Cone, J.W.

English

NARCIS 

Effects of maize cultivar and dry matter content at harvest on rumen fermentation properties.

Name not available

Wageningen Yield 

232 
 
Effects of maize cultivar and dry matter content at harvest on rumen fermentation properties 
J.W. Cone 
Animal Nutrition Group, Wageningen University, Wageningen, Netherlands 
Email:john.cone@wur.nl 
 
Introduction  Forage maize is mainly composed of starch in the ears and cell walls in the stover. Upon feeding maize to 
cattle starch can be fermented in the rumen, but after bypassing the rumen it can also be digested in the intestines. There is 
not much knowledge on the influence of maturation of the maize plants on the amount of rumen fermentable starch and on 
the kinetics of the rumen degradable part. There is also not much insight in the variation in rumen fermentation properties 
by different genotypes (cultivars). In many feed evaluation systems the total cell wall degradability of maize is valued and 
not its rate of degradation in the rumen. To get insight in the changes in cell wall and starch quality 4 different maize 
cultivars were harvested during the growing season and analysed for chemical composition and rumen fermentation 
kinetics, determined with the gas production technique. 
 
Materials and methods  Four maize cultivars were 
harvested at dry matter (dm) contents of 250 
(dm250), 320 (dm320) and 390 g/kg (dm390). 
Cultivar 1 (cv1) was an early dry down cultivar, cv2 
early stay green, cv3 late dry down and cv4 was a 
late stay green cultivar. Plants were separated in 
ears and stover, freeze dried and ground to pass a 1 
mm screen. Samples of 0.5 g dm were incubated in 
the gas production technique as described by Cone 
et al (1996). Non-lactating donor animals received 9 
kg DM grass hay and 1 kg DM concentrate daily. 
Gas production profiles were run in duplicate and 
fitted to a three-phasic model as described by Groot 
et al (1996). Presented are values for gas production 
after 20 h (GP20) and for A1 and A2, gas 
production caused by fermentation of the soluble 
and insoluble fraction respectively and B2 the time 
(h) needed to reach half of A2. Starch degradation 
after 10 h was calculated using gas production and 
starch content as described by Chai et al (2004). 
Statistical differences were recognised using 
analysis of variance. 
 
Results  Table 1, showing the main effects of the 
research, displays starch content, starch degradation 
after 10 h incubation and gas production parameters 
for the ear and stover samples. Dry matter content at 
harvest showed significant effects on all parameters.  
Cultivar was not significant for starch content and 
B2 in ears. Effects for dry matter x cultivar were 
only observed in ears for GP20, A1, A2 and 
degraded starch. 
 
Conclusions  Early harvest results in low starch 
contents and decreased fermentation of the non-
soluble fraction (A2). Upon maturation (higher dm 
content) rate of degradation of both starch and cell 
wall decreased (higher B2). This lead to a decrease in percentage starch degradation after 10 h incubation, which indicates 
a higher percentage of rumen escape starch. Prolonged maturation results in decreased cell wall degradability (low A2) and 
decreased rate of degradation (high B2). Expanded studies should point the optimum harvest date (dm content) to obtain 
maize with high yield, high starch content and high cell wall degradability and optimal starch degradation in the rumen 
with desired amounts of rumen escape starch and maximum digestibility in the intestine. 
 
References 
Chai, W.Z., Van Gelder, A.H. and Cone, J.W. 2004. Animal Feed Science and Technology 114, 195-204. 
Cone, J.W., Van Gelder, A.H., Visscher, G.J.W. and Oudshoorn, L. 1996. Animal Feed Science and Technology 61, 113-
128. 
Groot, J.C.J., Cone, J.W., Williams, B.A., Debersaques, F.M.A. and Lantinga, E.A. 1996. Animal Feed Science and 
Technology 64, 77-89. 
Table 1  Content of starch (g/kg DM), gas production (ml/g OM) 
after 20 h (GP20), caused by fermentation of the soluble fraction 
(A1) and the insoluble fraction (A2), time (h) needed to reach half 
the maximum of A2 (B2) and the starch degraded (g/kg) after 10 
h incubation. 
 Starch GP20 A1 A2 B2 Starch degr. 
 g/kg 
DM 
ml/g 
OM 
ml/g 
OM 
ml/g 
OM h g/kg 
Maize ears      
dm250 426 299 45.6 253 7.25 771 
dm320 630 310 28.2 282 7.54 665 
dm390 648 309 23.9 285 7.77 619 
lsd 29 5.2 1.9 4.2 0.23 13 
cv1 576 304 32.9 271 7.40 682 
cv2 563 312 32.1 280 7.61 694 
cv3 546 305 37.0 268 7.44 701 
cv4 586 303 28.3 275 7.64 650 
lsd 33 6.0 2.2 4.8 0.27 15 
Effect dm *** *** *** *** ** *** 
Effect cv ns * *** *** ns *** 
Effect dm x cv * ** * ns ** 
Maize stover      
dm250  210 52.1 158 8.47  
dm320  193 38.3 155 9.05  
dm390  191 43.3 147 9.40  
lsd  6.3 2.9 4.8 0.15  
cv1  190 40.1 150 9.34  
cv2  193 39.2 154 8.96  
cv3  211 52.8 158 8.84  
cv4  197 46.1 151 8.76  
lsd  7.2 3.3 5.6 0.17  
effect dm  *** *** ** ***  
effect cv  *** *** * ***  
effect dm x cv ns ns ns ns  


Effects of maize cultivar and dry matter content at harvest on rumen fermentation properties.

Abstract

Similar works

Full text

Available Versions

NARCIS

Name not available

Wageningen Yield