Impact of feed efficiency and diet on adaptive variations in the bacterial community in the rumen fluid of cattle Assessment of the microbial ecology of luminal methanogens in cattle with different feed efficiencies Characterization of variation in rumen methanogenic communities under different dietary and host feed efficiency conditions, as determined by PCR-Denaturing Gradient Gel Electrophor...

Metabolisable energy content of a feed or its components has been used to assess its feeding value for ruminants. The demonstration that VFA energy could, at times, be used highly inefficiently when included in a roughage diet, led to the suggestion that feeds for ruminants should be evaluated in terms of their net energy. The establishment of calorimetry technology in nutritional research was ...

Most breeding programs have focused on improving economically relevant output traits such as growth, carcass quality and fertility to enhance the economic viability of beef production systems. Generally absent from current breeding programs in the U.S. are avenues for exploiting genetic variation in feed efficiency, even though reductions in feed inputs would substantially improve profitability...

Intensive selection of sires is possible by using artificial insemination; coupled with accurate measurement of a potential sire’s genetic value, this has markedly improved genetics for easily measured traits like milk production and type traits. Increased milk production has in turn increased gross feed efficiency through dilution of maintenance. Additional genetic gains in feed efficiency wou...

Feed costs represent greater than 50% of the costs of producing milk. Several practical strategies have been applied to help minimize costs, including reduced feed losses during storage, reduced shrink at feed out, and determining favorable pricing for commodity feeds. Much less attention has been directed towards improving feed efficiency in dairy cattle. Although recognized as an important co...

One option that can be used to select cattle for improving feed efficiency is to select for genes affecting residual feed intake. Previous studies using two groups of cattle, the Trangie Angus residual feed intake (RFI) selection line cattle and the Davies Jersey x Limousin gene mapping cattle have identified five chromosomal regions or QTL that have significant effects on net feed efficiency. ...

Introduction Feed costs comprise the majority of variable expenses in beef cattle systems making feed efficiency an important economic consideration within the beef industry (Koch et al ., 1963; Dickerson et al ., 1974) . Aside from the direct economic impact of this trait complex at the individual producer level, the projections of global population growth provide extra pressure for efficient ...