Residual feed intake of Nellore calves is not repeatable across pre and post weaning periods

Luana Lelis Souza,Flávia Cristina Bis,Camila Delveaux Araújo Batalha,Leandro Sannomiya Sakamoto,Danielly Fernanda Broleze,Maria Eugênia Zerlotti Mercadante

doi:10.1590/0103-8478cr20200376

Luana Lelis Souza, Flávia Cristina Bis + Show 4 more

Open Access

https://doi.org/10.1590/0103-8478cr20200376

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Abstract

ABSTRACT: This study measured milk and solid feed intake in pre- weaning period and feed intake in postweaning period of Nellore calves, and to correlated them with performance traits and ingestive behavior of animals classified as most and least efficient. During pre weaning phase, feed efficiency was evaluated in 51 cow-calf pairs from 21±5 days after calving until weaning. During post-weaning phase, only male calves (n=23) were evaluated. Pre-weaning milk intake of calves was estimated based on cow’s milk production. Pre-weaning daily metabolizable energy intake (MEI) of calves was estimated as the sum of MEI from milk and solid diet. There was no difference in ADG between calves with negative and positive pre RFI, with a consequent better feed conversion to more efficient calves. The most efficient calves spent less time at the feed bunk, with a shorter feeding duration and higher rate of intake, compared to the least efficient animals. Correlations between feed intake and metabolic body weight of the animals during pre- and postweaning phases were positive, of medium to high magnitude, and significant, while correlation between ADG values was close to zero. Results suggested that part of the animals ranked based on pre weaning feed intake won’t maintain their rank during postweaning phase. In conclusion, calves classified as most efficient during pre-weaning phase have similar weight gain but lower milk intake and MEI than least efficient animals. The estimated pre RFI is weakly correlated with post RFI, showing that RFI is not consistent or repeatable across two periods.

Highlights

The advances achieved in livestock farming are notorious and are responsible for the productivity growth of the sector
The dry matter intake (DMI) increased during the postweaning period to 7.64±0.8 kg day-1, i.e., pre-weaning DMI accounted for 17% of the total amount ingested
The multiple regression model for the calculation of pre RFI captured only 15% of the variation in the metabolizable energy intake (MEI) of calves during the preweaning period, with 10% being explained by average daily gain (ADG), 3% by BW0.75, 2% by calf sex, and 1% by RFI of cows

Summary

Introduction

The advances achieved in livestock farming are notorious and are responsible for the productivity growth of the sector. There are few studies on feed efficiency involving cows and calves because of the Approved 11.03.20 Returned CR-2020-0376.R1 by the author. V.51, n.6, difficulty in measuring traits related to milk and solid feed intake during this phase (WALKER et al, 2015; SOUZA et al, 2019). Knowledge of the outcome of selecting cattle for feed efficiency, both on growing animals and on the performance of these animals when adults, is fundamental to fully understand the impact of feed efficiency on the productivity of the herd (BLACK et al, 2013). HERD et al (2004) reported the existence of at least five main factors that cause variation in the feed efficiency of growing animals, which are associated with feed intake, digestion, metabolism, activity, and thermoregulation. Few studies have so far evaluated the feed efficiency of calves during the pre- and postweaning phases

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