By: Glenn Selk, Oklahoma State University Extension
A relatively new arena of beef cattle research is labeled “fetal programming”. Fetal programming is generally considered the impact of nutritional and health status of the mother during pregnancy and its impact on the health and productivity of the offspring. Much of the research on maternal nutrition during pregnancy has focused on the last trimester when most fetal growth takes place. The relationship between late pregnancy nutrition and health of the calf is confounded by the colostrum production and intake. Undernourished cows in late gestation produce less colostrum and therefore calves with increased sickness and death loss.
However, little is known about the effect of nutrition on the middle third of gestation and subsequent health of the calf. The immune system of the fetal calf is developing at this time. Will an undernourished beef cow adversely affect the ability of her calf to ward off diseases after birth and into the feedlot phase of production? South Dakota State University scientists looked at the effects of cow energy status during mid-gestation on progeny performance including immune function. They used 151 cows fed to maintain a body condition score of 5.0 to 5.5 (positive energy status treatment) or fed cows to only 80% of what they needed to maintain body weight and condition (negative energy status treatment). These treatments were applied during the middle three months of gestation. During the first one-third of gestation and the last third of gestation all cows were fed similar diets.
After weaning, the calves were taken to a feedlot where growth and production traits could be monitored. A subsample of the calves was subjected to a foreign protein (ovalbumin) challenge 19 days after arrival at the feedlot. They then measured the antibody response to the ovalbumin challenge to determine immune activity by the calves. These scientists found no differences in birth weight, weaning weight, feedlot average daily gain, dry matter intake, or gain to feed ratio due to the nutrition of the cows in mid-gestation. However, the calves born to the positive energy status cows had significantly greater antibody titers when challenged than did the counter parts that were born to the cows with restricted energy in mid-gestation. They concluded that mid-gestation nutrition may very well have an effect on immune response of calves during a receiving period in the feedlot.