Maternal chromium propionate supplementation in late gestation and its association with cow performance and skeletal muscle programming in beef calves

This study aimed to evaluate the effects of maternal chromium propionate (CRP) supplementation during late gestation on cow-calf performance and skeletal muscle metabolism of neonatal calves. A total of 100 late gestation primiparous and multiparous Angus-Simmental cows (698.4 ± 95.6 kg) were randomly assigned to one of two treatment groups: control (CTRL; n = 50), receiving a basal diet, or CRP (n = 50), receiving the same basal diet supplemented with 4 mg/head/day of CRP from day 223 of gestation until parturition (54.4 ± 10.7 days). Cows were weighed, scanned via carcass ultrasound for body condition monitoring, and blood sampled every 28 days for glucose, insulin, β-hydroxybutyrate (BHB), and non-esterified fatty acids (NEFA). At birth, calves were separated from their dams prior to nursing for blood collection, birth weight, and colostrum yield and samples from the dam. Samples from the longissimus dorsi muscle were biopsied from calves at six days of age for analysis of mRNA expression and protein abundance related to adipogenesis and glucose metabolism. Pre-partum dry matter intake did not differ between treatments (kg/d, P = 0.13; % of body weight, P = 0.29). A tendency for a treatment x calf sex interaction was detected for cow average daily gain (ADG; P = 0.08), where CRP cows carrying male calves tended to have lower ADG compared to CTRL cows of either calf sex. A treatment x days pre-partum (DPP) interaction was observed for levels of BHB (P > 0.01) with CTRL cows showing increased BHB at 11 DPP, while concentrations remained stable in CRP cows. In the biopsied skeletal muscle, calves born to CRP-supplemented dams exhibited greater mRNA expression of PPARγ ( P < 0.01), ZFP423 ( P < 0.01), DLK1 ( P = 0.02), IRS1 ( P = 0.01), and GLUT4 ( P = 0.04), and tended to show greater protein abundance of IRS1 ( P = 0.08) compared to calves born to CTRL cows. These findings suggest that supplementing CRP during late gestation modified dam energy status dependent on fetal sex and influenced the programming of the skeletal muscle metabolism in offspring.