PMID- 19164663
OWN - NLM
STAT- MEDLINE
DCOM- 20090209
LR  - 20181217
IS  - 1525-3198 (Electronic)
IS  - 0022-0302 (Linking)
VI  - 92
IP  - 2
DP  - 2009 Feb
TI  - Somatotropic axis components and nutrient partitioning in genetically diverse 
      dairy cows managed under different feed allowances in a pasture system.
PG  - 526-39
LID - 10.3168/jds.2008-1421 [doi]
AB  - The somatotropic axis [including growth hormone (GH), GH receptor, and 
      insulin-like growth factor (IGF)-I] is uncoupled in high-producing cows in early 
      lactation so that the liver fails to respond to GH and produces less IGF-I. This 
      uncoupling was implicated in the process of nutrient partitioning, enabling high 
      milk production. Different genetic selection goals may affect functional 
      components of the somatotropic axis. Thus, the somatotropic axis was examined in 
      diverse genetic strains of dairy cows [North American Holstein 1990 (NA90), New 
      Zealand Holstein-Friesian 1990 (NZ90), and New Zealand Holstein-Friesian 1970 
      (NZ70)] that were managed similarly within a pasture-based system but were 
      offered feed allowances commensurate with their genetic ability to produce milk. 
      The NA90 cows produced more milk (26.2 +/- 0.3, 24.1 +/- 0.3, and 20.1 +/- 0.4 
      kg/d, for NA90, NZ90, and NZ70, respectively), but had lower milk fat percentages 
      (4.28 +/- 0.03, 4.69 +/- 0.03, and 4.58 +/- 0.04 kg/d for NA90, NZ90, and NZ70, 
      respectively) compared with both NZ strains. Milk protein percentages (3.38 +/- 
      0.02, 3.52 +/- 0.02, and 3.29 +/- 0.03 kg/d for NA90, NZ90, and NZ70, 
      respectively) were greater for NZ90 cows. During early lactation (wk 2 to 6), the 
      total net energy produced in milk was greater in NA90 compared with NZ90 or NZ70 
      cows, but total net energy in milk after wk 6 was equivalent for NA90 and NZ90 
      cows. The greater milk production in early lactation in NA90 cows was associated 
      with lower body condition scores (BCS; 1 to 10 scale; 4.0 +/- 0.1) elevated blood 
      GH concentrations (1.6 +/- 0.1 ng/mL), and low blood IGF-I concentrations (14.8 
      +/- 1.1 ng/mL), indicating an uncoupled somatotropic axis. In comparison, the 
      NZ70 cows retained a coupled somatotropic axis during early lactation, 
      maintaining greater BCS (4.6 +/- 0.1), lower blood GH (0.7 +/- 0.1 ng/mL), and 
      greater blood IGF-I (21.9 +/- 1.2 ng/mL). The degree of uncoupling in NZ90 cows 
      was intermediate between the other 2 strains. Additional feed allowance failed to 
      change blood IGF-I concentrations in NA90 cows but increased IGF-I concentrations 
      in NZ90 cows (20.9 +/- 1.4 and 13.2 +/- 1.4 ng/mL for the high and low feed 
      allowance, respectively). Furthermore, additional feed allowance in NZ90 cows 
      lessened BCS loss in early lactation, but did not affect BCS loss in NA90 cows. 
      Functional components of the somatotropic axis differed for the respective 
      strains and were consistent with strain differences in milk production, BCS, and 
      feed allowance.
FAU - Lucy, M C
AU  - Lucy MC
AD  - Department of Animal Sciences, University of Missouri, Columbia 65211, USA. 
      lucym@missouri.edu
FAU - Verkerk, G A
AU  - Verkerk GA
FAU - Whyte, B E
AU  - Whyte BE
FAU - Macdonald, K A
AU  - Macdonald KA
FAU - Burton, L
AU  - Burton L
FAU - Cursons, R T
AU  - Cursons RT
FAU - Roche, J R
AU  - Roche JR
FAU - Holmes, C W
AU  - Holmes CW
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Dairy Sci
JT  - Journal of dairy science
JID - 2985126R
RN  - 0 (Fats)
RN  - 0 (Hormones)
RN  - 0 (Milk Proteins)
RN  - J2B2A4N98G (Lactose)
SB  - IM
MH  - *Animal Nutritional Physiological Phenomena
MH  - Animals
MH  - Body Constitution/physiology
MH  - Cattle/*physiology
MH  - Dairying/*methods
MH  - Fats/analysis
MH  - *Feeding Methods
MH  - Female
MH  - Hormones/blood
MH  - Lactation
MH  - Lactose/analysis
MH  - Least-Squares Analysis
MH  - Milk/chemistry/metabolism
MH  - Milk Proteins/analysis
EDAT- 2009/01/24 09:00
MHDA- 2009/02/10 09:00
CRDT- 2009/01/24 09:00
PHST- 2009/01/24 09:00 [entrez]
PHST- 2009/01/24 09:00 [pubmed]
PHST- 2009/02/10 09:00 [medline]
AID - S0022-0302(09)70357-1 [pii]
AID - 10.3168/jds.2008-1421 [doi]
PST - ppublish
SO  - J Dairy Sci. 2009 Feb;92(2):526-39. doi: 10.3168/jds.2008-1421.