Background and objectives
One of the three component of the research program of the digestive ecosystem nutrition team of UMR
TANDEM covers maturation er orientation of the digestive ecosystem in dairy calves. The first results in the
team show that the implementation of the ruminal microbiota seems to unfold in three phases: an
inoculation taking place during the first days of life and certainly in direct contact with the environment of
the animal, a phase of disappearance / appearance of certain bacteria, called the selection phase and finally
a stabilization phase after 15 days of life during which bacterial groups represented in ruminal level are
similar to those shown in an adult cow even if a large inter-individual variability is observed. Note that the
selection phase is a period during which the calf begins to ingest solid food (especially forrage and
concentrate), therefore suggest the potential modulator role of the milk planning.
From a zootechnic perspective, a feed plan for young dairy calves by distributing only 6 meals per week
reduces the working time of the breeder, led to an increase (from 35 to 55%), the concentrated feed intake
in the pre-ruminant the day the feed is not distributed (Brunschwing and Plouzin, 2007).
In addition, the OAD technique (Bonilait Protéines, France) based on the distribution of one meal a day from
the 3rd day, which also simplifies the task of the breeder, would increase the total intake of concentrate
until weaning of about 25% (data unpublished, Bonilait Protéines).
With the OAD technique, the modulation of the quantity of milk replacer through by the number of meals
seems an interesting lever action on the level of concentrate intake. The effects of the implementation of the
ruminal microbiota and functional maturation should be be studied.
Hypothesis
Precocity and / or increase solid feed intake induced to compensate the lower distribution of milk replacer in
young receiving once meal a day (Technique OAD, Bonilait Protéines) would, during the maturation of the
rumen ecosystem: the acceleration phase of selection, the selection of flora more adapted to diets rich in
concentrates may therefore lead to improved feed efficiency of animals in the short term to medium and long
term.
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Aims of trial
To study the effect of Once A day programm (from the 4th day of life) versus twice a day on the temporal
and functional maturation of ruminal ecosystem from birth to weaning.
From the zootechnic point of view, it is:
- Ensure that once a day Technique gives breeders a level of growth that is equivalent to that permitted by a
twice a day program.
- Verify that the technique induced an earlier and / or more solid food consumption, especially concentrated
feed
From a scientific point of view, it is to understand the plasticity of the rumen ecosystem. This implies of
interest to both the adaptive mechanisms of ruminal ecosystem and their determinism between birth and
weaning:
-how to build the adaptive response of the rumen in response to factors of early ecosystem change,
particularly in link with feed intake?
- What are the amplitude and duration of the shift caused by the variation factor ecosystem?
Materials and methods
Animals and housing
16 Prim Holstein male calves are followed from birth until weaning (63 days) on the unit of INPT-ENSAT of
Poucharramet (France). They are housed in individual pens equipped with bucket holder and a rack. The
boxes are mulched every day and bedding is completely renewed every two days.
Feeding program
Upon arrival, the animals were subjected to one of two treatment (Table 1) corresponding to the two tested
program:
- Once A Day Technique (OAD)
- Conventional program Twice A Day (TAD)
Milk replacers, characterized by two different formulas, however, have the same levels of digestible protein
(18.7%) and metabolizable energy (4200 kcal / kg).
Moreover, the TAD program was drawn up to provide animals with the same volume of milk replacer by
meal for the OAD program (for experimental reasons), but with a concentration below: 125 g / L for TAD
program and 200 g / L for the OAD program. As a result, over a period of 63 days, the calves of OAD group
receive 34.1 kg / calf milk replacer while calves of TAD group receive 40.9 kg / calf milk replacer.
Nb meal/day
Quantity powder/meal (g)
Volume of milk
replacer/meal (L)
Control
milk
replacer
Solid feed
Nb meal/day
Quantity powder/meal (g)
Volume of milk
replacer/meal (L)
Colosturm* 2 L each 8
hours
Twice A
Day
Once A Day
Day 1
Technique
Once A
Day
Day 2&3 Day 4
2
AM
Whole
Whole
milk**
milk**
2
2
2
Whole
milk**
2
1
Whole
milk**
2
No
No
Water
A libitum
Lyophilized colostrums-30% Igg (g/meal)
100
50
No
*colostrums from mother (first milking) or from a reserve of frozen colostrums
**blend of whole milk
***concentrate starter Passio FLoc Junior (Sud Ouest Aliment, France)
Day 4
PM
Hydrating
sachet
D5-D7 W2
1
1
400
500
W3
600
W4 – W6
1
700
W7
1
600
W8
1
500
2
2
2.5
3
3.5
3
2.5
2
1
2
2
2
2
2
2
2
Hydrating
250
312.5
375
437.5
375
312.5
250
2
2.5
3
3.5
3
2.5
2
sachet
2
Concentrate ad libitum***
Straw ad libitum
The reconstituted milk replacer was distributed at a temperature between 40 ° C and 45 ° C at 8:00 for all
calves and 16.00 for calves TAD group. The animals will have clean water from D3 (renewal 2 times a day at
8:00 and 16:00)
2
W9
1
400
Measurement
1- Ingestion
The quantities offered and refusal of straw (1 time per day, 10.00), water and concentrated (8:00
AM and 16:00) are precisely weighed and recorded. The temperature of the milk replacer distributed
is measured and recorded individually at each meal. The amount of milk feed refused was weighed
and recorded individually at each meal.
2- Growth monitoring
The calves were weighed at birth before the first suckling, then once a week (at 15:30).
3- Ruminal histology
The last 8 calves (4 calves OAD and 4 calves TAD) of the trial are slaughtered between 64 and 68 days
of age at the slaughterhouse (Samatan, France).
