Milk urea-nitrogen negatively affected first-service breeding success in commercial dairy cows in Prince Edward Island, Canada.
Our objective of this study was to investigate the relationship between milk urea-nitrogen concentrations ([MUN]) and first-service breeding success (FSBS) in a large number of commercial dairy herds, using various timings on [MUN]. All commercial dairy herds in Prince Edward Island on monthly milk testing (n=198) formed the sampling frame. Milk components, [MUN], 24-h milk production, and breeding data for all cows from these farms were gathered electronically from a central database. A first service between 1 June 1999 and 31 May 2000 was classified successful (FSBS=1) if it was the cow's last service and she calved 270-290 d later. Mixed logistic-regression modeling was used to determine the association between FSBS (the outcome variable) and the [MUN] closest to first service, controlling for other possible confounders and clustering effects of cows within the study herds. The final dataset included 2787 successful and 3015 unsuccessful first services. A change in [MUN] on the test closest to first service from 10 to 20 mg/dL was associated with a 13.9% reduction in the odds of FSBS (controlled for parity, milk production and days in milk).
Arunvipas
P
P
Department of Large Animals and Wildlife Clinical Science, Kasetsart University, KamPhaengSaen Campus, NakhonPathom 73140, Thailand.
Vanleeuwen
J A
JA
Dohoo
I R
IR
Leger
E R
ER
Keefe
G P
GP
Burton
A S
AS
Lissemore
K D
KD
D000818:Animals; D001947:Breeding; D002417:Cattle / Q000502:physiology*; D003612:Dairying; D005260:Female; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis*; D011247:Pregnancy; D018873:Pregnancy Rate; D011325:Prince Edward Island / Q000453:epidemiology; D014508:Urea / Q000032:analysis*
D014508:Urea; D009584:Nitrogen