About Holstein

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Holstein

More than 1.7 million Holsteins and almost 150,000 Red Holsteins are registered in the herd book in Germany. With those figures, Germany has the largest herd book population worldwide. Moreover, Germany has approx. 3,800 Red & White dual-purpose (DN) cows within the scope of an independent breeding program and individual breeding value estimation.

Organized breeding started 125 years ago

There is a long tradition of German black-and-white breeding. Around 1847, the first cattle breeders association in the North Sea region of East Friesland – an area with good pastures because of the maritime climatic conditions – already organized cattle shows. In 1876, the first official herd book was founded where performance testing and conformation classifications were introduced. Today, many well-known East Frisian cow families, the basis of successful German breeding programs, can be traced back to the start of this herd book.

Europe's largest cattle breeding organization in East Prussia

As well as the North Sea region, many other regions of Germany developed numerous herd book organizations for black-and-white and red-and-white cattle. East Prussia was especially well-known for its black-and-white breeding. The first herd book organization in East Prussia was founded in 1882. With 6,000 members and 350,000 registered cows, it was the largest cattle breeding organization within Europe and at the forefront of the development of modern breeding until its breakup in 1944 during the troubled years of the war.

Uniform breeding goal

In order to protect Germany from foot and mouth disease, the government closed the borders with The Netherlands for the importation of bovine cattle in 1891. As a result of this, the independence of cattle breeding in Germany was significantly promoted. Around 1920, the breeding goal was at last standardized within all regions of Germany. Until then, German Holsteins were bred as dual purpose cattle with an equal balance between milk and beef production, but from then on, milk production was given a higher priority across the entire country. From that time on, a uniform black-and-white Holstein breed joined the international competition.

Development of German Holstein cattle

In 1964, a new breeding goal of 6,000 kg milk with 4 % fat, together with better development of body capacity, was set out for German black-and-whites. This aim was achieved by crossing German black-and-whites with Holstein Friesians from North America. Imported from Europe, the European Holstein Friesians in the U.S. had been exclusively selected for milk production since 1871. Due to the traditionally high meat consumption in the U.S., breeding of particular beef cattle breeds was established very early. As there was, in contrast to the numerous requirements in Europe, no demand for highly productive dual purpose cattle in North America, a pure dairy breed had been rapidly developed there from the European dual purpose cattle. Since 1989, German pedigrees do not show the Holstein Frisian percentage of the animal, as from that time, the Holstein percentage of younger black-and-white generations was almost 100 %. Nowadays, the German Holsteins and German Red Holsteins are aiming for milk production of at least 10,000 kg milk with 4 % fat and 3.5 % protein per lactation.

German reunification:
Successful proof of German Holstein breeding 

In 1990, the year of reunification, East German cattle breeding organizations became integrated in the German Holstein Association (DHV). Within a short time, they were re-organized into modern cattle breeding organizations following the Western model. Due to excellent breeding work and reorientation of the breeding goal for German Holsteins, an improvement in production in the East German Holstein population of more than 3,000 kg milk was achieved between 1990 and 2000. This enormous increase in production is even more remarkable as the farms in East Germany often house several hundred dairy coes.

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Largest herd book population worldwide

More than 1.7 million Holsteins and almost 150,000 Red Holsteins are registered in the herd book in Germany. With those figures, Germany has the largest herd book population worldwide. Moreover, Germany has approx. 3,800 Red & White dual-purpose (DN) cows within the scope of an independent breeding program and individual breeding value estimation.

Very high level of milk recording

2.1 million Holsteins and 226,000 Red Holsteins are controlled by independent milk recording (2018). With 90 % of cattle being milk recorded, it is a very important factor in successful breeding programs, and is higher than in any other country in the world.

Different production conditions

Herd size, herd management, and environmental conditions differ greatly between the various regions of Germany and make great demands on dairy cows. There are both family farms with less than 100 dairy cows as well as very large production farms with several thousand head of cattle.

Large number of test bulls

Approx. 12,000 male candidates were tested within the scope of genomic selection in 2014. About 450 of these were selected for breeding programs. A selection ratio of 1:40 is the result of this.

