*3.1. Growth Performance*

Animal performance and growth data are reported in Table 3. Maternal dietary treatment did not influence (*p* > 0.05) offspring BW, or DMI. In Period 1 (day 0–23) of the finishing phase, offspring from dams fed a forage-based diet tended (*p* = 0.079) to have an improved ADG compared to the offspring from dams fed a concentrate-based diet.


**Table 3.** Growth performance for progeny of dams fed a prepartum dietary carbohydrate source consisting of concentratebased (Conc) or forage-based (For) diet during mid- and late-gestation.

<sup>1</sup> Diets formulated based on NRC (2000) requirements for dams fed either a concentrate or forage diet during mid- and late-gestation. <sup>2</sup> Probability of difference among least square means. <sup>3</sup> Standard error of the mean. <sup>4</sup> ADG calculated from end of previous period to end of current period. <sup>5</sup> DMI: Dry matter intake. <sup>6</sup> G:F. gain to feed ratio. <sup>7</sup> Final BW, ADG, DMI, and G:F calculated based on when each animal was harvested at either d 131, d 145, or d 180. however, no differences (*p* > 0.05) in ADG were detected between treatment groups in subsequent periods.

> A tendency (*p* = 0.054) for a treatment × sex interaction was detected for ADG in Period 2 (Figure 1a). Steers from the concentrate treatment had greater (*p* < 0.04) ADG compared with steers from the forage treatment, while ADG of heifers did not differ (*p* > 0.05) between treatments. A tendency (*p* = 0.071) for a treatment × sex interaction was also detected for ADG in Period 3 (Figure 1b).

> Steers from the forage treatment had greater (*p* < 0.04) ADG than steers from the concentrate treatment as well as the heifers from either treatment, which were similar (*p* > 0.05). A tendency (*p* = 0.067) for a treatment × sex interaction was observed for ADG in Period 5 (Figure 1c). Steers from both treatments had similar (*p* > 0.05) ADG, and had similar (*p* > 0.05) ADG compared to both forage and concentrate heifers; however, forage heifers tended to have improved (*p* = 0.06) ADG compared to concentrate heifers.

**Figure 1.** Treatment by sex interaction for ADG (kg/d) of progeny in: (**a**) Period 2 (*p* = 0.054), (**b**) Period 3 (*p* = 0.071), and (**c**) Period 5 (*p* = 0.067) from dams fed a concentrate-based (Conc) or foragebased (For) diet during mid- and late-gestation. Diets formulated based on NRC (2000) requirements for dams fed either a concentrate or forage diet during mid- and late-gestation. x, y, z LSmeans lacking a common superscript differ (*p* ≤ 0.05).

No differences (*p* > 0.05) in G:F were observed between treatment groups; however, a tendency (*p* = 0.065) for a treatment × sex interaction was detected for G:F in Period 2 (Figure 2). Steers from both treatments had similar (*p* > 0.05) G:F, and had improved (*p* < 0.05) G:F compared to heifers from both treatments, however the forage heifers tended to have improved (*p* = 0.09) G:F compared to the concentrate heifers.

**Figure 2.** Treatment by sex interaction (*p* = 0.065) for G:F (kg/kg) of progeny in Period 2 from dams fed a concentrate-based (Conc) or forage-based (For) diet during mid- and/or late-gestation 1. <sup>1</sup> Diets formulated based on NRC (2000) requirements for dams fed either a concentrate or forage diet during mid- and late-gestation. x, y, z LSmeans lacking a common superscript differ (*p* ≤ 0.05).

