Session 06 "Sensing dynamics in livestock physiology disruption through images and other non-invasive alternatives" EAAP 2021 Par Adrien Lebreton, Idele & P. Faverdin, PEGASE-INRAE

1. Indirect approaches of digestive processes to determine
feed efficiency in dairy cows. Part 2
Session 06 "Sensing dynamics in livestock physiology disruption through images and
other non-invasive alternatives”
Faverdin P1, Fischer A2, Lebreton A1,2, Xavier C1,3, Le Cozler Y1
1 PEGASE, INRAE, Institut Agro, 35 590 Saint Gilles, France
2 IDELE, 75 595 Paris, France
3 Agroscope, Ruminants Research Unit, Tioleyre 4, 1725 Posieux,
Switzerland
Federal Department of Economic Affairs,
Education and Research EAER
Agroscope 1

2. Feeding efficiency: what are we talking about ?
• Feed efficiency (FE) is an indicator estimating the ability of cows to turn feed nutrients into
production (milk, growth, body reserves, maintenance…) components
• Feed efficiency (FE) : different mechanisms are involved, including feed intake and
digestion
Friggens et Martin (2020)
Inefficient cow (RI >0)
Efficient cow (RI < 0)
Predicted feed intake (kg DM/d)
Real
feed
intake
(kg
DM/d)
DMI = a x milk yield + b x BW … + e
∑ energy requirements
(growth, production…)
2
Feed efficiency (FE) = repeatable random components of a mixed model between observed
ingestion and predicted ingestion (Fischer et al., 2018) (FE = Residual ingestion = e)

3. Feeding efficiency: what are we talking about ?
• Hypothesis:
• The digestion and feed intake differences can be approached indirectly thanks to
• The more time the ration spends in the rumen, the better the digestibility is, and
thus, the better the FE
• If abdomen volume reflects residence time of the diet, it could be useful to find a
proxy of feed efficiency
Enteric CH4 using Green
Feed (GF) technology
(Hristov et al., 2015)
Changes in rumen
volume, using 3D
imaging technology
(Lebreton et al., 2021)
3

4. Question
Is 3D images based technology, a possible and non-invasive
method, to determine rumen volume, to be used in selection
for feed efficiency ?
FE ???
Part 1. Lebreton et al., 2021
Part 2. Faverdin et al., 2021
YES, it is possible
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5. • 38 lactating primiparous and multiparous Holstein cows
• LW 676 ± 61 kg, BCS 2.1 ± 0.25
• Fed a diet with 42% Neutral Detergent Fibres, 16.7 % crude protein, 0.84 UFL, 101.9
g/kg of PDIE (according to INRAE 2010 feeding system)
• Daily feed intake recorded individually
• Dry matter intake 22.2 ± 2.9 kg/d
• Gas emission recorded, averaged per day
• Animal “3D scan” once a month
(see Lebreton et al., 2021)
Materials and methods: animals and procedures
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6. For the same level of intake, the most efficient cows have a
larger abdominal volume
Rfi = -1.15 + 0.25 DMI – 0.015 x AV (R=0.74; RSD = 0.55 DMI)
Because of limited access of DMI, the AV/DMI ratio is a limited potential proxy
of efficiency
240
260
280
300
320
340
360
15 17 19 21 23 25 27 29 31 33
Dry Matter Intake (kg/d)
Inefficient cows (RFI>0)
Efficient cows (RFI<0)
Abdominal
volume,
L
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7. 240
260
280
300
320
340
360
20 22 24 26 28 30 32 34 36 38 40
Milk Yield (kg/j)
Efficient cows (RFI<0)
Inefficient cows (RFI>0)
Adominal
volume,
L
For the same milk yield, the most efficient cows have a larger
abdominal volume
(R = 0.36; P < 0.05)
The AV/milk yield ratio could be a potential proxy of efficiency
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8. No clear evidence between methane yield, feed efficiency…
… and abdominal volume
Efficient cows (RFI<0)
Inefficient cows (RFI>0)
Abdominal volume, L
200 220 240 260 280 300 320 340 360
15
17
19
21
23
25
27
29
Methane
yield
(g
/
kg
DM)
CH4/DMI = 33.6 - 1.55 x Rfi – 0.034 x AV (R = 0.49; RSD = 2.3 g / kg DMI)
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9. Conclusions
Relationship between abdomen volume and feed intake :
• The volume of the abdomen increases with dry matter intake …
… but at the same intake, cows with a larger abdomen volume are more
feed efficient
• CH4 yield per kg dry matter intake decreases when the volume of abdomen
increases…
… and the more efficient cows tend to have a higher CH4 yield at the same
abdomen volume
These results are consistent with an hypothesis of a better feed efficiency due to
a better digestion of the diet
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10. Knowledgments
These projects were supported by the National Fund CASDAR, which
supports innovation in agriculture (RFP “Recherche Technologique”
2015, no. 005), special funds from the INRAE Animal Physiology and
Livestock Systems division for innovative projects and the
collaborative ANR – APIS-GENE project DEFFILAIT.
These experimental projects have been submitted to the local Ethical
comity and approved (Trails 1 & 2: APAFIS # 18130. 2018121817178077
v3; Trial 3: APAFIS # 3122-2015112718172611)
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