ROLE OF VITAMIN E AND SELENIUM IN BOVINE REPRODUCTION
Soils according to geographical distribution in some areas of India are deficient in selenium.Therefore, crops grown on these soils also are low in selenium and produce deficiency diseases. As commercial dairy owners depend mostly on home grown grains, forages and less on purchased feed. Bio- availability of selenium after absorption through intestine to the animals depends mainly on physiological function. The relationship between nutrition and reproduction is of importance to dairy producers, veterinarians, feed producers and Extension workers, hence selenium and Vitamin E supplementation in mineral mixture will help in improving reproductive performance.
Vitamin E and Selenium have antioxidant properties that protect biological systems from oxidative damage. Vitamin E and selenium have been used in conjunction to lower the frequency of retained placenta, metritis (uterine infection), and cystic ovaries in herds deficient in both nutrients. Herds that exhibit these symptoms are routinely injected three weeks prior to calving with a vitamin E-selenium combination containing 680 IU vitamin E and 50 mg selenium as selenite. Se and vitamin E supplementation decreases the prevalence of retained placenta, metritis, cystic ovaries, and uterine involution time in metritic cows
Vitamin E and selenium
- Incidence of retained placenta was 17.5% in cows, it was reduced to 0% in cows receiving both selenium and vitamin E. • Incidence of metritis was 60% for cows injected with selenium and 84% for those not receiving selenium. • Cystic ovaries were diagnosed in 19% of cows injected with selenium, and incidence was 47% for cows not treated with selenium. • Prepartum selenium injections were effective for reducing the incidence of metritis and cystic ovaries during the early postpartum period. • Vitamin E > 2000 IU/day supplemented during transition phase (3 weeks before to 3 weeks after calving) lower incidence of mastitis and retained placenta.
Selenium
Selenium along with vitamin C is essential for an optimum immune response and influences both innate and acquired immune systems through a key role in redox regulation and anti-oxidant function and contributes to membrane integrity and protection against DNA damage (Wintergerst et al. 2007) Selenium deficiency presents a factor favouring the appearance of perinatal metritis and retention of placenta in dairy cattle (Spears, 2008 and Hefnawy, 2010). In addition, selenium deficiency can cause a malfunction of the testosterone and spermatozoon synthesis, which causes infertility in males (Rayman et al. 2012). Selenium is known to influence the gross and histological morphology of the testis (Ahsan et al. 2014). Selenium deficiency is often characterized by reduced spermatozoon motility due to the fragility of its intermediate piece (Maiorino et al. 1999) Some selenoproteins were localized in the testes as selenophosphate synthase-2 (SPS-2) and the mitochondrial capsule selenoprotein (MCSeP)( Davis et al. 2012) Selenium supplementation may reduce the incidence of metritis and ovarian cysts during the postpartum period(Wilde, D. et al. 2006). Selenium is important in normal cattle production systems as its apparent direct link to postpartum uterine involution (Arthington et al. 2005) Spears and Weiss, reported that selenium supplementation of dairy cows decreased the incidence of retained placenta. Furthermore, it appears from the study of Komisrud et al. (2005) reported that selenium supplementation in dairy cows deficient in selenium may improve the success rate to first service. Deficiency of selenium is also responsible for early embryonic deaths aand still birth (Randhawa and Randhawa, 1994).
Role of Selenium
- Selenium is a component of gluthathione peroxidase, an enzyme, protecting cell membrances from oxidative damage.
- Selenium has a sparing effect on vitamin E by ensuring normal absorption of the vitamin.
- Selenium also reduces the amount of vitamin E required to maintain the integrity of lipid membranes and aids the retention of Vitamin E in plasma.
Clinical signs
- The most frequent and the most important manifestation of Selenium deficiency in farm animals is muscle degeneration (myopathy).
- Nutritional myopathy, also known as muscular dystrophy, frequently occurs in cattle, particularly calves.
- The myopathy primarily affects the skeletal muscles and the affected animals have weak leg muscles, a condition manifested by difficulty in standing and after standing, a trembling and staggering gait. The animals are unable to rise and weakness of the neck muscles prevents them from raising their heads. This condition known as white muscle disease.
- The heart muscle may also be affected and death may result.
Selenium toxicity
- Animals grazing chronically some species of plants (Astragalus racemosa) that grow in seleniferous areas contain very high levels of selenium named as Alkali disease and blind staggers.
- Symptoms include dullness, stiffness of the joints, loss of hair from mane or tail and hoof deformities.
- Acute poisoning, which results in death from respiratory failure, can arise from sudden exposure to high selenium intakes.
Role of Vitamin E
- Vitamin E functions in the animal mainly as biological antioxidant.
- In association with the selenium-containing enzyme glutathione peroxidase, it protects cells against oxidative damage caused by free radicals.
- Vitamin E also plays an important role in the development and function of the immune system.
Clinical signs -Deficiency
- The most frequent and the most important manifestation of Selenium deficiency in farm animals is muscle degeneration (myopathy).
- Nutritional myopathy, also known as muscular dystrophy, frequently occurs in cattle, particularly calves.
- The myopathy primarily affects the skeletal muscles and the affected animals have weak leg muscles, a condition manifested by difficulty in standing and, after standing, a trembling and staggering gait.
- The animals are unable to rise and weakness of the neck muscles prevents them from raising their heads popularly known as white muscle disease.
- The heart muscle may also be affected and death may result.
Supplementation
- Green fodders,
- Cereal grains,
- Vegetable oils,
- Fats,
- Nuts,
- Oil seeds and
Compiled & Shared by- Team, LITD (Livestock Institute of Training & Development)
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Reference-On Request.