In the year 2018 the following average production of the herd book population was achieved (source: “milchrind” magazine issue 1/2019):

Breed

Cows

Milk kg

Fat %

Fat kg

Protein %

Protein kg

Holstein

1,701,632

9,666

3.95

382

3.41

329

Red Holstein

158,242

8,909

4.09

364

3.46

309

Red & White dual purpose

3,693

7,164

4.29

307

3.59

256

In Germany, 16 local organizations are now involved in Holstein and Red Holstein as well as Fleckvieh and Brown Swiss breeding. GGI-SPERMEX GmbH is responsible for the international marketing of 13 organizations.

Powerful organizations

Over the last few years, most of the herd book and A. I. organizations combined their sections to combine herd book work, breeding programs, artificial insemination, and marketing under the umbrella of larger organizations. Moreover, GGI-SPERMEX members have built two powerful, inter-regional co-operations: TopQ and NOG (Nord-Ost Genetic GmbH & Co KG). To improve efficiency, the cooperating partners run large testing programs together. Furthermore, the partners work closely together in the fields of research, product development and scientific analysis of breeding programs, and through co-operation with the Association for Bioeconomy Research (FBF).

German Livestock Association (BRS) acts as coordinator

The German Livestock Association (BRS) is the umbrella organization for organized German Holstein breeding. The main tasks of BRS are to harmonize the working methods of member organizations, determination of the breeding goal, organizing national shows and auctions, public relations as well as representing the interests of German Holstein breeding abroad. The BRS is also the first point of contact for data exchange with foreign herd books. An important task of the BRS is the collection of conformation data for breeding value estimation. For this, BRS works out the guidelines, trains classifiers in its member organizations and monitors data acquisition.

With umbrella organizations for the particular cattle breeds and the German Association for quality and performance testing (DLQ), cattle breeding organizations, A.I. studs, embryo transfer facilities, the state control associations and milk recording and milk survey organizations, as well as the data center in Verden are all affiliated with BRS – so the entire organized cattle breeding in Germany. With almost 12.3 million cattle on 143,000 farms, Germany is one of the largest producers of milk and beef in the European Union. The activities of BRS drive the advancement of all efforts focused on the improvement of breeding, housing, insemination and embryo transfer of cattle as well as the utilization of their products. Thus, to a great extent, German cattle breeding is geared to improve the traits of robustness, health and fertility of animals.

Independent milk recording

The 11 German state control associations for milk recording work independently of the breeding and insemination organizations and, because of that, offer the best opportunities for objective data collection. Data is collected monthly using a fixed uniform standard of milk recording from more than 90 % of all German cows. The level of milk recording in Germany, is higher than in any other country in the world. Comprehensive quality management systems help this national milk recording to have a world leading special position.

The independent milk recording organizations guarantee reliable data collection.

Central breeding value estimation under state control

Breeding value estimation in Germany is under state control. Under orders from the breeding organizations, the data centre, Vereinigte Informationssysteme Tierhaltung w.V. (VIT) carries out the nationwide breeding value estimation for the breeds Holstein, Red Holstein, Red Cattle/Angler, Jersey, Red & White dual purpose (DN) and German Friesian Cattle (DSN). The Bavarian Landesanstalt für Landwirtschaft (LfL) carries out the breeding value estimation for Fleckvieh and Brown Swiss. All data is centrally collated here. In addition, VIT and LfL provide the best data connection and “online networking” of all cattle breeding organizations.

Vereinigte Informationssysteme Tierhaltung w.V. (vit)

The data centre Vereinigte Informationssysteme Tierhaltung w.V. (vit) collects centrally all data for the dairy cattle breeds Holstein, Red Holstein, Angler, Red and White dual purpose (DN) and Jersey breeds as well as German Friesian cattle (DSN). This central data base which, compared internationally, is unique in terms of size and quality, acts as an independent institution carrying out the nationwide, state-controlled breeding value estimation for these breeds. The list of breeding values contains all the economically important traits from milk production to milking speed. The statistic models used are among the best in the world.

Detailed information on evaluation models, data and trait definitions can be obtained at www.vit.de.

