Persistence in CH 4 yield ranking across four seasons in sheep on - - PowerPoint PPT Presentation

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Feb 20, 2024 38 likes •171 views

Persistence in CH 4 yield ranking across four seasons in sheep on pasture AJ Jonker *, S Hickey, S MacLean, C Woju, M Calzada, W Yu, JC McEwan, S Rowe Variation in CH 4 from sheep Large variation in CH 4 yield found among sheep (e.g. Blaxter

SLIDE 1

Persistence in CH4 yield ranking across four seasons in sheep on pasture

AJ Jonker*, S Hickey, S MacLean, C Woju, M Calzada, W Yu, JC McEwan, S Rowe

SLIDE 2

Variation in CH4 from sheep

Large variation in CH4 yield found among sheep (e.g. Blaxter and Clapperton,

1965)

CH4 yield found to be repeatable trait in sheep (e.g. Pinares-Patiño et al., 2003,

2011)

SLIDE 3

Creation CH4 yield selection lines

Lucerne pellets (2×MEm)

SLIDE 4

Breeding values of low and high CH4 yield sheep

SLIDE 5

How about on pasture in different seasons

Objective: Determine CH4 emissions from CH4 yield selection line

sheep in respiration chambers when fed cut pasture in four seasons.

SLIDE 6

Methods

72 CH4 yield selection line rams

(born spring 2016)

4 seasons of cut pasture (ad

libitum)

CH4 in respiration chambers for

48 h

SLIDE 7

Results: Pasture species

27.8 57.7 84.9 54.3 45.2 9.0 1.5 8.5 21.0 21.4 12.7 36.9 6.0 11.8 0% 20% 40% 60% 80% 100% P1 P2 P3 P4 Proportion of DM (%) Other Dead matter Clover Grass

March (autumn) June (winter) September (spring) December (summer)

SLIDE 8

Results: Pasture composition

20.2 19.5 19.2 8.4 40.4 43.0 44.8 53.1 26.1 23.0 20.3 28.0 10.9 12.1 11.7 8.5 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Autumn Winter Spring Summer

(% of dry matter)

CP NDF NFC fat Ash

SLIDE 9

Results: Methane yield

18.3 19.3 21.8 19.2 19.6 21.1 23.5 20.9 4 8 12 16 20 24 28

Autumn Winter Spring Summer

CH4 (g/kg DMI) CH4Low CH4High

8% 7% 8% CH4Low line CH4High line 7% P-values CH4 line = P<0.001 Season = P<0.001 CH4 line × season = P=0.737 Autumn (March) Winter (June) Summer (December) Spring (September) (2017)

SLIDE 10

Results: Repeatability

Pasture (current study) (n=72) CH4 (g/d) 0.46±0.05 CH4 (g/kg DMI) 0.32±0.05

SLIDE 11

Discussion

SF6 method: 18% lower CH4 yield PAC CH4/(CH4+CO2) rg of 0.54 with respiration chamber CH4 yield

(Jonker et al., 2018; JAS, 96:3031) (Jonker et al., 2017; JAS, 95:3905) (Jonker et al., 2017; Proc BSAS)

Respiration chamber

SLIDE 12

Conclusion

The CH4 yield trait of selection lines sheep was repeatedly expressed on fresh

pasture across four seasons

Therefore, CH4 breeding values generated in sheep are applicable to pastoral

farming systems in New Zealand

SLIDE 13

Acknowledgements

Research was provided through the PGgRc-NZAGRC science programme.