Passive Immunity Affects Calves Long-term

Passive immunity affects a calf’s health and growth throughout its life.

by Glenn Selk, Oklahoma State University Extension

The first 24 hours of a calf’s life sets the stage for health and growth, and will affect the rest of its life. Veterinary scientists, while with the USDA experiment station at Clay Center, Neb., monitored health events and growth performance in a population of range beef calves to identify associations of production factors with passive immune status of baby calves.

Blood samples were collected at 24 hours after calving from 263 crossbred calves to determine the amount of passive maternal immunity that had been obtained from colostrum. Colostrum is the first milk produced by a cow upon giving birth. The baby calves were classified with “inadequate” or “adequate” passive immune status based on that blood sample at 24 hours of age. Growth performance and health events in the study population were monitored from birth to weaning and after weaning throughout the feedlot phase.

The lowest levels of passive immunity were observed among calves that were sick or died prior to weaning. Calves with inadequate passive immunity had a 6.4 times greater risk of being sick during the first 28 days of life, a 3.2 times greater risk of being sick any time prior to weaning, and a 5.4 times greater risk of death prior to weaning when compared to calves with adequate passive transfer. Passive immune status was also indirectly associated with growth rates through its effects on calf health. Sickness during the first 28 days of life was associated with a 35-pound (lb.) lower expected weaning weight.

Based on 24-hour proteins (most of which are antibodies or immunoglobulins) in the blood, the risk of being sick in the feedlot was also three times greater for inadequate compared to adequate calves. Respiratory disease in the feedlot resulted in a 0.09-lb. lower expected average daily gain.

Thus, passive immunity obtained from colostrum was an important factor determining the health of calves both pre- and postweaning, and indirectly influenced calf growth-rate during the same periods. The most likely candidates for inadequate passive immunity are calves born to first-calf 2-year-old heifers. Breeding heifers to high-calving-ease bulls should reduce the percentage of difficult deliveries and sluggish baby calves when born. Also, cow-calf producers can help themselves, and the future owners of their calves, by properly growing replacement heifers, providing a good health program for cows and heifers, and providing natural or commercial colostrum replacers to calves that do not receive it in adequate quantities on their own. Remember that most of the transfer of antibodies from colostrum to the calf happens in the first six hours. The first day sets the stage for the rest of his life.

Editor’s note: This article is reprinted with permission from the Jan 4 Cow-Calf Corner, a newsletter published by the Oklahoma Cooperative Extension Service, for which Glenn Selk is an emeritus extension animal scientist. The research referenced was from Wittum and Perino. 1995.Amer. Jour. Of Vet. Research. 56:1149. Photo by Dane Haverkamp from the 2020 NJAA/Angus Journal Photo Contest.