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Abstract

The objective of this study was to evaluate the effects of feeding lactating dairy cows with regrowth silages from different 2- and 3-cut harvesting systems on milk production, efficiency of N, arid energy utilization. Thirty Nordic Red cows were offered 5 experimental diets containing regrowth silages, crimped barley, and canola meal in replicated incomplete 5 x 4 Latin squares with four 21-d periods consisting of 14 d of feed adaptation and 7 d of sampling. Four second-cut silage diets were examined in a 2 x 2 factorial arrangement, enabling evaluation of effect of harvest time of the early or late first cut on second-cut silages, short or long regrowth interval within second cut, and their interaction on dairy cow performance. The third-cut silage diet harvested from early first cut and short regrowth interval of second-cut ley was compared with the second-cut silage diets to evaluate the difference in dairy cow performance between second- and third-cut silages. Postponing the first cut and extending the regrowth interval decreased dry matter intake (DMI), energy-corrected milk (ECM) yield, nutrient digestibility, and urinary energy output, but improved N efficiency (milk N/N intake). Postponing the first cut also decreased the efficiency of metabolizable energy use for lactation, but increased CH4 yield (CH4/DMI). Extending the regrowth interval decreased feed efficiency (ECM/DMI) and increased CH4 intensity (CH4/ECM). Thus, feeding regrowth silages in 2- or 3-cut systems harvested after an early first cut and short regrowth interval promoted better dairy performance and feed intake, and higher efficiency of feed and energy utilization, but with poorer N efficiency. Feeding third-cut silage improve milk yield and feed efficiency compared with second-cut silages.

Keywords

dairy cow; feed efficiency; grass silage; harvesting strategy

Published in

Journal of Dairy Science
2021, volume: 104, number: 1, pages: 367-380
Publisher: ELSEVIER SCIENCE INC

SLU Authors

  • Pang, Degong

    • Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences

  • Krizsan, Sophie Julie

    • Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences

UKÄ Subject classification

Animal and Dairy Science

Publication identifier

  • DOI: https://doi.org/10.3168/jds.2020-18888

Permanent link to this page (URI)

https://res.slu.se/id/publ/110160