The Evaluation of Vitamin A & Bet-Carotene Levels during Postpartum Period in Semi Industrial Dairy Farms in Iran

Abstract. Vitamin A, retinol, plays a vital role in vision sense. Due to the presence of large amounts of beta-carotene in cattle's foods & vitamin A stores in liver, the hypovitaminosis is not probable. Increased secretion of vitamin A in milk during postpartum period increases the risk of hypovitaminosis occurrence in cattle's feed on poor beta- carotene nutrition. The aim of this study was to evaluate the value of vitamin A & beta-carotene during postpartum period in some semi – industrial farms with poor beta-carotene based nutrition in Ghaemshahr – Iran.Keywords: Vitamin A, hypovitaminosis, bet-carotene levels during postpartum period

Material & methods: Blood samples were obtained from 88 dairy cows during postpartum period. The samples were centrifuged and froze pa at -20 C. To prevent direct contact of samples with air and light, serum were preserved at dark pockets. Cows were classified at 9 groups based on postpartum period ( 1,2,3,4,5,6,7,8,9 month after parturition).Vitamin A & beta-carotene were determined by spectrophotometric method .

Results: The mean value of vitamin A & beta-carotene were 38.06±9.16 µg/dl & 33.8±9.74 µg/dl respectively. The mean value of vitamin A in 1,2,3,4,5,6,7,8,9 month postpartum were 33.98±7.26 , 29.51±3.5 , 35.23±1.44 , 37.20±7.62 , 38.74±9.06 , 38.09±8.20 , 39.91±6.96 , 42.89±4.87 , 46.05±5.01 respectively . The mean value of beta-carotene in 1,2,3,4,5,6,7,8,9 month postpartum were 37.02±3.45 , 40.17±1.56 , 26.79±3.40 , 40.29±6.26 , 18.07±4.02 , 36.15±3.6 , 59.61±8.36 , 36.31±7.31, 31.11±8.19 respectively . Discussion: The mean value of vitamin A was normal in spite of consumption of poor beta- carotene based nutrition. It might be due to high level of liver stores. There were not significant differences in mean vitamin A during postpartum period. The mean beta-carotene was lower than reference ranges during post partum period. The decreased level of beta-carotene indicates the nutritional deficiency of beta-carotene. 

Introduction

  Vitamin A is an essential vitamin for sight, bone & muscle growth, protection of the integrity of epithelial cells, immune cell functions, gene arrangement, and normal reproductive activity in cows (1-5). The clinical signs of vitamin A deficiency towards the end of pregnancy are abortion, RP, night blindness, diarrhea and an increase in the number of dead, blind, weak and sick calves (2,4). Persistence of vitamin A deficiency after parturition may decrease the conception rate (5). An adult cow needs 76 IU of vitamin A/kg/d in the diet in order to maintain its normal reproductive function (4).β-carotene, the precursor of vitamin A, shows antioxidant effect and influences reproductive and thyroid functions (6). One mg of β-carotene is equivalent to 400 IU of vitamin A (5,4). Β carotene deficiency in cows prolongs the estrus period, delays ovulation, increases abortions and early embryonic death rates, weakens the estrus signs, increases ovarian cysts, RP and metritis risk, increases delivery rates of dead, weak, and blind calves and reduces fertility (2-6). An adult cow needs 0.18 mg of β-carotene/kg/d in order to maintain its normal reproductive functions (6). Vitamin Due to the presence of large amounts of beta-carotene in cattle's foods & vitamin A stores in liver, the hypovitaminosis is not provable. Increased secretion of vitamin A in milk during postpartum period increases the risk of hypovitaminosis occurrence in cattle's feed on poor beta- carotene nutrition. The aim of this study was to evaluate the value of vitamin A & beta-carotene during postpartum period in some semi – industrial farms with poor beta-carotene based nutrition in Ghaemshahr – Iran.

Material & Methods

The study was performed on 88 dairy cows during postpartum period, aged 2-9years, at the semi-industrial farms of ghaemshahr & Joibar in Iran. Jugular vein blood samples were collected into sterile containers between July till august 2007. The blood was centrifuged at 3000 r.p.m. for 20 min and sera were placed into sterile tubes and then frozen at –20°C. To prevent direct contact of samples with air and light, serum were preserved at dark pockets. Cows were classified at 9 groups based on postpartum period (1,2,3,4,5,6,7,8,9 month after parturition).Vitamin A & beta-carotene were determined by spectrophotometric method . 

Results

The serum vitamin A & Beta carotene values are given in Table 1 . The mean value of vitamin A & beta-carotene were 38.06±9.16 µg/dl & 33.8±9.74 µg/dl respectively. The mean value of vitamin A in 1,2,3,4,5,6,7,8,9 month postpartum were 33.98±7.26 , 29.51±3.5 , 35.23±1.44 , 37.20±7.62 , 38.74±9.06 , 38.09±8.20 , 39.91±6.96 , 42.89±4.87 , 46.05±5.01 respectively . The mean value of beta-carotene in 1,2,3,4,5,6,7,8,9 months postpartum were 37.02±3.45 , 40.17±1.56 , 26.79±3.40 , 40.29±6.26 , 18.07±4.02 , 36.15±3.6 , 59.61±8.36 , 36.31±7.31, 31.11±8.19 respectively . There were no significant differences in vitamin A & Beta carotene levels on different groups.

Table 1: The serum vitamin A & Beta carotene values during postpartum period

Discussion

It is well known that vitamin A and β-carotene deficiency causes negative impacts on fertility and increases RP incidence in cows. In addition, abortion, night blindness, increase in the birth of weak and sick calves, weakening the estrus symptoms, and delay in ovulation are other negative outcomes related to deficiency of vitamin A and β-carotene. Increased secretion of vitamin A in milk during postpartum period increases the risk of hypovitaminosis occurrence in cattle's feed on poor beta- carotene nutrition. Akar et al.(8) measured the vitamin A & Beta carotene levels at partitution & the days after till 4 weeks after . They found that there is a relationship between retained placenta and decreased level of vitamin A & Beta carotene. Michal et al. (21) found that vitamin A and β-carotene decreased at parturition  and tended to increase 1, 2, and 4 weeks postpartum. Johnston and Chew (19) reported that in non-mastitis cows, plasma vitamin A and β- carotene concentrations were decreased at calving (31and 230 μg/100 ml), but their levels increased 1, 2, and 4 weeks postpartum. Also, plasma β carotene levels in cows decreased in winter compared to the summer months; the levels also decreased during pregnancy, being the lowest during the last months of pregnancy and started to increase with the start of lactation(3).

Graves etal. Measure vitamin A & beta carotene postpartum for 4 weeks (Graves-Hoagland R.L., 1988). They found that Vitamin A & Beta carotene increased gradually after partitution. In this study the variation of vitamin A & beta carotene were determined through a long period during postpartum period. Our study demonstrated that semi-industrial farms are so high risk to hypovitaminosis. The mean value of vitamin A was normal in spite of consumption of poor beta- carotene based nutrition. It might be due to high level of liver stores. There were not significant differences in mean vitamin A during postpartum period. The mean beta-carotene was lower than reference ranges during post partum period. The decreased level of beta-carotene indicates the nutritional deficiency of beta-carotene. 

References

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