Document Detail

Extending lactation in pasture-based dairy cows. II: Effect of genetic strain and diet on plasma hormone and metabolite concentrations.
MedLine Citation:
PMID:  19620652     Owner:  NLM     Status:  MEDLINE    
Fifty-six genetically divergent New Zealand and North American Holstein-Friesian (HF) cows grazed pasture, and were offered 0, 3, or 6 kg of concentrate DM/cow per day for an extended lactation (605 +/- 8.3 d in milk; mean +/- standard error of the mean). Weekly blood samples collected from individual cows from wk 1 to 10 postpartum (early lactation), and from wk 47 to 63 postpartum (extended lactation) were analyzed for nonesterified fatty acids (NEFA), glucose, insulin, leptin, growth hormone (GH), insulin-like growth factor-I (IGF-I), calcium, and urea. During early lactation, NEFA and GH concentrations were greater and IGF-I concentrations were less, and increased at a slower rate in North American HF. During this 10-wk period, there were no strain effects on plasma glucose, leptin, insulin, or calcium. During the extended lactation period, North American HF had greater NEFA and GH concentrations; there were strain x diet interactions for insulin and leptin, and a tendency for a strain x diet interaction for glucose. These interactions were primarily due to greater plasma insulin, leptin, and glucose concentrations in the New Zealand HF fed 6 kg of concentrate DM/cow per day, a result of excessive body condition in this treatment. In this period, there was no strain effect on plasma IGF-I, calcium, or urea concentration. During early lactation, there was a linear increase in glucose and IGF-I, and a linear decrease in GH and urea with increasing concentrate in the diet. However, plasma calcium, NEFA, insulin, and leptin remained unchanged. During the extended lactation period, there was an effect of feed supplementation on GH and urea, which decreased linearly with increasing concentrate in the diet. There was, however, no supplementation effect on NEFA, calcium, or IGF-I. These data indicate potential strain differences in recoupling of the somatotropic axis, insulin resistance, and energy partitioning, and may help explain the physiology behind the previously reported greater milk production and body condition score loss in North American HF. The results have implications for breeding and diet management during an extended lactation.
J K Kay; C V C Phyn; J R Roche; E S Kolver
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of dairy science     Volume:  92     ISSN:  1525-3198     ISO Abbreviation:  J. Dairy Sci.     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-07-21     Completed Date:  2009-10-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2985126R     Medline TA:  J Dairy Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3704-13     Citation Subset:  IM    
DairyNZ Ltd., Private Bag 3221, Hamilton, 3240, New Zealand.
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MeSH Terms
Blood Glucose / analysis
Calcium / blood
Cattle / blood*,  genetics,  metabolism,  physiology*
Diet / veterinary*
Fatty Acids, Nonesterified / blood
Growth Hormone / blood
Insulin / blood
Insulin-Like Growth Factor I / analysis
Lactation / physiology*
Leptin / blood
Time Factors
Urea / blood
Reg. No./Substance:
0/Blood Glucose; 0/Fatty Acids, Nonesterified; 0/Leptin; 11061-68-0/Insulin; 57-13-6/Urea; 67763-96-6/Insulin-Like Growth Factor I; 7440-70-2/Calcium; 9002-72-6/Growth Hormone

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

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