Study: Brewer’s Yeast Benefits for Cows

Lithuanian agricultural advisors conducted a feeding test on cows at Mr. Irmantas Dikavičiaus’ farm in Radviliskis, Lithuania. They assessed the effects of dry brewer’s yeast on cow health, milk yield, composition, quality, and economic efficiency. The study also looked into the impact of yeast on calves, including health, parturition, and postnatal condition of cows. The optimal dosage of dry brewer’s yeast was determined for all lactating cows.

1. The control group (n-10). In order to allow comparison of test data, this group was made ​​up of different periods of lactation cows. The control group was fed by farm’s ration – dry brewer’s yeast for these cows was not given.
2. I experimental group (n-12) – early lactation cows (until 70 days after calving). Cows were fed daily by farm’s ration and 250 g of dry brewer’s yeast additionally. The main aim was to determine the optimal dry brewer’s yeast daily consumption rate, so in this group 10 of the most productive cows were selected. These cows were fed 50 g of dry brewer’s yeast more every two weeks until the milk yield increased. Later, the dose of dry brewer’s yeast was gradually reduced until the yield did not start to decline.
3. II experimental group (n-10) – early lactation cows, energy balance and feed usage at peak period (cows from 70 to 140 days after calving). Cows were fed daily by farm’s ration and 200 g of dry brewer’s yeast additionally.
4. III experimental group (n-10) – cows of mid and late lactation period. Cows were fed daily by farm’s ration and 100 g of dry brewer’s yeast additionally.
5. Dry cows. These cows were fed by farm’s ration. The experimental group was fed additionally 50 g per day of dry brewer’s yeast. The control group dry cows were not fed by dry brewer’s yeast.

The weight of all group cows, evaluation of their fattening, limb condition and general health was evaluated at the beginning and end of the experiment. During all experiment cows’ appetite, fattening, parturition and postnatal stages condition, intensity of fertility were observed. Milk yield, milk composition and quality indicators were determined during 7 control cows’ milking. Milk yield was determined on the farm, and milk composition and quality indicators in state-owned enterprise “Pieno tyrimai”.

The monitoring data

1. All experimental groups of cows had a better appetite and were well simulated. Their fur was shorter and shinier than cows of control group.
2. The cows of all experimental groups did not have calving, postnatal, and gastrointestinal problems. In the control group, these problems haven’t been avoided.
3. Cows from experimental groups did not have limb problems. Three cows from the control group began to limp after calving.
4. Healthy and strong calves were born in the experimental groups. The calves of control group’s cows were born smaller and less viable, had diarrhea problems.
5. The oestrus of cows from experimental groups was very significant. Cows from the control group had a cow calving and postnatal problems. 2 months after calving this group of cows still haven’t had oestrus.

The weight of cows

During the test period, cow weight, compared with control, increased by 1-3%.

The milk yield

Within 90 days of experiment, the biggest milk yield was recorded of I experimental group’s cows (approximately 29 kg of milk per day during the milking period, or 7 kg (132%) more than in the control group (P> 0.01). II and III experimental groups of cows had higher milk yield 105% and 107%, compared to a control group of cows’ milk yield.

Structure of milk and quality indicators

Concentration of fat

During the test the biggest quantity of fat was found in milk of cows from III experimental group, the least – in milk of I experimental group of cows. Not enough dry substances and easily assimilated fiber were in the ration of I experimental group of cows. Because of these reasons, fat concentration in milk decreased in this group of cows.

Concentration of proteins

The highest protein concentration was in III experimental group of cows’ milk. During the test period, protein concentration in the milk of control group’s cows was unequal while the quantity of proteins of experimental groups’ cows increased gradually.

Concentration of lactose

The concentration of lactose in the milk of cows of all groups has evolved within the normal range during all test period. However, lactose in the milk of cows from the experimental group was 0.10-0.15% higher than in the control group (P> 0.01).

Somatic cell in milk

The quantity of somatic cell in cows’ milk was different during whole test. The biggest quantity of somatic cells have been found in milk of control group’s cows, the least – in I experimental group of cows’ milk. The quantity of somatic cells in cow’s milk was higher than the norm in the control group and III experimental group. The quantity of somatic cell in the milk of III experimental group’s cows increased not because of mastitis, but the test of dry cow’s milk. Normally at the end of lactation the milk of dry cows has more somatic cells. The increase of somatic cell in the milk of cows from control group reveals the secret consequences of mastitis.

Urea content of milk

During the test period urea in all groups of cows’ milk was normal.

Veterinary expenses

There were no veterinary expenses for experimental groups of cows. 2 cows from the control group were led afterbirths, and then both had mastitis. Their calves had diarrhea problems. More than 145 Eur were spent for veterinary treatment.

Income from milk

Most of the income was received for the milk of I experimental group of cows. During the test period approximately 643 Eur were received (132% more than from the control group). 105% of income was received from II experimental group of cows’ milk, from the III experimental group – 107% of income more than for control group of cows’ milk.

The economic benefits

During whole test period economic benefits of dry brewer’s yeast, excluding veterinary costs were self-evident.

Study conclusions

1. Dry brewer’s yeast has a positive impact on cow health, milk yield, fat, protein, lactose, and urea concentration in milk during all periods of lactation.
2. Yeast has a positive impact on the prevention of mastitis and somatic cell amount in milk.
3. Dry brewer’s yeast has a positive effect on fetal development, parturition course, post-condition of cows and calves’ health.
4. Yeast has a positive impact on the involution of reproductive organs.
5. Dry brewer’s yeast is a cost-effective feed additive.

Recommendations

The usage of dry brewer’s yeast for cows