Milk production and udder health

Since 1997, breeding values for milk production and somatic cell score have been estimated directly on the basis of daily yields measured monthly on the farms using a test day model. Therefore a summary or expansion for lactation yields is not carried out. Correction for all non-genetic effects is optimal because performance is compared within herd-test-day, i.e. the same environment and management. Measuring the cell count in every milk sample is standard in Germany. Therefore the data base for udder health is exactly the same as for milk yield and it is unique in the world.

Conformation

Breeding value estimation for conformation contains all linear standard traits recommended by WHFF (World Holstein Friesian Federation) as well as, additionally, the trait “hock quality” for feet and legs. Moreover, using classifier information, breeding values are estimated for four composite scores: udder, feet and legs, body, dairy type. Within the RZE (relative breeding value conformation) as well as the four published composite figures, information from the linear traits and classifiers scores are all combined. The selection of test bull daughters and comparative daughters to be classified is done centrally by the VIT within all herds under official milk recording. Breeding values for conformation are based on the entire breadth of the population and, therefore, not for example, only on the basis of selected herd book herds.

Longevity

The breeding value for longevity (RZN) has been published based on nine survival breeding values since April. These survival breeding values themselves represent nine phases of life. From first to fourth calving, the 3 lactations resulting from them are divided in three phases. So first, real survival information will be already available on the 50th day of the first lactation marking the end of the first phase. So all bulls will get – at the same time – longevity breeding values based on daughter information with the first daughter proven breeding values for milk production/cell score. In line with other relative breeding values, a RZN for A.I. bulls is published if daughter information (1st phase 1st lactation) is based on at least 10 farms.

Total Merit Index RZG

The total merit index RZG, includes all important traits according to their economic importance. In 1997, Germany was one of the first countries to have a real total merit index with production, conformation and functional traits like longevity and fertility. Regarding the composition of the RZG, the functional traits are weighted at 40 %, conformation at 15 % and production at 45 %.

Fertility

Fertility of high performing cows is complex. Therefore breeding values are estimated for five different traits from the complexes “re-cycling after calving” and “conception ability”. The five breeding values are summarized in the RZR (relative breeding value reproduction) according to their economic significance. The data base includes all inseminations of all cows and young cattle in all herds under official milk recording.

Calving traits

Calving traits always include two aspects: the direct calf effect (e.g. size of the calf) and the effect of the dam (e.g. dam’s form of rump). Both aspects have the same impact on trouble-free calving. As there are two information traits, calving ease and vitality of calves (still birth rate), there are 4 single breeding values. Direct calving ease and direct still birth rate are summarized in the relative breeding value, direct calving ease (RZKd), describing the calving ease of a bull’s calves. The two maternal breeding values, maternal calving ease and maternal still birth rate, are summarized in the relative breeding value maternal calving ease (RZKm), describing the calving traits of a bull’s daughters.

More functional traits

In addition to the above-mentioned traits included in the total merit index, breeding values for more traits are available:
• Milking speed (based on measured milk flow and owner’s scores)
• Milking temperament (owner’s scores)
• Persistency (from lactation curves)
• Body condition score

Relative breeding values

All breeding values – except milk production traits – and summarizing indices are published as relative breeding values. Thus the figures are directly comparable across traits and the higher value always indicates the more desirable breeding performance. The scale for all relative breeding values uses 100 as average and a genetic standard deviation of 12 points.

Fitness

Since August 2009, vit had calculated and published a summarizing fitness index, the RZFit. The RZFit included the traits daughter fertility (RZR), maternal calving ease (RZKm), feet and legs, longevity (RZN), udder health, udder and milk production (RZM) which were clearly weighted in favor of the functional traits. These traits have in common that they describe aspects that allow conclusion of good fitness. In April 2019, the RZFit will be replaced by the newly developed RZhealth that includes traits that allow direct conclusion of health/fitness.

