Økologer lægger vægt på høj mælkeydelse som avlsmål

En spørgeskemaundersøgelse foretaget i forskningsprojektet SOBcows viser, økologiske mælkeproducenter lægger større vægt på at højere mælkeydelse gennem avlsarbejdet, end forskerne havde forventet

Resultater fra spørgeskemaundersøgelsen

Præsentation af resultaterne fra spørgeskemaundersøgelsen om avlsmål for økologiske malkekøer. Undersøgelsen blev sendt til alle økologiske mælkeproducenter

Organic dairy breeding lines? – Possibilities and Requirements

Genomic breeding schemes with large cow reference populations will give room for more line division within dairy cattle breeding and therefore also for organic breeding lines. The reason is that different economic values between organic and conventional production systems are expected in the future and the existence of genotype by environment interaction will presumably be even more recognized. Therefore, correlations between organic and conventional breeding goals are expected to be significantly lower than one. This in combination with increased future “break even” correlations opens up for specific organic breeding lines

Herd characteristics influence farmers’ preferences for trait improvements in Danish Red and Danish Jersey cows

ABSTRACT The aim of this study was to characterize preferences of farmers for breeding goal traits with Danish Red (DR) or Danish Jersey (DJ) cows. A breed-specific survey was established to characterize farmers’ preferences for improvements in 10 traits, by means of pairwise rankings using the online software 1000Minds. These pairwise rankings were based on equal economic worth of trait improvements. The DR survey was filled in by 87 farmers and the DJ survey by 76 farmers. Both DR and DJ farmers gave the highest preference to improvements in mastitis, and the lowest to calving difficulty. By means of a cluster analysis, three distinct clusters of farmers were identified per breed. Comparisons of herd characteristics between clusters suggest that farmers choose to improve traits that are problematic in their herds. This study shows that heterogeneity exists in farmers’ preferences for trait improvements and that herd characteristics influence these preferences in DR and DJ

Pre-selection against a lethal recessive allele in breeding schemes with optimum-contribution selection or truncation selection

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Organic dairy farmers put more emphasis on production traits than conventional farmers

The overall aim of this research was to characterize the preferences of Danish dairy farmers for improvements in breeding goal traits. The specific aims were (1) to investigate the presence of heterogeneity in farmers’ preferences by means of cluster analysis, and (2) to associate these clusters with herd characteristics and production systems (organic or conventional). We established a web-based survey to characterize the preferences of farmers for improvements in 10 traits, by means of pairwise rankings. We also collected a considerable number of herd characteristics. Overall, 106 organic farmers and 290 conventional farmers answered the survey, all with Holstein cows. The most preferred trait improvement was cow fertility, and the least preferred was calving difficulty. By means of cluster analysis, we identified 4 distinct clusters of farmers and named them according to the trait improvements that were most preferred: Health and Fertility, Production and Udder Health, Survival, and Fertility and Production. Some herd characteristics differed between clusters; for example, farmers in the Survival cluster had twice the percentage of dead cows in their herds compared with the other clusters, and farmers that gave the highest ranking to cow and heifer fertility had the lowest conception rate in their herds. This finding suggests that farmers prefer to improve traits that are more problematic in their herd. The proportion of organic and conventional farmers also differed between clusters; we found a higher proportion of organic farmers in the production-based clusters. When we analyzed organic and conventional data separately, we found that organic farmers ranked production traits higher than conventional farmers. The herds of organic farmers had lower milk yields and lower disease incidences, which might explain the high ranking of milk production and the low ranking of disease traits. This study shows that heterogeneity exists in farmers’ preferences for improvements in breeding goal traits, that organic and conventional farmers differ in their preferences, and that herd characteristics can be linked to different farmer clusters. The results of this study could be used for the future development of breeding goals in Danish Holstein cows and for the development of customized total merit indices based on farmer preferences

Possibilities for a specific breeding program for organic dairy production

Presentation on breeding programs for organic dairy production at the 70th Annual EAAP Meetin

Heterogeneity in farmer preferences for breeding goal traits - effects of herd characteristics and production system

The aim of this study is to quantify preferences of Danish dairy farmers for breeding goal traits and associations to herd characteristics and production system (organic versus conventional farming). The main conclusions are that: 1) heterogeneity exists within farmers’ preferences and clear groups of farmers are found for all breeds, 2) some herd characteristics can be linked to farmer groups, and 3) production system can be linked to farmer groups

Differential CCR7 Targeting in Dendritic Cells by Three Naturally Occurring CC-Chemokines

The CCR7 ligands CCL19 and CCL21 are increasingly recognized as functionally different (biased). Using mature human dendritic cells (DCs), we show that CCL19 is more potent than CCL21 in inducing 3D chemotaxis. Intriguingly, CCL21 induces prolonged and more efficient ERK1/2 activation compared to CCL19 and to a C-terminal truncated (tailless) CCL21 in DCs. In contrast, tailless-CCL21 displays increased potency in DC chemotaxis compared to native CCL21. Using a CCL21-specific antibody, we show that CCL21, but not tailless-CCL21, accumulates at the cell surface. In addition removal of sialic acid from the cell surface by neuraminidase treatment impairs ERK1/2 activation by CCL21, but not of CCL19 or tailless-CCL21. Using standard laboratory cell-lines, we observe low potency of both CCL21 and tailless-CCL21 in G protein activation and -arrestin recruitment compared to CCL19, indicating that the tail itself does not improve receptor interaction. Chemokines interact with their receptors in a stepwise manner with ultimate docking of their N-terminus into the main binding pocket. Employing site-directed mutagenesis we identify residues in this pocket of selective CCL21 importance. We also identify a molecular switch in the top of TM7 important for keeping CCR7 in an inactive conformation (Tyr312), as introduction of the chemokine receptor-conserved Glu (or Ala) induces high constitutive activity. Summarized, we show that the interaction of the tail of CCL21 with polysialic acid is needed for strong ERK-signaling, whereas it impairs CCL21-mediated chemotaxis and has no impact on receptor docking consistent with the current model of chemokine:receptor interaction. This indicates that future selective pharmacological targeting of CCL19 versus CCL21 should focus on a differential targeting of the main receptor pocket, while selective targeting of tailless-CCL21 versus CCL21 and CCL19 requires targeting of the glycosaminoglycan (GAG) interaction