Table 3.

Expected body weights, body condition scores, metabolizable energy (ME) allowable milk production, energy requirements and supplies, and feed energy balances throughout the calving interval for primiparous cows in Genesis^a herds calving in the season of scarce rain (October 1) under baseline nutrition management

Item	Lactation			Dry period
	Early	Mid	Late	Early	Late
Forage season	Early dry	Late dry	Early rains	Late rains	Early dry
Dry matter intake (DMI), kg/day
Grazed forageb	0.0	2.7	4.3	8.7	8.1
Other foragec	4.4	4.7	0.6
Supplementd	3.9	3.1	4.8
Total DMI, kg/day	8.3	10.5	9.7	8.7	8.1
Total dietary energy, Mcal ME/day	18.5	22.2	21.2	15.7	16.2
Total ME supply, Mcal/daye	20.7	22.2	21.2	16.9	17.4
Initial body weight (BW), kgf	426	385	430	446	415
Mean BW, kg	406	408	438	431	407
End BW, kg	385	430	446	415	398
Initial body condition score (BCS)g	2.75	2.00	2.75	2.75	2.50
End BCSh	2.00	2.75	2.75	2.50	1.50
ME allowable growth, kg/dayi			0.17
Total energy requirement, Mcal ME/dayj	20.8	19.4	21.2	16.9	17.4
Maintenance requirement, Mcal ME/dayk	11.9	11.5	13.7	16.0	12.4
Pregnancy requirement, Mcal ME/day				0.90	5.00
ME allowable milk production, kg/dayl	9.3	7.5	5.3
Feed energy balance, Mcal ME/daym	−2.3	2.8	0.0	−1.2	−1.2

^aThe Genesis farmer organization is part of a larger association called Grupo Ganadero para la Validación y Transferencia de Tecnología (Cattlemen’s Validation and Technology Transfer Group)

^bAverage chemical composition of Cynodon plectostachyus and Andropogon gayanus grasses for the seasons of early and late rains, and Andropogon gayanus for scarce and little rain seasons

^c Brachiaria ruziziensis × Brachiaria brizantha (Mulato) hay, maize silage and sugar cane bagasse for late rains, scarce rain and little rain seasons, respectively

^dForage-based diets supplemented with poultry manure, molasses and commercial concentrate

^eTotal ME supply = dietary ME plus ME from catabolized body tissue reserves

^fBody weight at calving corresponded to the expected weight and BCS for a primiparous cow with mature BW = 550 kg and BCS = 3.0. Average body weight loss in early lactation was 0.75 units of BCS

^gBCS at calving was the consensus judgment of a professional panel. Other BCS were predicted from assumed BW changes based on Fox et al. (2004)

^hThe ending BCS during late gestation corresponds to the expected score at next (second) calving

ⁱGrowth was assumed to be enabled (could occur) after recovery of initial BW and BCS at calving

^jTotal ME requirement during lactation includes the energy required for body maintenance and milk production. During the dry period, it includes the ME required for maintenance, repletion of tissue reserves, growth (if it is enabled), and pregnancy

^kMaintenance requirement was a weighted average of those for the parental (Brahman, Brown Swiss) breeds (Fox et al. 2004). Basal maintenance was adjusted for changes in BW and BCS

^lPredicted 270-day lactation milk production was 1,989 kg

^mFeed energy balance = feed energy supply (intake) minus total energy requirements for maintenance, lactation, pregnancy and growth (if allowed). A negative value during lactation represents the expected amount of ME supplied from catabolized body tissues to support milk synthesis. Positive feed energy balance signifies the amount of dietary ME available for tissue repletion (and growth). During late gestation (dry period), a negative value signifies a dietary energy deficit, which means diverting maternal tissue energy to the fetus