The Manipulation of Nutrition in Pregnancy to Increase Weaning Weights

Summary

Varying maternal nutrition during critical periods of foetal development can alter or 'program' body mass and body composition in later life. Protein is the most deficient nutrient in the Australian rangelands and, critically, low protein diets during pregnancy in laboratory animals show significant deleterious effects on post natal development.
This experiment aimed to determine if low dietary protein concentration in the first two trimesters of pregnancy alters calf growth and development. Results show:
There was no effect of nutrition during gestation on total calf body weight between 3 and 6 months of age. High nutrition in the second trimester resulted in heavier calf birth weights (2.2kg).

Dystocia occurred in 16% of heifers in the trial. This was associated with increased calf birthweight such that a 2.2kg increase in calf birth weight increased risk of dystocia by 3 times.

Pelvic area measure taken prior to joining was negatively correlated with dystocia. Low nutrition in the first trimester significantly increased milk intake in the calf.

There was a significant effect of nutrition on placental and foetal development in utero.

There was a significant effect of nutrition during gestation on IGF levels in the heifer.

There was a significant effect of nutrition in utero on ovarian development in the offspring.