Leadership in Quality Herefords

maintenance energy requirements during the dry period in Angus cows. Twenty-four mature fall-calving Angus cows were individually fed in amounts to ensure minimal weight and body condition change.

Recovered energy was calculated as the total of maternal tissue energy change (weight gain or loss) plus milk recovered energy (milk yield plus milk composition). From this information, maintenance energy requirements were calculated for each cow.

After calves were weaned, a voluntary feed intake study was conducted to determine the influence of total recovered energy during lactation and lactation maintenance energy requirement on voluntary intake of a low-quality grass hay diet. The energy required for maintenance declined as net energy recovery increased, but there was no relationship between the amount of daily milk energy produced to post-weaning voluntary forage intake.

However, increasing weight loss during lactation was associated with greater post-weaning feed intake. In contrast to previous work, these results suggest that cows within a breed that are better able to maintain their body condition and produce more milk energy at the same time have lower maintenance energy requirement. Around 74 percent of the maintenance energy required to produce beef is used by the beef cowherd and consequently about 70 percent of the greenhouse gas emissions generated by beef production are from the cowherd. Cow efficiency and greenhouse gas emissions are important to consumers and government regulators; thus, they are important for our industry.