Effects of ruminally protected methionine and/or phenylalanine on performance of high producing Holstein cows fed rations with very high levels of canola meal

Show simple item record

dc.contributor.author Swanepoel, Nadia
dc.contributor.author Robinson, P.H.
dc.contributor.author Erasmus, L.J. (Lourens Jacobus)
dc.date.accessioned 2016-04-14T07:36:08Z
dc.date.issued 2015-07
dc.description.abstract Canola meal is the second largest protein feed in the Northern latitudes and inclusion levels in dairy rations are expected to increase due to projected large increases in production of canola seed in Canada. However, a recent study (Swanepoel et al. 2014) showed that even though higher inclusions of canola meal (CM) had a positive effect on production when CM directly substituted for high protein corn based dried distillers grains (DDG), that there was an optimum point at 120 to 135 g/kg of diet dry matter (DM) after which animal performance seemed to decline. Only the amino acids (AA), methionine (Met), phenylalanine (Phe) and leucine (Leu) could have limited production based upon plasma AA concentrations at the highest CM inclusion level. Our objective was to determine if either Met or Phe, or both, was limiting performance of early lactation dairy cows fed a ration containing 180 g/kg of diet DM as CM, by supplementing a calculated target of 7.5 g of intestinally absorbable Phe/cow/d and/or 8.0 g of intestinally absorbable Met/cow/d in ruminally protected (RP) forms to four pens of ~320 early lactation cows/pen in a 4 x 4 Latin square with 28 d experimental periods. Dry matter intake was not affected (avg: 27.6 +/- 0.4 kg/d) by feeding either of the RP AA, or the combination. Phenylalanine supplementation alone had no effect on milk production or composition, and body condition score (BCS) change compared to Control. Supplemental Met alone modestly increased (P<0.01) milk protein and fat content, while decreasing (P<0.01) milk lactose content and yield, but with no impact on BCS change compared to Control. Combination Met and Phe supplementation decreased milk and lactose yields, as well as lactose content (P<0.01), while increasing milk protein content and the BCS change (P<0.01). Urine volume (avg: 16.7 +/- 0.31 L/d) and flow of microbial protein (MCP) from the rumen (avg: 2092 +/- 52.7 g CP/d) were not affected by any treatment. Plasma Met levels increased (P<0.01) with both Met treatments and plasma tryptophan (Trp) levels decreased (P<0.01) with both Phe treatments. However, plasma Phe levels did not change with any treatment. Results are interpreted to suggest that delivery of Met with RP Met feeding was higher than animal requirements and caused an oversupply of Met. Addition of Phe to the Met supplementation changed the way energy was utilized by the cows, redirecting energy liberated by Met from milk components toward BCS gain. It remains unclear if Phe was limiting in the Control ration or if RP Phe was not fed at high enough levels to have a measurable response on production. However, it is clear that AA limitations, requirements and production responses are governed by much more than plasma AA levels. Results further suggest that AA are bioactive metabolites to the extent that they can change animal performance, even when they are not „limiting‟ per se, and that their supplementation to practical dairy cattle diets should be approached with extreme caution for this reason. Keywords: Spot urine purine; Estimated microbial flow; Plasma amino acids; Protein feeding. Abbreviations: AA, amino acid; ADF, acid detergent fiber; ADICP, AD insoluble CP; ADIN, acid detergent insoluble N; AL, allantoin; aNDF, amylase-treated NDF; aNDFom, aNDF free of residual ash; BCS, body condition score; BCAA, branched-chain AA; BW, body weight; CM, canola meal; CP, crude protein; CR, creatinine; DC305, DairyComp 305 management system; DDG, dried distillers grains; DHIA, Dairy Herd Improvement Association; DIM, days in milk; DM, dry matter; MCP, microbial CP; NDF, neutral detergent fiber; NEL, net energy for lactation; OM, organic matter; PD, purine derivatives; RDP, rumen degradable CP; RP, rumen protected; SCC, somatic cell count; SG, specific gravity; TMR, total mixed ration; TP, true protein. en_ZA
dc.description.department Animal and Wildlife Sciences en_ZA
dc.description.embargo 2016-07-31
dc.description.librarian hb2016 en_ZA
dc.description.uri http://www.elsevier.com/locate/anifeedsci en_ZA
dc.identifier.citation Swanepoel, N, Robinson, PH & Erasmus, LJ 2015, 'Effects of ruminally protected methionine and/or phenylalanine on performance of high producing Holstein cows fed rations with very high levels of canola meal', Animal Feed Science and Technology, vol. 205, pp. 10-22. en_ZA
dc.identifier.issn 1367-9430 (print)
dc.identifier.issn 1469-1795 (online)
dc.identifier.other 10.1016/j.anifeedsci.2015.04.002
dc.identifier.uri http://hdl.handle.net/2263/51996
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2015 Elsevier B.V. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Animal Feed Science and Technology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Animal Feed Science and Technology, vol. 205, pp.10-22, 2015. doi : 10.1016/j.anifeedsci.2015.04.002. en_ZA
dc.subject Spot urine purine en_ZA
dc.subject Estimated microbial flow en_ZA
dc.subject Plasma amino acids en_ZA
dc.subject Protein feeding en_ZA
dc.subject Canola meal (CM) en_ZA
dc.subject Dried distillers grains (DDG) en_ZA
dc.subject Amino acids (AA) en_ZA
dc.subject Methionine (Met) en_ZA
dc.subject Phenylalanine (Phe) en_ZA
dc.subject Leucine (Leu) en_ZA
dc.title Effects of ruminally protected methionine and/or phenylalanine on performance of high producing Holstein cows fed rations with very high levels of canola meal en_ZA
dc.type Postprint Article en_ZA


Files in this item

This item appears in the following Collection(s)

Show simple item record