Dry matter and nutrient intake

During the first pre-weaning phase (1 to 21 days), no significant difference was observed in mean dry matter intake of calves fed different diets (Table 4.2). In the second pre-weaning phase (22-49 days), mean dry matter was greater in calves fed PSH than calves fed either HF or LF TMR (Table 4.2). Also during post-weaning (50-57 days), calves fed PSH showed greater mean dry matter intake than calves fed different moist alfalfa based TMRs (LF, HF) (Table 4.2).

Greater mean ME (MJ/hd/d) intake was observed in calves fed PSH diet than calves fed different moist alfalfa based TMRs (LF, HF), when measured at either 1 to 21 days of age, 22 to 49 days or at 50 to 57 days of age (Table 4.2).

During the early rearing phase, from 1 to 21 days of age, the CP (g/hd/d) intake was greater in calves fed PSH than calves fed either HF or LH TMR, while there was no difference between calves fed HF TMR and those fed LF TMR (Table 4.2). Between 22 to and 49 days of age, the CP intake was greater in calves fed PSH, intermediate in calves fed HF TMR and least in calves fed LF TMR. Post-weaning, CP intake was greater in calves fed PSH than in calves fed HF or LF TMR.

80 Table 4.2. Nutrient intake (LSM±SE) of dairy calves fed total mixed rations with low (LF) or high (HF) proportions of moist alfalfa, or starter with pasture hay (PSH) pre- and post-weaning.

LF HF PSH P value

Total dry matter intake, g/d

1 to 21 d 112.8 (130.5) 137.0 (142.9) 315.6 (142.8) 0.3801 22 to 49 d 1100.8b _{(74.6) 1209.3}b _{(80.3) 2323.7}a _{(86.9) 0.0001} 50 to 57 d 1740.7b _{(206.4) 1742.4}b _{(167.5) 3714.3}a _{(364.9) 0.0001} ME intake, MJ/kg DM/d 1 to 21 d 13.2b _{(3.9) 12.7}b _{(3.9) 32.4}a _{(3.9) 0.0007} 22 to 49 d 128.8b _{(9.0) 112.5}b _{(9.0) 238.2}a _{(9.0) 0.0001} 50 to 57 d 203.6b _{(25.7) 162.1}b _{(25.7) 380.7}a _{(25.7) 0.0001} Crude protein intake, g/d

1 to 21 d 16.7b _{(6.31) 27.6}b _{(6.31) 51.4}a _{(6.31) 0.0096} 22 to 49 d 162.9c _{(14.8) 244.2}b _{(14.8) 378.8}a _{(14.8) 0.0001} 50 to 57 d 257.6b _{(41.3) 351.9}b _{(41.3) 605.4}a _{(41.3) 0.0001} NDF intake, g/d 1 to 21 d 29.2b _{(34.5) 52.5}b _{(35.5) 145.5}a _{(24.7) 0.0370} 22 to 49 d 285.1c _{(25.6) 464.3}b _{(31.3) 1071.3}a _{(39.3) 0.0001} 50 to 57 d 450.8c _{(53.9) 669.0}b _{(65.9) 1712.3}a _{(168.5) 0.0001} ADF intake, g/d 1 to 21 d 18.7 (22.1) 42.1 (26.9) 78.9 (30.1) 0.3651 22 to 49 d 182.7c _{(29.4) 372.4}b _{(23.3) 580.9}a _{(19.6) 0.0001} 50 to 57 d 288.9c _{(32.1) 536.6}b _{(50.7) 928.6}a _{(89.9) 0.0003} a-c_{Means in the same row followed by differing superscript letters differ}

significantly at P<0.05.

From 1 to 21 days of age, the mean daily NDF intake was greater in calves fed PSH than calves fed either HF or LF TMR (Table 4.2). However, between 22 and 49 days of age and after weaning (50 to 57 days), the mean daily intake of NDF was greatest in calves fed PSH, intermediate with HF TMR and least in calves fed LF TMR.

81 At the early pre-weaning period, up to 21 days of age, no significant difference in mean ADF intake was observed among different groups (PSH, HF or LF TMR) (Table 4.2). However, the mean ADF intake was greater in calves fed PSH, compared to calves fed HF or LF TMR during 22 to 49 days and similar trent was observed during post-weaning period (50-57 days) (Table 4.2). Table 4.3. Liveweight and liveweight gain (LSM±SE) of dairy calves fed low (LF) or high (HF) proportions of moist alfalfa, or starter with pasture hay (PSH) pre- and post-weaning.

LF TMR HF TMR PSH P value Liveweight at age, kg 1 d 38.5 (0.84) 40.2 (0.85) 39.3 (0.83) 0.4417 21 d 50.2 (1.06) 52.1 (1.05) 53.2(1.03) 0.0996 49 d 66.3b _{(1.51) 69.8}a,b _{(1.51) 73.1}a _{(1.48) 0.0003} 57 d1 _70.3b _{(1.97) 73.8}b _{(1.98) 79.3}a _{(1.94) 0.0100} 70 d2 _76.6b _{(1.79) 80.5}b _{(1.79) 88.1}a _{(1.76) 0.0008} Liveweight gain, kg/day

1 to 21 d 0.56b _{(0.032) 0.57}b _{(0.032) 0.66}a _{(0.031) 0.0049} 22 to 49 d 0.57b _{(0.022) 0.63}b _{(0.022) 0.71}a _{(0.021) 0.0070} 50 to 57 d1 _0.55b _{(0.094) 0.56}b _{(0.094) 0.89}a _{(0.093) 0.0004} 58 to 70 d2 _0.46b _{(0.046) 0.49}b _{(0.046) 0.62}a _{(0.045) 0.0238} a-c_{Means in the same row followed by differing superscript letters differ} significantly at P<0.05.

