Submitted to: Small Ruminant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/5/2004
Publication Date: 7/1/2004
Citation: Luo, J., Goetsch, A.L., Nsahlai, I.V., Johnson, Z.B., Sahlu, T., Moore, J.E., Ferrell, C.L., Galyean, M.L., Owens, F.N. 2004. Maintenance energy requirements of goats: predictions based on observations of heat and recovered energy. Small Ruminant Research. 53:221-230.
Interpretive Summary: Regressions of treatment mean observations from energy balance publications indicate that BW0.75 is an appropriate scaler of goat energy requirements. Fasting heat production and metabolizable energy for maintenance estimates of 298 and 431 kJ/kg BW0.75, respectively, appear useful as general describers of maintenance energy needs of goats continuously consuming diets at, near or above maintenance. Further study is necessary to develop energy requirement expressions for goats more appropriate for specific production or experimental conditions.
Technical Abstract: A database including 80 treatment means, based on energy balance publications, was constructed and analyzed to estimate fasting heat production (FHP) and ME required for maintenance (MEm) of goats. Experiments entailed comparative slaughter, respiration calorimetry or CO2 entry rate techniques. Goats were of eight breeds and five physiological states (preweaning; growing; mature and non-lactating; early and mid-pregnancy; and lactating). Assuming that heat increment was 40% of total heat energy, unweighted, and weighted (number of observations per treatment mean) log'log regressions (n = 74 following removal of observations to increase explained variation) of FHP against BW resulted in FHP (kJ) = 299 x BW0.762 (R2 = 0.82) and 244 x BW0.826 (R2 = 0.75), respectively. The 0.762 and 0.826 BW scaling factors did not differ (P < 0.17) from 0.75. The slope and intercept of a regression of recovered energy (RE) against ME intake (MEI) for preweaning goats differed (P < 0.01) from those for other physiological states. A linear regression analysis of RE on MEI (both kJ/kg BW0.75) was conducted with the remaining 71 observations, after removing two observations with SD greater than 2.5 residual SD. The resultant equation was: RE = '298.0 (SE = 22.38) + (0.691 (SE = 0.028) x MEI) [n = 69; R2 = 0.90]. These estimates of FHP and efficiency of ME use yielded an estimate of MEm of 431 kJ/kg BW0.75. In summary, FHP and MEm of 298 and 431 kJ/kg BW0.75, respectively, appear appropriate as general descriptors of the maintenance energy requirement of goats consuming diets at, near or above maintenance.