|NELSON, CORWIN - University Of Florida|
|POWELL, TESSI - University Of Florida|
|DREWNOSKI, MARY - University Of Nebraska|
|O'NEILL, MATTHEW - Iowa State University|
|BEITZ, DONALD - Iowa State University|
|WEISS, WILLIAM - The Ohio State University|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/2016
Publication Date: 12/1/2016
Publication URL: http://handle.nal.usda.gov/10113/5564784
Citation: Nelson, C.D., Lippolis, J.D., Reinhardt, T.A., Sacco, R.E., Powell, T.L., Drewnoski, M.E., O'Neill, M., Beitz, D.C., Weiss, W.P. 2016. Vitamin D status of dairy cattle: Outcomes of current practices in the dairy industry. Journal of Dairy Science. 99:10150-10160.
Interpretive Summary: Vitamin D is a critical component to the diet of dairy cattle. This work tests whether current recommendations and practices for supplemental vitamin D are meeting the nutritional needs of dairy cattle. The vitamin D status of animals is indicated by the concentration of the 25-hydroxyvitamin D (25OHD) metabolite in the serum. The serum concentration of 702 samples collected from cows across various stages of lactation, management practices, and locations in the US was determined. In the majority of cases current vitamin D supplementation results in sufficient serum vitamin D levels. However, newborn calves and calves fed milk without supplemental vitamin D are prone to deficiency.
Technical Abstract: The need for vitamin D supplementation of dairy cattle has been known for the better part of the last century and is well-appreciated by dairy producers and nutritionists. Whether current recommendations and practices for supplemental vitamin D are meeting the needs of dairy cattle, however, is not well known. The vitamin D status of animals is reliably indicated by the concentration of the 25-hydroxyvitamin D [25(OH)D] metabolite in serum or plasma with a concentration of 30 ng/mL proposed as a lower threshold for sufficiency. The objective of this study was to determine the typical serum 25(OH)D concentrations of dairy cattle across various dairy operations. The serum 25(OH)D concentration of 702 samples collected from cows across various stages of lactation, management practices, and locations in the U.S. was 68 ± 22 ng/mL (mean ± SD) with the majority of samples between 40 and 100 ng/mL. Most of the 12 herds surveyed supplemented cows with 30,000 IU to 50,000 IU of vitamin D3/d and average serum 25(OH)D of cows at 100 to 300 DIM in each of those herds was near or above 70 ng/mL. In contrast, average serum 25(OH)D of a herd supplementing with 20,000 IU/d, was 42 ± 15 ng/mL with 22% below 30 ng/mL. Cows in early lactation (0 to 30 DIM) also had lower serum 25(OH)D than mid to late lactation cows (57 ± 17 ng/mL vs. 71 ± 20 ng/mL, respectively). Serum 25(OH)D of yearling heifers receiving 11,000 to 12,000 IU of vitamin D3/d was near that of cows at 76 ± 15 ng/mL. Serum 25(OH)D concentrations of calves, on the other hand, was 15 ± 11 ng/mL at birth and remained near or below 15 ng/mL through 1 month of age if they were fed pasteurized waste milk with limited summer sun exposure. In contrast, serum 25(OH)D of calves fed milk replacer containing 6,600 and 11,000 IU vitamin D2/kg DM were 59 ± 8 and 98 ± 33 ng/mL, respectively, at 1 month of age. Experimental data from calves similarly indicated that serum 25(OH)D achieved at approximately 1 month of age would increase 6 to 7 ng/mL for every 1,000 IU of vitamin D3/kg DM of milk replacer. In conclusion, vitamin D status of dairy cattle supplemented with vitamin D3 according to typical practices is, for the most part, sufficient as defined by serum 25(OH)D concentrations. However, newborn calves and calves fed milk without supplemental vitamin D3 are prone to deficiency.