Differing planes of nutrition alter serum amino acid composition in nonpregnant, multiparous beef cows on day 3 of the estrous cycle

Authors: SWANSON, REBECCA - North Dakota State University; NEVILLE, TAMMI - North Dakota State University; MCCARTHY, KACIE - University Of Nebraska; KASSETAS, CIERRAH - North Dakota State University; BOROWICZ, PAWEL - North Dakota State University; Crouse, Matthew; REYNOLDS, LAWRENCE - North Dakota State University; DAHLEN, CARL - North Dakota State University; CATON, JOEL - North Dakota State University

Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 4/29/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction Prior to placentation, embryo survival and growth rely on endometrial-derived histotroph to supply nutrients, hormones, growth factors, cytokines, adhesion proteins, and enzymes. Amino acid composition is altered in fetal fluids from nutrient restricted beef cows during early and late gestation (Crouse et al., 2019; Swanson et al., 2022). To maintain a 12-month calving interval, cows need to re-breed during the post-partum period, when they are often in negative energy balance. We hypothesized that differing planes of nutrition would alter performance characteristics, and serum and histotroph nutrient composition in beef cows on day 3 of the estrous cycle. Materials and Methods Nonpregnant, multiparous beef cows (n = 18) were stratified by body weight to differing planes of nutrition: maintain body weight (no change in body weight, n = 9; CON) or moderate body weight loss (-0.7 kg/d, n = 9, NEG) for 62 days. Baseline (day 0) and ending (day 62) body weights, carcass ultrasonography, and jugular venous blood was collected. Cows were subjected to the 7-day CO-synch+CIDR estrous synchronization protocol, and slaughtered 3 days after estrus (day 62) for collection of carcass characteristics and uterine histotroph ipsilateral and contralateral to the corpus luteum (CL). Amino acid concentrations were determined by Ultra Performance Liquid Chromatograph. Glucose, non-esterified fatty acids (NEFA), and blood urea nitrogen (BUN) were determined by colorimetric assays. Data were analyzed using the PROC GLM procedure of SAS 9.4 for fixed effects of plane of nutrition. The threshold for significance is P 0.05) in cow age, initial body condition score (BCS), or initial or final body weight between treatment groups. Final BCS, average daily gain, average daily feed intake, and feed efficiency were decreased (P < 0.05) in NEG compared with CON cows. There were no differences in carcass ultrasound or characteristics, except dressing percentage was increased (P = 0.02) in NEG compared with CON cows. Serum NEFA were increased (P < 0.01) in NEG compared with CON cows. There were no differences (P > 0.05) in serum BUN, glucose, essential, nonessential, or total amino acid concentrations between treatments. Serum histidine concentration was greater (P = 0.04) in NEG vs. CON cows. Serum alanine, isoleucine, and tryptophan concentrations were decreased (P = 0.02) in NEG vs. CON cows. There were no differences (P > 0.05) in glucose concentrations between histotroph ipsilateral or contralateral to the CL. Amino acid concentrations in histotroph ipsilateral and contralateral to the CL were previously reported (Neville et al., 2023), and interestingly most differences between NEG vs. CON cows were in histotroph contralteral to the CL. Conclusions Nutrients are vital for conceptus growth and development, and perturbations in maternal nutrient intake may negatively impact reproductive function, specifically in the uterus as it prepares for the embryo. Furthermore, reductions in trypotophan warrant further investigation due to its impact as an essential amino acid and notable bioactivity.