Less methane emissions and better productivity of dairy cows by dietary high-oil rapeseed cake amendment

Feeding the world with less environmental impact is one of the main future challenges of the livestock sector. Reducing the methane emission of ruminants falls well within this scope. Hankkija Oy took part in a collaborative research, led by Natural Research Institute Finland, Luke, which studied  the potential of high-oil rapeseed cake or natural additives on enteric methane (CH4) emissions, nutrient utilization, milk fatty acid (FA) profile, and performance of dairy cows. The study has now been published in the Journal of Dairy Sciences.

For the experiment, eight lactating Red Nordic dairy cows, fed with a grass-silage: concentrate ratio of 45:55, were randomly assigned to a replicated 4 × 4 Latin square design.

The dietary treatments were as follows:

1. Control containing 19.3% rapeseed meal on dry matter basis
2. Rapeseed cake: Control with full replacement of rapeseed meal with rapeseed cake
3. Progut^®+Progres^®: Control + 20 g/d Progut^® Extra and 30 g/d of Progres^® Dry
4. Mootral^®: Control + 20 g/d of a combination of garlic-citrus extract and essential oils

Each dietary period lasted for 21 days. The cows were housed in respiratory chambers for days 17-21 of each experimental period for measuring the methane emissions and energy balance.

Rapeseed cake significantly reduced methane emissions, whether they were calculated per day (–6.8%, p < 0.1), per kilogram of DMI (–7.1%; p < 0.01), per kilogram of milk (–15.8%; p < 0.05) or per kilogram of energy-corrected milk (–12.4%; p < 0.01). Thus, the rapeseed cake diet was very successful in reducing the methane emissions of milk production in this experiment.

The Rapeseed cake group produced significantly more milk (+10.7%) than the Control group. Rapeseed cake also improved the milk fatty acid profile by reducing the proportion of saturated fats in milk by 10%. None of the diets affected the dry matter intake or the energy balance of cows.

While the study did not find a significant effect of Progut^®+Progres^® on the daily CH4 emissions or milk production, this combo significantly improved nitrogen balance compared with the Control diet.

In conclusion, the study suggested that amending the diet of lactating dairy cows with high-oil rapeseed cake is an effective strategy to mitigate methane emissions and simultaneously to improve milk production and milk fatty acid composition.

REFERENCE

Bayat et al. 2021. Evaluating the effects of high-oil rapeseed cake or natural additives on methane emissions and performance of dairy cows In: Journal of Dairy Science.