RZcalfhealth

In addition to the new health breeding values and the already existing breeding value for stillbirths, it is now possible to develop a breeding value for the fitness and vitality of calves in the rearing period on the basis of the comprehensive data basis. Based on the data of approximately 8 million female calves born since 2006, the new RZcalfhealth describes the genetic ability to survive the rearing period from day 2 to 15 months of age. Only female calves are considered here as male calves usually are sold to fattening farms with 14 days of age. As losses within the different age segments are caused by different diseases, a distinction is made in the estimation model between five age segments (days 3-14, 15-60, 61-120, 121-200, 201-458). The RZcalfhealth is shown on the usual relative scale with an average of 100 and a genetic spread of 12. The reliability of the pure genomic RZcalfhealth is 51 %.

RZhealth

From April 2019, the new breeding value RZhealth will be published for every bull. It consists of the four complex breeding values RZudderfit, RZhoof, RZrepro and RZmetabol. RZEuter has the highest weighting here with 40 % as a relatively high percentage of cows at least contracts Mastitis once in their lifetime and costs per each Mastitis case are high. The second most important complex is hoof health which is why the RZhoof is weighted with 30 %. RZrepro is weighted with 20 % and the complex on metabolic persistency, the RZmetabol, has a weighting of 10 %. The four complex breeding values themselves consist of differently weighted single traits which can be seen in the table below.

Trait complex

Health trait

Index weight

Total

RZUdderfit

Mastitis resistance

100 %

40 %

RZHoof

DDcontrol (Dermatitis digitalis/Mortellaro)

30 %

20 %

Sole ulcer

15 %

Digital phlegmone

15 %

White line disease

15 %

Laminitis

15 %

Interdigital hyperplasia

10 %

RZRepro

Ovarian cycle disorders

50 %

15 %

Endometritis/Metritis

25 %

Retained placenta

25 %

RZMetabol

Abomasal displacement

40 %

25 %

Milk fever

30 %

Ketosis

30 %

RZHealth

 

 

100 %

 

Suitability for automatic milking systems


In August 2014, VIT released a new breeding index specifically for farms with automatic milking systems (AMS) in order to facilitate selection of particular bulls.
The RZRobot is built from the following traits: milking speed (≥ 94), somatic cell count, feet & legs, udder, rear teat placement (≤ 106) and teat length (≥ 94). These six traits have different weightings within the RZRobot. For the traits milking speed, rear teat placement and teat length, minimum requirements were defined which are shown in brackets.
Furthermore, it has been decided, that the RZRobot will only be published if it is ≥ 100, to make sure the bulls will really improve the suitability for AMS.

Genomic breeding values

Since August 2010, genomic breeding values for Holsteins (Black & White and Red & White) have been official and established in Germany. The previous, pure sire reference sample is set up by the EuroGenomics reference sample and includes more than 35,000 reliably daughter proven and, at the same time, genotyped bulls, thereof approx. 13,000 with daughters in Germany.

In line with the breeding value estimation in April 2019, the pure sire reference sample is changed to a mixed reference sample then including more than 38,000 bulls and 150,000 cows. The quality and unbiased nature of German genomic breeding values, which are very high, is not only confirmed by ICAR/Interbull validation, but also by almost 2,000 bulls, that previously only had genomic breeding values, and now have classical breeding values based on more than 100 daughters to date.
Information on genomic selection can be obtained at www.ggi.de – Holstein breeding – Genomic selection.

Please do not hesitate to contact us in case you have any further questions.

 
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The German Holstein breeding industry is characterized by very versatile breeding programs with different priorities. This is not only reflected in the wide-ranging product that is on offer, but also in the great variety of bloodlines used.

Verein Ostfriesischer Stammviehzüchter eG (VOSt): Proven cow families and high reliability

The open breeding program of VOSt uses the best Holstein breeding worldwide and selects according to its own, independent criteria. Really long lasting and deep cow families are the basis for this successful development in breeding. The main selection area for the breeding program is the European area along the coast of the North Sea, from the Bretagne in France in the South, up to Denmark in the North. Special attention is drawn to the East-Friesian breeding area with its traditional and deep cow families bred over many generations. The aim is to breed long lasting, healthy cows with top conformation. Annually about 45 – 50 Holstein and 2 – 3 Red Holstein bulls are tested.
The VOSt breeding program produced the internationally and successfully used GGI transmitters like Lukas, Black, Bob, Lentini RF, Louvre, Lasso and Derby.

