Figure 1.
Figure 1.

Diagram of experimental design. Multiparous, nonlactating beef cows were bred and fed similar diets until d 30 of gestation. On d 30 of pregnancy, cows were randomly assigned to dietary treatments: control (CON; 100% NRC; n = 18) and nutrient restriction (RES; 60% NRC; n = 30). On d 85 cows were either slaughtered (CON, n = 6; RES, n = 6) or remained on control (CC; n = 12) or restricted (RR; n = 12) or were realimented to control (RC; n = 11). On d 140 cows were ether slaughtered (CC, n = 6; RR, n = 6; RC, n = 5) or remained on control (CCC; n = 6; RCC; n = 5) or realimented to control (RRC; n = 6). On d 254 all remaining cows were slaughtered. An animal from the RC group was removed from the study because early embryonic loss and a second cow was removed from RCC group because the presence of twins. Diets consisted of grass hay and mineral and vitamin supplement at either 100% NRC recommendations for NE for maintenance and fetal growth (NRC, 2000). Nutrient restricted cows received 60% of the same control diet.

 


Figure 2.
Figure 2.

Cow BW (kg; panel A) and BW change (%; panel B) of cows slaughtered at d 85 of gestation. Cows received either control (CON) diet (100% NRC) or restricted (RES) from d 30 to 85 (60% NRC). There was no treatment (trt) × day interaction (P = 0.12) or treatment main effect (P = 0.49) for cow BW but there was a day effect (P < 0.001). There was a treatment × day interaction (P = 0.04) for cow BW change. *CON cows different (P < 0.05) from RES. The SEM is average of SEM for treatment × day interaction.

 


Figure 3.
Figure 3.

Cow BW (kg; panel A) and BW change (%; panel B) of cows slaughtered at d 140 of gestation. Cows received the control diet (100% NRC) from d 30 until 140 (CC), restricted from d 30 to 85 (60% NRC) and then realimented to 100% of the NRC requirements until d 140 (RC), and restricted from d 30 to 140 (60% NRC; RR). There was a treatment (trt) × day interaction (P ≤ 0.02) for cow BW and BW change. *CC cows significantly different (P < 0.05) from RR and RC being intermediate; **CC cows different (P < 0.05) from RR and RC; ***CC cows different (P < 0.05) from RC and RC different from RR. The SEM is average of SEM for treatment × day interaction.

 


Figure 4.
Figure 4.

Cow BW (kg; panel A) and BW change (%; panel B) of cows slaughtered at d 254 of gestation. Cows received the control diet (100% NRC) from d 30 until 254 (CCC), restricted from d 30 to 85 (60% NRC) and then realimented to 100% of the NRC requirements until d 254 (RCC), and restricted from d 30 to 140 (60% NRC) and then realimented to 100% of the NRC requirements until d 254 (RRC). There was a treatment (trt) × day interaction (P ≤ 0.01) for cow BW and BW change. *CCC cows different (P < 0.05) from RRC and RCC being intermediate; **CCC and RCC cows different (P < 0.05) from RRC; ***RCC cows different (P < 0.05) from RRC and CCC being intermediate; †RCC cows different (P < 0.05) from CCC and RRC; ‡CCC cows different (P < 0.05) from RCC and RRC being intermediate. The SEM is average of SEM for treatment × day interaction.