Accelerating Genetic Development And Progress


By Dr. John Eggert

Swine genetics companies not only strive to improve product performance for their customers but also to add value throughout the pork production chain. To accomplish these aims, we collect and connect multiple sources of data, including that on purebred and commercial crossbred production performance, reproduction, carcass and packer, genotypes and more. The goal is to improve performance and profitability for everyone that utilizes our products.

Selecting for a trait, without keeping track of other traits, might result in unexpected correlated responses. Balanced breeding for Topigs Norsvin means improving the pig in a range of economically important traits while preventing genetic drift by monitoring a wide range of other traits.

This article will provide insight into the many types of data and information that swine genetics companies collect in an effort to meet the demands of swine producers, pork packers/ processors and consumers.

Maximum genetic progress

The density of genotyping (from 80,000 SNPs to 660,000 SNPs to whole genome sequencing) is increasing. One benefit of this additional DNA information is that the actual genetic relationship between two animals can be calculated at the DNA level rather than solely relying on traditional family pedigree relationships.

Single step selection makes it possible to use DNA resemblance between animals in addition to family relations. This approach increases the accuracy of breeding values by 36 per cent, which translates directly into accelerated genetic progress. Researchers are genotyping nucleus selection candidates and crossbred animals in reference populations. Together with the phenotypic data, the genotypes are processed in the genetic evaluations using the latest technology.

Finishing and carcass traits have been split into purebred and crossbred traits. Multiple genetic companies are conducting performance testing of crossbred finishers in various commercial farms to account for genotype by environment interaction. Crossbred phenotyping includes gain, carcass quality and feed intake records. Many companies are evaluating nucleus animals with intensive exterior evaluation scoring systems. 3D camera technology is being developed as a more objective measure for exterior and conformation traits.

Less feed in – more pork out

Individual feed intake registration has been part of many breeding programs since the 1990s and has resulted in a significant reduction in feed usage per finisher. Beyond feed conversion in the finisher, Topigs Norsvin targets the improvement of total feed efficiency (TFE), which is the total amount of feed required to produce one pound (or kg) of pork. TFE takes into account the feed used during the rearing of gilts, the production of piglets (gestation and farrowing), the rearing of piglets after weaning, as well as finishing.

Every pig born should be weaned

Over the past few years, piglet production levels have been raised to over 35 pigs/sow/year (PSY). In fact, there is still an economic advantage for piglet producers to increase production levels and there is genetic potential to do so.

However, with increasing litter sizes, the marginal economic value of adding a piglet decreases while the economic value of survival rates increases.

A number of genetic improvement programs now include the collection of individual piglet birthweight data. Neonatal data may also include teat count, health trait evaluations and foster sow information. The data is used to evaluate health, litter quality and survival traits. Thus, as piglet production levels increase, piglet survival rates can be maintained or improved.

Balanced breeding

With a genetic model that improves the number of pigs born alive and the number weaned at the same time, prewean mortality will decrease. Including the trait “number of teats” helps to ensure that sows have the capacity to wean their own piglets.

Regarding reproductive traits, a balanced breeding program should be based on these principles:

  • Every extra piglet born should be weaned and make it to the slaughter plant.
  • There should be a teat available for every extra piglet.
  • Sows should be able to raise and wean their own piglets.
  • Birth weights should not decrease.

balanced breeding program

Scientific research has demonstrated that traits such as maternal ability, piglet vitality and uniformity have direct and indirect impacts on production.

Examples of these impacts include time interval between birth and colostrum uptake, glycogen energy reserves at birth, sow behavior and vocalization, and teat quality.

Boar fertility characteristics are monitored as well, including multiple semen parameters.

Robust sows and finishers

High production levels are demanding for the sow and piglets. Therefore, genetic companies are phenotyping, monitoring and beginning to include a wide range of robustness traits in selection programs. Important developments here are the inclusion of longevity in the breeding goal of the maternal lines.

