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Summary: This study's objective was to determine if nutrient restriction during late gestation affected beef heifer feed intake, body weight (BW) gain and endocrine regulation during a 10‐week feeding trial. During the last 100 days of gestation, control (CON) dams were fed to increase body condition score (BCS). Whereas, nutrient‐restricted dams (NR) and NR dams protein supplemented 3 days/week (NRS) were fed to decrease BCS by 1.2. After parturition, all cow‐calf pairs were moved to a common pasture and fed in excess of requirements until weaning. At 15 months of age, heifers were randomly sorted into two pens and adjusted to a commercial total mixed ration over a 2‐week period. Blood samples and BW were taken at the initiation of feeding and on a biweekly basis for the duration of the feeding trial. Feed intake was monitored for 10 weeks using a GrowSafe System. After 10 weeks, an intravenous glucose tolerance test (IVGTT) was performed on 21 randomly subsampled heifers. During the feeding trial, NR heifers consumed more feed than CON and NRS heifers. Heifers from NR dams tended to increase BW compared to NRS and CON heifers when adjusted for initial BW. Heifers from NR and NRS dams had a greater increase in BCS compared to heifers from CON dams. Plasma glucose and insulin concentrations during the feeding trial increased in NR heifers compared to the other groups beginning at 2 and 4 weeks respectively. Plasma leptin concentrations were increased in the NR and NRS heifers compared to the CON heifers beginning at week 4 of feeding. During the IVGTT at the conclusion of the feeding challenge, plasma glucose and insulin were increased in NR heifers compared to other treatment groups. These results show that nutrient restriction during late gestation alters appetite and endocrine regulation in heifer offspring. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine the effects of early and mid-gestation nutrient restriction on maternal metabolites and foetal growth. Primiparous Angus cows were synchronized and inseminated with semen from one sire. Dietary treatments were: control to gain 1 kg/week (CON) or 0.55% maintenance energy and CP requirements (nutrient restricted; NR). A subset of dams was fed NR (n=8) or CON (n=8) from days 30 to 110 of gestation. Another group was fed CON (n=8), days 30 to 190; NR (n=7), days 30 to 110 followed by CON days 110 to 190; or CON, (n=7) days 30 to 110 followed by NR days 110 to 190. Cows were harvested at days 110 or 190 of gestation, when foetal measurements and samples were collected. Cows that were NR during days 30 to 110 or 110 to 190 of gestation lost significant BW and body condition score (P<0.001), this was associated with reduced plasma glucose during NR (P<0.002). Foetal weights, empty foetal weights, abdominal and thoracic circumferences were all reduced (P<0.03) in day 110 NR animals. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.01) in NR day 110 female foetuses compared with CON foetus. Maternal serum triglycerides at day 110 of gestation were decreased (P<0.05) in NR dams, whereas foetal serum triglycerides were increased (P<0.05) in response to maternal NR. Foetal weights tended to be reduced (P=0.08) in NR/CON and CON/NR v. CON/CON cattle at day 190 of gestation. Empty foetal weights, abdominal and thoracic circumferences were reduced (P⩽0.03) in NR/CON and CON/NR v. CON/CON cattle. Brain weight as a percentage of empty foetal weight was increased (P<0.001) in NR/CON and CON/NR v. CON/CON cattle. Foetal perirenal adipose as a percentage of empty foetal weight was increased (P=0.003) in NR/CON and CON/NR v. CON/CON cattle. Maternal serum triglycerides at day 190 of gestation were decreased (P<0.05) in association with maternal NR. Foetal serum triglycerides at day 190 of gestation were increased (P<0.05) in response to maternal NR during early gestation but decreased by NR in mid gestation compared with CON foetuses. The data show that maternal nutrient restriction during early or mid-gestation cause’s asymmetrical foetal growth restriction, regardless if the restriction is preceded or followed by a period of non-restriction. [ABSTRACT FROM PUBLISHER]

