Associative effects of
feeds
Gbola Adesogan
Department of Animal Sciences
University of Florida
Associative effects
DEFINITION: Interaction between nutrients in
different ingredients in a ration which result in
performance that is greater or less than expected
from the individual ingredients
E.g. the NE of a mixed diet may not reflect the NE
calculated from the ME intakes of the ingredients
Reflect non-additivity of nutrients in feeds
May be positive, negative or absent
DE
A
B
actual
expected
Associative effect illustration
0.50 A +0.50 B
Positive associative effects
1. Increased fiber utilization after N supplementation
in N deficient forages
2. Increased fiber utilization after supplementation of
roughages with small quantities of sugars
3. Increased intake when more than one forage is fed
4. Increased microbial protein production due to
synchronized / balanced diets
Effect of supplementation with urea
or alfalfa hay on straw intake
Straw
Alfalfa
1200
1000
800
600
400
200
0
Straw (S)
S + 1% Urea
S + 150g
Alfalfa hay
S + 300 g
Alfalfa hay
S + 450 g
Alfalfa hay
Fiber digy. is often increased by N supplementation if feed
CP content is < 62 g/kg DM (Minson, 1990)
Effect of suppl. with urea or alfalfa
hay on rumen degradation
Rate (%/h)
Extent (g/g)
2.1
1.9
1.7
1.5
1.3
1.1
0.9
0.7
0.5
Straw (S)
S + 1% Urea
S + 150g
Alfalfa hay
S + 300 g
Alfalfa hay
S + 450 g
Alfalfa hay
Mixed forage diets
Grass silage
Other forage
0
25
50
75
100
0
25
50
75
100
(Phipps ‘92)
Effect of cereal silage inclusion on
DM intake (kg/d)
WS
MS
8
8
7.7
7.6
7.9
7.7
7.7
7.8
7.5
7
7
6.5
6.3 6.3
6
0
25%
50%
75%
100%
(Phipps ‘92)
Effect of cereal silage inclusion on
milk yield (kg/d)
WS
MS
19.4
19.3
19
18.8
18.118.1
18.5
18.1
18.2
18.4
18.2
17
15
0
25%
50%
75%
100%
(Phipps ‘92)
Effect of replacing corn in dairy cow
diets with barley on performance
% Barley1
contrast, P<
DMI
0
22.8
25
22.1
50
21.3
75
19.5
100
19.6
Lin
.01
Quad
NS
Milk (kg/d)
26.9
27.8
26.6
25.2
22.6
.002
.05
3.5% FCM (kg/d) 27.3
27.4
26.4
24.7
23.7
.003
NS
Fat (%)
3.58
3.37
3.50
3.41
3.91
NS
.03
Protein (%)
3.36
3.36
3.44
3.45
3.69
.003
NS
46.4
46.7
50.2
56.0
0.02
NS
Microbial N (%NAN) 46
(Overton et al., 1995
Effect of replacing grass silage
with WCW on starch digestibility
(%)
0
33
67
100
110
100
98
90
81
80
80
70
65
60
50
0
33
67
100
(Phipps ‘92)
Effect of processing maize on
performance of dairy cows
Rolling
Steam
flaking
% Change
DMI (kg/d)
26.5
26.5
0
Milk (kg/d)
35.8e
38.0f
6
Prot (%)
2.99g
3.06h
2
Prot (kg/d)
1.07e
1.16f
8
Fat (%)
3.11e
2.98f
-4
Fat (kg/d)
1.12
1.13
1
Total starch dig (%)
87.4i
95.7j
9
(Theurer et al., 1999)
Positive associative effects
High NSC and High RDP forages
Simultaneously offered cereal and legume forages
that respectively may enhance microbial protein
production and hence, animal performance.
Effect of replacing grass silage + 8kg conc
with pea-wheat silage + 4kg conc
Forage
Grass
silage
Grass
silage
Magnus
bi-crop
Setchey
bi-crop
Conc.
level
(kg/d)*
4
ID
GS4
8
GS8
4
MW4
4
SW4
Feed intake and Milk yield (kg/day)
30
Conc. Level
Forage DMI
Total DMI
Milk yield
Fat-corrected milk yield
20
10
0
GS8
GS4
MW4
SW4
Negative associative effects
1. Concentrate supplementation of forage diets in
excess of 600 g/kg DM depresses fiber utilization
2. Fat supplementation of diets in excess of 60g/kg
DM depresses fiber digestion
– Coats particles thereby preventing fermentation,
– Reduced intake due to chemostatic feedback
from high energy diets
– Certain PUFAs are toxic to ruminal microbes
3. Presence of antinutritive factors which hinder
nutrient utilization
Supplementation of grazing
ruminants with NDF / NSC
Anderson et al., 1988
Effect of rumen pH & starch
supplementation on NDF digestion
pH
5.8
602
6.8
5.8
6.2
6.8
Starch
-
-
-
+
+
+
Alfalfa hay
INDF
24.4a 25.4a
25.5a
19.9b
19.7b
20.3b
Bromegras
hay INDF
31.1a 29.3a
28.5a
16.6b
16.3b
17.1b
INDF = indigestible NDF
(Grant and Mertens, 1992)
Effect of rapeseed oil
supplementation on digestibility
10
9
8
7
6
5
4
3
2
1
0
Control
Fat content (%)
NDF digestibility
(g/10g
DM digestibility
(g/10g)
Control
Infused fat
Single dose
Factors determining
associative effects
Ingredient palatability
Nutrient content of dietary ingredients
Nutrient ratios e.g. energy:protein NSC vs NDF;
NSC vs RDP
Energy:protein ratio
Physical form of feed (due to conservation /
processing method)
Microbial activity
Substitution rate
Level of feeding and outflow rates
Measuring associative effects
Feeding supplements at different ratios to a basal diet
(Van Soest, 1994).
