Research Summary - 3
Evaluation of Three Complete Colostrum Replacement Strategies on Passive Immunity and Early-Life Performance in Beef Calves
| Date/Time: |
9/13/2025
09:30
|
| Author: |
Siena L Mitman |
| Clinic: |
North Carolina State University College of Veterinary Medicine |
| City, State, ZIP: |
Raleigh, NC 27606 |
S.L. Mitman, DVM, MPH
1
;
H. Jenkins, BS
1
;
M.F. Chamorro, DVM, PhD, DACVIM
2
;
D.A. Mzyk, DVM, PhD
1
;
D.M. Foster, DVM, PhD, DACVIM
1
;
L. Gamsjäger, Mag. Med. vet, PhD, DACVIM
1
;
1Department of Population Health and Pathobiology, North Carolina State University College of Veterinary Medicine, Raleigh, NC, 27606
2Department of Clinical Sciences, College of Veterinary Medicine, Auburn University, Auburn, AL, USA
Introduction:
Colostrum provides vital nutrients and critical immune protection to newborn calves. Up to 20% of beef calves require human assistance with colostrum intake, yet evidence-based colostrum replacement guidelines are lacking. The objective of this study was to compare the effects of three complete colostrum replacement strategies on serum IgG concentrations, transfer of passive immunity (TPI) status, morbidity, mortality, and pre-weaning average daily gain (ADG) in beef calves.
Materials and methods:
Forty-five newborn Angus and Angus x Santa Gertrudis beef calves were separated from their dams at birth and randomly assigned to one of three colostrum interventions: Group A) ~170g of IgG immediately after birth, Group B) ~250g in two feedings within 6-8h, and Group C) ~250g in three feedings within 12-14h. An additional fifteen control calves were left with their dams for natural nursing. Serum IgG concentrations at 24 hours of age were determined by Radial Immunodiffusion and compared between intervention groups using multivariable linear regression modeling. Serum IgG, TPI status, morbidity, mortality, and ADG were also compared between all intervention groups and control calves using a Fisher’s exact test or multivariable linear or logistic regression models, as appropriate.
Results:
Mean 24-hour serum IgG concentrations were 19.7 ± 5.0 g/L, 22.4 ± 5.6 g/L, 20.0 ± 3.8 g/L, and 33.8 ± 26.3 for Groups A, B, C, and Controls, respectively, with no difference between intervention groups alone (p>0.39) or between intervention groups and the control group (p>0.06). The proportions of adequate TPI (24h [IgG] ≥24 g/L) in Groups A, B, C, and control calves were 7% (1/14), 29% (4/14), 14% (2/14) and 67% (10/15), respectively. Only 1 calf in Group A (1/14, 7%) and 2 control calves (2/15, 13%) had failed TPI (24h [IgG] <10g/L). The proportion of calves with adequate TPI and failed TPI was not statistically different among intervention and control groups (FTPI p=0.6, ATPI p=0.06-0.80). Two calves required treatment (1 in Group A and 1 in Group B), and three calves died in the pre-weaning period (1 in each intervention group). Median ADG was 0.76 kg (0.50-0.82 kg, Group A), 0.72 kg (0.40-0.93 kg, Group B), 0.78 kg (0.37-1.05 kg, Group C), and 0.81 kg (0.57-1.04 kg, Controls). Pre-weaning morbidity (p=0.52), mortality (p=0.7), and ADG (p=0.17) were similar among all intervention and control groups.
Significance:
While timely feeding of ≥170g IgG most often prevented failed TPI (24h [IgG] <10g/L) in beef calves, ≥250g IgG may be necessary to achieve adequate TPI (24h [IgG] ≥24 g/L). There was no difference in health and growth outcomes assessed between intervention and control groups. Producers and veterinarians should thus not hesitate to intervene early to ensure timely colostrum ingestion.
