Variation in rate of body weight gain during pregnancy in beef heifers: association with early life health events and influence on progeny performance

Authors: Cushman, Robert; HAUXWELL, KATHLYN - North Dakota State University; CATON, JOEL - North Dakota State University; FREETLY, HARVEY - Retired ARS Employee

Submitted to: Translational Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/25/2025
Publication Date: 1/19/2026
Citation: Cushman, R.A., Hauxwell, K.M., Caton, J.S., Freetly, H.C. 2026. Variation in rate of body weight gain during pregnancy in beef heifers: association with early life health events and influence on progeny performance. Translational Animal Science. 10. Article txal176. https://doi.org/10.1093/tas/txaf176.
DOI: https://doi.org/10.1093/tas/txaf176

Interpretive Summary: Experimental models have demonstrated that nutrient status during pregnancy can influence the weights of calves at birth and weaning. The current study examined inherent variation in rate of gain of Angus-based beef heifers on pasture throughout breeding and pregnancy and its influence on performance of the calves. The association of the number of health events during the first 24 months of the life of the heifers with rate of gain during pregnancy was investigated. Increased number of health events were associated with lower rates of gain during pregnancy. Heifers that experienced a low rate of gain at any period during pregnancy produced calves that were lighter at birth and weaning. Efforts should be made to minimize health events in replacement heifers because these health events may not only be detrimental to the performance of the heifer but to the performance of the first calf.

Technical Abstract: Nutrient status during pregnancy can impact fetal development and progeny performance in beef females. Many experimental models have examined the impact of reduced nutrient status during late gestation because 75% of fetal growth occurs after 200 days of gestation. More recently, experimental models evaluated the impacts of nutritional status during the first trimester on organ development and progeny performance. The current study examined the variation in ADG during the first trimester (ADG1) in combination with variation in ADG during the last two trimesters (ADG23) of pregnancy and their relationship to progeny performance in beef heifers (n = 2,305) bred by bulls during the breeding season with no form of synchronization of estrus. We further examined the association between early life health events and rate of body weight (BW) gain of heifers during pregnancy. We hypothesized that there would be inherent variation in rate of BW gain during pregnancy among heifers, that this variation would influence progeny performance even when estrus was spread across the breeding season, and that heifers with reduced rates of BW gain during gestation would have an increased number of health events that coincided with the reduced rates of BW gain. Patterns of BW gain were classified as low (L, < median) or high (H, > median) for the first trimester (ADG1) and for the last two trimesters (ADG23), resulting in four patterns of gain for the dams (LL, LH, HL, or HH). Heifers in the LL group produced offspring with the lightest weights at birth and weaning, while heifers in the HH group produced offspring with greatest weights at birth and weaning (P < 0.0001). The heifers in the LH and HL group produced offspring with intermediate weights at birth and weaning. There was an interaction of age in months and pattern of rate of gain on the cumulative number of health events until 24 months (P = 0.05). Heifers in the LL and HL group had the greatest number of health events throughout the first 12 months, and then heifers in the HL group had a greater number of health events during gestation. Thus, the largest differences in health events were before the heifers were weaned, not necessarily during gestation. Variation in rates of gain during pregnancy in beef heifers bred by bulls with no form of synchronization can impact progeny performance, and early life health events may have long-term impacts on the performance of the heifer and the performance of her first calf.