title: Maintenance requirements in metabolizable energy of adult, nonpregnant, nonlactating Charolais cows.
abstract: The objective of this study was to determine the maintenance requirements in metabolizable energy (MEm) of adult, nonlactating, nonpregnant Charolais cows. A feeding trial was conducted using 12 cows fed at one of two feeding levels (75 [L] and 113 [H] kcal of ME.kg BW-.75.d-1) for 116 d. Body composition was estimated from subcutaneous adipocyte diameter. Body weight changes averaged -468 and +46 g/d, respectively. Diet DM digestibility averaged .496. The L cows spent less time eating and ruminating but had other behavioral characteristics similar to those of H cows. Estimates of MEm were calculated from BW or body composition changes and amounted to 109 and 124 kcal of ME.kg BW-.75.d-1, respectively. Heat production (HP) was then measured over 67 d in a second trial on two L and two H cows from the feeding trial and planes of feeding were switched after 14 d. Estimates of MEm varied from 112 to 105 kcal.kg BW-.75.d-1. Within animal, day-to-day variations in heat production were high (4.6% on average) and prevented the detection of any precise changes of HP with time on treatment. None of the trials showed any significant effect of level of feeding on MEm.
authors.affiliation: Laboratoire Croissance et Métabolismes des Herbivores, INRA, Theix, Saint Genès Champanelle, France.
authors.forename: I
authors.initials: I
authors.lastname: Ortigues
authors.forename: M
authors.initials: M
authors.lastname: Petit
authors.forename: J
authors.initials: J
authors.lastname: Agabriel
authors.forename: M
authors.initials: M
authors.lastname: Vermorel
mesh_terms: D020155:3-Hydroxybutyric Acid; D000273:Adipose Tissue / Q000166:cytology; D000821:Animal Feed; D000818:Animals; D001522:Behavior, Animal; D001823:Body Composition; D001833:Body Temperature Regulation; D001835:Body Weight; D002151:Calorimetry; D002417:Cattle / Q000097:blood / Q000378:metabolism*; D004063:Digestion; D004435:Eating; D002149:Energy Intake; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006728:Hormones / Q000097:blood; D006885:Hydroxybutyrates / Q000097:blood; D011897:Random Allocation
chemical_list: D005230:Fatty Acids, Nonesterified; D006728:Hormones; D006885:Hydroxybutyrates; D020155:3-Hydroxybutyric Acid