Relationship between feed crude protein and nitrogen content in dairy cow manure | Barības kopproteīna satura sakarība ar slāpekļa saturu slaucamo govju mēslos
2020
Ruska, D., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Faculty of Agriculture | Jonkus, D., Latvia Univ. of Life Sciences and Technologies, Jelgava (Latvia). Faculty of Agriculture
The objective of this study was to evaluate the relationship between feed crude protein (CP) and nitrogen content in dairy cow manure. The study was conducted with three groups (A, B, C) of lactating dairy cows from the 10th to the 30th days in milk. Total mixed rations containing different levels of CP (18.0%, 17.5% and 17.0% for A, B and C group, respectively) were fed. The amount of feed consumed by each cow was measured and samples collected during the trial. Milk yields (kg dE−1) and faeces amounts were recorded, and samples were collected for analysis at the 21st day of the study. The results showed that milk yield, fat, total protein and urea content were not significantly different among groups and was not affected by the dietary CP levels. The correlation between faecal nitrogen content and CP content in feed was moderately positive and significant (r=0.443), while the correlation between faecal nitrogen content and urea content tended to be moderately negative (r=−0.391; p=0.06).
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