Loading…

Age at weaning and the endocrine response to stress

Seventy-five Angus x MARC II crossbred heifers were used to assess the effects of age at weaning on calf performance and blood constituents. Calves were weaned at 150, 210, or 270 days of age with comparisons made to their non-weaned counterparts. Changes in blood chemistry and hematology (cortisol,...

Full description

Saved in:
Bibliographic Details
Published in:Arquivo brasileiro de medicina veterinária e zootecnia 2003-02, Vol.55 (1), p.1-7
Main Authors: Bueno, A.R, Rasby, R, Clemens, E.T
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Seventy-five Angus x MARC II crossbred heifers were used to assess the effects of age at weaning on calf performance and blood constituents. Calves were weaned at 150, 210, or 270 days of age with comparisons made to their non-weaned counterparts. Changes in blood chemistry and hematology (cortisol, glucose, T3, total proteins, packed cell volume and the differential white blood cell count) were recorded on the day of weaning (day-0), and at 2, 7, 14, and 28 days post-weaning. Calves weaned at 210 days of age presented the highest plasma cortisol, glucose, and total protein concentrations during their early post-weaning period. Calves weaned at 150 days of age had significantly lower plasma T3 values. Packed cell volume and differential white blood cell counts showed no relationship to age at weaning. Calves weaned at 210 days of age presented the most rapid post-weaning growth performance, relative to the 150 or 270 days of age weaned calves. Setenta e cinco bezerras cruzadas Angus x MARC II foram usadas para determinar os efeitos da idade à desmama sobre a performance e sobre os constituintes do sangue. As bezerras foram desmamadas com 150, 210 ou 270 dias de idade e foram sempre comparadas com um grupo de não desmamadas. Alterações plasmáticas nas características hematológicas e químicas (cortisol, glicose, T3, proteínas totais, contagem diferencial de células brancas) foram determinadas no dia da desmama (dia-0) e nos dias 2, 7, 14 e 28 após a desmama. As bezerras desmamadas aos 210 dias de idade apresentaram as maiores concentrações de cortisol, glicose e proteínas totais no início do período pós-desmama. Bezerras desmamadas aos 150 dias de idade apresentaram valores de T3 significativamente menores. As características hematológicas (PCV e contagem diferencial de células brancas) não apresentaram relação direta com a desmama. As bezerras desmamadas aos 210 dias de idade apresentaram resposta mais rápida de crescimento no período pós-desmama, comparadas com as desmamadas aos 150 e 270 dias de idade.
ISSN:0102-0935
1678-4162
1678-4162
0102-0935
DOI:10.1590/S0102-09352003000100001