Abstract
Effects of solid feed (SF) level and roughage-to-concentrate (R:C) ratio
on ruminal drinking and passage kinetics of milk, concentrate, and
roughage in veal calves were studied. Eighty calves (2 wk of age, 45 kg
bodyweight) were divided over 16 pens. Pens were randomly assigned to
a low (LSF) or a high (HSF) SF level, and to one of 2 R:C ratios; 20:80
or 50:50 on a DM basis. Roughage was composed of 50% corn silage
and 50% chopped straw on a DM basis. During the measurement period
at 27 wk of age, SF intake was 1.2 kg DM/d for LSF and 3.0 kg DM/d
for HSF, and milk (replacer) intake averaged 2.3 kg DM/d for LSF and
1.3 kg DM/d for HSF. To estimate passage kinetics of milk, concentrate,
and straw, indigestible markers (respectively CoEDTA, hexatriacontane
C36, Cr-NDF) were supplied with the feed as a single dose at respectively
4, 24, and 48 h before slaughter. At slaughter, marker recovery was
quantified in the rumen, abomasum, small intestine, and large intestine.
Rumen Co recovery averaged 20% of the last milk meal. Recoveries of
milk remained largely unaffected by SF level and R:C ratio. Ruminal
recovery of C36 and Cr was unaffected by R:C ratio. Rumen fractional
passage rate of concentrate was estimated from recovery of C36 in the
rumen and increased (P <0.001) from 3.3%/h for LSF to 4.9%/h for
HSF. Rumen fractional passage rate of straw was estimated from Cr
recovery in the rumen and increased (P <0.01) from 1.3%/h for LSF
to 1.7%/h for HSF. A greater SF level increased (P <0.001) fresh and
dry rumen contents. In HSF calves, pH decreased (from 6.9 to 6.0; P
<0.01) and VFA concentrations increased (P <0.05) with a lower R:C
ratio, indicating increased fermentation. The Cr:C36 ratio was similar in
the small and large intestine, indicating that passage of concentrate and
straw was mainly determined by rumen and abomasum emptying. In
conclusion, SF level rather than R:C ratio influences rumen passage of
concentrate and roughage. Our data provide insight in passage kinetics
of milk and SF and may contribute to the development of feed evaluation
models for veal calves
| Original language | English |
|---|---|
| Title of host publication | Book of abstracts of 2015 Joint Annual Meeting of ADSA-ASAS |
| Pages | 869 |
| Volume | 98 |
| Publication status | Published - 2015 |
| Event | Joint Annual Meeting 2015 ADSA-ASAS - Orlando Duration: 12 Jul 2015 → 16 Jul 2015 |
Conference
| Conference | Joint Annual Meeting 2015 ADSA-ASAS |
|---|---|
| City | Orlando |
| Period | 12/07/15 → 16/07/15 |