Genetic background of methane emission by Dutch Holstein Friesian cows measured with infrared sensors in automatic milking systems

Abstract

International environmental agreements have led to the need to reduce methane emission by dairy cows. Reduction could be achieved through selective breeding. The aim of this study was to quantify the genetic variation of methane emission by Dutch Holstein Friesian cows measured using infrared sensors installed in automatic milking systems (AMS). Measurements of CH and CO on 1,508 Dutch Holstein Friesian cows located on 11 commercial dairy farms were available. Phenotypes per AMS visit were the mean of CH, mean of CO, mean of CH divided by mean of CO, and their log-transformations. The repeatabilities of the log-transformated methane phenotypes were 0.27 for CH, 0.31 for CO, and 0.14 for the ratio. The log-transformated heritabilities of these phenotypes were 0.11 for CH, 0.12 for CO, and 0.03 for the ratio. These results indicate that measurements taken using infrared sensors in AMS are repeatable and heritable and, thus, could be used for selection for lower CH emission. Furthermore, it is important to account for farm, AMS, day of measurement, time of day, and lactation stage when estimating genetic parameters for methane phenotypes. Selection based on log-transformated CH instead of the ratio would be expected to give a greater reduction of CH emission by dairy cows.

Enteric methane emission from Jersey cows during the spring transition from indoor feeding to grazing

“…5 times higher than that reported for Jersey cows in the present study. However, the ratio reported by van Engelen et al (2018) might have been inflated due to the lower CO 2 concentrations reported. The CO 2 concentrations obtained in the current study support those obtained by other studies on Holsteins cows fed PMR indoors in the United Kingdom and Denmark (e.g., Bell et al, 2014;Difford et al, 2016).…”

“…The mean ratio value from the study of Jersey cows was very similar to the one obtained in the current study, whereas the ratio obtained for the Holstein breed was higher. van Engelen et al (2018) reported a CH 4 : CO 2 concentration ratio in Dutch Holstein-Friesians fed PMR indoors, which was up to Figure 3. Correlations between weeks for daily averaged CH 4 (a) and CO 2 (b) gas measurements and CH 4 : CO 2 ratio (c).…”

“…Therefore, factors other than random animal effects must be responsible for differences of such magnitudes, such as the difference between the current study and that of van Engelen et al (2018). The study by van Engelen et al (2018) obtained records in the Lely A4 Astronaut (Lely, Maassluis, the Netherlands), which has a more open feeding bin than the Delaval AMS used in our study. One possibility is the dilution of gases due to differences in feed bin dimensions or in environmental factors, such as variable wind speed between installations (Wu et al, 2018).…”

“…The CO 2 emission trait tends to be repeatable (e.g., Lassen et al, 2012;Bell et al, 2014;Difford et al, 2016;Lassen and Løvendahl, 2016). Therefore, factors other than random animal effects must be responsible for differences of such magnitudes, such as the difference between the current study and that of van Engelen et al (2018). The study by van Engelen et al (2018) obtained records in the Lely A4 Astronaut (Lely, Maassluis, the Netherlands), which has a more open feeding bin than the Delaval AMS used in our study.…”

Letter to the Editor: A response to

“…One of the issues raised by Huhtanen and Hristov (2018) is that measurements of methane by using the sniffer method are significantly influenced by external conditions. Indeed, the effects of specific conditions during the day of measurement, farm, automatic milking system, and sensor explained 56% of the total variation in our data (van Engelen et al, 2018). Consequently, we believe that the setup of the sniffer method as used in our experiments is not suited for ranking herds, for example, or for assessing the effect of diets on methane emission.…”