Genetic parameters of colostrum and calf serum antibodies in Swedish dairy cattle

Background: Colostrum with sufficient IgG content is essential for the newborn calf, as it provides passive immunity which substantially affects the probability of survival during rearing. Failure of passive transfer occurs when a calf does not absorb enough antibodies from the colostrum as indicated by less than 10 g/L of IgG in calf serum. Besides delayed access to colostrum, this can be due to low IgG production of the mother or poor IgG absorption by the calf. The aim of this study was to estimate the genetic background of antibody levels and indicator traits for antibodies in colostrum and calf serum, and their correlation with milk production and health. Results: Colostrum data were available from 1340 cows with at least one calving and calf serum data were available from 886 calves from these cows. Antibody concentrations were estimated using refractometry (digital Brix refractometer for colostrum and optical refractometer for serum) as indicator traits and established using ELISAs to determine total IgG and natural antibodies [NAb] of various antibody isotypes in colostrum and serum. Colostrum traits had heritabilities ranging from 0.16 to 0.31 with repeatabilities from 0.21 to 0.55. Brix had positive genetic correlations with all colostrum antibody traits including total IgG (0.68). Calf serum antibody concentrations had heritabilities ranging from 0.25 to 0.59, with a significant maternal effect accounting for 17 to 27% of the variance. When calves later in life produced their first lactation, lactation-average somatic cell score was found to be negatively correlated with NAb in calf serum. Conclusions: Our results suggest that antibody levels in colostrum and calf serum can be increased by means of selection.

Mapping geographical areas at risk for tick-borne encephalitis (TBE) by analysing bulk tank milk from Swedish dairy cattle herds for the presence of TBE virus–specific antibodies

Background The vector-borne human viral zoonosis tick-borne encephalitis (TBE) is of growing concern in Sweden. The area where TBE is considered endemic has expanded, with an increasing geographical distribution of Ixodes ricinus as the tick vector and a rising number of reported TBE cases in humans. Efforts to map TBE risk areas have been carried out by sentinel monitoring, mainly based on individual sampling and analysis of wild and domestic animals, as well as ticks, for tick-borne encephalitis virus (TBEV). However, the interpretation of the geographical distribution has been hampered by the patchy and focal nature of TBEV occurrence. This study presents TBEV surveillance data based on antibody analysis of bulk tank milk collected from dairy herds located throughout Sweden before (May) and after (November) the vector season. A commercial TBEV antibody ELISA was modified and evaluated for use in this study. Results The initial comparative TBEV antibody analysis revealed a good correlation between milk and serum antibody levels from individually sampled cows. Also, the TBEV-antibody levels for the mean-herd serum showed good comparability with TBEV antibody levels from bulk tank milk, thus indicating good predictability of seroprevalence when analysing bulk tank milk from a herd. Analyses of bulk tank milk samples collected from 616 herds in May and 560 herds in November showed a geographical distribution of TBEV seropositive herds that was largely consistent with reported human TBE cases. A few TBEV-reactive herds were also found outside known locations of human TBE cases. Conclusion Serological examination of bulk tank milk from dairy cattle herds may be a useful sentinel surveillance method to identify geographical presence of TBEV. In contrast to individual sampling this method allows a large number of animals to be monitored. TBEV seropositive herds were mainly found in coastal areas of southern Sweden similar to human TBE cases. However, some antibody-reactive herds were found outside known TBE areas at the time of the study.

Use and non-use values to explain farmers’ motivation for the provision of animal welfare

This paper examines how differences in motivation in terms of use and non-use values affect the choice of animal welfare improvement practices. The application is focused on Swedish dairy farmers’ preferences for different flooring systems’ attributes. Using multiple indicators and multiple causes and hybrid latent class models, the findings demonstrate that dairy farmers who favour flooring solutions that enhance farm animal welfare are motivated by a complex set of both use values relating to internal and external pressures and non-use values linked to animal freedom, ethical codes of farmers and building business-to-customer relationships. The findings imply that measures to stimulate more uptake of animal welfare improvement practices can be better targeted by using insights into motivational constructs of farmers and by adopting policy communication that captures the whole breadth of use and non-use motivational constructs held by farmers.

No Detection of Methicillin-Resistant Staphylococcus aureus in Dairy Goats

This short communication addresses the hypothesis that the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) is low in dairy goats in Sweden. Methicillin-resistant S. aureus is a widespread zoonotic bacterium of clinical importance in both animals and humans. In Sweden, MRSA is rare among both animals and humans. However, MRSA has been detected in a few goat herds in Sweden with a high within-herd occurrence of mecC-MRSA, but only a limited number of herds were investigated and most of them were not producing milk for human consumption. The prevalence of MRSA among dairy goat herds in Sweden is not known and a cross-sectional prevalence study was therefore conducted. A total of 22 bulk milk samples from the same number of herds, and pooled swabs from nose, mouth, and perineum from 113 goats, were collected during August and September 2019 for bacteriological investigation. After culturing on selective media, suspected isolates were confirmed as S. aureus using MALDI-TOF and subjected to PCR targeting the mecA and mecC genes to confirm MRSA status. No samples were found to be positive for MRSA, and there are therefore no indications of a spread of MRSA in Swedish dairy goat herds.

Influence of Dry Period Length of Swedish Dairy Cows on the Proteome of Colostrum

The aim of this study was to evaluate the influence of applying a 4-week instead of an 8-week dry period to dairy cows on the proteome of colostrum (first sample) and of transition milk (the fifth postpartum milk sample). Individual milk serum samples of colostrum and transition milk were analysed from 12 Swedish Holstein (SH) and 12 Swedish Red (SR) cows. Samples were prepared by filter-aided sample preparation and dimethyl labelling and analysed by liquid chromatography tandem mass spectrometry. Shortening the dry period resulted in upregulation of 18 proteins in colostrum and transition milk of SR, whereas no statistical differences were found for SH colostrum and transition milk. These upregulated proteins may reflect a specific immune response in the SR samples that was reflected in colostrum as well as in transition milk. Upregulated proteins in colostrum seemed to reflect increased mammary epithelial cell proliferation in the periparturient period when a 4-week dry period was applied. The proteome data indicate that a dry period of 4 weeks to SR cows may not be sufficient for complete regeneration of the mammary epithelium.