Effect of feeding different sources of rumen-protected methionine on milk production and N-utilization in lactating dairy cows
- 1 April 2011
- journal article
- research article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 94 (4), 1978-1988
- https://doi.org/10.3168/jds.2010-3578
Abstract
Objectives of this study were to quantify production responses of lactating dairy cows to supplying absorbable Met as isopropyl-2-hydroxy-4-(methylthio)-butanoic acid (HMBi), or rumen-protected Met (RPM, Smartamine M; Adisseo, Alpharetta, GA) fed with or without 2-hydroxy-4-(methylthio)-butanoic acid (HMB), and to determine whether Met supplementation will allow the feeding of reduced dietary crude protein (CP). Seventy cows were blocked by parity and days in milk into 14 blocks and randomly assigned within blocks to 1 of the 5 dietary treatments based on alfalfa and corn silages plus high-moisture corn: 1 diet with 15.6% CP and no Met source (negative control); 3 diets with 15.6% CP plus 0.17% HMBi, 0.06% RPM + 0.10% HMB, or 0.06% RPM alone; and 1 diet with 16.8% CP and no Met supplement (positive control). Assuming that 50% of ingested HMBi was absorbed from the gastrointestinal tract and 80% of the Met in RPM was absorbed at intestine, the HMBi and RPM supplements increased metabolizable Met supply by 9 g/d and improved the Lys:Met ratio from 3.6 to 3.0. After a 2-wk covariate period during which all cows received the same diet, cows were fed test diets continuously for 12 wk. Diet did not affect dry matter intake (mean ± SD, 25.0±0.3 kg/d), body weight gain (0.59±0.2 kg/d), or milk yield (41.7±0.6 kg/d). However, feeding HMBi increased yield of energy-corrected milk and milk content of protein and solids-not-fat. Moreover, trends were observed for increased milk fat content and yield of fat and true protein on all 3 diets containing supplemental Met. Apparent N efficiency (milk N/N intake) was highest on the RPM treatment. Feeding 16.8% CP without a Met source elevated milk urea N and urinary excretion of urea N and total N and reduced apparent N efficiency from 34.5 to 30.2%, without improving production. Overall results suggested that feeding HMBi or RPM would give similar improvements in milk production and N utilization.Keywords
Funding Information
- US Dairy Forage Center Research Farm
This publication has 41 references indexed in Scilit:
- Effect of dietary protein concentration and degradability on response to rumen-protected methionine in lactating dairy cowsJournal of Dairy Science, 2009
- Effect of Supplementing Rumen-Protected Methionine on Production and Nitrogen Excretion in Lactating Dairy CowsJournal of Dairy Science, 2008
- Milk Production During the Complete Lactation of Dairy Cows Fed Diets Containing Different Amounts of ProteinJournal of Dairy Science, 2000
- USE OF PROTECTED METHIONINE (MEPRON M 85) IN CATTLEActa Veterinaria Hungarica, 1999
- Effects of dl-methionine hydroxyanalogue (MHA) or dl-methionine (dl-Met) on N-retention in broiler chickens and pigsAnimal Feed Science and Technology, 1999
- Protected proteins and amino acids for ruminantsPublished by Wiley ,1995
- Milk production and composition as a function of postruminal lysine and methionine supply: a nutrient-response approachLivestock Production Science, 1993
- Determination of protein degradation rates using a rumen in vitro system containing inhibitors of microbial nitrogen metabolismBritish Journal of Nutrition, 1987
- Dry Matter Level Effects on Alfalfa Silage Quality I. Nitrogen TransformationsTransactions of the ASAE, 1987
- Differential analyses of glyoxylate derivativesAnalytical Biochemistry, 1970