Year: 2025
Type: article
Abstract: Feed additives such as 3-nitrooxypropanol (3-NOP) can reduce the dairy cow's enteric methane (CH 4 ) emissions.Our study aimed to examine whether there is genetic variation in the cow's response in reduction of CH 4 emission after receiving 3-NOP feed additives.Data were available from a project where the CH 4 -mitigating effect of 3-NOP (Bovaer®) was tested for Norwegian dairy cows.The one-year trial took place in a commercial dairy herd and included 79 Norwegian Red cows.The cows' CH 4 emissions were measured by GreenFeed.A total of 14,166 daily CH 4 measures were analyzed, and the overall mean (standard deviation) was 387 (96) grams CH 4 per cow per day.Cows were divided into 2 groups, where 54 cows received between 1.2 and 1.5 g 3-NOP per day, and 25 cows were in a control group without any feed additives.The trait of interest, CH 4 -response, was defined as the cow's change in CH 4 after introducing 3-NOP in the diet compared with the "base level CH 4 " in periods without 3-NOP.The base level period consisted of 3 weeks in September 2023 and 4 weeks in January/February 2024.The trait daily CH 4 (gram per day) was analyzed with a linear animal repeatability model with fixed effects of 3-NOP group, parity, lactation week, and test-day, and random animal genetic and permanent environment effects.Fixed effect solutions from this model were used to compute "Yield Deviations" for CH 4 (YD_CH 4 ), a corrected phenotype, i.e., daily CH 4 corrected for effects of parity, lactation stage and test-day.For cows fed 3-NOP, we calculated their individual base level CH 4 as the average YD_CH 4 from the periods without 3-NOP.The trait CH 4 -response was then calculated as YD_CH 4 minus base level CH 4 .The new CH 4 -response trait had a total of 7,293 daily records from 42 cows and was analyzed with a linear animal repeatability model with fixed effect of test-day and random additive genetic effect of cow.Although this is a small data set and results should be interpreted with caution, the estimated heritability of 0.15, with standard error 0.03, suggests that genetic variation in response in the reduction of CH 4 emission after receiving 3-NOP feed additives exists for Norwegian Red dairy cows.
Source: JDS Communications
Authors: Bj⊘rg Heringstad, Karoline A. Bakke
Institutions: Geno (Norway), Norwegian University of Life Sciences
Language: English
Subfield: Genetics
Domain: Life Sciences
SDGs: Zero hunger, Climate action
Open Access status: gold
Estimated APC paid: $1,310
Funder: Norges Forskningsråd
Award: G7149977624
OpenAlex ID: W4416265682