Is rumination time an indicator of methane production in dairy cows?

Abstract

As long as large-scale recording of expensive-to-measure and labor-consuming traits, such as dry matter intake (DMI) and CH 4 production (CH 4 P), continues to be challenging in practical conditions, alternative traits that are already routinely recorded in dairy herds should be investigated. An ideal indicator trait must, in addition to expressing genetic variation, have a strong correlation with the trait of interest. Our aim was to estimate individual level and phenotypic correlations between rumination time (RT), CH 4 P, and DMI to determine if RT could be used as an indicator trait for CH 4 P and DMI. Data from 343 Danish Holstein cows were collected at the Danish Cattle Research Centre for a period of approximately 3 yr. The data set consisted of 14,890 records for DMI, 15,835 for RT, and 6,693 for CH 4 P. Data were divided in primiparous cows only (PC) and all cows (MC), and then divided in lactation stage (early, mid, late, and whole lactation) to analyze the changes over lactation. Linear mixed models, including an animal effect but no pedigree, were used to estimate the correlations among traits. Phenotypic and individual level correlations between RT and both CH 4 P and DMI were close to zero, regardless of lactation stage and data set (PC or MC). However, CH 4 P and DMI were highly correlated, both across lactation stages and data sets. In conclusion, RT is unsuitable to be used as an indicator trait for either CH 4 P or DMI. Our study failed to validate RT as a useful indicator trait for both CH 4 P and DMI, but more studies with novel phenotypes can offer different approaches to select and incorporate important yet difficult to record traits into breeding goals and selection indexes.

Mitigation of greenhouse gases in dairy cattle via genetic selection: 1. Genetic parameters of direct methane using noninvasive methods and proxies of methane

“…Animals that ruminate longer tend to exhale less CH 4 (MeC and MeP). This result differs from that of Zetouni et al (2018), who showed a null association between MeP and RT. Some of the factors that influence CH 4 production can also affect rumination time.…”

Assessing Influence Factors on Daily Ammonia and Greenhouse Gas Concentrations from an Open-Sided Cubicle Barn in Hot Mediterranean Climate

“…According to other authors [13,26,45], hot climate conditions cause a depressive effect on dry matter intake because the reduction of time spent at feeding reduces the dry matter intake. Moreover, Zetouni et al [46] proved how there is a high correlation between CH 4 production and dry matter intake; consequently, the observed decrease in CH 4 production between W1 and W2 in this study could be ascribed to a reduction of dry matter intake due to hot climate conditions.…”

Review: Genetic and genomic selection as a methane mitigation strategy in dairy cattle

“…The tags record the amount of time a cow spends chewing the cud and are thus implicated in CH 4 emissions through the digestion and fermentation of fibre. Interestingly, Zetouni et al (2018a) compared the rumination time (415.1 ± 116.7; mean ± SD) with CH 4 production (405.2 ± 115.8), with these similar means and variances being promising. However, estimates of individual level correlations were very close to zero (−0.10 ± 0.07).…”