It's just that keeping your heart rate in the target range during regular aerobic exercise has been shown to be safe and effective for increasing your aerobic fitness. Exercising above this range can be very uncomfortable and may increase your risk of injury.
Typical daily weight gains for feedlot animals ranges between 0.5kg to 2.5kg per day, while grass fed animals are somewhat lower than this. The following data was collected from a small beef cattle company in Dallarnil in Queensland (approximately 300km north of Brisbane).
1 Weight of typical mature cow: -380 kg to 450 kg. 2  Steers reared on grass: - ready for slaughter between 3 to 3.5 yrs36 -42 months) 420-460 kg. 3  Steers, supplementary fed: -ready for slaughter between 18 to 22months @ 380 to 400 kg.