Abstract

An experiment was conducted to quantify the effects of incremental levels of heat-moisture-treated canola meal (TCM) fed to dairy cows on the relationship between ruminal nutrient digestion and milk production. Experimental diets were fed to 4 multiparous rumencannulated Nordic Red cows, averaging (mean standard deviation) 681 +/- 54.8 kg of body weight, 111 +/- 16 d in milk, and 29.1 +/- 9.1 kg of milk/d at the start of the study, in a Latin square design with four 21-d periods. The 4 experimental dietary treatments consisted of a basal diet of grass silage and crimped barley, and 3 diets in which the crimped barley was replaced with TCM, giving 3 incremental levels of protein supplementation. Nutrient flow was quantified by the omasal sampling technique using 3 markers (Cr, Yb, and indigestible neutral detergent fiber). Continuous infusion of N-15 was used to label bacterial crude protein. Additionally, ruminal sampling and evacuations and measurements of total-tract digestibility were conducted. The experimental diets provided 132, 148, 164, and 180 g of crude protein/kg of dry matter. The increased level of TCM linearly increased dry matter intake from 15.1 to 16.6 kg/d and energy-corrected milk yield from 21.0 to 25.6 kg/d. The increased proportion of TCM when substituting barley with TCM was associated with greater total-tract digestibility of neutral detergent fiber and potentially digestible neutral detergent fiber, which could be explained by increased digestion rate of potentially digestible neutral detergent fiber. Omasal flow of nonammonia N naturally increased with greater dietary TCM inclusion, but the increased intestinal supply of rumen-undegradable protein was partly offset by diminished microbial protein synthesis when feeding more TCM. This was also reflected in a decreased proportion of milk protein from ruminal bacterial protein when TCM supplementation increased.

Keywords

canola meal; dairy cow; microbial protein; milk protein

Published in

Journal of Dairy Science
2017, Volume: 100, number: 10, pages: 8004-8017
Publisher: ELSEVIER SCIENCE INC

SLU Authors

• Krizsan, Sophie Julie

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

• Gidlund, Helena

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

• Fatehi, Farhang

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

• Huhtanen, Pekka

  • 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.2017-12625

Permanent link to this page (URI)

https://res.slu.se/id/publ/92779