Supplementation of dry cows with natural contra synthetic E-vitamin

By

Henning Lyngsø Foged

M. Sc. agricultural science

Increase of productivity and tendency towards use of more biased feeds like maize silage in the feed rations strengthens the importance of supplementation of cows with trace minerals and vitamins. The content of E-vitamin in the cows feed ration is critical in the weeks before and after calving due to the importance of E-vitamin for the immune status and the fertility, both for the cow and for the newborn calf. E-vitamin consists of 8 different chemical forms of which only one (RRR-α-tocopherol) is the natural form found in plant material, while other forms are synthetic. Newer scientific research with dry cows has revealed, that the bioavailability is far higher for the natural form of E-vitamin from plants. Only 12.5% of the synthetically produced E-vitamin is on the natural form. Our recommendations concerning mineral supplements for grazing dry cows are, that they do not need supplementation with E-vitamin because grass contains large amounts of natural E-vitamin.

Natural contra synthetic E-vitamin¹

Vitamin E (α-tocopherol) is of great importance for cows' immune systems and is an important factor in connection with, among other things, mastitis, lack of heat, metritis and weak-born calves. Vitamin E also has an effect on the quality of the milk, as it counteracts oxidation and bad taste. As milk and blood analyzes of dry cows and cows in early lactation often show low vitamin E content, many advisers and veterinarians have begun to recommend extra supplements of vitamin E.

Cows that are fed with large amounts of grass or grass silage of good quality would normally have their needs for E-vitamin covered, while cows fed on concentrate, maize silage or whole crop silage could be in deficiency with E-vitamin, as these feeds have a low content of E-vitamin.

The E-vitamin status by calving is crucial for the immune status of both the cow itself and its calf.

E-vitamin is traditionally supplemented in a synthetic form. It is well described in the literature that the bio-availability of synthetically produced E-vitamin is lower than that of the natural E-vitamin. Trials with rats has proven that they utilise synthetic E-vitamin with only 2/3 of their utilisation of supplemented natural E-vitamin - a knowledge that has been transferred to cows. However, there has in the last years been raised doubts whether cows are able to utilise synthetically produced E-vitamin as effective as single-stomached animals. A new Danish/Swedish trial aims at enlighten this question.

Department of Animal Nutrition and Physiology at Danish Institute of Agricultural Sciences has in cooperation with Swedish Veterinary Institute conducted trails with the supplementation of cows with E-vitamin from 3 weeks before calving until 2 weeks after calving. The effect of no, 1000 IU synthetic or 1000 IU natural E-vitamin per cow per day on the content of E-vitamin in blood and milk was investigated.

Preliminary results of the trial shows that supplementation with 1000 IU natural E-vitamin increases the level of E-vitamin in blood and milk in comparison with the control group that was not supplemented with E-vitamin. Supplementation with 1000 IU of synthetic E-vitamin did not give any noteworthy effect on the E-vitamin content in blood and milk. The results suggests that cows distinguish more between natural and synthetic E-vitamin than single-stomached animals, and that the bio-availability of the synthetic form is lower than earlier thought.

It is on this background necessary to adopt a more varied and strategic view on the way that cows should be supplemented with E-vitamin in the weeks before and after calving, not at least in case maize silage or other feeds with a low E-vitamin content is used in the feed ration.

E-vitamin - the fertility vitamin that has "multiplied" its justification²

A trial concluded that cows with less than 3 mg/l α-tokopherol in plasma at calving has 9 times higher risk of mastitis in the first two weeks after calving. That 3 mg/ l seem to be the threshold for optimal effect on the immune system is also proven by another trial, which shows that neutrophiles ability to kill  bacteria by calving first are on full effect at α-tokopherol values above 3 mg/l plasma.

Vitamins and minerals in relation to the immune system of cows³

Calves have practically no E-vitamin in the body at birth. They are dependent on the transfer of E-vitamin from their mother via colostrum. Colostrum contains 8-10 times as much (natural) E-vitamin as milk produced 4 days after calving, and it is of course detrimental for the content of E-vitamin in the colostrum if the E-vitamin status of the cow is too low; calving ease as well as vitality and health of the calf is therefore closely connected with the E-vitamin status of the cow by calving.

American research

Research in USA has shown that daily supplementation of 3,000 mg synthetic E-vitamin in the last 2 weeks before calving was an efficient way to avoid the typical fall in the E-vitamin status of cows around calving and to reduce the number of udder-infections, here under mastitis, and the frequency of retained placenta⁵.

A large Canadian trial, comprising 21 herds and in total 1,142 cows, found a positive effect of a single subcutaneous injection of 3,000 IU RRR-α-tocopheryl acetate (natural E-vitamin) 7 days before expected calving on retained placenta at cows with initial low E-vitamin status in serum (< 2 mg/l), but no effect on mastitis or other production diseases. The injection increased the level of E-vitamin in serum from 2.4 mg/l to 3.1 mg/l the day after calving (P= 0.01)⁵.

These research results underpins that the natural E-vitamin has a high bio-availability, and that synthetically produced E-vitamin must be supplemented in large amounts to give similar effects.

MicroFeeders recommendations

MicroFeeders recommendations concerning mineral supplementation of dry cows are dealing with grazing dry cows. Grass contains large amounts of natural E-vitamin and  it is therefore not necessary to add E-vitamin to the mineral supplements for grazing dry cows. To let dry cows graze could on the contrary be claimed to be a secure way to hinder problems affiliated with low E-vitamin status of calving cows and newborn calves. Grass contains according Dansk Kvæg ⁴ 150 mg E-vitamin per kg dry matter, and an intake of around 5 kg dry matter in fresh grass would therefore be sufficient to cover the Danish norms on 800 mg E-vitamin per day for dry cows.

References

1. Søren Krogh Jensen. 2003. Naturligt kontra syntetisk E-vitamin (In English: Natural contra synthetic E-vitamin). Ny KvægForskning, 1. årgang, Juni 2003, Nr. 3.

2. Nicolai Agger.2003. E-vitamin - Frugtbarhedsvitaminet, som har "mangfoldiggjort" sin berettigelse (In English: E-vitamin - the fertility vitamin that has "multiplied" its justification). Danske Mælkeproducenter. juni 2003.

3. Niels Justesen. 2003. Vitaminer og mineraler i relation til koens immunforsvar (In English: Vitamins and minerals in relation to the immune system of the cow). Danske Mælkeproducenter. juni 2003.

4. Jens Møller et. al. 2005. Fodermiddeltabel (In English: Feedstuff table). Rapport Nr. 112. Dansk Kvæg.

5. Søren Krog Jensen. 2003. Goldkøernes E-vitaminforsyning er vigtig (In English: The E-vitamin supply to dry cows is important). KvægInfo nr. 1266.