SHORT COMMUNICATION
Meta-analysis of the effect of forage type on the efficiency of utilization of energy for milk production in dairy cows
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1
Department of Animal Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
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Animal Nutrition Group, Wageningen Institute of Animal Sciences, Wageningen University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands
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Centre for Nutrition Modelling, Department of Animal and Poultry Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada
CORRESPONDING AUTHOR
E. Kebreab   

Department of Animal Science, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
Publication date: 2007-09-17
 
J. Anim. Feed Sci. 2007;16(Suppl. 2):184–188
 
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ABSTRACT
The study investigated the effect of forage type on maintenance energy (MEm, MJ/kg BW0.75 per day) requirement and the efficiency of utilization of metabolizable energy intake for milk production (kl). A database containing 652 observations was assembled from calorimetry studies. The data was subdivided into six sets. These were grass silage 1, maize silage 2, fresh grass 3, mixed silage 4, dried grass 5, and straw 6, based diets. Meta-analysis estimated the values of MEm and kl to be 0.54, 0.56, 0.56, 0.60, 0.72, 0.59, 0.54, 0.58, 0.55, 0.58 and 0.61, 0.60 for subsets 1-6, respectively. There was no significant difference in the estimate of fasting heat production (FHP) in all subsets except fresh grass. This resulted in a significant difference in MEm when compared to cows fed other diets. Although differences in kl were observed when data were fitted with fixed FHP, unconstrained fitting showed that kl was about 59%.
ISSN:1230-1388