NOG Nord-Ost Genetic GmbH & Co KG (NOG: RBB, RinderAllianz, MAR and RSH)

From July 1st 2012, the partners of the NOG NORD-OST Genetic GmbH & Co KG decided to merge their breeding programs into NOG.
Key points of the agreement are specifically the joint selection of desired genetics, increased application of modern biotechnical methods as well as effective use of top bulls through more intensive exchange of semen and organization of the members’ bull stocks. The entire selection work in the breeding areas of the NOG partners is carried out according to consistent selection criteria the particular breeding organizations. The terms of the contract with local breeders for the support of the execution of biotechnical activities as well as the purchase of bull calves is standardized. The coordination of breeding programs within NOG offers the opportunity to select the best young cattle and cows for mating nationally and internationally. Top-class young cattle with high genomic breeding values can be used intensively for breeding purposes in the biotechnology station in Nückel. Selection work in outside breeding areas is coordinated within NOG and carried out by the sire analysts responsible for all NOG partners.

All young bulls selected for purchase are allocated to the NOG partners, according to demand, and will then be owned by the particular organization. Former NOG bulls are allocated to the NOG partners as well so that NOG will, in future, no longer house bulls. With the selection of all bull calves being from one list, what is purchased, will be better for quality and breeding values as well as pedigree variety.

The semen exchange program, proven over the years, now ensures that the breeders in the NOG area have access to all bulls of the NOG partners: an important requirement for the widespread use of the best genetics. With the above mentioned methods, the NOG partners will improve the efficiency of their breeding work, decrease breeding costs and provide its member farms with a choice of genomic and daughter proven sires of improved quality.

TopQ (Qnetics, RUW: Search for top-class genetics from all over the world

TopQ is the merger of the Rinder-Union West eG (RUW) with the Qnetics GmbH that represents the breeding areas Hesse and Thuringia. TopQ was founded to continuously offer the member farms of the partners, semen from interesting Holstein bulls and Red Holstein bulls of the highest genetic level. The basis for this is a strict breeding program which is one of the biggest programs in the world. Within TopQ, approx. 2,000 Holstein and 1,000 Red Holstein bulls are genomically tested each year. During this process, the entire breadth of internationally available top genetics is used both on the sire’s and the dam’s side. The sire analysts of the TopQ breeding organizations work together on the selection. Due to allocation of Germany and the other most important genetic markets worldwide between the sire analysts, selection efficiency is increased. For the selection of sires of sons, the world’s Holstein population is analyzed intensively and frequently, and a specific selection of sires of sons is made among the best sires of the worldwide Holstein population, taking into account the latest breeding value data. Outstanding bull dams are selected from the worldwide Holstein genetics pool on the female side as well. The selection is carried out using all available state-of-the-art information media on the basis of genomic and conventional breeding value information as well as all production figures to hand. All bull candidates being considered for the insemination breeding program are genomically tested and selected on the basis of their genomic and conventional breeding value. Selection of the worldwide genomic tested young bulls is done continuously based on the total merit index (gRZG) of the German genomic system for breeding value estimation. Bulls chosen have to be at the absolute top of the population and offer good all-round predisposition as well as alternative bloodlines as far as possible. The young bulls purchased are allocated among the TopQ breeding organizations according to defined rules and standards. Internationally popular and proven sires like Mascol, Gibor, Tableau, Elburn RDC and Goldday as well as high genomic young bulls like Lexington, Big Point, Sundance and Label P are the results of this intensive breeding policy.

German black & white and red & white Holsteins are bred for high lifetime production. The breeding goal is a profitable, dairy type cow that can be kept on the farm for many lactations because of good health, robustness and good fertility and that has adequate development potential with high forage and dry matter intake capacity. For overall milk production, a genetic potential of 10,000 kg milk (305 days production) with 4 % fat and 3.5 % protein percentage is pursued in order to achieve a lifetime production of more than 40,000 kg milk.

