Benefits of including methane measurements in selection strategies

Abstract

Estimates of genetic/phenotypic covariances and economic values for slaughter weight, growth, feed intake and efficiency, and three potential methane traits were compiled to explore the effect of incorporating methane measurements in breeding objectives for cattle and meat sheep. The cost of methane emissions was assumed to be zero (scenario A), A$476/t (based on A$14/t CO equivalent and methane's 100-yr global warming potential [GWP] of 34; scenario B), or A$2,580/t (A$30/t CO equivalent combined with methane's 20-yr GWP of 86; scenario C). Methane traits were methane yield (MY; methane production divided by feed intake based on measurements over 1 d in respiration chambers) or short-term measurements of methane production adjusted for live weight (MPadjWt) in grazing animals, e.g., 40-60 min measurements in portable accumulation chambers (PAC) on 1 or 3 occasions, or measurements for 1 wk using a GreenFeed Emissions Monitor (GEM) on 1 or 3 occasions. Feed costs included the cost of maintaining the breeding herd and growth from weaning to slaughter. Sheep were assumed to be grown and finished on pasture (A$50/t DM). Feed costs for cattle included 365 d on pasture for the breeding herd and averages of 200 d postweaning grow-out on pasture and 100 d feedlot finishing. The greatest benefit of including methane in the breeding objective for both sheep and cattle was as a proxy for feed intake. For cattle, 3 GEM measurements were estimated to increase profit from 1 round of selection in scenario A (no payment for methane) by A$6.24/animal (from A$20.69 to A$26.93) because of reduced feed costs relative to gains in slaughter weight and by A$7.16 and A$12.09/animal, respectively, for scenarios B and C, which have payments for reduced methane emissions. For sheep, the improvements were more modest. Returns from 1 round of selection (no methane measurements) were A$5.06 (scenario A), A$4.85 (scenario B), and A$3.89 (scenario C) compared to A$5.26 (scenario A), A$5.12 (scenario B), and A$4.72 (scenario C) for 1 round of selection with 3 PAC measurements. Including MY in the selection index was less profitable because it did not reduce feed costs relative to weight gain. Consequently, for strategies measuring MY but not MPadjWt (and with no estimate of feed intake in the production environment), proportionately greater emphasis was placed on increasing slaughter weight, and as a result, the decreases in methane emissions per animal and per unit of feed intake were smaller than for strategies that measured MPadjWt.

Improved region-specific emission factors for enteric methane emissions from cattle in smallholder mixed crop: livestock systems of Nandi County, Kenya

“…This was despite animals in LH1 generally being heavier. With LW being a key determinant of MER M (Touchberry and Lush 1950), enteric CH 4 being positively correlated with feed intake (Molano and Clark 2008) and voluntary intake being positively correlated with LW (Robinson and Oddy 2016), it would be expected that differences in calculated EF would align with observed LW differences across the AEZs. That this was not so can probably be attributed to a combination of the observed differences among zones in LW flux and locomotion, plus small differences among zones in average DMD, along with the assumption that CH 4 yield is a constant fraction of DM in forages, unrelated to digestibility.…”

More feed efficient sheep produce less methane and carbon dioxide when eating high-quality pellets

“…Therefore, genetic improvement of gas production is one way to get permanent and continuous reductions in CH 4 and simultaneously potentially improve efficiency. Robinson and Oddy (2016) found that including CH 4 into a breeding index will improve profit because of its high genetic relationship with feed intake, particularly when feed intake is not measured. Therefore, the high economic value of intake and the strong genetic correlation between intake and CH 4 , CO 2 , and O 2 could make these traits very important.…”

Creating a low enteric methane emission ruminant: what is the evidence of success to the present and prospects for developing economies?

“…The second approach is that of identifying individuals within the population who possess the desired phenotype, then selecting for those animals. In the case of the LMP, it needs to be considered that: (1) the technical requirements for identifying and testing animals are prodigious; (2) the differences between identified LMY and HMY animals are only in the region of 12-15% (Goopy et al 2014;Kittelmann et al 2014) and there is no evidence that this will be increased through trait selection; and (3) there is little if any, economic benefit to be gained by farmers in selecting for LMP under prevailing economic conditions (Robinson and Oddy 2016). Further, Eckard et al (2010) has warned that even though genetic selection for LMP animals is theoretically possible, the rate of genetic gain for the trait will necessarily be low in any multi-trait breeding program.…”