As expected, steers had greater (*p* < 0.05) BW compared to heifers at all time periods and had an increased (*p* < 0.05) ADG from day 37–83. Steers also had increased (*p* < 0.05) ADG in Period 2 (day 23–51) and Period 3 (day 51–78) compared to heifers. However, heifers had an increased (*p* < 0.05) ADG in Period 4 (day 78–106) and tended to have an increased (*p* = 0.051) ADG compared to steers in Period 1 (day 0–23). Heifers had greater (*p* < 0.05) DMI during Period 1, however, DMI did not differ (*p* > 0.05) between steers and heifers for the remainder of the finishing period. Steers had improved (*p* < 0.05) G:F during Period 2 (day 23–51) and 3 (day 51–78), while heifers had improved (*p* < 0.05) G:F during Period 4 (day 78–106). It is likely that differences in G:F were driven by differences in ADG rather than DMI.

#### *3.2. Ultrasound Measurements*

Ultrasound measurements are reported in Table 4. Maternal treatment did not influence (*p* > 0.05) offspring BF, IMF percentage or muscle depth during the finishing phase. A treatment × sex interaction (*p* = 0.028) was detected for muscle depth during the backgrounding phase (Figure 3). Heifers from the concentrate treatment tended to have increased (*p* = 0.07) muscle depth compared with heifers from the forage treatment, while muscle depth of steers did not differ (*p* > 0.05) between treatments. Heifers had increased (*p* < 0.05) BF compared to steers at the initial ultrasound during the backgrounding phase.

**Table 4.** Least square means for ultrasound measurements of progeny from dams fed a prepartum dietary carbohydrate source consisting of concentrate-based (Conc) or forage-based (For) diet during mid- and late-gestation.



**Table 4.** *Cont.*

<sup>1</sup> Diets formulated based on NRC (2000) requirements for dams fed either a concentrate or forage diet during mid- and late-gestation.

<sup>2</sup> Standard error of the mean <sup>3</sup> Probability of difference among least square means.

**Figure 3.** Treatment by sex interaction (*p* = 0.028) for muscle depth measured via ultrasound during backgrounding (d 36) of progeny from dams fed a concentrate-based (Conc) or forage-based (For) diet during mid- and/or late-gestation. Diets formulated based on NRC (2000) requirements for dams fed either a concentrate or forage diet during mid- and late-gestation. y,z LSmeans lacking a common superscript differ (*p* ≤ 0.05).

#### *3.3. Carcass Characteristics*

Carcass measurements are reported in Table 5. Maternal treatment did not influence (*p* > 0.05) offspring HCW, REA, marbling score, *L\** values, or the proportion of carcasses in each USDA Quality and Yield Grade category. Offspring from the forage treatment tended to have decreased (*p* = 0.060) 12th rib fat thickness and tended to have lower (*p* = 0.084) USDA Yield Grades compared to offspring from the concentrate treatment. Offspring from the concentrate treatment had increased (*p* < 0.05) *a\** and *b\** values compared to the forage treatment. As expected, steers had heavier (*p* < 0.05) HCW and larger (*p* < 0.05) REA than heifers. Heifers had increased (*p* < 0.05) BF and marbling scores, as well as increased (*p* < 0.05) *a\** and *b\** values and tended (*p* = 0.070) to have higher USDA Yield Grades.

**Table 5.** Least square means for carcass characteristics and meat quality of progeny from dams fed a prepartum dietary carbohydrate source consisting of concentrate-based (Conc) or forage-based (For) diet during mid- and late-gestation.



**Table 5.** *Cont.*

<sup>1</sup> Diets formulated based on NRC (2000) requirements for dams fed either a concentrate or forage diet during mid- and late-gestation. <sup>2</sup> Probability of difference among least square means <sup>3</sup> Standard error of the mean. <sup>4</sup> Marbling score: 200 = Traces 0, 300 = Slight 0, 400 = Small 0, 500 = Modest 0. <sup>5</sup> Recorded 3 d postmortem; *L\**: 0 = Black, 100 = White; *a\**: Negative values = green; Positive values = red; *b\**: Negative values = blue; Positive values = yellow. <sup>6</sup> Calculated proportions of USDA Quality and Yield Grade (data did not converge for a quality grade of USDA Select, or USDA Yield Grade less than a 2 or greater than a 3).
