Nitrogen metabolism and milk production in dairy cows fed semi‐restricted amounts of ryegrass–legume silage with birdsfoot trefoil (Lotus corniculatus L.) or white clover (Trifolium repens L.)

Abstract

This is an author produced version of a paper published in Grass and forage science. This paper has been peer-reviewed but may not include the final publisher proof-corrections or pagination.Citation for the published paper: Eriksson, T., Norell, L. and Nilsdotter-Linde, N. (2012) Nitrogen metabolism and milk production in dairy cows fed semi-restricted amounts of ryegrass-legume silage with birdsfoot trefoil (Lotus corniculatus L.) or white clover (Trifolium repens L. AbstractIn change-over trials, mid-lactation dairy cows were fed concentrate-supplemented, isonitrogenous and iso-fibrous perennial ryegrass-legume silage diets that satisfied energy requirements but were sub-optimal with respect to metabolisable protein supply. Legumes were either birdsfoot trefoil with low levels of condensed tannins (typical for hemiboreal conditions), or white clover. Averaged over two experimental years, birdsfoot trefoil-based silage resulted in lower digestibility (P < 0.001) of dry matter (50 g kg -1 ), organic matter (52 g kg -1 ), neutral detergent fibre (120 g kg -1 ) and nitrogen (24 g kg -1 ) and lower rumen total volatile fatty acid concentration (7 mM; P = 0.009). Milk protein yield was 36 g d -1 higher with birdsfoot trefoil silage (P = 0.002), while raw milk yield tended to be 0.8 kg d -1 higher (P = 0.06). Rumen ammonia concentration was similar between diets, but milk urea concentration (P < 0.001), urinary urea excretion (P = 0.002) and faecal N proportion (P = 0.001) were higher with birdsfoot trefoil silage. The results suggest that grass-birdsfoot trefoil silage produced in hemiboreal areas exhibits a protein-sparing effect in dairy rations, despite a low condensed tannin content that is further diluted by companion grasses and ration concentrate proportion.

Effect of replacing organic grass-clover silage from primary growth with regrowth on feed intake and milk yield of dairy cows

“…This shows that clover had a poorer conversion rate than grasses due to higher CP levels (Dewhurst et al 2003). Still, compared to other studies with conversion rates ranging from 0.25 to 0.33 (Kuoppala et al 2008;Eriksson et al 2012;Randby et al 2012), all the conversion rates in the present study were good (0.30-0.32), due to the overall moderate CP intake.…”

Effects on milk urea concentration, urine output, and drinking water intake from incremental doses of potassium bicarbonate fed to mid-lactation dairy cows

“…Rumen ammonia peaks mainly resulted from the added urea to the experimental rations, where both silage proportions and silage CP concentrations were low. However, the peaks were very similar in magnitude to what occurs after a silage meal of a typical Scandinavian dairy ration dominated by grass-legume silage (Eriksson, 2010;Eriksson et al, 2012). The fed urea amount would, for instance, correspond to a ruminal liquid concentration of 38 mg of NH 3 -N/dL, if rumen liquid volume is assumed to be 86 L, as in recent rumen evacuations at our laboratory .…”

“…The samples were then milled through a 1-mm screen in a hammer mill (Kamas, Malmö, Sweden). Feeds were analyzed for DM, ash, acid-insoluble ash (AIA), ash-free NDF, Kjeldahl N, minerals, and silage OM digestibility by the standard procedures described by Eriksson et al (2012). Silage orts were analyzed for DM, ash, and mineral content, whereas concentrate orts were analyzed for DM, ash, and Kjeldahl N content.…”

Nighttime pasture access: Comparing the effect of production pasture and exercise paddock on milk production and cow behavior in an automatic milking system

“…The hand-plucked pasture samples and silage samples from feed troughs were pooled weekly over the experimental periods before drying, milling, and laboratory analysis of DM, ash, Kjeldahl N, ash-free NDF, and 96 h in vitro digestibility for ME estimation, using standard methods (Eriksson et al, 2012). Dry matter content in silage and pasture herbage was expressed at 103°C with no correction for volatiles.…”

“…Dry matter content in silage and pasture herbage was expressed at 103°C with no correction for volatiles. Fortnightly pooled samples of silage sampled directly from the silo were used for obtaining silage juice for subsequent determination of pH and content of fermentation acids and alcohols (Eriksson et al, 2012). Ammonia concentration in the silage juice was determined by flow injection analysis (Fiastar 5010, Tecator, Sweden).…”