Carmona, Peter

Costa, Diogo Fleury Azevedo

Lima, Lais de Oliveira

Mota, Veronica

Silva, Luis Felipe Prada

Yang, Jiailiang O

University of Queensland eSpace

“More efficient steers on good diets are not the most efficient ones on limiting diets” 
 
Carmona, P.; Lima, L.O.; Mota, V.; Yang, J.O.; Costa, D.F.A. and Silva, L.F.P. 
 
Summary 
As nutrition represents the major operative cost in beef cattle production, small 
improvements on feed efficiency (FE) may lead to significant economic benefits and 
parallelly, reduce its environmental footprint. Usually, animals are selected on high-protein 
(HP) diets and are expected to perform as efficient on low-protein (LP) diets. This experiment 
used 30 Bos indicus steers (398 ± 24 kg BW) with the objective of demonstrating whether 
FE in a HP diet is correlated to FE in a LP diet. The hypothesis suggested that there would 
be a strong correlation between diets. Steers were fed for two periods of 70 days, supplying 
either 100% or 70% of their rumen degradable protein requirements. Traits studied were 
average daily gain (ADG), dry matter intake (DMI), feed conversion ratio (FCR) and residual 
feed intake (RFI). In the LP diet, ADG was 0.93 kg/d (0.38 to 1.47), DMI averaged 9.67 kg/d 
(7.9 to 12.1), FCR averaged 11.14 kg/kg (6.6 to 27.8), and RFI varied from -1.55 to 1.84. In 
the HP diet, ADG was 1.16 kg/d (0.77 to 1.56), DMI was 9.87 kg/d (4.79 to 11.87), FCR was 
8.73 kg/kg (5.3 to 12.4), and RFI varied from -2.53 to 1.61. There was no correlation for FCR 
(P = 0.71; R2 = 0.005) nor for RFI (P = 0.08; R2 = 0.11) between both diets. These results 
suggest that different physiological mechanisms are responsible for FE regulation in both 
diets; thus, standard diets should not be used when targeting performance in low-protein 
diets. 


More efficient steers on good diets are not the most efficient ones on limiting diets

https://espace.library.uq.edu.au/view/UQ:56733c0/PeterCarmonaAbstract.pdf

More efficient steers on good diets are not the most efficient ones on limiting diets

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