The development of new traits happens mainly in the areas of functionality and environmental impact of our livestock. The most important keywords are health, fertility, feed efficiency and methane (CH4) emissions. A few selected contributions are explained in more detail below. 

Typical calf diseases, such as respiratory diseases and diarrhea, can often only be controlled with antibiotics. In order to be able to take preventative measures through animal breeding, the genetic background of these calf diseases was investigated in almost 1,900 Holstein herds in Canada. First results show; heritabilities are low: 0.01 – 0.04. Literature values tend to be higher. However, recording protocols needs to be more accurate and discipline in recording needs to be greater. If phenotyping can be improved and genomic selection can be implemented for the traits studied, there is a good chance that classical calf diseases can also be controlled by breeding.

As shown by a French study in Holstein cows, economically important diseases such as abomasal displacement, milk fever, uterine inflammation and postpartum behavior have, as expected, very low heritabilities. However, it follows from this study that positive genetic trends are observed in the French Holstein population, with the exception of milk fever. As this study shows, the recording of health data, i.e. phenotype recording, is the basis for successful breeding work. In addition, it is apparent that genomic selection, in the form of single-step breeding value estimation, can yield significant progress. 

 The above-mentioned studies are representative for further presentations: for a good phenotyping – especially for traits with low heritabilities – it is essential to collect as much data as possible over a long period of time and to establish an integral collection in the whole herd. In combination with a single-step breeding value estimation, a successful breeding program can be implemented.  

As was made clear at the conference, working on functional traits, especially health traits, is of great importance in all livestock and positive genetic trends are achieved in many livestock populations. This is based on the fact that the functionality of livestock in breeding has been given much more weight in recent years than pure production performance.  

In monogastrics, the feed efficiency trait has long been the subject of breeding efforts.  

In order to make optimum use of available resources and to reduce feed costs, this trait has become enormously important in the cattle sector in recent years. Worldwide, political pressure has also increased to include this trait in breeding programs. At the World Genetics Congress, two main topics dealt with feed efficiency: animal-specific recording (phenotyping) and the genetic background of this trait. 

The gold standard for measuring animal-specific feed intake is the so-called weighing trough. This device is very expensive and labor intensive. That is why research is being done on alternatives. A representative from Viking Genetics in Denmark presented a new approach. In this, 3D cameras are used to record feed intake at the feed table, animal weight and animal identification. Validation results for feed intake are promising (r2=0.90), as are estimates for body weight. In addition, the system provides administration tools for breeders. 

To avoid costly facilities, intensive research is also being conducted on auxiliary traits (proxies). Researchers from Norway tried to estimate daily roughage intake via MIR spectral data of milk samples and via performance data of individual cows using “deep learning” methods. The initial results are positive, but the methods need to be refined and validated on larger data sets. Researchers from Mexico and the U.S. found similar results; in addition, they emphasized the importance of selecting the correct wavebands of spectral data for predictions. 

All the papers that dealt with the genetic roots of feed efficiency pointed in a very similar direction: this trait is heritable and can be edited by breeding. Heritabilities are mostly in a medium range (e.g., Lidauer, M.H. et al. 2022 or Navajas, E.A, et al. 2022).  

In the context of genetic evaluations for feed efficiency, questions are quickly raised regarding genetic correlations to other traits. 

Efforts are underway at a variety of levels to reduce CH4 emissions from livestock. Besides feeding, there are also breeding possibilities. But again, phenotypes are needed for active breeding efforts, and collecting these phenotypes at the individual animal level is difficult. Research groups from Wageningen University have developed so-called sniffers that are mounted in the milking robot and can measure the gas output for each cow. The heritability for the trait CH4 output is in the medium range and the genetic correlation to measurements with so-called GreenFeed is close to 0.8. GreenFeed is a different measurement method in which the CH4 output of the cattle is measured in a box similar to a concentrated feed station. A paper from Norway, CH4 emissions measured with GreenFeed in commercial herds, shows similar heritabilities.   

The genetic correlations between feed efficiency and methane emissions are of great interest.  Both traits are environmentally relevant. Thus, there is hope that the correlations point in a positive direction: better feed efficiency results in lower methane emissions. At the moment, no consistent pattern emerges. One Australian research team showed antagonistic relationships, while others found slightly positive relationships. Many other contributions dealt with this area of controversy.  

In general, it can be said that methane emissions can be reduced at the breeding level in ruminants. However, this requires large data sets (phenotypes), which can usually only be obtained through international collaborations. In addition, the relationships to other traits need to be investigated in more detail and the weighting of this trait in a selection strategy, or in an index, needs to be clarified in more detail.