Document Detail

Undegradable protein supplementation to early-lactation dairy cows in grazing conditions.
MedLine Citation:
PMID:  11467808     Owner:  NLM     Status:  MEDLINE    
To determine the production responses to rumen undegradable protein (RUP) feeding in grazing conditions, we fed 18 multiparous Holstein cows concentrates containing either soybean meal (SBM) or blood meal (BM) during the first 8 wk of lactation. One cow from the SBM treatment was removed because of mastitis. Six additional dairy cows in late lactation fitted with ruminal cannula were used to evaluate the rumen environment and the in situ crude protein (CP) degradability of concentrates. On a dry matter (DM) basis, concentrates contained SBM (33%) or BM (13%), corn grain (64 and 84% for SBM and BM, respectively) and a mineral-vitamin complex (3%). Concentrates were offered at a rate of 6.6 kg/d per cow and herbage allowance averaged 31 kg/d of DM per cow. The BM reduced ruminal ammonia-N levels and had no effect on ruminal pH and molar volatile fatty acid concentration. The degradable fraction (63.59 vs. 22.46%) and the rate of disappearance of the CP (9.68 vs. 1.69%/h) were greater for the SBM compared with the BM concentrate. Cows fed the BM concentrate produced more milk (29.3 vs. 24.9 kg/d) and more milk protein (0.85 vs. 0.74 kg/d) than did those fed the SBM concentrate. Milk fat yield and percentages of milk fat, lactose and protein were not affected. Forage DMI was increased by BM (17.19 vs. 13.17 kg/d per cow). The in vivo responsiveness to lipolytic stimuli were increased by BM but enhanced body weight loss or higher plasma nonesterified fatty acids concentration were not observed. Results indicated that a concentrate with a high RUP content increased milk and milk protein yields when spring pasture was the sole forage. The highest milk yield was more likely caused by increased DM than by enhanced body lipid mobilization.
A Schor; G A Gagliostro
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of dairy science     Volume:  84     ISSN:  0022-0302     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  2001 Jul 
Date Detail:
Created Date:  2001-07-24     Completed Date:  2001-12-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1597-606     Citation Subset:  IM    
Facultad de Agronomía, University of Buenos Aires, Argentina.
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MeSH Terms
Animal Feed
Cattle / metabolism,  physiology*
Dietary Proteins / administration & dosage*,  metabolism
Dietary Supplements
Lactation / physiology*
Milk / chemistry*
Milk Proteins / analysis
Rumen / metabolism*
Time Factors
Reg. No./Substance:
0/Dietary Proteins; 0/Milk Proteins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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