Relationships between digestible energy and metabolizable energy in current feedlot diets1

Abstract

It is commonplace that metabolizable energy (ME) is calculated from digestible energy (DE) as DE × 0.82. However, recent published literature suggests that the relationship between DE and ME is variable depending on the type of diet used, and is typically > 0.90 when high-concentrate diets are fed. Literature means were compiled from 23 respiration calorimetry studies where total fecal and urine collections were conducted and gaseous energy was measured. The relationship between experimentally observed and predicted ME (DE × 0.82) was evaluated using these previously reported treatment means. Additionally, a previously published linear regression equation for predicting ME from DE was also evaluated using a residual analysis. Published (Hales, K. E., A. P. Foote, T. M. Brown-Brandl, and H. C. Freetly. 2017. The effects of feeding increasing concentrations of corn oil on energy metabolism and nutrient balance in finishing beef steers. J. Anim. Sci. 95:939–948. doi:10.2527/jas.2016.0902 and Hemphill, C. N., T. A. Wickersham, J. E. Sawyer, T. M. Brown-Brandl, H. C. Freetly, and K. E. Hales. 2018. Effects of feeding monensin to bred heifers fed in a drylot on nutrient and energy balance. J. Anim. Sci. 96:1171–1180. doi:10.1093/jas/skx030) and unpublished data (K. E. Hales, unpublished data) were used to develop a new equation for estimating ME from DE (megacalories/kilogram [Mcal/kg] of DM; ME = −0.057 ± 0.022 DE2 + 1.3764 ± 0.1197 DE – 0.9483 ± 0.1605; r2 = 0.9671, root mean square error = 0.12; P < 0.01 for intercept, P < 0.01 for linear term, and P < 0.01 for quadratic term). To establish a maximum biological threshold for the conversion of DE to ME, individual animal data were used (n = 234) to regress the ME:DE on DE concentration (1.53 to 3.79 Mcal DE/kg). When using experimentally derived data and solving for the first derivative, the maximum biological threshold for the conversion of DE to ME was 3.65 Mcal DE/kg. Additionally, the quadratic regression (equation 1) was used to predict ME from a wide range of DE (1.8 to 4.6 Mcal/kg). The ME:DE ratio was then calculated by dividing predicted ME by DE. The maximum biological threshold for the conversion of DE to ME was estimated by solving for the first derivative and was 3.96 Mcal DE/kg. In conclusion, this review suggests that the relationship between DE and ME is not static, especially in high-concentrate diets. The equation presented here is an alternative that can be used for the calculation of ME from DE in current feedlot diets, but it is not recommended for use in high-forage diets. The maximization of ME in current diets, maximum biological threshold, occurs between 3.65 and 3.96 Mcal DE/kg in the diet, which based on these data is approximately 3.43 to 3.65 Mcal/kg of ME consumption.

Functional Changes of the Community of Microbes With Ni-Dependent Enzyme Genes Accompany Adaptation of the Ruminal Microbiome to Urea-Supplemented Diets

“…Dietary Ni supplementation has been shown previously to increase urease activity in the rumen ( Spears et al, 1977 ; Singh et al, 2019 ; Spears, 2019 ). By contrast, methane production, which requires the Ni-dependent cofactor F430 for coenzyme M reductase reaction, is mostly not influenced by dietary Ni supplementation ( Oscar et al, 1987 ; Oscar and Spears, 1988 ). Virtually nothing is known about the regulation of other Ni-dependent enzymes or the microbes expressing those enzymes by Ni concentration in the rumen.…”

Genetic Parameters for Tolerance to Heat Stress in Crossbred Swine Carcass Traits

“…All individuals were crossbred gilts and barrows, progeny of Duroc sires, and different purebred or crossbred dam lines. Animals were born in three sow farms and raised between September 2015 and November 2019 on two commercial grower–finisher flows ( Bergamaschi et al, 2019 ). The initial data set was composed by 135,768 records, which were edited by removing outliers (exceeding three SD from the mean) for each trait.…”

Accounting for Genetic Differences Among Unknown Parents in Bubalus bubalis: A Case Study From the Italian Mediterranean Buffalo

“…According to official data [ Associazione Nazionale Allevatori Specie Bufalina (ANASB), 2020 ] and following a worldwide tendency ( Singh and Balhara, 2016 ; Purohit et al, 2019 ), the proportion of natural mating in IMB decreased from around 76 to 62% from 2010 to 2019 [ Associazione Nazionale Allevatori Specie Bufalina (ANASB), 2020 ]. These values, even if promising, are still lower than what it is observed in other species such as in dairy cattle, where the use of artificial insemination is close to 100% ( Rodríguez-Martínez and Peña Vega, 2013 ; Ugur et al, 2019 ). Among the reasons why natural mating is still the most common reproduction technology for water buffalo there are physiological and reproductive aspects, herd management, breeding techniques, and organization ( Neglia et al, 2020 ).…”

“…To mitigate this undesirable effect, several statistical methods have been developed over the years. The use of genetic grouping, parentage probabilities, use of phenotypic information to increase the probability of defining the paternity, iterative empirical Bayesian model (ITER), Bayesian hierarchical model (HIER), and model based on the average relationship matrix (ANRM), have been applied to account for uncertain paternity ( Henderson, 1988 ; Peškovičová et al, 2004 ; Sapp et al, 2007 ; Petrini et al, 2015 ; Carneiro et al, 2017 ; Shiotsuki et al, 2018 ; Macedo et al, 2020 ).…”

“…The inclusion of genetic groups in VC and EBV is a method that has been adopted and extensively validated, as an example, in beef and dairy cattle ( Perez-Enciso and Fernando, 1992 ; Sullivan, 1995 ; Theron et al, 2002 ; Peškovičová et al, 2004 ; Phocas and Laloë, 2004 ; Petrini et al, 2015 ; Wolak and Reid, 2017 ). The assignment of genetics groups to animals with uncertain genealogy represents a simple and effective solution to increase the accuracy of genetic evaluations ( Henderson, 1988 ; Cardoso and Tempelman, 2003 ).…”