1_Housed

2_{Grazing pasture}

4.3.2. Liveweight and liveweight gain

The liveweights of calves at 49 days of age were greater in calves fed PSH and HF TMR, compared with calves fed LF TMR. Post-weaning, at day 57 and day 70, the mean individual liveweight was greater in calves fed PSH, compared with calves fed HF and LF TMR (Table 4.3). During all the pre- and

82 post-weaning periods, the liveweight gain were greater in calves fed PSH, compared with calves fed LF and HF TMR (Table 4.3).

4.3.3. Stature

At 49 day of age, mean hip width was significantly greater in PSH calves compared with LF TMR-fed calves (Table 4.4). Post-weaning at day 57 and 70, the mean hip width of PSH-fed calves was greater than either the HF TMR or LF TMR-fed calves. At 49 day of age, mean hip height was significantly greater in calves fed PSH or HF TMR compared with LF TMR fed calves. Post-weaning, the mean hip height of calves fed PSH was greater than calves fed the HF or LF TMR at both post-weaning periods (Table 4.4). The mean last rib girth was significantly greater, in calves fed PSH than LF TMR when measured at the day 21 and 49 pre-weaning period (Table 4.4). Post- weaning, the mean last rib girth of PSH fed calves was greater than that of calves fed HF or LF TMR. When the calves were turned out to pasture there was no difference observed between calves fed PSH and HF TMR. However, calves fed PSH and HF TMR had greater last rib girth than calves fed LF TMR at this time period (Table 4.4).

4.3.4. Feed conversion efficiency

Greater feed conversion efficiency (FCE) was observed in calves fed moist alfalfa based TMRs (LF, HF) than PSH fed calves (Table 4.5) during two phases of pre-weaning period (1 to 21 days, 22 to 49 days). However, no significant difference was observed among different treatment groups post- weaning.

83 Table 4.4. Stature (LSM±SE) of dairy calves fed low (LF) or high (HF) proportions of moist alfalfa, or starter with pasture hay (PSH) pre- and post- weaning. LF TMR HF TMR PSH P Value Hip width, cm 2 d 17.2 (0.16) 17.5 (0.16) 17.3 (0.16) 0.5406 21 d 18.6 (0.16) 18.8 (0.16) 19.0 (0.16) 0.1099 49 d 20.0b _{(0.19) 20.4}a,b _{(0.19) 20.7}a _{(0.19) 0.0038} 57 d1 _20.3b _{(0.23) 20.7}b _{(0.23) 21.3}a _{(0.23) 0.0005} 70 d2 _21.1b _{(0.20) 21.5}b _{(0.20) 22.2}a _{(0.20) <.0001} Hip Height, cm 2 d 634.4 (6.17) 637.6 (6.19) 638.5 (6.09) 0.5394 21 d 671.5 (4.57) 671.1 (4.51) 677.2 (4.44) 0.3636 49 d 727.2b _{(5.55) 735.1}a,b _{(5.54) 743.9}a _{(5.44) 0.0115} 57 d1 _741.6b _{(5.87) 742.4}b _{(5.88) 760.2}a _{(5.77) 0.0089} 70 d2 _767.6b _{(6.32) 769.2}b _{(6.35) 788.2}a _{(6.25) 0.0017} Last rib girth, cm

2 d 83.7 (1.37) 84.6 (1.38) 85.0 (1.37) 0.2121 21 d 95.5b _{(1.08) 97.3}a,b _{(1.08) 98.3}a _{(1.07) 0.0073} 49 d 106.3b _{(1.38) 108.5}a,b _{(1.39) 110.8}a _{(1.37) 0.0025} 57 d1 _108.4b _{(1.59) 111.4}b _{(1.59) 115.5}a _{(1.57) <.0001} 70 d2 _117.3b _{(2.07) 120.6}a _{(2.08) 121.0}a _{(2.05) 0.0305} a-c_{Means in the same row followed by differing superscript letters differ} significantly at P<0.05.

1_{Weaned calves housed.} 2_{Calves on pasture.}

84 Table 4.5. Feed conversion efficiency (LSM±SE) of dairy calves fed low (LF) or high (HF) proportions of moist alfalfa, or starter with pasture hay (PSH) pre- and post-weaning.

Total mixed rations

Period LF TMR HF TMR PSH

1 to 21d 4.9a _{(0.081) 4.2}a _{(0.081) 2.09}b _(0.081) 22 to 49d 0.52a _{(0.050) 0.53}a _{(0.050) 0.31}b _(0.050) 50 to 57d 0.32 (0.090) 0.32 (0.090) 0.24 (0.090) a-b_{Means in the same row followed by differing superscript letters differ} significantly at P<0.05.

LWG – Liveweight gain.

FCE: Feed conversion effeciency calculated as LWG/total DMI (kg) per day. 4.4. Discussion