that organism, but as it replicates it goes through peaks and valleys and sometimes you’ll get a false negative on the initial test. The older test (checking samples under a microscope for the actual organism) required 3 tests—several weeks apart—to make sure a bull was negative. The newer PCR test checks for the actual DNA, but can still occasionally come up negative on an infected bull,” says.

A single test will catch most of them, but not all, so it’s sometimes good to repeat the test,” he says. On rare occasion it may take 3 tests to conclusively prove that a bull is negative.

Home – American Cattlemen

March 2021

Convenience Traits Are Important

Posted on by Amy Wold

ItConvenience traits are those cattle traits that contribute directly to savings in time, facilities, drugs and labor in a cow-calf enterprise. Some examples of these traits would be temperament, polledness, structural and udder soundness, disease and pest resistance, heat tolerance, doing or fleshing ability, mothering ability and calving ease. Many of these traits of convenience are not highly heritable but contribute to the ease of participating in and enjoyment of the beef cattle industry.

Temperament

Temperament is a measure of the relative docility, wildness or aggression of an animal toward unfamiliar situations, human handlers or management interventions.  It reflects the ease with which animals respond to handling, treatment and routine management. Animals with bad disposition problems are a safety risk to handlers, themselves and other animals within the herd. Disposition affects handling equipment requirements, operation liability exposure, beef quality assurance, carcass quality and performance.

Wild, hard to handle cattle are a danger to themselves and the people working with them. They are the ones that create handling and gathering problems. Once they are confined, they are the gate and fence crashers. They are wild eyed upon leaving the chute and exit the head gate on the run. They may look for something to hit and when extremely agitated may look for a human being and charge.

In addition those wild, unmanageable animals do not perform as well as calmer cattle in the feedlot. Research from Iowa State University has shown that these types of cattle gain nearly one-half pound per day less than easily managed cattle and returned $61 less profit. Also easily excited cattle tend to produce carcasses that have a higher incidence of dark cutters, which are heavily discounted in market price in the packing industry.

Results of a survey of Tennessee cow-calf producers, conducted during three performance tested bull sales, revealed that temperament was rated 4.13 out of 5.0 as being important in sire selection. Cow-calf producers do not want a bull with a bad attitude. Heritability of temperament is moderately high and directional change can be made by selection and culling. The North American Limousin Foundation has developed their own breed EPD for docility or temperament which aids in making directional change in their breed for disposition.

Dr. Temple Grandin, has found that location of the hair whorl on the forehead in cattle is associated with temperament. Cattle with hair whorls above the midpoint of the eyes are more susceptible to excitement than cattle with hair whorls below the midpoint of the eyes. Excitability is measured when the cattle are in the chute by temperament scores assigned to them according to their response to restraint.

Udder Soundness

One of the most important functional traits of a beef cow is udder and teat conformation.

Beef producers are less likely to consider udder shape and characteristics as would dairy producers, but these attributes affect cow productivity and longevity and should be considered in a beef cow-calf operation. Udder and teat quality are important functional traits and appear to be heritable. Their soundness should be an important concern because of their relationship to injury and mastitis and calf performance affected by reduction of milk flow.

Oversized teats provide difficulty for newborn calves to nurse and receive adequate colostrum, which could lead to a higher incidence of scours or decreased immunity levels in the newborn calf.

Research at the New Liskeard Agricultural Research Station in Canada examined factors related to the transfer of antibodies from the dam to her calf during the first four hours post-calving. Measurements were recorded for maternal behavior, calf vigor, calf time to first standing after birth, calf time to first suckling after birth and physical structure of the cow’s udder. Cows with higher (more desirable) maternal behavior scores had calves with higher calf vigor scores. Calf vigor scores were highly related to time to first standing of the newborn calf and time to first suckling for the newborn. Also, time to first suckling for the newborn was related to teat size score in which cows with more desirable teat scores had calves that nursed sooner after birth.

Usually teat circumference will cause problems much more often than teat length. Short to medium length teats are preferred over long teats. Sound, well attached udders are less susceptible to injury than very pendulous poor attached udders. The teats should be placed squarely under each quarter. When viewing the udder from the side view, the udder should display a level udder floor without any quartering. The median suspensory ligament is the support that ties the udder to the cow’s body wall. A weak suspensory ligament allows the udder to hang down too far from the body and subject the udder to serious problems.

Structural Soundness

Sound feet and legs are essential in order for bulls to cover many acres of pasture for mating with cows and obtaining adequate nutrition. Structural soundness is not an all or none situation but expressed in various degrees. Inspect prospective sires in a systematic manner. Inspect the bull’s feet, toes, heels, pasterns, knees, hocks and sheath. When viewed from the front, the feet should point straight ahead, both when the bull is standing and walking. The feet should be large and round with a deep heel and with toes that are similar in size. When viewing from the rear, the legs should be equally far apart at the hocks and pasterns and then toe out slightly from the pasterns to the ground. The bull should move freely with each hoof striking the ground evenly. When on the walk, a structurally sound individual’s hindfeet will cover the footprints made by the front feet. Short, choppy strides are usually the result of the hind leg being too straight (post legged) and/or not enough angulation to the shoulder. Bad feet, pigeon toes, excessively straight or sickle hocks and loose pendulous sheaths are examples of the more common structural problems.

Replacement females should remain functionally sound to advanced ages. Proper foot, leg and udder structure is important in the beef cow or replacement heifer to insure longevity. A cow’s udder should be well attached, level across the bottom and have small to moderate sized teats that are not excessively long or excessively large in circumference. Soundness of the udder will generally deteriorate with age. Cows with impaired mobility, unsound mouths, pendulous udders or excessively large or a balloon teats are candidates for culling.

Polledness

De-horning is a labor intense management practice that requires additional health attention. Polled cattle are less troublesome when working them the possibility of injury to both producer and animal is reduced. Cattle without horns require less time and labor. De-horning can be accomplished by selection of a polled bull since the polled gene is dominant to the horned gene.

Calving Ease

Assistance at calving is labor intense and can be greatly reduced by selecting herd sires that have below breed average birth weight EPDs or an excellent EPD for calving ease. Also, stress incurred by the cow and calf at birth can lower the resistance of the newborn calf and make it more susceptible to disease and health problems. In addition, stress incurred by the cow during a difficult birth may delay her return to estrus following calving and lengthen the following year’s calving season.

Disease and Heat Resistance

There are breed differences in cattle for heat tolerance and disease resistance. The Bos Indicus (Brahman based) cattle are known to be more heat and disease resistant than the British and continental breeds other than the Senepol breed.

Doing Ability

Doing ability or fleshing ability is a measure of the adaptability of the cattle with their given resources on which to produce. Hard doers are those that do not adapt to their given set of resources and require extra attention or feed to produce. It also affects the longevity of the animal in question. The Red Angus Association has developed a Stayability EPD, which measures the likelihood that an individual will stay in the herd past six years of age.

The cow-calf industry is composed of many part-time operations that are maintained to supplement other farm enterprises or off-farm income. Labor is a limiting resource in many of these operations. There is a trend in selecting for improvement in convenience traits while maintaining optimum performance. Many of these convenience traits are not highly heritable, but by selecting for them and culling those that do not fit the producer’s objectives, improvement can be realized and enjoyment increased.

Reprinted from www.southernlivestock.com

Home – American Cattlemen

July 2020

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