Date of Graduation
Master of Science in Agriculture
College of Agriculture
beef cattle, calving season, ruminan nutrition, metabolizable energy efficiency, seasonal economics
Agricultural Economics | Agricultural Science | Agriculture | Animal Sciences | Beef Science | Life Sciences | Nutrition
The purpose of this study is to determine if a optimal time of year exists for beef producers to have cows give birth in southwest Missouri for maximal net returns from calf sales and increased cow reproductive performance. To make this determination, data were collected which included year-round forage nutritive value, calf pre-weaning growth, cow energy efficiency and reproductive performance, and income and cost values. Cow and calf field data were gathered for the 2014-2018 production years at Missouri State University’s Leo Journagan Ranch. Monthly forage samples were collected from study cow pastures from 2016 through 2018. Calf, cull cow, and hay prices for 2014 through 2018 were recorded from USDA Market News Archives. The Cattle Value Discovery System model was used to predict cow energy efficiency and requirements based on cow and calf performance and feed and forage inputs. Cow/calf pairs were grouped for comparison by calving month. Bull calves had greater BW, WW, and sale value than heifer calves, and cows with bull calves had greater energy requirements and milk production and better cow energy efficiency. Calves born January through May had heavier BW than calves born August and September. Calves which had the greatest weaning age (January, August, and September) also had the greatest WW, and the youngest calves at weaning (April, May) had the lightest WW. However, 205-d adjusted WW were not different between months. Cows that calved in September and October had greater BCS at calving than cows that calved in January through April; however, Weaning BCS were not significantly different between calving months. Pregnancy rate and CI were not consistent for particular times during the year, but significant differences were observed between some months. No significant differences were observed for energy for maintenance or total energy, but energy for pregnancy was lesser for cows that calved in August and September than calved January through May and October. Cows that calved in January through March had greater MEL than cows that calved in May, June, and August through November. In both EEI categories, September calving cows had significantly more desirable EEI than some months, and May calving cows significantly less desirable EEI than some months. Cows that calved in January through May had greater peak milk yields than cows that calved August through October. Calves born in September had the greatest sale value and, along with January, the greatest net returns.
© Briana Rose VerPloeg
VerPloeg, Briana Rose, "Optimal Calving Time for Beef Cows in Southwest Missouri" (2020). MSU Graduate Theses. 3520.