Plasma Vitamin C Concentration is Not Related to the Incidence of Ketosis in Dairy Cows during the Early Lactation Period

Abstract

ABSTRACT. Many animals including cattle can synthesize vitamin C from glucose. The objective of this study was to investigate plasma vitamin C concentration in ketotic cows during the early lactation period because glucose supply for vitamin C synthesis might be limited in these cows. We measured plasma β -hydroxybutyrate (BHBA) concentration in 118 cows within 2 months after parturition. Subclinical/clinical ketosis was quantitatively determined using a plasma BHBA threshold of 1,200 µM. Plasma glucose concentration was lower in the ketotic cows than in the control cows but plasma vitamin C concentration did not differ between the control and the ketotic cows. Then we measured plasma vitamin C, BHBA and glucose levels in 7 cows during the periparturient period. Plasma BHBA increased and plasma glucose decreased after parturition but plasma vitamin C did not change. These results indicate that plasma vitamin C is not related to the incidence of ketosis in the early lactation period. We suggest that ketotic cows have the ability to produce vitamin C to meet its requirement in the early lactation period although glucose supply is not sufficient for milk production. Vitamin C synthesis is possibly given a high metabolic-priority for glucose in lactating cows.KEY WORDS: dairy cow, β -hydroxybutyrate, ketosis, vitamin C.

Relationship between Plasma Vitamin C and Serum Diagnostic Biochemical Markers in Lactating Cows

“…These cows consisted of cows diagnosed as ketosis and clinically normal cows in the same herds, which were used in our previous report [14]. Blood sample was collected once from the jugular vein of each cow within 2 months after parturition.…”

“…However, we reported that the incidence of ketosis did not affect the plasma vitamin C concentration in dairy cows during the early lactation period, suggesting that ketotic cows had the ability to produce vitamin C to meet its requirement although Glu supply was not sufficient for milk production [14]. On the other hand, this report indicated that the averaged plasma vitamin C concentration was approximately 16 µM in the lactating cows [14]. Furthermore, the plasma vitamin C concentration differed largely among the cows (ranged from 6 to 28 µM) and the plasma vitamin C concentration was lower than 10 µM in 17 cows of 118 cows (Unpublished data).…”

“…Thus, lactating cows were suggested to have a decreased synthesis of vitamin C resulting from the shortage of Glu, especially in the early lactation period [11]. However, we reported that the incidence of ketosis did not affect the plasma vitamin C concentration in dairy cows during the early lactation period, suggesting that ketotic cows had the ability to produce vitamin C to meet its requirement although Glu supply was not sufficient for milk production [14]. On the other hand, this report indicated that the averaged plasma vitamin C concentration was approximately 16 µM in the lactating cows [14].…”

“…Although the reference level of plasma vitamin C concentration has not been clarified, the plasma vitamin C concentration in healthy lactating cows is 19µM in the report of Weiss [25] or 20 µM in the report of Hidiroglou [5] and Padilla et al [15]. Therefore, it was postulated that some factors decreased plasma vitamin C concentration in the cows that we used previously [14]. We determined the relationship between circulating vitamin C level and some diagnostic biochemical markers in the early lactating cows.…”

L-Ascorbic acid (vitamin C) supplementation to optimize health and reproduction in cattle

“…However, few authors do not approve this hypothesis. Padilla et al (2005) observed that even ketotic cows have the ability to produce sufficient vitamin C and concluded that vitamin C synthesis is possibly given a high-metabolic priority. Santos et al (2001) also reported that high milk production in cattle is not associated with decrease in the plasma Vitamin C level.…”