Ultrasound scanning

The use of real-time ultrasonic scanning (RTUS) is widespread and provides precise measurements to quantify the amount of fat and lean in live animals. RTUS data can be automatically incorporated into swine selection programs. The next generation of scanning for live animals, computed tomography (CT), provides additional and more accurate data than RTUS and multiple genetic companies have implemented this type of scanning.

CT Scanning

CT Scanning

Detailed images of selection candidates are obtained from carcass and bone tissue through computed tomography scanning technology in mature, live animals. With this data, swine genetic companies obtain traits for lean percentage and primal yields, as well as for bone quality (which is used for selection against osteochondrosis). Each CT scan includes over 1,000 CT photos per animal and creates over 500 megabytes of data.

chromosomes v pvalue

Higher carcass yield

Carcass lean meat percentage and carcass yield are two of the most important traits underlying the current payment system between packers highly accurate estimations of whole carcass lean meat percentage and carcass yield, which allows for accelerated genetic improvement in these traits.

higher carcass yield

Future applications of CT technology will include automated estimations of organ weights and other anatomical measurements. Data from CT scanners will provide the means for packers to change their focus for the selection of carcass value traits. Rather than the simple measures of fat reduction, the focus will be on increasing carcass yield and the yield of valuable cuts at higher slaughter weights.

Data from slaughterhouses

Genetics can add value for packers as well as producers. Carcasses with aberrations such as pneumonia and bursitis represent economic losses for packers because these carcasses cannot be processed into high value products. Many aberrations appear to be moderately heritable, which means that genetics could positively influence their occurrence.

More meat of better quality

Globally, meat quality is gaining importance with both packers and consumers. Water-holding capacity (WHC) of fresh pork is considered to be one of the most important meat quality traits by packers and consumers alike. In many breeding programs, pork from culled selection candidates is evaluated for a wide number of meat quality traits, including meat color, pH, water holding capacity, boar taint and intramuscular fat percentage (IMF).

More meat of better quality

Intramuscular fat percentage and fat quality are further evaluated by near-infrared spectroscopy (NIRS). Fatty acid composition of pork (e.g. saturated:unsaturated fat ratios) is strongly influenced by nutrition but a better understanding of the genetic influence on such parameters is becoming clearer as well. Boar taint levels are estimated using fat biopsies and chemical analysis of selection candidates. Genomic selection can now be applied as some specific DNA markers are also significantly associated with boar taint.

Big data … and getting bigger

For individual animals, we now measure the amount of data collected in terms of gigabytes and 100,000s of data points – and the volume of data will increase. While sows are often recognized as individuals for data collection purposes, the pork production chain does not usually recognize individual finishers. Finisher data tends to reflect the performance of groups of dozens, hundreds or even thousands of animals

Looking forward, however, technologies such as RFID or other animal identification methods could help to sort finishers into pens, based on their parentage and birth weight. This type of sorting could optimize pen performance and bring performance information back to the biological mother. Genotyping of these mothers, the commercial sows, will become a must in the near future. Genotyping (a sample) of finishers presents another opportunity. Expansion of single step selection to genotyped crossbred animals could further increase the accuracy of breeding values in the next few years and create additional value throughout the pork production chain. The ability to collect and combine all these data sources and technologies allows swine genetic companies to make genetic progress faster, balanced and optimized to meet customer needs.

Dr. John Eggert, Technical director for Topigs Norsvin USA
As technical director for Topigs Norsvin USA since 2010, Dr. John Eggert oversees and coordinates U.S.-based research, marketing, CRM administration, and key account management. He serves on the board of directors for the National Swine Improvement Federation. Dr. Eggert received a Bachelor’s degree in 1991 from Harvard College. He received a MS (1995), PhD (Animal Sciences – Genetics; 1999), MBA (2012) and Distinguished Alumni Award (2015) from Purdue University.

The added value created by the technologies and efforts described in this article is delivered to our customers in every boar, gilt and tube of semen that we sell. This level of commitment underlines Topigs Norsvin’s position as The World’s Most Innovative Pig Breeding Company.