Effects of replacing corn silage and soybean meal with an increasing percentage of fresh herbage on dairy cow nitrogen use efficiency and flows.

To improve sustainability, dairy farms can reduce protein-rich concentrate in the cows' diet providing fresh herbage produced on-farm. This study aimed to quantify effects of increasing the percentage of fresh herbage (0%, 25%, 50%, and 75%, on a dry matter [DM] basis) in a partial mixed ration-based diet on cow N use efficiency and excretion. The study was performed with five lactating cows, in a 4 × 4 Latin square design for four 3 week periods.

CowNflow: A dataset on nitrogen flows and balances in dairy cows fed maize forage or herbage-based diets.

Diet and animal characteristics have a significant impact on the nitrogen (N)-use efficiency of dairy cows. A dataset (CowNflow) was built that compiles 28 N-balance experiments with Holstein dairy cows from 1983 to 2019, corresponding to 414 individual N flows, for a wide range of diets and animal characteristics. The dataset is composed of six Microsoft® Excel files that correspond to six levels of information.

Identification of rumen microbial biomarkers linked to methane emission in Holstein dairy cows.

Mitigation of greenhouse gas emissions is relevant for reducing the environmental impact of ruminant production. In this study, the rumen microbiome from Holstein cows was characterized through a combination of 16S rRNA gene and shotgun metagenomic sequencing. Methane production (CH ) and dry matter intake (DMI) were individually measured over 4-6 weeks to calculate the CH yield (CH y = CH /DMI) per cow.

NDIR Gas Sensor for Spatial Monitoring of Carbon Dioxide Concentrations in Naturally Ventilated Livestock Buildings.

The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ventilation rate. The aim of this research was to assess the performance of a low-cost Non-Dispersive Infra-Red (NDIR) sensor for intensive spatial field monitoring of CO2 concentrations in a NV dairy cow house. This was achieved by comparing NDIR sensors with two commonly applied methods, a Photo-Acoustic Spectroscope (PAS) Gas Monitor and an Open-Path laser (OP-laser).