Figure 1: table for cutting the digestive tract following the taking on the slaughter line.
The digestive system is cut at the esophagus and pylorus and is taken by the staff of the slaughterhouse. It is
then opened along the plane of Figure 1, drained and washed. The whole is weighed first and then the
reticulo-rumen, omasum and abomasum are separated to be weighed individually.
Finally samples for histological measurements are made in three standard sites (Figure 2).
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Figure 2: positioning of the sampling sites of ruminal epithelium.
On the one hand, the samples taken are then fixed in formalin, included in paraffin and a series of
histological cuts were stained with hematoxylin and eosin for histopathological analysis on sites 1, 2 and 3.
Histological sections taken at the site 1 (ventral sac) are then subjected to morphometric analysis by image
analysis (Visilog, VSG, France) to measure:
- The length of the papillae (average of 10 buds / calf)
- The basal width of the papillae (average of 10 buds / calf)
- The apicale width of the papillae (average of 10 buds / calf)
On the other hand, the density of the papillae at the site 1 (ventral sac) is evaluated by counting on samples
preserved in formalin solution (10%) at 3 square of 1 cm ² by image analysis (Visilog, VSG, France).
Figure 3: counting of rumen papillae density (a) and morphometry of rumen papillae on histological
section under the microscope (b) of samples taken at the ventral sac of the rumen.
Statistical analysis
Statistical analysis is made with R (R.2.14).
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Results – discussion
1- Zootechnical performances
a- Growth
The level of growth is satisfactory. Indeed, the milk replacer OAD in association with a relatively
palatable concentrate and straw can achieve a level of growth ensuring weaning weight higher than:
an average live weight of 93.4 for calves OAD and 99.1 kg for calves TAD for a similar birth weight (46
kg on average).
Figure 4: effect of feed program on the growth of calves from birth to weaning
The observed average daily gain from birth to weaning is respectively 755 and 842 g/d for calves
OAD and TAD (table 2). Calves receiving the OAD program have a level of ADG significantly lower (p =
0.011) from birth to J22, but ADG from D22 to weaning did not differ between the two groups and
reach an average value of 1017 g / d.
Table 2: Evolution of body weight from birth to weaning for each lot
Body weight (kg)
Day 0
Day 8
Day 15
Day 22
Day 29
Day 36
Day 43
Day 50
Day 57
Day 63
ADG (g/d)
Day 0-day 63
Day 0-day 22
Day 22-day 63
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b Ingestion
The quantity of straw and concentrate intake between birth and weaning is no different:
respectively 3.3 and 50.4 kg kg on average (Table 3).
Table 3: quantity (g) of straw and concentrate intake from birth to D22, from D22 to weaning,
during week 9 and during all the period (birth-weaning)
Straw intake (g)
Birth – Day22
Day 22- day 63
Week 9
Total
Concentrate intake (g)
Birth – Day22
Day 22- day 63
Week 9
Total
The minimum of concentrate intake usually set to wean calves that is 2 kg of concentrate per day is
largely achieved in week 9 for calves in both groups, thus leaving predict good conditions for
weaning.
About 6-8 weeks, there was a significant positive effect (p = 0.047) of the interaction of age x
treatment on the average quantity of concentrated feed intake per day starting reflecting the slower
increase this intake for calves TAD compared to calves OAD ( Figure 5). In week 9, the daily feed
intake of calves receiving all TAD and OAD milk replace once a day did not differ (Table 3) and
reached 2330 g/d on average.
Concentrate intake
(g/day)
Figure 5: effect of treatment (OAD vs TAD) on concentrate intake from birth to weaning.
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2- Anatomy of rumen
First, weight of calves TAD (cold carcass) tends (p = 0.09) to be higher (12%) than calves OAD. The
relative weight of the reticulo-rumen (62.9%), of the omasum (16.8%) and of the abomasum
((20.3%) , relative to the total weight of the four stomachs did not differ with treatment.
The density of rumen papillae (PR) is higher (P = 0.006) for calves OAD (84.8 PR/cm²) than for calves
TAD (64.7 PR/cm²). Moreover, microscopic observation of longitudinal sections taken at the three
sampling sites it does not show major histopathological abnormalities of the rumen wall regardless
of the treatment.
Cold carcass weight (kg)
Weight of empty stomachs (kg)
Reticulo-rumen
Omasum
Abomasum
Total
Weight of empty stomachs (% total weight)
Reticulo-rumen
Omasum
Abomasum
Weight of empty stomachs (% total Cold carcass weight)
Reticulo-rumen
Omasum
Abomasum
Rumen papillae
Length (mm)
Basal width (mm)
Apical width (mm)
Area (mm²)*
Density (n/cm²)
Absorbing surface / cm² (mm²)
*Area = (Length x (apical width + basal width)))/2
** Absorbing surface = area x density x 2
As a result, the calculated ruminal surface absorption is significantly higher for calves OAD (98.1 mm²/cm²)
than for calves TAD (62.4 cm²/mm²).
CONCLUSION
The test resulted in a reduced number of animals (n = 16) from February to August 2012 reveals some key
findings:
The OAD technique ensures a satisfactory level of animal growth, comparable to that obtained with a
conventional technique twice a day day while reducing routine work for the farmer.
In our experimental conditions, the technique "Once a Day" did not lead to a higher consumption of
solid feed (straw and concentrated feed), or at an earlier consumption as it was expected.
The OAD technique allows development of rumen weight identical to that of calves led with a classic
technique twice a day
The OAD technique seems to favor the development of rumen papillae increasing their density (+ 31%
at weaning) and consequently the surface of ruminal absorption: + 57% at weaning.
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