Table 3 In vivo studies incorporating seaweeds as anti-methanogenic agents in ruminants’ feed

Asparagopsis taxiformis

Brahman-Angus cross steers

Total mixed ration containing Rhodes grass hay, barley, grain/mineral/vitamin blend

4 dosage rates: 0, 0.05%, 0.10%, and 0.2% of total feed organic matter

0.1% and 0.2% dosage rates reduced CH₄ emissions by 40% and 92%, respectively

[36]

Asparagopsis taxiformis

Merino-cross wethers sheep

Commercial pelleted ration containing high fibre diet (< 2% organic matter)

5 dosage rates: 0, 0.5%, 1%, 2%, and 3% on organic matter basis

3% dosage rate decreased CH₄ emissions by 80% compared to control

[95]

Asparagopsis armata

One Jersey and one Holstein

Total mixed ration

3 dosage rates: 0, 0.5%, and 1% on organic matter basis

0.5% inclusion rate decreased CH₄ emission by 26.4%

1% inclusion rate decreased CH₄ emission by 67.2%

[15]

Asparagopsis taxiformis

Angus-Hereford beef steers

3 diets fed over time to achieve low forage total mixed ration diet:

- Starter diet (63 d) high forage diet

- Transition diet (21 d) medium forage

- Finisher diet (63 d)

Forage contained varying proportions of alfalfa hay, wheat hay, dry distiller grain, and concentrates

3 dosage rates: 0, 0.25%, and 0.5% on organic matter intake basis

Low forage total mixed ration diet supplemented with 0.25% A. taxiformis reduced CH₄ by 69.8%

Low forage total mixed ration diet supplemented with 0.5% A. taxiformis reduced CH₄ by 80%

[94]

Asparagopsis taxiformis

Lactating Holstein cows

Total mixed ration

3 dosage rates: 0, 0.25%, and 0.5% on dry matter basis

0.5% A. taxiformis decreased CH₄ emission by 65%

[16]