Body composition and tissue distribution from birth to 14 months for three biological types of beef heifers.

Abstract

Thirty-four heifers were sampled randomly from each of the Hereford (He), Charolais (Ch) and Simmental (Si) herds at the U.S. Meat Animal Research Center at 2 d to 14 mo of age to examine body chemical composition and tissue distribution. Six heifers per breed were slaughtered after calorimetry at 2 d, 3 mo, 7 mo, 10 mo and 14 mo of age, and four others at 8 mo, to measure weight of empty body (EBW), water, fat, ash and protein as residual, in four fractions: carcass (CAR), head, hide and shanks (HHS), gastrointestinal tract plus internal fat (GIF) and visceral organs plus blood (VOB). Fasted live weight from birth to 14 mo increased from 39 to 414 kg for Ch, 38 to 385 kg for Si and 33 to 356 kg for He. Corresponding mean composition of EBW increased from 58 to 67% CAR and from 7 to 13% GIF but declined from 26 to 15% HHS and from 9 to 6% VOB. The water content of EBW declined from 73 to 51%, protein from 20 to 18% and ash from 4.3 to 3.5%, whereas fat increased from 3 to 28% and protein content of fat-free OM increased from 22% to 26%. Composition of CAR was similar to EBW but fat content increased more with age in GIF, less in HHS and least in VOB. Distribution of fat-free tissue changed from 58 to 66% in CAR, 26 to 18% in HHS, 7 to 8% in GIF and 9 to 8% in VOB. The EBW of Ch contained more CAR but less HHS than EBW of Si and HE. The EBW of Si and Ch contained more water and protein and less FAT than EBW of HE. The fatter He had proportionately less of their fat-free tissue in CAR (63%) and more in HHS (21%) and GIF (9%) than the Ch (66, 19, and 8%), with Si (64, 20 and 8%) intermediate. These age and breed differences in composition and tissue distribution may explain some of the variation in maintenance requirements.

Male pre- and post-pubertal castration effect on live weight, components of empty body weight, estimated nitrogen excretion and efficiency in Piemontese hypertrofic cattle

“…Moreover, they displayed lower fractional degradation rates. Comparing the relative body components of empty body weight found in our trial with other breeds, Piemontese cattle showed higher carcass weight, lower weights as regards head plus hide and shank, visceral organs plus blood and gastrointestinal tract than 14 month old Hereford, Charolais and Simmental heifers (Buckley et al, 1990). Furthermore, Piemontese cattle have a prevalence of higher protein tissue content with potential consequences on N efficiency.…”

Body composition and metabolic profiles associated with puberty in beef heifers1

“…Nutrition, breed, and physiological status alter weights of the gastrointestinal tract and visceral organs in livestock (Ferrell, 1988). Also, Buckley et al (1990) reported a dramatic increase in internal fat stores in beef heifers between 8 and 14 mo of age, a time that normally corresponds to puberty onset. In the present study, diet and biotype independently altered weights of visceral organs and associated internal fat depots at puberty.…”

Relationship of post-weaning growth and age at puberty in crossbred beef heifers

“…This measurenment will provide valuable information to evaluate FAT at eleven months of age prior to puberty to indicate the need to target puberty earlier. The effects of FAT at specific age can alter the proportion of metabolically active tissues that influences the maintenance requirements (Buckley et al, 1990). Lammoglia et al (2000) observed that feeding 4.4% dietary fat increased the percentage of pubescent heifers by the beginning of the breeding season.…”