1764
Effect of oat grain variety on methane emissions from mature sheep
Methane emissions from ruminants are driven by DM intake and feeds characteristics such as oil concentration and OM fermentability; an oat breeding program at Aberystwyth aims to breed new varieties for livestock feeding that help reduce pollutant emissions by manipulating nutritional characteristics. To study the effect of feeding different varieties of oat grains on enteric methane emissions from sheep, eight mature barren ewes, four each of two breeds (Welsh Mountain and Welsh Mule; mean LW 41.5 ±1.93 and 64.9 ±1.46 kg respectively) were fed diets comprising ryegrass silage and oats in a 1:1 ratio (on a DM basis) in a Latin square changeover design experiment. Feed was offered at rates (i.e. restricted) designed to supply ME requirements for maintenance (according to AFRC 1992 guidelines). The same grass silage was used throughout, fed with 1 of 4 oat grain treatments: A) a husked oat, cv Balado, B) a naked oat, cv Racoon, C) a new breeding line husked oat, NewLine, and D) a 1:1 (fresh) mix of B and C, Mix. Each of the 4 periods of the experiment consisted of 14 days for diet adaptation and 6 days for measurements of feed intake, whole tract apparent diet DM digestibility, and methane emission. Methane emissions were measured for each animal for 3 days in open-circuit respirations chambers. There were no significant sheep breed effects on measurements except for LW and therefore DMI (grand mean 637 g/d). There were significant effects of oat variety on methane emissions, both in g/d and when expressed in relation to intake and metabolic LW. Differences in methane emissions from the sheep are likely to be related to differences in fiber and oil concentrations of the oat grains. In conclusion, the Mix treatment composition is a good breeding target for new varieties of oats.
|
Oat treatment |
|
|
|||
|
Balado |
Racoon |
NewLine |
Mix |
SED |
P |
Oat CP, % DM |
10.5 |
10.5 |
10.9 |
10.7 |
- |
|
Oat NDF, % DM |
23.1 |
6.1 |
9.5 |
6.0 |
- |
|
Oat total oil, % DM |
5.6 |
10.2 |
4.9 |
7.5 |
- |
|
|
|
|
|
|
|
|
CH4, g/d |
15.2a |
14.7a |
17.2b |
14.7a |
0.60 |
0.002 |
CH4/DMI, g/kg |
24.1ab |
23.0a |
26.9b |
23.9a |
0.96 |
0.003 |
CH4/dig. DMI, g/kg |
3.11ab |
2.88a |
3.45b |
2.85a |
0.227 |
0.001 |
CH4/LW0.75, g/kg |
0.78a |
0.74a |
0.88b |
0.75a |
0.031 |
0.002 |
CH4E/GE intake, % |
7.3ab |
6.9a |
8.1b |
6.9a |
0.29 |
0.003 |
Values in rows with different superscripts differed significantly, P < 0.05.
Keywords: sheep, oats, methane