Marc Bauer, NDSU Department of Animal Science

On day 201 of pregnancy, 27 aged cows were divided randomly into a control group (CON; n = 15) or a supplemented group (SUP; n = 12) and provided the same basal diet of corn stover and silage for ad libitum intake. Supplemented cows were additionally fed DDGS at 0.3% of body weight. On day 270 of pregnancy, all cows were placed on the same diet, which was fed through the first 56 days of lactation. To investigate the effects of DDGS supplementation, cows were weighed every 2 weeks, uterine arterial blood flow (BF) was measured three times during the pregnancy period, calf birth weights and placenta weights were collected, and cows and calves were weighed again every 2 weeks until day 56 after birth. Colostrum and milk samples also were collected to assess nutrient delivery to the calf after birth. Throughout the study, individual intake behavior was monitored using Insentec feeders. Finally, the weaning weight of calves was obtained in the subsequent autumn.

Treatment differences were observed for voluntary intake behavior during late gestation, maternal body condition and weight, uterine blood flow, calf birth and weaning weights, and milk production measures. Our study found numerous advantages to supplementing DDGS to gestating beef cows during late pregnancy, further highlighting the importance of high-quality nutrition during pregnancy, specifically in regard to protein availability in the diet. Advantages in calf weights, as well as enhanced milk production in their dams can be of great economic value to the cow-calf producer. The present study suggests these benefits could be as result of altered uterine blood flow or mammary gland function.