Statistical methods
– Continuous analysis
– Response Surface Methodology
Estimation of associative effect
(Van Soest, 1994)
Associative effect of fermenting
two forages together
data – obtained from fermentation of individual components
I.e. half of (100:0 and 0:100)
• Expected
observed data (50:50)
(Rosales et al., 1998)
Associative effects –
implications
Not built into most current feeding systems yet
they:
– Over or undervalue nutrients / ingredients
– Prevent determination of digestibility of
components of a mixed ration by difference.
– Limit the usefulness of nutritive value indices
measured on individual foods.
Conclusion
Associative effects are real and nutritionists should
complement the science of feeding, with the “art” of
feeding, by utilizing positive associative
interactions….. to increase flexibility of diets as
typical grain and roughage prices fluctuate.
(Erasmus 2002)
Negative interactions must also be avoided.
References
Erasmus (2002) Associative effects in dairy feeds – are they real?
http://www.agri24.com/AFMA_Template/1,2491,7105_1842,00.html
Ferlay A, Doreau M Influence of method of administration of rapeseed oil
in dairy-cows .1. Digestion of nonlipid components
J DAIRY SCI 75 (11): 3020-3027 Nov 1992
Grant RJ, Mertens DR Influence of Buffer Ph and Raw Corn Starch
Addition on Invitro Fiber Digestion Kinetics
J DAIRY SCI 75 (10): 2762-2768 Oct 1992
Vogel, Phillips et al., 1988. Effects of supplemental silage on forage intake
and utilization by steers grazing wheat pasture or bermudagrass.
Journal of Animal Sci. 67:232-240
Haddad, S G., 2000. Associative effects of supplementing barley straw
diets with alfalfa hay on rumen environmenta nd nutrient intake and
digestibility for ewes. Animal Feed Science and Technology. 87:163171
Franci, O et al., 1997. Response surface analysis of the associative
effects of lucerne hay, wheat straw and maize gluten feed on growing
lambsa. Animal Feed Science and Technology. 279-290
Van Soest. P. J. 1994. Nutritional Ecology of the ruminant
Casper, D.P. and D.J. Schingoethe. 1989. Lactational response of dairy cows to diets varying in
ruminal solubilities of carbohydrate and crude protein. J. Dairy Sci. 72:928.
Casper, D.P., D. J. Schingoethe and W.A. Eisenbeisz. 1990. Response of early lactation dairy
cows fed diets varying in source of nonstructural carbohydrate and crude protein. J. Dairy Sci.
73:1039.
Firkins, J.L. 1997. Effects of feeding nonforage fiber sources on site of fiber digestion. J. Dairy Sci.
80:1426.
Overton, T.R., M.R. Cameron, J.P. Elliot and J.H. Clark. 1995. Ruminal fermentation and passage
of nutrients to the duodenum of lactating cows fed mixtures of corn and barley. J. Dairy Sci.
78:1981.
Ramanzin, M., L. Bailoni, S. Schiavon and G.B. Hante. 1997. Effect of monensin on milk
production and efficiency of dairy cows fed two diets differing in forage to concentrate ratio. J.
Dairy Sci. 80:1136.
Sinclair, L.A., Garnsworthy, P.C., Newbold, J.R. and Buttery P.J. 1995. Effect of synchronizing the
rate of dietary energy and nitrogen release in diets with a similar carbohydrate composition on
rumen fermentation and microbial protein synthesis in sheep. J. Agric. Sci. Camb. 124:463.
Kolver, E.S. and L.D. Muller. 1998. Performance and nutrient intake of high producing Holstein
cows consuming pasture or a total mixed ration. J. Dairy Sci. 81:1403.
Anderson, S. J., J. K. Merrill, and T. J. Klopfenstein. 1988a. Soybean hulls as an energy
supplement for the grazing ruminant. J. Anim. Sci. 66:2959.
Theurer, C.B. 1996. Steam flaking improves starch utilization and milk production parameters.
Page 121 in Proc. Cornell Nutr. Conf. Food Manuf., Dept. Anim. Sci., Cornell Univ., Ithaca, NY.
Theurer, C.B., J.T. Huber and A. Delgado - Elorduy. 1997. Steam flaked versus steam rolled corn
for dairy cows. Page 79 in Proc. 4 - State Applied Nutr. and Manage. Conf., Dept. Dairy Science,
Univ. Wisconsin, Madison.
Theurer, C.B., R. Wanderley and J.T. Huber. 1999. Steam flaking grains may improve nutritional
value. Feedstuffs 71 (20):16.
Varga, G.A. and P. Kononoff. 1999. Dairy rationing using structural and nonstructural
carbohydrates: from theory to practice. Page 77 in. Proc. Southwest Nutr. Management Conf., Feb
25 - 26. Dept. Anim Sci., Univ. Arizona, Tucson, AZ.