failure of passive transfer

 FAILURE OF PASSIVE TRANSFER

Newborn foals come to life without antibody protection. They mainly depend on antibodies absorbed following ingestion of mare’s colostrum in the first few hours of life for protection against infectious diseases. So that explain how important is the colostrum

Pregnant mares produce colostrum only during the last 1 to 2 weeks of pregnancy as antibodies are actively transported from their blood and concentrated in the mammary gland. After nursing the colostrum, specialized cells that line the small intestine of the newborn foal absorb the antibodies and transfer them into the foal’s blood.( Absorption of antibodies by these specialized cells is greatest during the first 6 to 8 hours after birth and stops by 24 to 36 hours of age)

Failure of passive transfer (FPT) of antibodies occurs in 10 to 20% of newborn foals. A foal greater than 24 hours of age is considered to have failure of passive transfer if circulating antibody (also called immunoglobulins or IgG) levels are less than 400 mg/dl. A level of 400 to 800 mg/dl is considered partial failure of passive transfer and a blood IgG concentration greater than 800 mg/dl is considered adequate. . 

The most common causes of FPT are poor quality colostrum and premature lactation. Early testing for antibody levels in a neonatal foal can identify potential cases of FPT and allow for early intervention

It is recommended that a blood sample be collected from a newborn foal approximately 12 hours after birth to evaluate circulating IgG levels prior to ‘closure’ of the gastrointestinal tract to antibody absorption. If IgG levels are <400 mg/dl at 12 hours, oral supplementation with frozen-thawed colostrum or a commercial colostrum substitute should be performed. If IgG levels are 400 to 800 mg/dl, the need for intervention and therapy is dependent on potential pathogen exposure and/or the medical condition of the foal.

Foals with partial failure of passive transfer at risk of developing infections may benefit from IgG supplementation. In contrast, foals with 

 Foals greater than 24 hours of age identified with FPT require intravenous administration of plasma or a commercial equine IgG preparation to successfully increase blood antibody levels.

 

Posted by : vetweb April 23, 2022 Tags : immunity

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