Maternal nutrient restriction during late gestation reduces vigor and alters blood chemistry and hematology in neonatal beef calves

Abstract

Fall-calving primiparous beef females [body weight: 451 ± 28 (SD) kg; body condition score: 5.4 ± 0.7] were individually-fed either 100% (control; CON; n = 13) or 70% (nutrient restricted; NR; n = 13) of metabolizable energy and metabolizable protein requirements for maintenance, pregnancy, and growth from day 160 of gestation to parturition. Calves were reared naturally by their dams and monitored for latency times from birth to first sternal recumbency, attempt to stand, and stand; vigor scores were assigned at 2, 5, 10, and 20 min of age. Rectal temperatures and jugular blood were obtained at 0 (pre-suckling), 6, 12, 24, and 48 h of age, and blood chemistry, hematology, cortisol, and insulin were determined. Data were analyzed with fixed effects of late gestational nutritional plane (single data point) or nutritional plane, hour, and their interaction (data over time, repeated measures). Calving date was a fixed effect; calf sex was included when P < 0.25. We previously reported that late gestational nutritional plane did not affect gestation length or calf size at birth, but calving assistance and fetal malpresentations occurred more often in NR. Nutritional plane did not affect (P = 0.65) duration of parturition, but calves born to NR dams had slower times to attempt to stand (P = 0.09), slower times to stand (P = 0.02), and had poorer 20 min vigor scores (P = 0.05). Serum immunoglobulin G and A concentrations at 48 h were greater (P ≤ 0.03) for NR calves. Rectal temperature of NR calves was less (P = 0.02) at 0 h, but greater (P = 0.04) at 24 h compared with CON. Circulating glucose, non-esterified fatty acids, triglycerides, cortisol, and insulin were not affected by nutritional plane (P ≥ 0.18). Total protein and globulin from 6 to 48 h were greater (P ≤ 0.02) in NR calves. Calves from NR dams had greater (P < 0.08) gamma-glutamyl transferase at 6, 12, and 48 h. Serum aspartate aminotransferase was greater (P ≤ 0.07) from 0 to 24 h and creatine kinase was greater (P ≤ 0.04) from 6 to 24 h in NR calves. At 0 h, potassium was greater (P = 0.03) in NR calves. Calves born to CON had greater chloride (P = 0.08; main effect), sodium (P ≤ 0.09) from 0 to 48 h, and anion gap (P = 0.02) at 6 h. Hematocrit from 6 to 24 h and red blood cells and hemoglobin at 6 and 12 h were greater (P ≤ 0.09) in CON calves. These data indicate that nutrient restriction during late gestation resulted in less vigorous calves with more indicators of trauma in early life.

Late gestational nutrient restriction in primiparous beef females: Performance and metabolic status of lactating dams and pre-weaning calves

“…We reported that calf BW and size at birth were not affected by late gestational nutrient restriction ( Redifer et al, 2023 ), but fetal growth is not necessarily indicative of fetal development. Late gestational nutrient restriction resulted in less vigorous calves with more indicators of stress and less red blood cells over the first 48 h of life ( Wichman et al, 2023 ). Calves born to nutrient restricted dams had greater serum immunoglobulin concentrations at 48 h of age, but calves born to dams on both late gestational nutritional planes achieved successful transfer of passive immunity ( Wichman et al, 2023 ).…”

“…We reported that neonatal circulating glucose, urea N, triglycerides, and NEFA during the first 2 d of age were not affected by late gestational nutritional plane ( Wichman et al, 2023 ). Despite the large discrepancy in milk nutrients available ( Redifer et al, 2024 ), calf metabolic status pre-weaning was also minimally affected by late gestational nutritional plane.…”

“…Beginning on day 274 of gestation, heifers were closely monitored 24 h per day by trained personnel to ensure the time of calving was observed. Peripartum dams and neonatal calves were managed as described in Redifer et al (2023) and Wichman et al (2023) .…”

“…Calves were naturally reared by their dams, with data collected at birth and during the first 48 h of age described in Redifer et al (2023) and Wichman et al (2023) , respectively. Calf size at birth was determined pre-suckling (0.9 ± 0.3 h of age).…”

“…We reported that maternal growth was slowed for nutrient restricted heifers during late gestation, and they mobilized maternal stores so that fetal growth was spared ( Redifer et al, 2023 ). Still, calves born to nutrient restricted dams were less vigorous with altered blood chemistry and hematology over the first 48 h of age ( Wichman et al, 2023 ). We hypothesized that dams nutrient restricted during late gestation then fed to meet estimated nutrient requirements during lactation would experience compensatory growth and reach a similar body weight and body condition as control dams by weaning.…”