Is it possible to use genomics to increase the resistance of dairy cattle to bronchopneumonia in calves?

ZAVADILOVÁ, Ludmila, FLEISCHER, Petr, ŠLOSÁRKOVÁ, Soňa KAŠNÁ, Eva, KRUPOVÁ, Zuzana, PECHOVÁ, Alena and KUČERA, Josef. Is it possible to use genomics to increase the resistance of dairy cattle to bronchopneumonia in calves?. Černostrakaté novinky, 2025, vol. 2025(2), p. 11-13. ISSN .
Year2025
CathegoryOthers
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Abstract

Bronchopneumonia in calves is a significant breeding problem. The advantage of breeding for resistance to respiratory diseases in calves is the possibility of obtaining data on the disease in an individual at an early age, as well as the fact that this trait can be monitored in both sexes. In this paper, we evaluate the incidence of bronchopneumonia in calves (BP) of dairy cattle in the Czech Republic and try to show that it is possible to estimate genomic breeding values (GBV) that can be used for breeding to increase the genetically determined resistance of the Holstein breed to the occurrence of BP in calves. Information on the occurrence of this disease was obtained from the web application „Diary of Diseases and Treatment.“ In the entire set (281,728 calves), bronchopneumonia was recorded in the Diary in 11.6% of calves. All the above-described information obtained from the Diary on the occurrence of BP in calves was used to predict (GBV) for the Holstein breed. From the dataset, only Holstein (H) heifers with an H breed of 75% or more, including the red variant, were selected for GBV prediction. For the actual GBV prediction, a linear animal model and a single-step genomic prediction method were used, which is used in the routine GBV estimation for the Holstein breed in the Czech Republic.Genomic information on 51,407 individuals was used to create the genomic part of the relationship matrix, of which 5,696 were bulls and 45,711 cows and heifers, of which 39,481 BP was monitored. When predicting GBV, a heritability of 2.28% for the trait was used, which was estimated based on a subset of 91,368 heifers. The average reliability of breeding values for BP was 22%, whereas for genomic heifers, it was 29%, and for non-genomic heifers, it was 17%. We compared the incidence of health disorders in daughters of bulls with low RBV (below 95%) for resistance to BP with a group of daughters of bulls with high RBV for this trait (above 129%). It turned out that in addition to respiratory diseases, daughters of bulls with lower RBV also have a higher incidence of registered diseases per daughter for mastitis, diarrhoea, hoof diseases and metritis. Consistent evidence of the occurrence of health disorders in livestock forms the basis for successful breeding work aimed at developing resistance to them. This applies in particular to diseases/traits such as bronchopneumonia in calves (i.e. up to 180 days of age), which is characterised by low heritability. Only based on adequate evidence are breeders able to provide a reliable prediction of the breeding value for resistance to bronchopneumonia in calves, which can be used for the selection of resistant parents of the next generation of dairy cattle. The occurrence of BP itself does not indicate a hereditary basis for the carrier’s resistance to calf bronchopneumonia due to low heritability. We have demonstrated that it is possible to estimate breeding values for resistance to BP in calves, with the notable difference that there are differences between the bulls currently used that can be utilised for selection. The same applies to heifers and cows. We have confirmed the importance of genotyping cattle. Its breeders need to practice constant and consistent recording of data on diseases, which can then be used for both herd management and breeding. For many years, dairy cattle breeders have had access to the free Disease and Treatment Diary web application, which provides the outputs of the farm’s Health Assessment, including the Calf Health Assessment. Additionally, for approximately two years, breeders have had the opportunity to compare the annual morbidity rates of their bred animals. Clear benchmarking is available in the Morbidity Comparison web application, also under the umbrella of the Data Access application of ČMSCH, a.s.