Failure of passive transfer in foals: incidence and outcome on four studs in New South Wales.
OBJECTIVE
To determine the regional incidence and effectiveness of treatment of failure of passive transfer (FPT) in foals.


METHODS
A study of disease incidence.


METHODS
Eighty-eight foals and 57 mares from four studs in the practice area of the Rural Veterinary Centre were tested.


METHODS
Foals were tested for their serum IgG and total serum protein (TSP) concentration within the first 72 hours of life. Colostrum was collected from mares and specific gravity determined. FPT and partial failure of passive transfer (PFPT) of immunoglobulins was diagnosed when serum IgG concentrations were < 4 g/L and 4 to 8 g/L respectively. Owners of foals diagnosed with FPT were offered treatment with 1 to 2 L plasma (TSP > 70 g/L); 9 (64%) of the affected foals were treated.


RESULTS
Fourteen foals (16%) had FPT whereas 15 (17%) had PFPT. There were significant differences between the mean TSP concentration in foals with FPT (42.6 +/- 4.2 g/L), PFPT (48.1 +/- 3.9 g/L) and those acquiring adequate passive immunity (58.9 +/- 5.5 g/l) (p < 0.01). Sixteen (29%) mares had pre-suck colostral specific gravity < 1.060 and 12 (71%) foals raised by these mares had FPT or PFPT. The incidence of severe disease (categorised by a sepsis score > 11, positive culture of bacteria from blood or disease requiring hospitalisation) in all foals in the first 2 months of life was 10%. However, none of the nine foals with FPT that received plasma experienced severe disease. In contrast, foals with PFPT had an increased susceptibility to severe disease (p < 0.001) when compared with normal foals.


CONCLUSIONS
Treatment of foals with FPT may reduce the subsequent incidence of severe disease. Pre-suck colostral specific gravity and foal TSP may be used to predict the likelihood of FPT and PFPT. Even though the number of foals studied is small the results highlight the importance of optimal management practices in reducing the incidence of FPT and disease associated with this process.
Tyler-McGowan
C M
CM
Rural Veterinary Centre, University of Sydney, Camden, New South Wales.
Hodgson
J L
JL
Hodgson
D R
DR
D000818:Animals; D001798:Blood Proteins / Q000032:analysis; D003126:Colostrum / Q000737:chemistry / Q000276:immunology; D004196:Disease Outbreaks / Q000662:veterinary; D004198:Disease Susceptibility / Q000276:immunology / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000097:blood / Q000453:epidemiology* / Q000276:immunology*; D006736:Horses / Q000097:blood / Q000276:immunology* / Q000502:physiology; D007112:Immunity, Maternally-Acquired / Q000276:immunology* / Q000502:physiology; D007116:Immunization, Passive; D007074:Immunoglobulin G / Q000097:blood; D015994:Incidence; D008297:Male; D009517:New South Wales / Q000453:epidemiology; D011247:Pregnancy; D013046:Specific Gravity; D016896:Treatment Outcome
D001798:Blood Proteins; D007074:Immunoglobulin G