Feed efficiency, blood parameters, and ingestive behavior of young Nellore males and females

Abstract

This study aimed to evaluate differences in efficiency of feed utilization between young Nellore males and females by comparing growth traits, feed intake, blood parameters, and ingestive behavior of the animals. Data from 768 Nellore males and females that participated in eight performance tests for individual feed intake evaluation were used. Performance and feed efficiency measures, efficiency-related hematological, metabolic and hormonal variables, and data regarding ingestive behavior were collected. Feed efficiency measures were defined by the relationship between performance and feed intake. Data were analyzed using mixed models that included the fixed effects of sex, herd, and the covariate age within sex and the random effects of facility within year, year, and residual. Significant differences between males and females were observed for traits related to weight gain and feed intake. Although individual dynamics of feed efficiency measures differed between males and females, no significant differences in residual feed intake, feed efficiency, or relative growth rate were observed between sexes. Significant differences between sexes were found for platelets, red blood cells, hemoglobin, creatinine, glucose, urea, triglycerides, insulin, cortisol, and IGF-I. Females spent more time feeding and less time ruminating when compared to males. However, males exhibited higher feeding efficiency and lower rumination efficiency than females. Growing Nellore males and females are efficient in feed utilization, and the differences in blood variables observed are probably due to differences in body size and feed intake. Males spend less time eating, consume more food, and spend more time ruminating than females.

Phenotypic and Genetic Correlations of Feed Efficiency Traits with Growth and Carcass Traits in Nellore Cattle Selected for Postweaning Weight

“…This percentage was 44.76% for males and 49.48% for females, suggesting that females were less efficient than males. In fact, a study [ 13 ] analyzing part of the same database as used here, reported a better gain:feed ratio for males compared to females. Finishing Bos taurus steers attending the Australian, Korean and Japanese markets required 67%, 72% and 61% of DMI for maintenance [ 12 ].…”

Effects of Feeding and Drinking Behavior on Performance and Carcass Traits in Beef Cattle

“…Studies have reported variations in feed efficiency phenotypes for animals of the same breed and under the same diet [ 1 , 8 , 9 , 10 ]. These findings may be explained by the fact that this trait is controlled by various physiological processes such as feed intake, digestion, metabolism, and thermoregulation [ 8 ].…”

Evaluation of reactivity and stunning efficiency in cattle before and after slaughterhouse staff training

“…In this sense, Probst et al (2014) found a higher serum concentration of cortisol in heifers when compared to bulls and steers subjected to pre-slaughter stress (electric shock and length of stay in the stunning box), indicating that females are more reactive than males. On the other hand, Bonilha et al (2015) found higher cortisol levels in males in comparison to females.…”