It has previously been shown that late gestation nutrient restriction results in altered postnatal endocrine regulation and growth in newborn calves. The objective of this study was to determine if nutrient restriction during late gestation affected heifer offspring's DMI, BW gain, and endocrine regulation during a 10 wk feeding trial. During the last 100 d of gestation, control (CON, n = 11) dams were fed to increase BCS by 0.6 ± 0.1. Whereas, nutrient restricted dams (NR, n = 10) and NR dams offered protein supplement three d/wk (NRS, n = 13) were fed to decrease BCS by 1.2 ± 0.2. After parturition, all cow-calf pairs were moved to a common pasture and fed at or in excess of requirements until weaning. After weaning, all heifers were maintained as a single group. At 15 mo of age, heifers were randomly sorted into 2 pens and adjusted to a pelleted TMR over a 2 wk period. Blood samples and BW were taken at initiation of feeding and on a biweekly basis for the duration of the feeding trail. Feed intake was monitored for 10 wk using a GrowSafe System. After 10 wk, an intravenous glucose tolerance test (IVGTT; dose: 0.3g dextrose/kg BW) was performed on 21 randomly subsampled heifers. The NR heifers consumed more feed (P = 0.01) than CON and NRS (1328 ± 49, 1110 ± 45 and 1197 ± 41 kg, respectively). Heifers from NR dams tended (P = 0.07) to increase BW compared to NRS and CON heifers when adjusted for initial BW (26 ± 2, 23 ± 2 and 20 ± 2%, respectively). Heifers from NR and NRS dams had a greater increase (P < 0.01) in BCS compared to heifers from CON dams (1.4 ± 0.2, 1.2 ± 0.1, and 0.7 ± 0.1, respectively). Plasma glucose and insulin concentrations during the feeding trial increased (P < 0.03 and P < 0.0001, respectively) in NR heifers compared to the other groups beginning at 2 and 4 wks, respectively. Plasma leptin concentrations were increased (P = 0.045) in the NR and NRS heifers compared to the CON heifers beginning at 4 wks of feeding. During the IVGTT at the conclusion of the feeding challenge, plasma glucose and insulin were increased (P = 0.02 and P < 0.001) in NR heifers compared to other treatment groups. These results show that nutrient restriction during late gestation alters appetite and endocrine regulation in heifer offspring. [ABSTRACT FROM AUTHOR]

It has previously been shown that late gestation nutrient restriction results in altered postnatal endocrine regulation and growth in newborn calves. The objective of this study was to determine if nutrient restriction during late gestation affected heifer offspring's DMI, BW gain, and endocrine regulation during a 10 wk feeding trial. During the last 100 d of gestation, control (CON, n = 11) dams were fed to increase BCS by 0.6 ± 0.1. Whereas, nutrient restricted dams (NR, n = 10) and NR dams offered protein supplement three d/wk (NRS, n = 13) were fed to decrease BCS by 1.2 ± 0.2. After parturition, all cow-calf pairs were moved to a common pasture and fed at or in excess of requirements until weaning. After weaning, all heifers were maintained as a single group. At 15 mo of age, heifers were randomly sorted into 2 pens and adjusted to a pelleted TMR over a 2 wk period. Blood samples and BW were taken at initiation of feeding and on a biweekly basis for the duration of the feeding trail. Feed intake was monitored for 10 wk using a GrowSafe System. After 10 wk, an intravenous glucose tolerance test (IVGTT; dose: 0.3g dextrose/kg BW) was performed on 21 randomly subsampled heifers. The NR heifers consumed more feed (P = 0.01) than CON and NRS (1328 ± 49, 1110 ± 45 and 1197 ± 41 kg, respectively). Heifers from NR dams tended (P = 0.07) to increase BW compared to NRS and CON heifers when adjusted for initial BW (26 ± 2, 23 ± 2 and 20 ± 2%, respectively). Heifers from NR and NRS dams had a greater increase (P < 0.01) in BCS compared to heifers from CON dams (1.4 ± 0.2, 1.2 ± 0.1, and 0.7 ± 0.1, respectively). Plasma glucose and insulin concentrations during the feeding trial increased (P < 0.03 and P < 0.0001, respectively) in NR heifers compared to the other groups beginning at 2 and 4 wks, respectively. Plasma leptin concentrations were increased (P = 0.045) in the NR and NRS heifers compared to the CON heifers beginning at 4 wks of feeding. During the IVGTT at the conclusion of the feeding challenge, plasma glucose and insulin were increased (P = 0.02 and P < 0.001) in NR heifers compared to other treatment groups. These results show that nutrient restriction during late gestation alters appetite and endocrine regulation in heifer offspring. [ABSTRACT FROM AUTHOR]