In natural ventilation system-enabled dairy buildings (NVDB), achieving accurate gas emission values is highly complicated. The external weather affects measurements of the gas concentration of pollutants ($c_P$) and volume flow rate (Q) due to the open-sided design. Previous research shows that increasing the number of sensors at the side opening is not cost-effective. However, accurate measurements can be achieved with fewer sensors if an optimal sampling position is identified. Therefore, this study attempted to calibrate the outlet of an NVDB for the direct emission measurement method. Our objective was to investigate the $c_P$ gradients, in particular, for ammonia ($c_{N{H}_3}$), carbon dioxide ($c_{C{O}_2}$), and methane ($c_{C{H}_4}$) considering the wind speed (v) and their mixing ratios ([$\overline{{\mathrm{c}}_{{\mathrm{CH}}_4}/{\mathrm{c}}_{{\mathrm{NH}}_3}}$]) at the outlet, and assess the effect of sampling height (H). The deviations in each $c_P$ at six vertical sampling points were recorded using a Fourier-transform infrared (FTIR) spectrometer. Additionally, wind direction and speed were recorded at the gable height (10 m) by an ultrasonic anemometer. The results indicated that, at varied heights, the average $c_{N{H}_3}$ (p < 0.001), $c_{C{O}_2}$ (p < 0.001), and (p < 0.001) were significantly different and mostly concentrated at the top (H = 2.7). Wind flow speed information revealed drastic deviations in $c_P$, for example up to $+105.1\%$ higher $c_{N{H}_3}$ at the top (H = 2.7) compared to the baseline (H = 0.6), especially during low wind speed (v < 3 m s${}^{-1}$) events. Furthermore, [$\overline{{\mathrm{c}}_{{\mathrm{CH}}_4}/{\mathrm{c}}_{{\mathrm{NH}}_3}}$] exhibited significant variation with height, demonstrating instability below 1.5 m, which aligns with the average height of a cow. In conclusion, the average $c_{C{O}_2}$, $c_{C{H}_4}$, and $c_{N{H}_3}$ measured at the barn’s outlet are spatially dispersed vertically which indicates a possibility of systematic error due to the sensor positioning effect. The outcomes of this study will be advantageous to locate a representative gas sampling position when measurements are limited to one constant height, for example using open-path lasers or low-cost devices.

Ammonia and greenhouse gases have a negative impact on the environment. The most important agricultural sources of ammonia are dairy cattle housing systems, which are mainly naturally ventilated. Estimating emissions for naturally ventilated barns (NVB) is challenging due to the large number of influencing factors. Most notably, the direct coupling of the inside flow regime with ambient and turbulent weather conditions causes difficulties in measuring ventilation rates, gas concentrations and emissions; thus, different methods are available. In this study, we compared the outputs of total volume flow obtained by two indirect methods (CO${}_2$ mass balance) to the direct method. The latter we assume in this study as the reference method since it is a fundamental approach that estimates airflow on the inlet. In the context of mass balancing, we compared wind related (sampling method 1) and non-wind related (sampling method 2) approaches for measuring CO${}_2$ concentrations. The total volume flow calculations were based on hourly measurements of CO${}_2$ concentrations obtained by Fourier transform infrared (FTIR) spectrometer. Data were collected over a period of six months. The values of the total volume flow were filtered for prevailing southern winds (90${}^{\circ }$ angle). The wind related method (sampling method 1) in stable cross-inflow conditions produces more accurate and realistic values in terms of the general representation of the values in comparison with direct method and can be considered further for measurements of volume flow in the NVBs.

Prepartum vaccinations against neonatal calf diarrhea pathogens are administered in late pregnancy to provide passive immunity to calves through protective colostral antibodies. Potential non-specific effects of the vaccine on maternal innate immune responses and disease susceptibility during the sensitive transition period have not been addressed so far. In this retrospective study, data from 73,378 dairy cows on 20 farms in Germany were analyzed, using linear mixed-effects regression, quantile regression, and decision-tree-algorithms, to investigate the effects of prepartum vaccination on mammary health and milk yield by comparing non-vaccinated and vaccinated transition periods. Herd management-related factors were found to be most influential for mammary health and milk yield. Vaccinated cows were not significantly more likely to develop mastitis and did not have significantly different somatic cell counts and milk yields compared to non-vaccinated cows. Healthy primiparous cows with and without vaccination had similar energy-corrected milk yields. The study concludes that prepartum vaccination against calf diarrhea has no significant effects on mammary health and milk yield. Further research is recommended to investigate potential non-specific vaccine effects on other organ systems, infectious diseases, and production metrics of the dairy cow.

Prepartum vaccination of dairy cows against newborn calf diarrhea protects calves during the first weeks of life via the colostrum. Vaccination may also induce non-specific effects (NSE) beyond antibody production, altering disease susceptibility and productivity of the vaccinated mother. This retrospective study analyzed herd records and on-site survey data from 73,378 dairy cows on 20 German farms using linear mixed-effects models and random forest algorithms. Management practices and milk yield showed stronger associations with outcomes than vaccination. However, cows vaccinated with non-live vaccines had increased odds of retained placenta and metritis (OR: 1.5–1.7), and endometritis (OR: 3–6), and were 20–24% less likely to be successfully inseminated than non-vaccinated cows. Among non-live vaccinated cows, those vaccinated 2.5–4 weeks before calving had an 8% higher non-return rate compared to those vaccinated 6–8 weeks prior. Multiparous cows receiving live vaccine components were 1.9 times more likely to be successfully inseminated, compared to non-live vaccinated multiparous cows. These findings suggest poten-tial NSE of prepartum vaccination on uterine health and fertility. However, the study’s retro-spective design limits causal interpretation, and the benefits in calves may outweigh possible adverse effects. Further research should clarify mechanisms and optimize vaccine timing and composition.

Prepartum vaccination of dairy cows against newborn calf diarrhea protects calves during the first weeks of life via the colostrum. Vaccination may also induce non-specific effects (NSEs) beyond antibody production, altering the disease susceptibility and productivity of the vaccinated mother. This retrospective study analyzed herd records and on-site survey data from 73,378 dairy cows on 20 German farms using linear mixed-effects models and random forest algorithms. Management practices and milk yield showed stronger associations with outcomes than vaccination. However, the cows vaccinated with non-live vaccines had increased odds of retained placenta and metritis (OR: 1.5–1.7), as well as endometritis (OR: 3–6), and were 20–24% less likely to conceive than non-vaccinated cows. Among non-live vaccinated cows, those vaccinated 2.5–4 weeks before calving had an 8% higher non-return rate compared to those vaccinated 6–8 weeks prior. Multiparous cows receiving live vaccine components were 1.9 times more likely to conceive, compared to non-live vaccinated multiparous cows. These findings suggest potential NSE of prepartum vaccination on uterine health and fertility. However, this study’s retrospective design limits causal interpretation, and the benefits in calves may outweigh possible adverse effects. Further research should clarify the mechanisms and optimize vaccine timing and composition.