Mature cows are supposed to achieve a height of between 145 and 156 cm as well as a weight of 650 and 750 kg. Body and motion traits including correct and sound feet and legs have to contribute to the high production level and good longevity. In addition, a healthy udder is required that is easy to milk and allows high daily production over many lactations with regard to quality and efficiency and that also meets the requirements of modern milking systems. On the sire’s side, German Holstein breeding guarantees, with its total merit index RZG – introduced in 1997 – balanced breeding for economic as well as health-relevant traits in milk production, conformation, udder health, functional longevity and breeding ability. The total merit index combines a variety of individual pieces of information and offers the breeder selection criteria for bulls which does not only consider milk production, but also functional traits according to their economic importance.

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The basis for genomic bulls of GGI-SPERMEX is genomic selection. In the points below, you will learn a lot more about the aims, background and technique of genomic selection.

Fundamental thoughts on animal breeding

The aim of animal breeding is to diversify genetic endowments of animals and, therefore, improve their traits. In doing so it is not about genetic manipulation in the animal itself, but specific selection using different, desirable traits. Congenitally these traits were only phenotypic (shown) before the introduction of genomic selection. So production performed and conformation traits were taken as indicators for predispositions connected with it and selection was done on that basis-

Of course, an old dream of research and science is to extract information directly from the animals’ genes without going the long way round by using the indirect phenotypical way. Genomic breeding value evaluation and selection is now really close to this desire.

Even though the cattle genome is sequenced now we just do not know much about the position and effect of genes for the majority of the transmission traits. So genomic breeding value estimation does not only work directly based on gene information, but based on markers. The development of these processes of genetic analysis and adaptions of breeding value estimation were developed supported by the Federal Ministry of Education and Research (BMBF) on occasion of the funding FUGATO.

It is so-called SNP (Single Nucleotide Polymorphism) markers that are used. They are composed of only one genetic letter and there are two different models for every marker in the entire population. Every animal has the genetic information in the form of a double chromosome set; one set from the father and one set from the mother.

The result is that every marker for an animal can have three combinations:

  • homozygous option AA
  • homozygous option BB or
  • heterozygous AB.

Heterozygous AB means that the animal received different options from the father and the mother.

Many hundreds of thousands of such SNP markers of cattle are known. 54,001 of them are shared equally in the entire genome i.e. all chromosomes, can now be extracted through a relatively cheap lab method in a one step process. This process is called “typing“. The unit used in the laboratory for testing the 54,001 markers is called a chip or 54K chip to indicate the number of markers simultaneously tested.

A little of the animal’s genetic material is used for the typing. As all cells of an animal have genetic material, blood (approx. 2 ml) or semen (approx. 2 doses) can be used. You can also extract enough gene material for the typing from approx. 30 roots of hair. However, the danger of contamination of hair samples with genetic material of other animals is higher and the result could be incorrect. The typing’s result is 54,001 times AA or BB or AB.

As a result of the equal spread of many markers over the entire genome, it is assumed that close to every gene, which influences the production of one of the transmission traits, is one of the 54,001 markers. This means that the marker is transmitted almost every time, together with the appropriate combination of genes. We do not know however, the different genes and their effect. In order to be able to evaluate an animal’s genomic breeding value using its markers, certain advanced tests are first necessary.

To find out which SNPs, i.e. which markers are connected with which trait, the SNP samples first have to be compared with known (genetic) production traits of selected animals. Animals, with known genetic production are daughter proven bulls as well as typed cows having production data. From the comparison of the SNP sample with the genetic production of these animals, it can be determined which SNP has how much influence on the trait, so the genomic evaluation formulas are conveyed that way. The more reliably proven reference sample animals you have available for this formula, the better you can allocate the SNP to a trait and indicate the extent of the influence. Proven bulls and typed cows including their production data that are included in this analysis are the so-called “training sample“. The conversion from the pure bull reference sample to a mixed reference sample of bulls and cows will be done with the proof run in April 2019. The genomic evaluation formulas conveyed from the training sample are then used for the calculation of the genomic breeding values of other (usually younger) animals without their own reliable conventional breeding value information.

