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Effect of replacing organic grass-clover silage from primary growth with regrowth on N digestion in dairy cows

Naadland, Sondre Stokke; Steinshamn, Håvard; Krizsan, Sophie Julie and Randby, Åshild T. (2016) Effect of replacing organic grass-clover silage from primary growth with regrowth on N digestion in dairy cows. Animal Feed Science and Technology, 220, pp. 57-66.

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Summary

Clover proportions, and thereby chemical composition of herbage, differ between primary growth (PG) and regrowth (RG) in organic managed grass-clover fields. The characteristics of PG and RG silages suggest different supplementary feeding strategies to sustain an efficient milk production in dairy cows. Silage made of the RG generally offers more crude protein (CP) in the diet than silage made of the PG because of an increasing proportion of clover later in the season. Additionally, grass and clover have different amino acid (AA) profiles. His has been suggested to be the first limiting AA in grass silage, while Met has been suggested to be the primarily limiting AA in red clover silage. Eight rumen cannulated Norwegian Red cows were used in two replicated 4 × 4 Latin squares with 21-days periods. Organic PG and RG silages were fed ad libitum in four diets with RG replacing PG silage in ratios of 0, 0.33, 0.67 and 1 on dry matter (DM) basis. Changing RG silage proportions from 0 to 1 increased daily CP intake from 2.90 to 3.08 kg and rumen NH3-concentrations from 4.9 to 8.4 mmol/L, but did not promote a better protein supply. Neither total ruminal outflow of AA nor the AA profile in the small intestine differed between dietary treatments. Met and His were probably the most limiting AA for a higher milk production. Limitations by His may be more related to diets based on PG, while production by cows fed diets based on more RG herbage were more likely limited by Met.


EPrint Type:Journal paper
Keywords:Dairy cows, Nitrogen, Grass-clover, Organic milk production, Regrowth
Subjects: Animal husbandry > Production systems > Dairy cattle
Animal husbandry
Animal husbandry > Feeding and growth
Research affiliation: Norway > NMBU - Norwegian University of Life Sciences
Norway > NIBIO – Norwegian Institute of Bioeconomy Research
Sweden > Swedish University of Agricultural Sciences (SLU) > Agricultural Research for Northern Sweden
DOI:10.1016/j.anifeedsci.2016.07.012
Deposited By: Steinshamn, Dr Håvard
ID Code:30593
Deposited On:16 Dec 2016 09:58
Last Modified:16 Dec 2016 09:58
Document Language:English
Status:Published
Refereed:Peer-reviewed and accepted

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