Expected consequences of including methane footprint into the breeding goals in beef cattle. A Spanish Blonde d'Aquitaine population as a case of study

Abstract

This study evaluates two potential scenarios for including methane (CH ) emissions in the breeding objectives of beef cattle, using the Spanish population of Blonde d'Aquitaine as a case of study. First, CH emissions were included as a cost using a shadow carbon price of 1.22€/CH kg (0.044€/CO kg) (carbon tax scenario). In the other scenario, a CH quota was applied, optimizing emissions per unit of product. The current production system was used as benchmark scenario (Scenario 1). The economic value of CH was calculated under all scenarios using a bioeconomic model that translated the production system into a mathematical function. Then, CH emissions were included with proper relative weight in the selection index under each scenario. The economic value of CH production from cows was -0.54€/year and -0.16€/year in a carbon tax and in a CH quota scenario, respectively. Economic values for CH production from fattening calves were -1.22€/year and -0.34€/year in a carbon tax and a quota scenario, respectively. The relative weights of total CH traits in the indices were 4.9% and 1.8% in a carbon tax and quota scenario. The carbon tax scenario led to smaller cows (-7.59 kg of mature weight) and a decrease in carcass weight gain of calves (-4.78 g/day) involving a reduction in emissions in comparison with Scenario 1 (-0.76 CH kg/slaughtered calf/year). However, it also led to a lower expected gain in profit per unit of product (-7.86 €/slaughtered calf/year). A carbon quota scenario would select slightly smaller cows (-0.48 kg) with similar responses in maternal abilities (age at first calving, calving interval, maternal weaning weight, and calving ease) and growth, and lower emissions (-0.22 CH kg/slaughtered calf/year) regarding the benchmark scenario. Profit per cow would increase by +1.52€/slaughtered calf/year although this scenario implies a reduction in the number of cows per herd. In a carbon tax scenario, higher reduction in emissions implied a reduction of profitability per animal.

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

“…Methane is not only an environment-related trait, it is also associated with feed efficiency, because enteric methane is not transformed into metabolized energy for the animal and is exhaled to the atmosphere, with a subsequent feeding cost for the producer (Johnson and Johnson, 1995). Several authors have proposed incorporating environment-related traits, mainly methane production, into breeding goals (Bell et al, 2016;Amer et al, 2018;López-Paredes et al, 2018). Measuring methane on farms requires less infrastructure than other feed efficiency-related traits (e.g., feed intake).…”

Mitigation of greenhouse gases in dairy cattle via genetic selection: 2. Incorporating methane emissions into the breeding goal

“…Bell et al (2016) estimated the economic value of methane in the UK at −£1.68/kg of CH 4 (≃€1.77/kg of CH 4 ). López-Paredes et al (2018) formulated a similar bio-economic model that included CH 4 emissions in the breeding goal in beef cattle, resulting in an economic value from −€0.16 to −€0.54/kg of CH 4 /calf per year for cows and from −€0.34 to −€1.22/kg of CH 4 /calf per year for calves in a feedlot. In this study, we proposed scenarios that serve as theoretical situations in which exhaled CH 4 is considered in the breeding goal, either as a direct carbon tax or as a waste of energy exhaled by the cow.…”

“…Livestock farming is responsible for 13% of global greenhouse gas (GHG) emissions (Leip et al, 2010); in particular, methane emission is an important contributor because it has a global warming potential 28 times greater than that of CO 2 (Myhre et al, 2013). Ruminants are considered one of the most important sources of global CH 4 emissions from livestock, producing around 4,623 Mt of CO 2 equivalents (CO 2 e) per year, with dairy cattle being responsible for 2,128 Mt of CO 2 e per year (Gerber et al, 2013).…”

Breeding for reduced methane emission and feed-efficient Holstein cows: An international response

“…Furthermore, care must be taken when including MeP in the breeding goal, that reductions are not achieved by breeding for smaller and low-milkproducing cows. Likewise, Lopez-Paredes et al (2018) concluded that a carbon quota scenario (that included CH 4 ) would select smaller cows and consequently lower CH 4 emissions in a study that measured expected consequences of including CH 4 footprint into the breeding goal of beef cattle. Additionally, it is important to mention that in the indexes 1 and 2 the reduction of MeP is only a reduction in the expected gain, given that the values are positive, and it is only by including RMet that a real reduction (negative values) is achieved.…”