Association of neonatal serum immunoglobulin G1 concentration with health and performance in beef calves.
OBJECTIVE
To evaluate associations between neonatal serum IgG1 concentration and pre- and postweaning morbidity and mortality rates and average daily gains (ADGs) in beef calves and define a cutoff point for serum IgG1 concentration necessary for optimal health and performance of beef calves.


METHODS
Nonconcurrent cohort study.


METHODS
1,568 crossbred beef calves.


METHODS
Single radial immunodiffusion was used to quantitate IgG1 concentration in sera collected from calves between 24 and 72 hours after birth. Logistic regression, ANCOVA, and likelihood ratios were used to analyze data.


RESULTS
In the preweaning period, lower perinatal IgG1 concentrations were significantly associated with higher morbidity rates, higher mortality rates, and lower ADGs. Calves with serum IgG1 concentration < 2,400 mg/dL were 1.6 times as likely to become ill before weaning and 2.7 times as likely to die before weaning as calves with higher serum IgG1 concentrations. Calves with serum IgG1 concentration of at least 2,700 mg/dL weighed an estimated 3.35 kg (7.38 lb) more at 205 days of age than calves with lower serum IgG1 concentration. No significant association of serum IgG1 concentration with feedlot morbidity, death, or ADG was identified.


CONCLUSIONS
By use of likelihood ratios, the threshold of serum IgG1 concentration for optimal health and performance of calves was higher than values reported previously. Implementation and maintenance of management and intervention strategies designed for early detection and treatment of calves at risk for failure of passive transfer will likely result in increases in preweaning health and performance parameters.
Great Plains Veterinary Educational Center, University of Nebraska, Clay Center, NE 68933-0148, USA.
Reneé D
RD
Dewell
Laura L
LL
Hungerford
James E
JE
Keen
William W
WW
Laegreid
D Dee
DD
Griffin
Gary P
GP
Rupp
Dale M
DM
Grotelueschen
D000375:Aging / Q000097:blood / Q000276:immunology; D000818:Animals; D000831:Animals, Newborn / Q000097:blood* / Q000276:immunology*; D002417:Cattle / Q000097:blood / Q000254:growth & development / Q000276:immunology; D015331:Cohort Studies; D005260:Female; D006304:Health Status; D007074:Immunoglobulin G / Q000097:blood*; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D014886:Weaning; D015430:Weight Gain
D007074:Immunoglobulin G