This is a draft schedule. Presentation dates, times and locations may be subject to change.
611
Varying Levels of Low Quality Grass Hay NDF in Finishing Diets for Nellore Cattle
Monday, July 10, 2017
Exhibit Hall (Baltimore Convention Center)
Flávio Augusto P Santos, University of São Paulo, Piracicaba, Brazil
Juliano José de Rezende Fernandes, UFG, Goiania, Brazil
James S. Drouillard, Kansas State University, Manhattan, KS
Leonardo G. Oliveira, Nutripura Nutrição Animal Ltda, Goiânia, Brazil
Lainer Souza Leite, Nutripura Nutrição Animal Ltda, Rondonópolis, Brazil
Roughage is included in feedlot diets primarily for maintaining rumen health and increasing dry matter and energy intakes. The objective of this trial was to evaluate the effects of varying levels of low quality tropical grass hay NDF (4, 7, 10 and 13%) in finishing diets for Nellore bulls. Seven hundred and twenty (720) Nellore bulls (425.9 kg ± 29.9 IBW) were blocked by IBW and randomly allotted to 24 pens. Animals were adapted gradually to the final diets for 14 days and the experimental period lasted 96 days. Experimental diets contained 4, 7, 10 or 13% grass hay NDF (5.7 to 18.5% grass hay), ground corn (64.7 to 52.5%), soy hulls (14.5 to 13.8%), 8% whole cottonseed, 3% cottonseed meal, 1% urea and 3% minerals/vitamin mix with monensin. Data were analyzed using R statistical software. Increasing grass hay NDF content of the diets caused a quadratic response on DMI,TDN intake, ADG, FBW and HCW. Dressing and G/F decreased linearly, while kg of DMI/15 kg of carcass increased linearly as roughage NDF was increased in the diet. Due to the small differences on HCW among treatments, no differences were observed for BFT and REA. In conclusion, for zebu cattle fed typical Brazilian finishing diets containing ground corn plus byproducts, inclusion of 7% grass hay NDF in the diet increases DMI and optimizes energy intake, ADG, FBW and HCW while feed efficiency is greater with 4% grass hay NDF in the diet.
Table 1. Effects of varying levels of low quality grass hay NDF in the diet on performance of finishing Nellore cattle
|
Dietary grass hay NDF
|
SEM
|
P value
|
4%
|
7%
|
10%
|
13%
|
IBW, kg
|
427.2
|
427
|
425.7
|
424.5
|
1.952
|
0.742
|
FBW, kg**
|
554.5
|
569.3
|
569.1
|
568.1
|
2.665
|
0.003
|
DMI, kg**
|
9.722
|
11
|
11.318
|
11.604
|
0.16
|
<0.001
|
TDN intake, kg**
|
7.603
|
8.429
|
8.487
|
8.513
|
0.151
|
0.002
|
ADG, kg**
|
1.342
|
1.483
|
1.503
|
1.484
|
0.034
|
0.016
|
HCW, kg**
|
319.3
|
326.8
|
324.7
|
321.4
|
1.419
|
0.01
|
Dressing, (%)*
|
57.61
|
57.42
|
57.2
|
56.75
|
0.173
|
0.019
|
BFT, mm
|
4.99
|
4.92
|
5.31
|
5.36
|
0.23
|
0.468
|
REA, cm2
|
74.51
|
73.48
|
75.36
|
74.46
|
1.071
|
0.68
|
G/F*
|
0.138
|
0.135
|
0.133
|
0.128
|
0.003
|
0.083
|
DMI/15 kg of carcass, kg*
|
138.8
|
148.7
|
158
|
164.4
|
3.019
|
<0.001
|
*Linear effect; **Quadratic effect.
|