24 NEBRASKA CATTLEMAN February 2026 Late Gestational Undernutrition IMPACTS IN BEEF HEIFERS ON DAM AND OFFSPRING OUTCOMES COLBY A. REDIFER AND ALLISON M. MEYER | DIVISION OF ANIMAL SCIENCES, UNIVERSITY OF MISSOURI Nutrient requirements increase dramatically in the late gestation beef female to allow for proper growth and function of the uteroplacenta, fetus and mammary gland. Even in well-managed herds, it is possible for cows and heifers to be nutrient restricted during this time due to challenges of low forage quality or availability and environmental stress brought on by cold (spring calving) or heat (fall calving). For heifers, the added nutrient requirements of growth and establishment of a functional uterus and mammary gland for the first time pose an even greater challenge during their first pregnancy. A growing body of research demonstrates that nutrient restriction during pregnancy can have long-lasting effects on calves resulting from impaired development before and after birth. This is not surprising, as calves depend on their dams for all nutrients before birth and the majority of nutrients pre-weaning. Late-gestational nutrient restriction research generally associates decreased nutrient delivery during gestation with programming fetal growth and development, resulting in poor postnatal outcomes. However, the effects gestational nutrient partitioning may have on programming the mammary gland to decrease milk yield and therefore postnatal nutrient delivery is far less understood. It is also generally unknown how poor nutrition during one pregnancy impacts cows during their next pregnancy and lactation. Experimental Model To determine the effects of late gestational nutrient restriction in first-parity females, fall-calving Hereford × Simmental-Angus heifers were bred to a single sire. From day 160 of pregnancy until calving, one group was fed to fully meet energy and protein needs, while another group received about 70 percent of those requirements. The heifers were fed individually using Calan gates so intake could be tightly controlled. From day 160 to 265 of gestation, diets were based on low-quality chopped sorghum sudan hay and for the rest of gestation and lactation, diets were based on chopped tall fescue hay. Heifers were supplemented daily with whole corn, dried distillers grains and soyhull pellets to meet targeted nutritional planes. After calving, treatments were terminated and all cows were fed to meet energy and protein requirements for maintenance, lactation and growth. Females continued to be fed individually in Calan gates to ensure individual nutrient intakes remained similar and to prevent calves from having access to feed other than milk. At 5 months post-calving, cowcalf pairs were co-mingled and group-fed hay and supplement until calves were weaned at 8 months of age. Post-weaning, calves were backgrounded in drylots for two months and then placed into the feedlot for finishing. Cattle were harvested at a similar number of days on feed. Outcomes Major findings of late gestational nutrient restriction on dam and offspring outcomes are shown in Figure 1. Nutrient-restricted females lost body weight and condition and had fewer nutrients in maternal circulation during late pregnancy. Post-calving, nutrient-restricted dams weighed 141 pounds less and were 2 lower body condition score. Nutrient-restricted dams had lower maternal heart rates during pregnancy and altered placental growth, yet total uterine blood flow and placental weight were maintained and ensured calf birth weights similar to control dams. Fetal presentation at calving was normal for all control births, while 23.1 percent (3 of 13) of nutrient-restricted dams had calf malpresentations. It should be noted that when we conducted a similar study using the same experimental model the following year, calf birth weight was reduced by 15 percent and placental weight by 17 percent, but uterine blood flow remained unaffected. In PRODUCTION
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