Effects of nutrient restriction of bovine dams during early gestation on postnatal growth and regulation of plasma glucose1

Abstract

Angus x Hereford heifers (15 mo and AI to a single sire) were used to evaluate the effect of prenatal nutritional restriction on postnatal growth and regulation of glucose in plasma. Dams (d 32 of gestation) were stratified by BW and BCS and allotted to low [LN, 55% of NRC (1996) requirements, n = 7] or moderate nutrition [MN, 100% of NRC (1996) requirements, n = 7]. After 83 d of feeding, dams were commingled and received a diet in excess of requirements. Dams were allowed to calve naturally, and bull calves were castrated at birth. Dams and calves were maintained as a group until weaning, and calves were maintained as a group after weaning. Calves (15 mo of age) were adapted to a similar diet during 2 wk; catheters were placed in both jugular veins; and calves were confined in stalls. Two days later, calves were subjected to an intravenous glucose challenge and the next day to an insulin challenge. Dams had similar (P = 0.31) BW at the beginning of the experiment. At the end of restriction, LN dams weighed less (P ≤ 0.01) and had less BCS (P < 0.001) compared with MN dams. Length of gestation was not affected by prenatal nutritional treatment. Nutrient restriction during gestation did not influence birth weight or postnatal growth. Concentrations of glucose (P = 0.49) and insulin (P = 0.29) were not different in plasma of LN and MN calves before glucose infusion. Plasma concentrations of glucose, after intravenous administration of glucose, decreased more rapidly (P = 0.05) in LN compared with MN calves. Concentrations of glucose (P = 0.68) and insulin (P = 0.55) in plasma of LN and MN calves were similar after infusion of insulin. Nutritional restriction of dams during early gestation did not influence postnatal growth, but altered clearance of glucose after a bolus infusion of glucose.

Effects of Developmental Programming Caused by Maternal Nutrient Intake on Postnatal Performance of Beef Heifers and Their Calves

“…In our experiment, the lack of differences in glucose concentrations throughout rearing between CONTROL and SUBNUT heifers indicated that glucose metabolism was not affected in their postnatal lives. Similarly, other studies have described no effect of nutritional restriction during early pregnancy on calf basal glucose concentration [11]. Regarding the breed, the higher glucose concentration at AI in PA than in PI could suggest that PA could have consumed more hay and straw (which were offered ad libitum, unlike the concentrate) than PI.…”

“…However, the impact of gestational undernutrition, either in early, mid or late gestation, on the reproductive performance of the progeny is not fully understood. Several studies reported negative effects on reproductive traits of the female offspring, with lower antral follicle counts [9], impaired ovulation rate [10] or decreased fertility [10,11]. In contrast, other studies described equal [12] or higher [13] numbers of antral follicles and higher ovulation rate [13] in females from nutrient-restricted dams.…”

The effects of late gestation nutrient restriction of dams on beef heifer intake, metabolites and hormones during an ad libitum feeding trial

“…Similarly, in this study, the increased insulin level exhibited by NR heifers is accompanied by an increase in BCS. Intrauterine growth restriction induced by a variety of maternal models such as glucocorticoid exposure (Long, Shasa, Ford, & Nathanielsz, ), obesity (Ford et al., ; Long, George et al., ) and nutrient restriction (Matveyenko, Singh, Shin, Georgia, & Devaskar, ) has been shown to alter offspring pancreatic and β‐cell function resulting in increased insulin secretion. Our data coincide with these findings as NR heifers show an increase in insulin concentrations during both the feeding trial and IVGTT suggesting altered pancreatic and β‐cell function.…”

“…After 10 weeks of feed intake monitoring, 21 heifers (7 per treatment group) were randomly chosen (via a random number generator) for intravenous glucose tolerance testing (IVGTT) using methods described by Long, Prado‐Cooper, Krehbiel, and Wettemann () with modifications. Heifers were removed from feed 18 hr before IVGTT, but were still allowed access to water.…”

The Effects of Developmental Programming upon Neonatal Mortality

“…A disproportionately large calf is the major contributor to dystocia in heifers 24,25 with calf birthweight 28 and heifer size 15 considered the primary factors causing this fetal- 1 feto-placental unit responds to nutrient intake, 1a: Epigene c changes in feto-placental genes in response to nutri on; 2 blood flow to the placenta and transporter changes affect placental permeability and func on 2a Gesta onal diet alters colostrum quality (Igs) and quan ty; 3 Plancental hormonal output modulates fetal environment. As illustrated in Table 1, the timing of dietary interventions impacts the observed effect upon birthweight: Interventions imposed prior to 100 days post-conception (dpc), although causing greater effects upon fetal organ development 34 , generally result in similar birthweights at term 35,36 . Nutrient restriction during the second trimester, however, may have the greatest influence on calf birthweight 30 2,37 sufficient to influence dystocia and thereby survival in the neonate.…”