Some further notes on the mixed reference sample

The basis of the primary, pure bull reference sample were bulls selected by the test bull process due to their pedigree breeding value and completed their test period. The selection intensity was relatively low and bulls therefore reflected the entire genetic variety of their population. With increasing genomic selection, selection intensity goes up as well running the risk of a biased reference sample because only bulls enter service that are already genomically pre-selected. Thus you do not have a cross section of genetic width of the actual population and the estimation of transmission power of bulls on occasion of conventional breeding value estimation is more difficult. Reliable, conventional breeding value estimation is the basis for reliable genomic breeding value estimation. The solution of this problem is to type all female calves in the dairy herds in order to have a non-selective and representative basis to the greatest possible extent. This was realized in the project “KuhVision” and numerous herds were typed so far. In April 2019, the current reference sample will be changed to a mixed reference sample. The reference sample will then consist of more than 38,000 bulls and approx. 150,000 cows.

Reliability

The reliability of genomic breeding values mainly depends on the extent and structure of the training sample. The complexity and the reliability of the conventional breeding vales for all – as well as for all functional traits – are No 1 in the world. The size and structure of the German training sample is also unique worldwide because of the exchange of information with three European partners from France, Scandinavia and The Netherlands. None of the other training samples worldwide is so well-structured, i.e. represents the entire, latest Holstein genetics from Europe and North America. The genomic formulas can only convey reliably the breeding values of younger cows when their genetics (SNP sample) are well-represented via preferably many related animals in the training sample. So the training sample has to be continuously expanded and updated alongside the population development. This will be ensured with the introduction of the mixed reference sample as actual genetics of the current population are realistically reflected through female animals.

The reliability of breeding values for younger animals based solely on genomic data (SNP typing) is shown by the figure in the middle column. The reliability shown is the actual reliability; i.e. it has already been corrected for the overestimation observed in all genomic evaluation methods.

Combined genomic breeding values

The direct genomic values (dGW) are calculated from the typings (SNP samples) for all traits. There is also more conventional breeding value information for all animals with known pedigree, namely the pedigree’s breeding value. In order that every animal has only one breeding value with maximum information and reliability at a particular time, the direct genomic value is not published but the genomically improved breeding value (gZW) which is a combination of the direct genomical value and the conventional breeding value is given.

The weighting is done on the basis of the reliability of both values; i.e. for young animals with only a pedigree breeding value, the direct, genomical value counts the most and the unreliable pedigree breeding value can increase the reliability of the genomically improved breeding value ([ZW] gZW) by only approx. 3-5% (please see right column of the figure). Once the conventional breeding value is clearly more reliable from daughter information than from the direct genomic value, it has a higher weighting in the combined gZW. So the combined gZW of daughter proven bulls is usually little different from the purely conventional breeding value.

What are genomic breeding values able to do?

The actual reliability of genomically improved breeding values of young bulls – approx. 75% for the milk yield traits and 50% for daughter fertility – is clearly higher than the reliability of the current pedigree breeding value of test bulls. So young bulls with their official gZW qualify formally as sires, and there are no longer test bulls as they were previously known.
The comparison of the reliabilities of daughter proven sires (Figure 2) shows however, that even bulls with only test daughters in first lactation have higher breeding value reliabilities for high heritability and important traits like production, conformation and udder health.

Even though German genomic breeding values are the most reliable when compared internationally, because of the structure and extent of thetraining sample , the genomic breeding values are more unreliable than those of the daughter proven sires’. With stronger emphasis on the functional traits, the significance of sires with thousands of second crop daughters has increased over the past years because they also offer high reliability for traits like longevity and daughter fertility. The actual reliability of genomic breeding values for those functional traits is still limited to approx. 50%. So if you normally think that the reliability of the firstly published daughter breeding values of new sires are too low, young bulls, only genomically tested, may not be an option for you. On the other hand the young generation of genomically tested bulls provides a new breeding opportunity. When using those young genomic-bulls, you should always be aware of the limited reliability, so the risk should be spread by using several such bulls. The reliability calculations and data for genomic breeding values are not yet standardized internationally. The data of the German genomic breeding values are realistic however, and the quality of the German genomic breeding values is the best internationally. For correct evaluation of the German breeding values, as well as reliability expressed in percentages, the number of daughters with production information will still be given. This means that everybody is able – on an impartial basis – to select a suitable sire with a choice between a young genomically tested bull or the latest, proven bull with test daughters or even a proven second crop sire.

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