View Full Table | Close Full ViewTable 1.

Ingredients and composition of concentrate and alfalfa hay provided to heifers during the lactation (0–6 mo) and rearing (6–15 mo) periods1

 
Concentrate
Item Lactation Rearing Alfalfa hay
Ingredient (as-fed basis), %
    Corn 30.00 44.00
    Soybean flour 16.50 4.60
    Barley 15.50 21.60
    Corn gluten 15.00
    Extruded cereal 15.00
    Wheat bran 15.00
    Rapeseed flour 5.00
    Milk byproducts 3.00
    Beet pulp 2.00 3.00
    Palm oil 1.30 2.90
    Calcium carbonate 1.00 1.20
    Vitamin–mineral premix2 0.20 2.00
    Sodium chloride 0.50 0.20
    Urea 0.50
Nutrient composition
    DM, g/kg 894 900 851
    ME, MJ/kg DM 15.1 15.2 9.2
    CP, g/kg DM 166 147 98
    NDF, g/kg DM 214 252 462
1Lactation concentrate was provided ad libitum to heifers in the high lactation treatment. Rearing concentrate was provided in amounts of 12 g/kg BW to the high rearing treatment and 6 g/kg BW to the low rearing treatment heifers. Alfalfa hay was provided ad libitum in the rearing period to all heifers.
2 Vitamin A, 7,000 IU/kg; Vitamin D3, 1,500 IU/kg; Copper (cupric sulfate pentahydrate), 2 mg/kg; Iodine (potassium iodide), 0.5 mg/kg; Cobalt (cobaltous carbonate monohydrate), 0.5 mg/kg; Zinc (zinc oxide), 40 mg/kg; Manganese (manganese oxide), 30 mg/kg; Selenium (sodium selenite), 0.2 mg/kg; Iron (ferrous carbonate), 5 mg/kg; Butylhydroxytoluene, 2 mg/kg.



View Full Table | Close Full ViewTable 2.

Rate of weight gain (kg/d) of heifers from birth to first breeding according to the feed management applied in the lactation period (LACT) and the rearing period (REAR)

 
LACT (0–6 mo)
P-value
LO1
HI1
REAR (6–15 mo)
LACT REAR LACT × REAR
Item LO HI LO HI SEM
ADG LACT 0.643b 0.699b 1.046a 1.080a 0.03 <0.001 0.18 0.72
ADG REAR 0.744c 0.998a 0.593d 0.925b 0.05 <0.001 <0.001 0.10
ADG birth to puberty 0.680c 0.863b 0.833b 1.085a 0.02 <0.001 <0.001 0.14
a–dMeans within a row with different superscripts differ significantly (P < 0.05).
1LO = 0.7 kg/d target ADG; HI = 1.0 kg/d target ADG.



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Size measures of heifers (cm) at 6 and 15 mo of age according to feed management applied in the lactation period (LACT) and the rearing period (REAR)

 
LACT (0–6 mo)
LO1
HI1
P-value
REAR (6–15 mo)
Item LO HI LO HI SEM LACT REAR LACT × REAR
Height at withers
    6 mo 98.0c 99.0b 103.9bc 104.6a 1.8 0.004 0.64 0.94
    15 mo 118.6b 122.8a 120.1ab 122.0ab 1.4 0.78 0.04 0.42
Heart girth
    6 mo 124.3b 127.9b 141.9a 143.8a 2.1 <0.001 0.24 0.78
    15 mo 168.0d 182.9b 173.3c 188.6a 1.7 0.002 <0.001 0.79
Rump width
    6 mo 29.7b 29.9b 32.9a 34.8a 0.8 <0.001 0.20 0.28
    15 mo 41.3b 46.5a 45.6a 45.4a 0.8 0.05 0.004 0.002
Rump length
    6 mo 32.5b 32.9b 36.1a 37.5a 1.0 <0.001 0.41 0.64
    15 mo 43.4b 47.4a 46.3a 48.0a 0.7 0.02 <0.001 0.14
a-cMeans within a row with different superscripts differ significantly (P < 0.05).
1LO = 0.7 kg/d target ADG; HI = 1.0 kg/d target ADG.



View Full Table | Close Full ViewTable 4.

Reproductive performance according to feed management applied in the lactation period (LACT) and the rearing period (REAR)

 
LACT (0–6 mo)
LO1
HI1
P-value
REAR (6–15 mo)
Item LO HI LO HI SEM LACT REAR LACT × REAR
Weight at puberty, kg 330.6 313.7 326.2 328.8 14.18 0.71 0.62 0.50
Age at puberty, mo 13.5a 10.2bc 11.3b 9.2c 0.52 0.005 <0.001 0.26
Percent MBW2 at puberty 57.0 54.1 56.2 56.3 0.02 0.75 0.56 0.53
Pubertal heifers3 4/7 8/8 7/7 7/7 0.08 0.06
Weight at first AI, kg 388.1d 464.5b 424.8c 513.1a 12.03 0.001 <0.001 0.62
Age at first AI, mo 15.8 15.6 15.7 15.9 0.15 0.67 0.93 0.26
Conception BW, kg 382.3d 486.2b 431.7c 530.2a 11.36 <0.001 <0.001 0.71
Conception age, mo 15.9b 16.7a 15.9b 16.4ab 0.25 0.55 0.02 0.64
Number of AI 1.20b 2.25a 1.33b 1.67a 0.30 0.49 0.04 0.27
Fertility at first AI 4/7 2/8 4/7 3/7 0.58 0.19
Fertility 5/7 8/8 6/7 6/7 0.94 0.25
a–dMeans within a row with different superscripts differ significantly (P < 0.05).
1LO = 0.7 kg/d target ADG; HI = 1.0 kg/d target ADG.
2MBW = mature BW.
3Pubertal heifers is the number of heifers pubertal at first day of the synchronization protocol.