Seasonal variation in vitamin D status of beef cattle reared in the central United States.
The objective was to retrospectively measure seasonal sunlight-associated variation in serum concentrations of 25-hydroxyvitamin D (25OHD) in beef cattle. The concentration of 25OHD was measured in crossbred animals born from March to May in 2011 and 2012. Vitamin D status 2 to 3 mo after birth (period 1) was only available for 2012 calves and was measured in June 2012. Period 1 animals had serum 25OHD concentrations of 26.3 ± 1.5 ng/mL. The 25OHD concentrations for late summer (period 2) were 46.6 ± 1.4 and 51.0 ± 1.5 ng/mL for 2011 and 2012, respectively. Serum concentration of 25OHD in early fall (period 3) were 63.8 ± 1.4 and 55.2 ± 1.5 ng/mL for calves in 2011 and 2012, respectively. Values observed for both late summer and early fall indicated vitamin D sufficiency (P < 0.001) compared with period 1. With diminishing exposure to ultraviolet B and consuming ∼800 IU or 1800 IU (2011 and 2012, respectively) of supplemental vitamin D, the calves' midwinter (period 4) 25OHD concentrations fell to 15.2 ± 1.6 and 16.7 ± 1.5 ng/mL for 2011 and 2012, respectively, after 4 to 5 mo on a finishing diet (P < 0.0001). This is considered vitamin D insufficiency in most species. Results indicate that calves are marginally sufficient to insufficient for vitamin D based on serum 25OHD concentrations soon after birth and during winter. Some individual animals would be classified vitamin D deficient. In the absence of sufficient UVB exposure, the dietary vitamin D requirements for rapidly growing beef cattle may need to be increased.
USDA, ARS, National Animal Disease Center, Ames, IA 50010, USA.
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E
Casas
USDA, ARS, National Animal Disease Center, Ames, IA 50010, USA.
J D
JD
Lippolis
USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933, USA.
L A
LA
Kuehn
USDA, ARS, National Animal Disease Center, Ames, IA 50010, USA. Electronic address: Tim.Reinhardt@ARS.USDA.GOV.
T A
TA
Reinhardt
D000818:Animals; D002417:Cattle / Q000097:blood*; D002418:Cattle Diseases / Q000453:epidemiology; D019587:Dietary Supplements; D009751:Nutritional Requirements; D009752:Nutritional Status; D012621:Seasons; D014466:Ultraviolet Rays; D014481:United States; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology / Q000662:veterinary
D014807:Vitamin D; C104450:25-hydroxyvitamin D
Beef cattle; Seasonal vitamin D; Vitamin D requirement; Vitamin D status