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Difference in the levels of Vitamin C between high versus low Producing Dairy Cows
By: Alecia P. Knapp, Advisor - J.H. Hampton
University of Wisconsin-Platteville Animal Science Department
Abstract
We hypothesize that high-producing dairy cows will have lower Vitamin C
concentrations versus low-producing dairy cows due to their bodies’ higher demand for glucose.
Lactating Holstein cows (n=40) were randomly selected from the University of Wisconsin
Platteville milking herd and assigned to either high production (HP; n=20) or low-production
(LP; n=20) group based on DHI predicted 305-day milk yields (Ag Cooperative Services). Cows
in the HP group had predicted 305-day milk yields ≥27,000 lbs. of milk while cows in the LP
group had predicted 305-day milk yields <26,999 lbs. of milk. Neither number of days in milk
(DIM) or lactation number were significant between groups (P =.3041; P=.1983). Serum samples
were used to measure Vitamin C concentrations using the Cayman Chemical Ascorbate Assay
kit. The average Vitamin C concentration for the HP group was 17.871.03 and the LP group
was 31.831.03 (P <0.0001). Results support previous studies, which showed that lactating cows
may not have enough dietary glucose to produce milk and also produce enough Vitamin C
(MacLeod, 1999). Further studies are necessary to determine if supplementation of glucose
increases Vitamin C concentrations in high producing dairy cows.
Introduction
Vitamin C (C6H8O6) is a water soluble vitamin with antioxidant properties. Some species,
such as humans, cannot manufacture their own, while others, including ruminants, can perform
biosynthesis of vitamin C. Vitamin C biosynthesis in ruminants occurs in the liver and process
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glucose. Because ruminants are able to produce their own vitamin C a dietary requirement has
yet to be determined. It is important that ruminants produce their own vitamin C as the bacteria
in the rumen break down a high majority of any dietary supplements of the vitamin.
Glucose is a precursor to both vitamin C and milk, so it is in high demand in the body of
a lactating dairy cow. Studies have shown that when a high producing dairy cow is lactating, her
body allocates glucose to milk production over that of Vitamin C, which can lead to a shortage of
Vitamin C.
A lactating dairy cow’s body is under a high level of stress, and antioxidants, such as
vitamin C, help to manage that stress level. When there is a shortage of vitamin C this reduces
the body’s ability to handle the stress from lactating, which can be measured via cortisol
concentrations. Cortisol is a glucocorticoid produced by the bovine adrenal gland and is released
in response to chronic stress. Cortisol increases coincident with peak lactation (40-60 days postcalving) in dairy cows (Sartin et al., 1988) indicating that during this time period cattle are under
greater stress. Previous studies have indicated that Vitamin C, an antioxidant, has the ability to
inhibit cortisol production (Montalvo et al., 2001). Thus, the effect of reduced vitamin C is
amplified in high-producing versus low-producing dairy cows, since high producing dairy cows
have higher blood concentrations of cortisol (Sartin et al., 1988).
We hypothesize that high-producing dairy cows will have lower Vitamin C
concentrations versus low-producing dairy cows due to their bodies’ higher demand for glucose.
Materials and Methods
All procedures were approved by the University of Wisconsin-Platteville Animal Care
and Use Committee. Lactating Holstein cows (n=40) were randomly selected from the
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University of Wisconsin Platteville milking herd and assigned to either high production (HP;
n=20) or low-production (LP; n=20) group based on DHI predicted 305-day milk yields (Ag
Cooperative Services). Cows in the HP group had predicted 305-day milk yields ≥27,000 lbs. of
milk while cows in the LP group had predicted 305-day milk yields <26,999 lbs. of milk.
Number of days in milk (DIM) ranged from 10-230, and lactation number ranged from 1st to 4th
lactation. All cattle were housed at the University of Wisconsin-Platteville Dairy Center in 2
adjacent free-stall pens and were provided a balanced TMR, free choice mineral mix, and water.
Blood was collected from the coccygeal vein at the underside of the base of the tail. All
samples were collected after morning milking, on the same day within four hours of each other.
SST 8.5 mL BD Vacutainers with clot activator were used. After collection the blood was
allowed to clot for approximately 30 minutes and then placed on ice. Samples were then
centrifuged within two hours of collection for 30 minutes at 1800 G. Serum was then separated
and put into deep well plates. Protocol was then followed to the point of sample storage for the
Cayman Chemical Ascorbate Assay kit. Samples were then stored at -80◦ C until they were
shipped to the Pennington Biomedical Research Center in Baton Rouge, Louisiana for the
completion of the assay.
Results
All statistical measures were performed using SAS. Average DIM = 102  7 days, and
was not significantly different between groups (P=0.3041). Average lactation number = 2.10.2,
and was not significantly different between groups (P=0.1983). Predicted 305-day milk averages
were 31,887± 606.23 lbs. of milk (HP) and 23,155±606.23 lbs. of milk (LP) and were
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significantly different (P <0.0001). Vitamin C concentration averages were significantly lower in
the HP group (17.87±1.03) than the LP group (31.83±1.03) with P<0.0001 (Figure 1).
Serum Ascorbic Acid Concentration (uM)
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Serum Ascorbic Acid Concentrations (mM) of High vs Low
Producing Dairy Cows
31.83282922
30
25
20
15
17.87122288
10
5
0
High
Low
Production Level
Figure 1: Serum Vitamin C levels in Lactating Dairy Cows with. High Production Mean =17.87
±1.03. Low Production Mean = 31.83 ±1.03 (P <0.0001)
Discussion
Our results support the hypothesis that high producing dairy cows have a lower vitamin C
due to reduced glucose availability. When both high and low producing dairy cows are feed the
same ration, the lower producing cows will use less of the glucose gained from their diet for
milk, leaving more left over for vitamin C production and other biological processes. Further
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research will need to be done comparing cortisol levels in high and low producing dairy cows to
see if there is a correlation with the vitamin C levels. Also, research can be done looking at
glucose supplementation and vitamin C levels in lactating dairy cows.
References
MacLeod, D. D., X. Zhang, L. Ozimeck and J. J. Kennelly. Ascorbyl-2-polyphosphate as a
source of ascorbic acid for dairy cattle. Milchwissenschaft. 1999. V54:123-129.
Montalvo, CP, NH Díaz, LA Galdames, ME Andrés, and RE Larraín. Short communication:
effect of vitamins E and C on cortisol production by bovine adrenocortical cells in vitro.
Journal of Dairy Science. 2011. V 94(7):3495-7
Sartin, JL, RJ Kemppainen, KA Cummins, and JC Williams. Plasma Concentrations of
Metabolic Hormones in High and Low Producing Dairy Cows. Journal of Dairy Science.
1988. V71 (3):650-657