anne laarman, m.sc. ph.d. student university of guelph [email protected]
TRANSCRIPT
EFFECTS OF SOLID FEED ON RUMEN pH AND MOLECULAR
ADAPTATIONS IN DAIRY CALVES
Anne Laarman, M.Sc.Ph.D. Student
University of [email protected]
VFAs(incl. butyrate)
Rumen Development
Starter
Acidotic pressure
Protein
Epithelium
Rumen Development
With low pH, fermentation bacteria start to die off
Starter VFAs
(incl. butyrate)
Acidotic pressure
Protein
Epithelium
Calf Starter Study
MilkHay
MilkHay
Starter
Weaning
Weaning
• Experiment set-up for investigating the role of calf starter in rumen pH and metabolic adaptations
Small Ruminant pH Logger System
Dosing Small Ruminant pH Logger System
Sample pH Results
6:00
7:59
9:59
11:5
9
13:5
9
15:5
9
17:5
9
19:5
9
21:5
9
23:5
91:
593:
595:
594.5
5.0
5.5
6.0
6.5
7.0
7.5
Duration of Acidosis (pH < 5.8)
Area under the curve (pH < 5.8)
Time of Day
pH
Hay DMI and Average Rumen pH
Calves that consume more hay have a higher rumen pH
Laarman et al., 2012. In press
0 0.1 0.2 0.3 0.4 0.5 0.64.8
5
5.2
5.4
5.6
5.8
6
6.2
6.4
Hay DMI
Avera
ge p
H
Hay intake and Severity of Rumen Acidosis
Calves that consume very little hay are at greater risk of more rumen acidosis (pH < 5.8)
0 0.1 0.2 0.3 0.4 0.5 0.6 0.70
50
100
150
200
250
Hay DMI, kg/d
Are
a u
nd
er
the
Cu
rve,
pH
*min
/d
Laarman and Oba, 2011
Rumen pH profile Milk & Hay Milk & Hay &
StarterAverage pH 6.42 ± 0.10 6.27 ± 0.12
Duration Rumen Acidosis, min/d
101 ± 100 237 ± 126
Area under the Curve, pH*min/d
49.3 ± 36.5 64.2 ± 47.4
Total VFA, mM 64.6 ± 8.6 99.1 ± 8.1*
Butyrate, % Total 7.9 ± 1.9 15.6 ± 1.7*
Hay DMI, kg/d 0.23 ± 0.07 0.34 ± 0.8
Starter DMI, kg/d N/A 0.76 ± 0.04• Hay consumption appears unrelated
to calf starter intakeLaarman and Oba, 2011
Forage Consumption
Hay intake increases with age Doesn’t appear directly related to feeding
program
De Passillé et al., 2011
Rumen pH profile Milk & Hay Milk & Hay &
StarterAverage pH 6.42 ± 0.10 6.27 ± 0.12
Duration Rumen Acidosis, min/d
101 ± 100 237 ± 126
Area under the Curve, pH*min/d
49.3 ± 36.5 64.2 ± 47.4
Total VFA, mM 64.6 ± 8.6 99.1 ± 8.1*
Butyrate, % Total 7.9 ± 1.9 15.6 ± 1.7*
Hay DMI, kg/d 0.23 ± 0.07 0.34 ± 0.8
Starter DMI, kg/d N/A 0.76 ± 0.04• Despite higher VFA concentrations, calves fed calf starter did not have lower rumen pH
Laarman and Oba, 2011
Adaptations in the Rumen Epithelium
• Changes in gene expression suggest epithelium is adapting on a metabolic level
Milk & Hay
Milk & Hay & Starte
r
NHE-3 0.82 ± 0.12
0.37 ± 0.12*
NHE-2 0.84 ± 0.16
0.86 ± 0.17
MCT-1 0.53 ± 0.23
1.45 ± 0.22*
Laarman et al., 2012
Adaptations don’t just happen in the rumen
epithelium, but also in the liver
Urea Cycle - Liver Milk & Hay
Milk & Hay & Starter
Carbamoyl phosphate synthetase
8.67 ± 1.10 9.90 ± 1.10
Ornithine transcarbamoylase
1.34 ± 0.11 1.64 ± 0.11*
Arginosuccinate synthetase
1.56 ± 0.29 2.67 ± 0.29*
Arginosuccinate lyase
0.99 ± 0.10 1.44 ± 0.10*
Arginase 1.74 ± 0.32 3.21 ± 0.32*Laarman et al., 2012. In press
• Calf starter increases gene expression of 4 out of 5 urea cycle genes
Conclusion
Feeding solid feed can affect gene expression in rumen epithelium and liver pH regulation in epithelium Urea cycle in liver
Roughage can help manage rumen pH
Developing rumen adapts to increased acidotic pressure from calf starter fermentation
Acknowledgements
Dr. Tom Wright, University of Guelph Dr. Brian McBride, University of Guelph Dr. Masahito Oba, University of Alberta
OMAFRA HQP Program Japanese Federation of Dairy Co-Ops Agriculture and AgriFood Canada