Higher plane of nutrition pre-weaning enhances Holstein calf mammary gland development through alterations in the parenchyma and fat pad transcriptome

Table 1 Summary of Holstein heifer calf (n = 6/treatment) performance when fed during the pre-weaning period (week 1 to 8 of life) an enhanced (EH) (1.08 kg of powder/calf/day, 28.9% crude protein, 26.2% fat, DM basis) or restricted (R; represents the industry standard or control) milk replacer (0.44 kg of powder/head/day, 20.9% crude protein, 19.8% fat, DM basis)

Parameters	R¹	EH²	%³
Milk replacer
DMI⁴ (kg/d)	0.44^a	1.02^b	131.82
CP⁵ intake (kg/d)	0.09^a	0.30^b	233.33
Fat intake (kg/d)	0.09^a	0.27^b	200.00
Starter feed
DMI (g/d)	286.00^a	237.00^b	−17.13
VCP intake (g/d)	73.30^a	60.90^b	−16.92
Fat intake (g/d)	11.50^a	9.50^b	−17.39
NDF⁶ intake (g/d)	56.60^a	46.90^b	−17.14
ADF⁷ intake (g/d)	26.40^a	21.90^b	−17.05
Growth
BW⁸ week 0 (kg)	39.80	39.40	−1.01
BW week 8 (kg)	51.29^a	73.71^b	43.70
ADG⁹ week 1 (kg/d)	−0.06^a	0.36^b	700.00
ADG week 7 (kg/d)	0.41^a	1.00^b	143.90
ADG week 8 (kg/d)	0.35^a	0.31^b	−11.43
ADG tot (kg/d)	0.20^a	0.60^b	208.21
Feed:Gain	1.33^a	1.42^b	6.77
Hip Height week 8 (cm)	87.90^a	94.30^b	7.28
Slaughter
Carcass (kg)	48.60^a	77.60^b	59.67
Whole mammary gland (g)	66.10^a	255.20^b	286.08
Whole mammary gland (g/kg of BW)	1.34^a	3.32^b	147.76
Trimmed mammary gland (g)	37.80^a	197.60^b	422.75
Trimmed mammary gland (g/kg BW)	0.39^a	1.30^b	233.33
Mammary parenchyma (g)	1.42^a	10.46^b	636.62
Mammary parenchyma (g/kg BW)	0.02^a	0.07^b	250.00
Mammary fat pad (g)	29.20^a	172.80^b	491.78
Mammary fat pad (g/kg BW)	0.30^a	1.13^b	276.67
Mammary fat pad
Total protein (g)	0.46^a	2.11^b	358.70
Protein (mg/g)	15.60^a	12.20^b	−21.79
Total DNA (mg)	4.10^a	22.50^b	448.78
DNA (mg/g)	0.14	0.13	−7.14
Total fat (g)	3.27^a	116.00^b	3447.40
Fat (mg/g)	112.00^a	667.00^b	495.54
Mammary parenchyma
Total protein (g)	0.20^a	1.36^b	580.00
Protein (mg/g)	14.10	13.00	−7.80
Total DNA (mg)	2.70^a	20.40^b	655.56
DNA (mg/g)	1.87	1.95	4.28
Total fat (g)	0.15	2.10	1300.00
Fat (mg/g)	106.00	201.00	89.62

¹R = restricted plane of nutrition (0.44 kg of powder/calf per day, 20.9% crude protein, 19.8% fat, DM basis)
²EH = enhanced plane of nutrition (1.08 kg of powder/head per day, 28.9% crude protein, 26.2% fat, DM basis)
³% = percentage increase or decreased in EH compared to R
⁴DMI dry matter intake
⁵CP crude protein
⁶NDF neutral detergent fiber
⁷ADF acid detergent fiber
⁸BW body weight
⁹ADG average daily gain

ISSN: 1471-2164